Spring Data and Native Query with pagination

Removing \n#pageable\n from both query and count query worked for me. Springboot version : 2.1.5.RELEASE DB : Mysql

Base64: java.lang.IllegalArgumentException: Illegal character

I encountered this error since my encoded image started with data:image/png;base64,iVBORw0....

This answer led me to the solution:

String partSeparator = ",";
if (data.contains(partSeparator)) {
  String encodedImg = data.split(partSeparator)[1];
  byte[] decodedImg = Base64.getDecoder().decode(encodedImg.getBytes(StandardCharsets.UTF_8));
  Path destinationFile = Paths.get("/path/to/imageDir", "myImage.jpg");
  Files.write(destinationFile, decodedImg);
}

java.lang.NoClassDefFoundError: org/json/JSONObject

No.. It is not proper way. Refer the steps,

For Classpath reference: Right click on project in Eclipse -> Buildpath -> Configure Build path -> Java Build Path (left Pane) -> Libraries(Tab) -> Add External Jars -> Select your jar and select OK.

For Deployment Assembly: Right click on WAR in eclipse-> Buildpath -> Configure Build path -> Deployment Assembly (left Pane) -> Add -> External file system -> Add -> Select your jar -> Add -> Finish.

This is the proper way! Don't forget to remove environment variable. It is not required now.

Try this. Surely it will work. Try to use Maven, it will simplify you task.

Using if-else in JSP

Instead of if-else condition use if in both conditions. it will work that way but not sure why.

how to fix Cannot call sendRedirect() after the response has been committed?

you have already forwarded the response in catch block:

RequestDispatcher dd = request.getRequestDispatcher("error.jsp");

dd.forward(request, response);

so, you can not again call the :

response.sendRedirect("usertaskpage.jsp");

because it is already forwarded (committed).

So what you can do is: keep a string to assign where you need to forward the response.

    String page = "";
    try {

    } catch (Exception e) {
      page = "error.jsp";
    } finally {
      page = "usertaskpage.jsp";
    }

RequestDispatcher dd=request.getRequestDispatcher(page);
dd.forward(request, response);

How to create an alert message in jsp page after submit process is complete

You can also create a new jsp file sayng that form is submited and in your main action file just write its file name

Eg. Your form is submited is in a file succes.jsp Then your action file will have

Request.sendRedirect("success.jsp")

getting error HTTP Status 405 - HTTP method GET is not supported by this URL but not used `get` ever?

I think your issue may be in the url pattern. Changing

<servlet-mapping>
    <servlet-name>Register</servlet-name>
    <url-pattern>/Register</url-pattern>
</servlet-mapping>

and

<form action="/Register" method="post">

may fix your problem

How to pass the values from one jsp page to another jsp without submit button?

I dont exactly know what you want to do.But you cant send data of one form using a submit button of another form.

You could do one thing either use sessions or use hidden fields that has the submit button. You could use javascript/jquery to pass the values from the first form to the hidden fields of the second form.Then you could submit the form.

Or else the easiest you could do is use sessions.

<form>
<input type="text" class="input-text " value="" size="32" name="user_data[firstname]" id="elm_6">
<input type="text" class="input-text " value="" size="32" name="user_data[lastname]" id="elm_7">
</form>

<form action="#">
<input type="text" class="input-text " value="" size="32" name="user_data[b_firstname]" id="elm_14">
<input type="text" class="input-text " value="" size="32" name="user_data[s_firstname]" id="elm_16">

<input type="submit" value="Continue" name="dispatch[checkout.update_steps]">
</form>


$('input[type=submit]').click(function(){
$('#elm_14').val($('#elm_6').val());
$('#elm_16').val($('#elm_7').val());
});

This is the jsfiddle for it http://jsfiddle.net/FPsdy/102/

Create a simple Login page using eclipse and mysql

You Can simply Use One Jsp Page To accomplish the task.

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<%@page import="java.sql.*"%>
<!DOCTYPE html>
<html>
   <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>JSP Page</title>
</head>
<body>
    <%
        String username=request.getParameter("user_name");
        String password=request.getParameter("password");
        String role=request.getParameter("role");
        try
        {
            Class.forName("com.mysql.jdbc.Driver");
            Connection con=DriverManager.getConnection("jdbc:mysql://localhost:3306/t_fleet","root","root");
            Statement st=con.createStatement();
            String query="select * from tbl_login where user_name='"+username+"' and password='"+password+"' and role='"+role+"'";
            ResultSet rs=st.executeQuery(query);
            while(rs.next())
            {
                session.setAttribute( "user_name",rs.getString(2));
                session.setMaxInactiveInterval(3000);
                response.sendRedirect("homepage.jsp");
            }
            %>



        <%}
        catch(Exception e)
        {
            out.println(e);
        }
    %>

</body>

I have use username, password and role to get into the system. One more thing to implement is you can do page permission checking through jsp and javascript function.

Name [jdbc/mydb] is not bound in this Context

you put resource-ref in the description tag in web.xml

How to pass a value from one jsp to another jsp page?

Using Query parameter

<a href="edit.jsp?userId=${user.id}" />

Using Hidden variable .

<form method="post" action="update.jsp">  
...  
   <input type="hidden" name="userId" value="${user.id}">

you can send Using Session object.

   session.setAttribute("userId", userid);

These values will now be available from any jsp as long as your session is still active.

   int userid = session.getAttribute("userId");

The server encountered an internal error that prevented it from fulfilling this request - in servlet 3.0

I found solution. It works fine when I throw away next line from form:

enctype="multipart/form-data"

And now it pass all parameters at request ok:

 <form action="/registration" method="post">
   <%-- error messages --%>
   <div class="form-group">
    <c:forEach items="${registrationErrors}" var="error">
    <p class="error">${error}</p>
     </c:forEach>
   </div>

How To Inject AuthenticationManager using Java Configuration in a Custom Filter

In addition to what Angular University said above you may want to use @Import to aggregate @Configuration classes to the other class (AuthenticationController in my case) :

@Import(SecurityConfig.class)
@RestController
public class AuthenticationController {
@Autowired
private AuthenticationManager authenticationManager;
//some logic
}

Spring doc about Aggregating @Configuration classes with @Import: link

insert data into database using servlet and jsp in eclipse

String user = request.getParameter("uname");
out.println(user); 
String pass = request.getParameter("pass");
out.println(pass); 
Class.forName( "com.mysql.jdbc.Driver" );
Connection conn = DriverManager.getConnection( "jdbc:mysql://localhost:3306/rental","root","root" ) ;
out.println("hello");
Statement st = conn.createStatement();
String sql = "insert into login (user,pass) values('" + user + "','" + pass + "')";
st.executeUpdate(sql);

Android Camera Preview Stretched

F1Sher's solution is nice but sometimes doesn't work. Particularly, when your surfaceView doesn't cover whole screen. In this case you need to override onMeasure() method. I have copied my code here for your reference.

Since I measured surfaceView based on width then I have little bit white gap at the end of my screen that I filled it by design. You are able to fix this issue if you keep height and increase width by multiply it to ratio. However, it will squish surfaceView slightly.

public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {

    private static final String TAG = "CameraPreview";

    private Context mContext;
    private SurfaceHolder mHolder;
    private Camera mCamera;
    private List<Camera.Size> mSupportedPreviewSizes;
    private Camera.Size mPreviewSize;

    public CameraPreview(Context context, Camera camera) {
        super(context);
        mContext = context;
        mCamera = camera;

        // supported preview sizes
        mSupportedPreviewSizes = mCamera.getParameters().getSupportedPreviewSizes();
        for(Camera.Size str: mSupportedPreviewSizes)
                Log.e(TAG, str.width + "/" + str.height);

        // Install a SurfaceHolder.Callback so we get notified when the
        // underlying surface is created and destroyed.
        mHolder = getHolder();
        mHolder.addCallback(this);
        // deprecated setting, but required on Android versions prior to 3.0
        mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    }

    public void surfaceCreated(SurfaceHolder holder) {
        // empty. surfaceChanged will take care of stuff
    }

    public void surfaceDestroyed(SurfaceHolder holder) {
        // empty. Take care of releasing the Camera preview in your activity.
    }

    public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
        Log.e(TAG, "surfaceChanged => w=" + w + ", h=" + h);
        // If your preview can change or rotate, take care of those events here.
        // Make sure to stop the preview before resizing or reformatting it.
        if (mHolder.getSurface() == null){
            // preview surface does not exist
            return;
        }

        // stop preview before making changes
        try {
            mCamera.stopPreview();
        } catch (Exception e){
            // ignore: tried to stop a non-existent preview
        }

        // set preview size and make any resize, rotate or reformatting changes here
        // start preview with new settings
        try {
            Camera.Parameters parameters = mCamera.getParameters();
            parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height);
            mCamera.setParameters(parameters);
            mCamera.setDisplayOrientation(90);
            mCamera.setPreviewDisplay(mHolder);
            mCamera.startPreview();

        } catch (Exception e){
            Log.d(TAG, "Error starting camera preview: " + e.getMessage());
        }
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        final int width = resolveSize(getSuggestedMinimumWidth(), widthMeasureSpec);
        final int height = resolveSize(getSuggestedMinimumHeight(), heightMeasureSpec);

        if (mSupportedPreviewSizes != null) {
            mPreviewSize = getOptimalPreviewSize(mSupportedPreviewSizes, width, height);
        }

        if (mPreviewSize!=null) {
            float ratio;
            if(mPreviewSize.height >= mPreviewSize.width)
                ratio = (float) mPreviewSize.height / (float) mPreviewSize.width;
            else
                ratio = (float) mPreviewSize.width / (float) mPreviewSize.height;

            // One of these methods should be used, second method squishes preview slightly
            setMeasuredDimension(width, (int) (width * ratio));
  //        setMeasuredDimension((int) (width * ratio), height);
        }
    }

    private Camera.Size getOptimalPreviewSize(List<Camera.Size> sizes, int w, int h) {
        final double ASPECT_TOLERANCE = 0.1;
        double targetRatio = (double) h / w;

        if (sizes == null)
            return null;

        Camera.Size optimalSize = null;
        double minDiff = Double.MAX_VALUE;

        int targetHeight = h;

        for (Camera.Size size : sizes) {
            double ratio = (double) size.height / size.width;
            if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE)
                continue;

            if (Math.abs(size.height - targetHeight) < minDiff) {
                optimalSize = size;
                minDiff = Math.abs(size.height - targetHeight);
            }
        }

        if (optimalSize == null) {
            minDiff = Double.MAX_VALUE;
            for (Camera.Size size : sizes) {
                if (Math.abs(size.height - targetHeight) < minDiff) {
                    optimalSize = size;
                    minDiff = Math.abs(size.height - targetHeight);
                }
            }
        }

        return optimalSize;
    }
}

How to set a header in an HTTP response?

Header fields are not copied to subsequent requests. You should use either cookie for this (addCookie method) or store "REMOTE_USER" in session (which you can obtain with getSession method).

HTTP Status 500 - org.apache.jasper.JasperException: java.lang.NullPointerException

In Tomcat a .java and .class file will be created for every jsp files with in the application and the same can be found from the path below, Apache-Tomcat\work\Catalina\localhost\'ApplicationName'\org\apache\jsp\index_jsp.java

In your case the jsp name is error.jsp so the path should be something like below Apache-Tomcat\work\Catalina\localhost\'ApplicationName'\org\apache\jsp\error_jsp.java in line no 124 you are trying to access a null object which results in null pointer exception.

Creating java date object from year,month,day

Java's Calendar representation is not the best, they are working on it for Java 8. I would advise you to use Joda Time or another similar library.

Here is a quick example using LocalDate from the Joda Time library:

LocalDate localDate = new LocalDate(year, month, day);
Date date = localDate.toDate();

Here you can follow a quick start tutorial.

oracle.jdbc.driver.OracleDriver ClassNotFoundException

In Eclipse,

When you use JDBC in your servlet, the driver jar must be placed in the WEB-INF/lib directory of your project.

Getting request payload from POST request in Java servlet

With Apache Commons IO you can do this in one line.

IOUtils.toString(request.getReader())

java.lang.ClassNotFoundException: oracle.jdbc.driver.OracleDriver

I was getting same kinda error but after copying the ojdbc14.jar into lib folder, no more exception.(copy ojdbc14.jar from somewhere and paste it into lib folder inside WebContent.)

Subtract two dates in Java

Edit 2018-05-28 I have changed the example to use Java 8's Time API:

LocalDate d1 = LocalDate.parse("2018-05-26", DateTimeFormatter.ISO_LOCAL_DATE);
LocalDate d2 = LocalDate.parse("2018-05-28", DateTimeFormatter.ISO_LOCAL_DATE);
Duration diff = Duration.between(d1.atStartOfDay(), d2.atStartOfDay());
long diffDays = diff.toDays();

Spring MVC: How to perform validation?

Find complete example of Spring Mvc Validation

import org.springframework.validation.Errors;
import org.springframework.validation.ValidationUtils;
import org.springframework.validation.Validator;
import com.technicalkeeda.bean.Login;

public class LoginValidator implements Validator {
    public boolean supports(Class aClass) {
        return Login.class.equals(aClass);
    }

    public void validate(Object obj, Errors errors) {
        Login login = (Login) obj;
        ValidationUtils.rejectIfEmptyOrWhitespace(errors, "userName",
                "username.required", "Required field");
        ValidationUtils.rejectIfEmptyOrWhitespace(errors, "userPassword",
                "userpassword.required", "Required field");
    }
}


public class LoginController extends SimpleFormController {
    private LoginService loginService;

    public LoginController() {
        setCommandClass(Login.class);
        setCommandName("login");
    }

    public void setLoginService(LoginService loginService) {
        this.loginService = loginService;
    }

    @Override
    protected ModelAndView onSubmit(Object command) throws Exception {
        Login login = (Login) command;
        loginService.add(login);
        return new ModelAndView("loginsucess", "login", login);
    }
}

Create a sample login page using servlet and JSP?

As I can see, you are comparing the message with the empty string using ==.

Its very hard to write the full code, but I can tell the flow of code - first, create db class & method inide that which will return the connection. second, create a servelet(ex-login.java) & import that db class onto that servlet. third, create instance of imported db class with the help of new operator & call the connection method of that db class. fourth, creaet prepared statement & execute statement & put this code in try catch block for exception handling.Use if-else condition in the try block to navigate your login page based on success or failure.

I hope, it will help you. If any problem, then please revert.

Nikhil Pahariya

How do I pass multiple parameter in URL?

You can pass multiple parameters as "?param1=value1&param2=value2"

But it's not secure. It's vulnerable to Cross Site Scripting (XSS) Attack.

Your parameter can be simply replaced with a script.

Have a look at this article and article

You can make it secure by using API of StringEscapeUtils

static String   escapeHtml(String str) 
          Escapes the characters in a String using HTML entities.

Even using https url for security without above precautions is not a good practice.

Have a look at related SE question:

Is URLEncoder.encode(string, "UTF-8") a poor validation?

SSLHandshakeException: No subject alternative names present

Unlike some browsers, Java follows the HTTPS specification strictly when it comes to the server identity verification (RFC 2818, Section 3.1) and IP addresses.

When using a host name, it's possible to fall back to the Common Name in the Subject DN of the server certificate, instead of using the Subject Alternative Name.

When using an IP address, there must be a Subject Alternative Name entry (of type IP address, not DNS name) in the certificate.

You'll find more details about the specification and how to generate such a certificate in this answer.

JQuery $.ajax() post - data in a java servlet

To get the value from the servlet from POST command, you can follow the approach as explained on this post by using request.getParameter(key) format which will return the value you want.

Http Servlet request lose params from POST body after read it once

The above answers were very helpful, but still had some problems in my experience. On tomcat 7 servlet 3.0, the getParamter and getParamterValues also had to be overwritten. The solution here includes both get-query parameters and the post-body. It allows for getting raw-string easily.

Like the other solutions it uses Apache commons-io and Googles Guava.

In this solution the getParameter* methods do not throw IOException but they use super.getInputStream() (to get the body) which may throw IOException. I catch it and throw runtimeException. It is not so nice.

import com.google.common.collect.Iterables;
import com.google.common.collect.ObjectArrays;

import org.apache.commons.io.IOUtils;
import org.apache.http.NameValuePair;
import org.apache.http.client.utils.URLEncodedUtils;
import org.apache.http.entity.ContentType;

import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.nio.charset.Charset;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;

/**
 * Purpose of this class is to make getParameter() return post data AND also be able to get entire
 * body-string. In native implementation any of those two works, but not both together.
 */
public class MultiReadHttpServletRequest extends HttpServletRequestWrapper {
    public static final String UTF8 = "UTF-8";
    public static final Charset UTF8_CHARSET = Charset.forName(UTF8);
    private ByteArrayOutputStream cachedBytes;
    private Map<String, String[]> parameterMap;

    public MultiReadHttpServletRequest(HttpServletRequest request) {
        super(request);
    }

    public static void toMap(Iterable<NameValuePair> inputParams, Map<String, String[]> toMap) {
        for (NameValuePair e : inputParams) {
            String key = e.getName();
            String value = e.getValue();
            if (toMap.containsKey(key)) {
                String[] newValue = ObjectArrays.concat(toMap.get(key), value);
                toMap.remove(key);
                toMap.put(key, newValue);
            } else {
                toMap.put(key, new String[]{value});
            }
        }
    }

    @Override
    public ServletInputStream getInputStream() throws IOException {
        if (cachedBytes == null) cacheInputStream();
        return new CachedServletInputStream();
    }

    @Override
    public BufferedReader getReader() throws IOException {
        return new BufferedReader(new InputStreamReader(getInputStream()));
    }

    private void cacheInputStream() throws IOException {
    /* Cache the inputStream in order to read it multiple times. For
     * convenience, I use apache.commons IOUtils
     */
        cachedBytes = new ByteArrayOutputStream();
        IOUtils.copy(super.getInputStream(), cachedBytes);
    }

    @Override
    public String getParameter(String key) {
        Map<String, String[]> parameterMap = getParameterMap();
        String[] values = parameterMap.get(key);
        return values != null && values.length > 0 ? values[0] : null;
    }

    @Override
    public String[] getParameterValues(String key) {
        Map<String, String[]> parameterMap = getParameterMap();
        return parameterMap.get(key);
    }

    @Override
    public Map<String, String[]> getParameterMap() {
        if (parameterMap == null) {
            Map<String, String[]> result = new LinkedHashMap<String, String[]>();
            decode(getQueryString(), result);
            decode(getPostBodyAsString(), result);
            parameterMap = Collections.unmodifiableMap(result);
        }
        return parameterMap;
    }

    private void decode(String queryString, Map<String, String[]> result) {
        if (queryString != null) toMap(decodeParams(queryString), result);
    }

    private Iterable<NameValuePair> decodeParams(String body) {
        Iterable<NameValuePair> params = URLEncodedUtils.parse(body, UTF8_CHARSET);
        try {
            String cts = getContentType();
            if (cts != null) {
                ContentType ct = ContentType.parse(cts);
                if (ct.getMimeType().equals(ContentType.APPLICATION_FORM_URLENCODED.getMimeType())) {
                    List<NameValuePair> postParams = URLEncodedUtils.parse(IOUtils.toString(getReader()), UTF8_CHARSET);
                    params = Iterables.concat(params, postParams);
                }
            }
        } catch (IOException e) {
            throw new IllegalStateException(e);
        }
        return params;
    }

    public String getPostBodyAsString() {
        try {
            if (cachedBytes == null) cacheInputStream();
            return cachedBytes.toString(UTF8);
        } catch (UnsupportedEncodingException e) {
            throw new RuntimeException(e);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    /* An inputStream which reads the cached request body */
    public class CachedServletInputStream extends ServletInputStream {
        private ByteArrayInputStream input;

        public CachedServletInputStream() {
            /* create a new input stream from the cached request body */
            input = new ByteArrayInputStream(cachedBytes.toByteArray());
        }

        @Override
        public int read() throws IOException {
            return input.read();
        }
    }

    @Override
    public String toString() {
        String query = dk.bnr.util.StringUtil.nullToEmpty(getQueryString());
        StringBuilder sb = new StringBuilder();
        sb.append("URL='").append(getRequestURI()).append(query.isEmpty() ? "" : "?" + query).append("', body='");
        sb.append(getPostBodyAsString());
        sb.append("'");
        return sb.toString();
    }
}

commons httpclient - Adding query string parameters to GET/POST request

If you want to add a query parameter after you have created the request, try casting the HttpRequest to a HttpBaseRequest. Then you can change the URI of the casted request:

HttpGet someHttpGet = new HttpGet("http://google.de");

URI uri = new URIBuilder(someHttpGet.getURI()).addParameter("q",
        "That was easy!").build();

((HttpRequestBase) someHttpGet).setURI(uri);

How to get the request parameters in Symfony 2?

Inside a controller:

$request = $this->getRequest();
$username = $request->get('username');

Include another JSP file

At page translation time, the content of the file given in the include directive is ‘pasted’ as it is, in the place where the JSP include directive is used. Then the source JSP page is converted into a java servlet class. The included file can be a static resource or a JSP page. Generally, JSP include directive is used to include header banners and footers.

Syntax for include a jsp file:

<%@ include file="relative url">

Example

<%@include file="page_name.jsp" %>

What does request.getParameter return?

String onevalue;   
if(request.getParameterMap().containsKey("one")!=false) 
{
onevalue=request.getParameter("one").toString();
}

How to send parameters with jquery $.get()

Try this:

$.ajax({
    type: 'get',
    url: 'manageproducts.do',
    data: 'option=1',
    success: function(data) {

        availableProductNames = data.split(",");

        alert(availableProductNames);

    }
});

Also You have a few errors in your sample code, not sure if that was causing the error or it was just a typo upon entering the question.

Accessing the logged-in user in a template

You can access user data directly in the twig template without requesting anything in the controller. The user is accessible like that : app.user.

Now, you can access every property of the user. For example, you can access the username like that : app.user.username.

Warning, if the user is not logged, the app.user is null.

If you want to check if the user is logged, you can use the is_granted twig function. For example, if you want to check if the user has ROLE_ADMIN, you just have to do is_granted("ROLE_ADMIN").

So, in every of your pages you can do :

{% if is_granted("ROLE") %}
    Hi {{ app.user.username }}
{% endif %}

Turn ON/OFF Camera LED/flash light in Samsung Galaxy Ace 2.2.1 & Galaxy Tab

I will soon released a new version of my app to support to galaxy ace.

You can download here: https://play.google.com/store/apps/details?id=droid.pr.coolflashlightfree

In order to solve your problem you should do this:

this._camera = Camera.open();     
this._camera.startPreview();
this._camera.autoFocus(new AutoFocusCallback() {
public void onAutoFocus(boolean success, Camera camera) {
}
});

Parameters params = this._camera.getParameters();
params.setFlashMode(Parameters.FLASH_MODE_ON);
this._camera.setParameters(params);

params = this._camera.getParameters();
params.setFlashMode(Parameters.FLASH_MODE_OFF);
this._camera.setParameters(params);

don't worry about FLASH_MODE_OFF because this will keep the light on, strange but it's true

to turn off the led just release the camera

HttpServletRequest - Get query string parameters, no form data

Java 8

return Collections.list(httpServletRequest.getParameterNames())
                  .stream()
                  .collect(Collectors.toMap(parameterName -> parameterName, httpServletRequest::getParameterValues));

How to force browser to download file?

You are setting the response headers after writing the contents of the file to the output stream. This is quite late in the response lifecycle to be setting headers. The correct sequence of operations should be to set the headers first, and then write the contents of the file to the servlet's outputstream.

Therefore, your method should be written as follows (this won't compile as it is a mere representation):

response.setContentType("application/force-download");
response.setContentLength((int)f.length());
        //response.setContentLength(-1);
response.setHeader("Content-Transfer-Encoding", "binary");
response.setHeader("Content-Disposition","attachment; filename=\"" + "xxx\"");//fileName);
...
...
File f= new File(fileName);

InputStream in = new FileInputStream(f);
BufferedInputStream bin = new BufferedInputStream(in);
DataInputStream din = new DataInputStream(bin);

while(din.available() > 0){
    out.print(din.readLine());
    out.print("\n");
}

The reason for the failure is that it is possible for the actual headers sent by the servlet would be different from what you are intending to send. After all, if the servlet container does not know what headers (which appear before the body in the HTTP response), then it may set appropriate headers to ensure that the response is valid; setting the headers after the file has been written is therefore futile and redundant as the container might have already set the headers. You could confirm this by looking at the network traffic using Wireshark or a HTTP debugging proxy like Fiddler or WebScarab.

You may also refer to the Java EE API documentation for ServletResponse.setContentType to understand this behavior:

Sets the content type of the response being sent to the client, if the response has not been committed yet. The given content type may include a character encoding specification, for example, text/html;charset=UTF-8. The response's character encoding is only set from the given content type if this method is called before getWriter is called.

This method may be called repeatedly to change content type and character encoding. This method has no effect if called after the response has been committed.

...

White spaces are required between publicId and systemId

I just found my self with this Exception, I was trying to consume a JAX-WS, with a custom URL like this:

String WSDL_URL= <get value from properties file>;
Customer service = new Customer(new URL(WSDL_URL));
ExecutePtt port = service.getExecutePt();
return port.createMantainCustomers(part);

and Java threw:

XML reader error: javax.xml.stream.XMLStreamException: ParseError at [row,col]:[1,63]
Message: White spaces are required between publicId and systemId.

Turns out that the URL string used to construct the service was missing the "?wsdl" at the end. For instance:

Bad:

http://www.host.org/service/Customer

Good:

http://www.host.org/service/Customer?wsdl

Creating a mock HttpServletRequest out of a url string?

Here it is how to use MockHttpServletRequest:

// given
MockHttpServletRequest request = new MockHttpServletRequest();
request.setServerName("www.example.com");
request.setRequestURI("/foo");
request.setQueryString("param1=value1&param");

// when
String url = request.getRequestURL() + '?' + request.getQueryString(); // assuming there is always queryString.

// then
assertThat(url, is("http://www.example.com:80/foo?param1=value1&param"));

Object cannot be cast from DBNull to other types

Reason for the error: In an object-oriented programming language, null means the absence of a reference to an object. DBNull represents an uninitialized variant or nonexistent database column. Source:MSDN

Actual Code which I faced error:

Before changed the code:

    if( ds.Tables[0].Rows[0][0] == null ) //   Which is not working

     {
            seqno  = 1; 
      }
    else
    {
          seqno = Convert.ToInt16(ds.Tables[0].Rows[0][0]) + 1;
     }

After changed the code:

   if( ds.Tables[0].Rows[0][0] == DBNull.Value ) //which is working properly
        {
                    seqno  = 1; 
         }
            else
            {
                  seqno = Convert.ToInt16(ds.Tables[0].Rows[0][0]) + 1;
             }

Conclusion: when the database value return the null value, we recommend to use the DBNull class instead of just specifying as a null like in C# language.

Extension methods must be defined in a non-generic static class

A work-around for people who are experiencing a bug like Nathan:

The on-the-fly compiler seems to have a problem with this Extension Method error... adding static didn't help me either.

I'd like to know what causes the bug?

But the work-around is to write a new Extension class (not nested) even in same file and re-build.

Figured that this thread is getting enough views that it's worth passing on (the limited) solution I found. Most people probably tried adding 'static' before google-ing for a solution! and I didn't see this work-around fix anywhere else.

how to convert object to string in java

I'm afraid your map contains something other than String objects. If you call toString() on a String object, you obtain the string itself.

What you get [Ljava.lang.String indicates you might have a String array.

Java List.add() UnsupportedOperationException

You cannot modify a result from a LDAP query. Your problem is in this line:

seeAlso.add(groupDn);

The seeAlso list is unmodifiable.

An item with the same key has already been added

I faced similar exception. Check if all columns has header names( from select query in database) with exactly matching property names in model class.

How to avoid Number Format Exception in java?

In Java there's sadly no way you can avoid using the parseInt function and just catching the exception. Well you could theoretically write your own parser that checks if it's a number, but then you don't need parseInt at all anymore.

The regex method is problematic because nothing stops somebody from including a number > INTEGER.MAX_VALUE which will pass the regex test but still fail.

How to test my servlet using JUnit

Another approach would be to create an embedded server to "host" your servlet, allowing you to write calls against it with libraries meant to make calls to actual servers (the usefulness of this approach somewhat depends on how easily you can make "legitimate" programatic calls to the server - I was testing a JMS (Java Messaging Service) access point, for which clients abound).

There are a couple of different routes you can go - the usual two are tomcat and jetty.

Warning: something to be mindful of when choosing the server to embed is the version of servlet-api you are using (the library which provides classes like HttpServletRequest). If you are using 2.5, I found Jetty 6.x to work well (which is the example I'll give below). If you're using servlet-api 3.0, the tomcat-7 embedded stuff seems to be a good option, however I had to abandon my attempt to use it, as the application I was testing used servlet-api 2.5. Trying to mix the two will result in NoSuchMethod and other such exceptions when attempting to configure or start the server.

You can set up such a server like this (Jetty 6.1.26, servlet-api 2.5):

public void startServer(int port, Servlet yourServletInstance){
    Server server = new Server(port);
    Context root = new Context(server, "/", Context.SESSIONS);

    root.addServlet(new ServletHolder(yourServletInstance), "/servlet/context/path");

    //If you need the servlet context for anything, such as spring wiring, you coudl get it like this
    //ServletContext servletContext = root.getServletContext();

    server.start();
}

Difference between getAttribute() and getParameter()

getParameter() returns http request parameters. Those passed from the client to the server. For example http://example.com/servlet?parameter=1. Can only return String
getAttribute() is for server-side usage only - you fill the request with attributes that you can use within the same request. For example - you set an attribute in a servlet, and read it from a JSP. Can be used for any object, not just string.

Could not connect to SMTP host: localhost, port: 25; nested exception is: java.net.ConnectException: Connection refused: connect

The mail server on CentOS 6 and other IPv6 capable server platforms may be bound to IPv6 localhost (::1) instead of IPv4 localhost (127.0.0.1).

Typical symptoms:

[root@host /]# telnet 127.0.0.1 25
Trying 127.0.0.1...
telnet: connect to address 127.0.0.1: Connection refused

[root@host /]# telnet localhost 25
Trying ::1...
Connected to localhost.
Escape character is '^]'.
220 host ESMTP Exim 4.72 Wed, 14 Aug 2013 17:02:52 +0100

[root@host /]# netstat -plant | grep 25
tcp        0      0 :::25                       :::*                        LISTEN      1082/exim

If this happens, make sure that you don't have two entries for localhost in /etc/hosts with different IP addresses, like this (bad) example:

[root@host /]# cat /etc/hosts
127.0.0.1 localhost.localdomain localhost localhost4.localdomain4 localhost4
::1       localhost localhost.localdomain localhost6 localhost6.localdomain6

To avoid confusion, make sure you only have one entry for localhost, preferably an IPv4 address, like this:

[root@host /]# cat /etc/hosts
127.0.0.1 localhost  localhost.localdomain   localhost4.localdomain4 localhost4
::1       localhost6 localhost6.localdomain6

How to retrieve raw post data from HttpServletRequest in java

We had a situation where IE forced us to post as text/plain, so we had to manually parse the parameters using getReader. The servlet was being used for long polling, so when AsyncContext::dispatch was executed after a delay, it was literally reposting the request empty handed.

So I just stored the post in the request when it first appeared by using HttpServletRequest::setAttribute. The getReader method empties the buffer, where getParameter empties the buffer too but stores the parameters automagically.

    String input = null;

    // we have to store the string, which can only be read one time, because when the
    // servlet awakens an AsyncContext, it reposts the request and returns here empty handed
    if ((input = (String) request.getAttribute("com.xp.input")) == null) {
        StringBuilder buffer = new StringBuilder();
        BufferedReader reader = request.getReader();

        String line;
        while((line = reader.readLine()) != null){
            buffer.append(line);
        }
        // reqBytes = buffer.toString().getBytes();

        input = buffer.toString();
        request.setAttribute("com.xp.input", input);
    }

    if (input == null) {
        response.setContentType("text/plain");
        PrintWriter out = response.getWriter();
        out.print("{\"act\":\"fail\",\"msg\":\"invalid\"}");
    }

How do I read configuration settings from Symfony2 config.yml?

While the solution of moving the contact_email to parameters.yml is easy, as proposed in other answers, that can easily clutter your parameters file if you deal with many bundles or if you deal with nested blocks of configuration.

First, I'll answer strictly the question.
Later, I'll give an approach for getting those configs from services without ever passing via a common space as parameters.

FIRST APPROACH: Separated config block, getting it as a parameter

With an extension (more on extensions here) you can keep this easily "separated" into different blocks in the config.yml and then inject that as a parameter gettable from the controller.

Inside your Extension class inside the DependencyInjection directory write this:

class MyNiceProjectExtension extends Extension
{
    public function load( array $configs, ContainerBuilder $container )
    {
        // The next 2 lines are pretty common to all Extension templates.
        $configuration = new Configuration();
        $processedConfig = $this->processConfiguration( $configuration, $configs );

        // This is the KEY TO YOUR ANSWER
        $container->setParameter( 'my_nice_project.contact_email', $processedConfig[ 'contact_email' ] );

        // Other stuff like loading services.yml
    }

Then in your config.yml, config_dev.yml and so you can set

my_nice_project:
    contact_email: [email protected]

To be able to process that config.yml inside your MyNiceBundleExtension you'll also need a Configuration class in the same namespace:

class Configuration implements ConfigurationInterface
{
    public function getConfigTreeBuilder()
    {
        $treeBuilder = new TreeBuilder();
        $rootNode = $treeBuilder->root( 'my_nice_project' );

        $rootNode->children()->scalarNode( 'contact_email' )->end();

        return $treeBuilder;
    }
}

Then you can get the config from your controller, as you desired in your original question, but keeping the parameters.yml clean, and setting it in the config.yml in separated sections:

$recipient = $this->container->getParameter( 'my_nice_project.contact_email' );

SECOND APPROACH: Separated config block, injecting the config into a service

For readers looking for something similar but for getting the config from a service, there is even a nicer way that never clutters the "paramaters" common space and does even not need the container to be passed to the service (passing the whole container is practice to avoid).

This trick above still "injects" into the parameters space your config.

Nevertheless, after loading your definition of the service, you could add a method-call like for example setConfig() that injects that block only to the service.

For example, in the Extension class:

class MyNiceProjectExtension extends Extension
{
    public function load( array $configs, ContainerBuilder $container )
    {
        $configuration = new Configuration();
        $processedConfig = $this->processConfiguration( $configuration, $configs );

        // Do not add a paramater now, just continue reading the services.
        $loader = new YamlFileLoader( $container, new FileLocator( __DIR__ . '/../Resources/config' ) );
        $loader->load( 'services.yml' );

        // Once the services definition are read, get your service and add a method call to setConfig()
        $sillyServiceDefintion = $container->getDefinition( 'my.niceproject.sillymanager' );
        $sillyServiceDefintion->addMethodCall( 'setConfig', array( $processedConfig[ 'contact_email' ] ) );
    }
}

Then in your services.yml you define your service as usual, without any absolute change:

services:
    my.niceproject.sillymanager:
        class: My\NiceProjectBundle\Model\SillyManager
        arguments: []

And then in your SillyManager class, just add the method:

class SillyManager
{
    private $contact_email;

    public function setConfig( $newConfigContactEmail )
    {
        $this->contact_email = $newConfigContactEmail;
    }
}

Note that this also works for arrays instead of scalar values! Imagine that you configure a rabbit queue and need host, user and password:

my_nice_project:
    amqp:
        host: 192.168.33.55
        user: guest
        password: guest

Of course you need to change your Tree, but then you can do:

$sillyServiceDefintion->addMethodCall( 'setConfig', array( $processedConfig[ 'amqp' ] ) );

and then in the service do:

class SillyManager
{
    private $host;
    private $user;
    private $password;

    public function setConfig( $config )
    {
        $this->host = $config[ 'host' ];
        $this->user = $config[ 'user' ];
        $this->password = $config[ 'password' ];
    }
}

Hope this helps!

How to set Android camera orientation properly?

I finally fixed this using the Google's camera app. It gets the phone's orientation by using a sensor and then sets the EXIF tag appropriately. The JPEG which comes out of the camera is not oriented automatically.

Also, the camera preview works properly only in the landscape mode. If you need your activity layout to be oriented in portrait, you will have to do it manually using the value from the orientation sensor.

HTTP Status 405 - HTTP method POST is not supported by this URL java servlet

If you're still facing the issue even after replacing doGet() with doPost() and changing the form method="post". Try clearing the cache of the browser or hit the URL in another browser or incognito/private mode. It may works!

For best practices, please follow this link. https://www.oracle.com/technetwork/articles/javase/servlets-jsp-140445.html

HTML Submit-button: Different value / button-text?

There are plenty of answers here explaining what you could do (I use the different field name one) but the simple (and as-yet unstated) answer to your question is 'no' - you can't have a different text and value using just HTML.

Error inflating when extending a class

I had the same problem extending a TextEdit. For me the mistake was I did non add "public" to the constructor. In my case it works even if I define only one constructor, the one with arguments Context and AttributeSet. The wired thing is that the bug reveals itself only when I build an APK (singed or not) and I transfer it to the devices. When the application is run via AndroidStudio -> RunApp on a USB connected device the app works.

Convenient way to parse incoming multipart/form-data parameters in a Servlet

Solutions:

Solution A:

Download http://www.servlets.com/cos/index.html
Invoke getParameters() on com.oreilly.servlet.MultipartRequest

Solution B:

Download http://jakarta.Apache.org/commons/fileupload/
Invoke readHeaders() in org.apache.commons.fileupload.MultipartStream

Solution C:

Download http://users.boone.net/wbrameld/multipartformdata/
Invoke getParameter on com.bigfoot.bugar.servlet.http.MultipartFormData

Solution D:

Use Struts. Struts 1.1 handles this automatically.

Reference: http://www.jguru.com/faq/view.jsp?EID=1045507

How can I avoid Java code in JSP files, using JSP 2?

You raised a good question and although you got good answers, I would suggest that you get rid of JSP. It is outdated technology which eventually will die. Use a modern approach, like template engines. You will have very clear separation of business and presentation layers, and certainly no Java code in templates, so you can generate templates directly from web presentation editing software, in most cases leveraging WYSIWYG.

And certainly stay away of filters and pre and post processing, otherwise you may deal with support/debugging difficulties since you always do not know where the variable gets the value.

Undefined reference to vtable

What is a `vtable`?

It might be useful to know what the error message is talking about before trying to fix it. I'll start at a high level, then work down to some more details. That way people can skip ahead once they are comfortable with their understanding of vtables. …and there goes a bunch of people skipping ahead right now. :) For those sticking around:

A vtable is basically the most common implementation of polymorphism in C++. When vtables are used, every polymorphic class has a vtable somewhere in the program; you can think of it as a (hidden) static data member of the class. Every object of a polymorphic class is associated with the vtable for its most-derived class. By checking this association, the program can work its polymorphic magic. Important caveat: a vtable is an implementation detail. It is not mandated by the C++ standard, even though most (all?) C++ compilers use vtables to implement polymorphic behavior. The details I am presenting are either typical or reasonable approaches. Compilers are allowed to deviate from this!

Each polymorphic object has a (hidden) pointer to the vtable for the object's most-derived class (possibly multiple pointers, in the more complex cases). By looking at the pointer, the program can tell what the "real" type of an object is (except during construction, but let's skip that special case). For example, if an object of type A does not point to the vtable of A, then that object is actually a sub-object of something derived from A.

The name "vtable" comes from "virtual function table". It is a table that stores pointers to (virtual) functions. A compiler chooses its convention for how the table is laid out; a simple approach is to go through the virtual functions in the order they are declared within class definitions. When a virtual function is called, the program follows the object's pointer to a vtable, goes to the entry associated with the desired function, then uses the stored function pointer to invoke the correct function. There are various tricks for making this work, but I won't go into those here.

Where/when is a `vtable` generated?

A vtable is automatically generated (sometimes called "emitted") by the compiler. A compiler could emit a vtable in every translation unit that sees a polymorphic class definition, but that would usually be unnecessary overkill. An alternative (used by gcc, and probably by others) is to pick a single translation unit in which to place the vtable, similar to how you would pick a single source file in which to put a class' static data members. If this selection process fails to pick any translation units, then the vtable becomes an undefined reference. Hence the error, whose message is admittedly not particularly clear.

Similarly, if the selection process does pick a translation unit, but that object file is not provided to the linker, then the vtable becomes an undefined reference. Unfortunately, the error message can be even less clear in this case than in the case where the selection process failed. (Thanks to the answerers who mentioned this possibility. I probably would have forgotten it otherwise.)

The selection process used by gcc makes sense if we start with the tradition of devoting a (single) source file to each class that needs one for its implementation. It would be nice to emit the vtable when compiling that source file. Let's call that our goal. However, the selection process needs to work even if this tradition is not followed. So instead of looking for the implementation of the entire class, let's look for the implementation of a specific member of the class. If tradition is followed – and if that member is in fact implemented – then this achieves the goal.

The member selected by gcc (and potentially by other compilers) is the first non-inline virtual function that is not pure virtual. If you are part of the crowd that declares constructors and destructors before other member functions, then that destructor has a good chance of being selected. (You did remember to make the destructor virtual, right?) There are exceptions; I'd expect that the most common exceptions are when an inline definition is provided for the destructor and when the default destructor is requested (using "= default").

The astute might notice that a polymorphic class is allowed to provide inline definitions for all of its virtual functions. Doesn't that cause the selection process to fail? It does in older compilers. I've read that the latest compilers have addressed this situation, but I do not know relevant version numbers. I could try looking this up, but it's easier to either code around it or wait for the compiler to complain.

In summary, there are three key causes of the "undefined reference to vtable" error:

A member function is missing its definition.
An object file is not being linked.
All virtual functions have inline definitions.

These causes are by themselves insufficient to cause the error on their own. Rather, these are what you would address to resolve the error. Do not expect that intentionally creating one of these situations will definitely produce this error; there are other requirements. Do expect that resolving these situations will resolve this error.

(OK, number 3 might have been sufficient when this question was asked.)

How to fix the error?

Welcome back people skipping ahead! :)

Look at your class definition. Find the first non-inline virtual function that is not pure virtual (not "= 0") and whose definition you provide (not "= default").
- If there is no such function, try modifying your class so there is one. (Error possibly resolved.)
- See also the answer by Philip Thomas for a caveat.
Find the definition for that function. If it is missing, add it! (Error possibly resolved.)
- See also the answer by RedSpikeyThing for a caveat.
Check your link command. If it does not mention the object file with that function's definition, fix that! (Error possibly resolved.)
Repeat steps 2 and 3 for each virtual function, then for each non-virtual function, until the error is resolved. If you're still stuck, repeat for each static data member.

Example
The details of what to do can vary, and sometimes branch off into separate questions (like What is an undefined reference/unresolved external symbol error and how do I fix it?). I will, though, provide an example of what to do in a specific case that might befuddle newer programmers.

Step 1 mentions modifying your class so that it has a function of a certain type. If the description of that function went over your head, you might be in the situation I intend to address. Keep in mind that this is a way to accomplish the goal; it is not the only way, and there easily could be better ways in your specific situation. Let's call your class A. Is your destructor declared (in your class definition) as either

virtual ~A() = default;

virtual ~A() {}

? If so, two steps will change your destructor into the type of function we want. First, change that line to

virtual ~A();

Second, put the following line in a source file that is part of your project (preferably the file with the class implementation, if you have one):

A::~A() {}

That makes your (virtual) destructor non-inline and not generated by the compiler. (Feel free to modify things to better match your code formatting style, such as adding a header comment to the function definition.)

Is there a max size for POST parameter content?

There is no defined maximum size for HTTP POST requests. If you notice such a limit then it's an arbitrary limitation of your HTTP Server/Client.

You might get a better answer if you tell how big the XML is.

How to draw an overlay on a SurfaceView used by Camera on Android?

SurfaceView probably does not work like a regular View in this regard.

Instead, do the following:

Put your SurfaceView inside of a FrameLayout or RelativeLayout in your layout XML file, since both of those allow stacking of widgets on the Z-axis
Move your drawing logic into a separate custom View class
Add an instance of the custom View class to the layout XML file as a child of the FrameLayout or RelativeLayout, but have it appear after the SurfaceView

This will cause your custom View class to appear to float above the SurfaceView.

See here for a sample project that layers popup panels above a SurfaceView used for video playback.

How to upload files to server using JSP/Servlet?

I am Using common Servlet for every Html Form whether it has attachments or not. This Servlet returns a TreeMap where the keys are jsp name Parameters and values are User Inputs and saves all attachments in fixed directory and later you rename the directory of your choice.Here Connections is our custom interface having connection object. I think this will help you

public class ServletCommonfunctions extends HttpServlet implements
        Connections {

    private static final long serialVersionUID = 1L;

    public ServletCommonfunctions() {}

    protected void doPost(HttpServletRequest request,
            HttpServletResponse response) throws ServletException,
            IOException {}

    public SortedMap<String, String> savefilesindirectory(
            HttpServletRequest request, HttpServletResponse response)
            throws IOException {
        // Map<String, String> key_values = Collections.synchronizedMap( new
        // TreeMap<String, String>());
        SortedMap<String, String> key_values = new TreeMap<String, String>();
        String dist = null, fact = null;
        PrintWriter out = response.getWriter();
        File file;
        String filePath = "E:\\FSPATH1\\2KL06CS048\\";
        System.out.println("Directory Created   ????????????"
            + new File(filePath).mkdir());
        int maxFileSize = 5000 * 1024;
        int maxMemSize = 5000 * 1024;
        // Verify the content type
        String contentType = request.getContentType();
        if ((contentType.indexOf("multipart/form-data") >= 0)) {
            DiskFileItemFactory factory = new DiskFileItemFactory();
            // maximum size that will be stored in memory
            factory.setSizeThreshold(maxMemSize);
            // Location to save data that is larger than maxMemSize.
            factory.setRepository(new File(filePath));
            // Create a new file upload handler
            ServletFileUpload upload = new ServletFileUpload(factory);
            // maximum file size to be uploaded.
            upload.setSizeMax(maxFileSize);
            try {
                // Parse the request to get file items.
                @SuppressWarnings("unchecked")
                List<FileItem> fileItems = upload.parseRequest(request);
                // Process the uploaded file items
                Iterator<FileItem> i = fileItems.iterator();
                while (i.hasNext()) {
                    FileItem fi = (FileItem) i.next();
                    if (!fi.isFormField()) {
                        // Get the uploaded file parameters
                        String fileName = fi.getName();
                        // Write the file
                        if (fileName.lastIndexOf("\\") >= 0) {
                            file = new File(filePath
                                + fileName.substring(fileName
                                        .lastIndexOf("\\")));
                        } else {
                            file = new File(filePath
                                + fileName.substring(fileName
                                        .lastIndexOf("\\") + 1));
                        }
                        fi.write(file);
                    } else {
                        key_values.put(fi.getFieldName(), fi.getString());
                    }
                }
            } catch (Exception ex) {
                System.out.println(ex);
            }
        }
        return key_values;
    }
}

doGet and doPost in Servlets

Introduction

You should use doGet() when you want to intercept on HTTP GET requests. You should use doPost() when you want to intercept on HTTP POST requests. That's all. Do not port the one to the other or vice versa (such as in Netbeans' unfortunate auto-generated processRequest() method). This makes no utter sense.

GET

Usually, HTTP GET requests are idempotent. I.e. you get exactly the same result everytime you execute the request (leaving authorization/authentication and the time-sensitive nature of the page —search results, last news, etc— outside consideration). We can talk about a bookmarkable request. Clicking a link, clicking a bookmark, entering raw URL in browser address bar, etcetera will all fire a HTTP GET request. If a Servlet is listening on the URL in question, then its doGet() method will be called. It's usually used to preprocess a request. I.e. doing some business stuff before presenting the HTML output from a JSP, such as gathering data for display in a table.

@WebServlet("/products")
public class ProductsServlet extends HttpServlet {

    @EJB
    private ProductService productService;

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        List<Product> products = productService.list();
        request.setAttribute("products", products); // Will be available as ${products} in JSP
        request.getRequestDispatcher("/WEB-INF/products.jsp").forward(request, response);
    }

}

Note that the JSP file is explicitly placed in /WEB-INF folder in order to prevent endusers being able to access it directly without invoking the preprocessing servlet (and thus end up getting confused by seeing an empty table).

<table>
    <c:forEach items="${products}" var="product">
        <tr>
            <td>${product.name}</td>
            <td><a href="product?id=${product.id}">detail</a></td>
        </tr>
    </c:forEach>
</table>

Also view/edit detail links as shown in last column above are usually idempotent.

@WebServlet("/product")
public class ProductServlet extends HttpServlet {

    @EJB
    private ProductService productService;

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        Product product = productService.find(request.getParameter("id"));
        request.setAttribute("product", product); // Will be available as ${product} in JSP
        request.getRequestDispatcher("/WEB-INF/product.jsp").forward(request, response);
    }

}

<dl>
    <dt>ID</dt>
    <dd>${product.id}</dd>
    <dt>Name</dt>
    <dd>${product.name}</dd>
    <dt>Description</dt>
    <dd>${product.description}</dd>
    <dt>Price</dt>
    <dd>${product.price}</dd>
    <dt>Image</dt>
    <dd><img src="productImage?id=${product.id}" /></dd>
</dl>

POST

HTTP POST requests are not idempotent. If the enduser has submitted a POST form on an URL beforehand, which hasn't performed a redirect, then the URL is not necessarily bookmarkable. The submitted form data is not reflected in the URL. Copypasting the URL into a new browser window/tab may not necessarily yield exactly the same result as after the form submit. Such an URL is then not bookmarkable. If a Servlet is listening on the URL in question, then its doPost() will be called. It's usually used to postprocess a request. I.e. gathering data from a submitted HTML form and doing some business stuff with it (conversion, validation, saving in DB, etcetera). Finally usually the result is presented as HTML from the forwarded JSP page.

<form action="login" method="post">
    <input type="text" name="username">
    <input type="password" name="password">
    <input type="submit" value="login">
    <span class="error">${error}</span>
</form>

...which can be used in combination with this piece of Servlet:

@WebServlet("/login")
public class LoginServlet extends HttpServlet {

    @EJB
    private UserService userService;

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String username = request.getParameter("username");
        String password = request.getParameter("password");
        User user = userService.find(username, password);

        if (user != null) {
            request.getSession().setAttribute("user", user);
            response.sendRedirect("home");
        }
        else {
            request.setAttribute("error", "Unknown user, please try again");
            request.getRequestDispatcher("/login.jsp").forward(request, response);
        }
    }

}

You see, if the User is found in DB (i.e. username and password are valid), then the User will be put in session scope (i.e. "logged in") and the servlet will redirect to some main page (this example goes to http://example.com/contextname/home), else it will set an error message and forward the request back to the same JSP page so that the message get displayed by ${error}.

You can if necessary also "hide" the login.jsp in /WEB-INF/login.jsp so that the users can only access it by the servlet. This keeps the URL clean http://example.com/contextname/login. All you need to do is to add a doGet() to the servlet like this:

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    request.getRequestDispatcher("/WEB-INF/login.jsp").forward(request, response);
}

(and update the same line in doPost() accordingly)

That said, I am not sure if it is just playing around and shooting in the dark, but the code which you posted doesn't look good (such as using compareTo() instead of equals() and digging in the parameternames instead of just using getParameter() and the id and password seems to be declared as servlet instance variables — which is NOT threadsafe). So I would strongly recommend to learn a bit more about basic Java SE API using the Oracle tutorials (check the chapter "Trails Covering the Basics") and how to use JSP/Servlets the right way using those tutorials.

Reflection: How to Invoke Method with parameters

On .Net 4.7.2 to invoke a method inside a class loaded from an external assembly you can use the following code in VB.net

        Dim assembly As Reflection.Assembly = Nothing
        Try
            assembly = Reflection.Assembly.LoadFile(basePath & AssemblyFileName)
            Dim typeIni = assembly.[GetType](AssemblyNameSpace & "." & "nameOfClass")
            Dim iniClass = Activator.CreateInstance(typeIni, True)
            Dim methodInfo = typeIni.GetMethod("nameOfMethod")

            'replace nothing by a parameter array if you need to pass var. paramenters
            Dim parametersArray As Object() = New Object() {...}
            'without parameters is like this
            Dim result = methodInfo.Invoke(iniClass, Nothing)
        Catch ex As Exception
            MsgBox("Error initializing main layout:" & ex.Message)
            Application.Exit()
            Exit Sub
        End Try

java.lang.IllegalStateException: Cannot (forward | sendRedirect | create session) after response has been committed

even adding a return statement brings up this exception, for which only solution is this code:

if(!response.isCommitted())
// Place another redirection

Parsing query strings on Android

Apache AXIS2 has a self-contained implementation of QueryStringParser.java. If you are not using Axis2, just download the sourcecode and test case from here -

http://svn.apache.org/repos/asf/axis/axis2/java/core/trunk/modules/kernel/src/org/apache/axis2/transport/http/util/QueryStringParser.java

http://svn.apache.org/repos/asf/axis/axis2/java/core/trunk/modules/kernel/test/org/apache/axis2/transport/http/util/QueryStringParserTest.java

What's the best way to get the current URL in Spring MVC?

Well there are two methods to access this data easier, but the interface doesn't offer the possibility to get the whole URL with one call. You have to build it manually:

public static String makeUrl(HttpServletRequest request)
{
    return request.getRequestURL().toString() + "?" + request.getQueryString();
}

I don't know about a way to do this with any Spring MVC facilities.

If you want to access the current Request without passing it everywhere you will have to add a listener in the web.xml:

<listener>
    <listener-class>org.springframework.web.context.request.RequestContextListener</listener-class>
</listener>

And then use this to get the request bound to the current Thread:

((ServletRequestAttributes) RequestContextHolder.currentRequestAttributes()).getRequest()

Modify request parameter with servlet filter

I had the same problem (changing a parameter from the HTTP request in the Filter). I ended up by using a ThreadLocal<String>. In the Filter I have:

class MyFilter extends Filter {
    public static final ThreadLocal<String> THREAD_VARIABLE = new ThreadLocal<>();
    public void doFilter(HttpServletRequest request, HttpServletResponse response, FilterChain chain) {
        THREAD_VARIABLE.set("myVariableValue");
        chain.doFilter(request, response);
    }
}

In my request processor (HttpServlet, JSF controller or any other HTTP request processor), I get the current thread value back:

...
String myVariable = MyFilter.THREAD_VARIABLE.get();
...

Advantages:

more versatile than passing HTTP parameters (you can pass POJO objects)
slightly faster (no need to parse the URL to extract the variable value)
more elegant thant the HttpServletRequestWrapper boilerplate
the variable scope is wider than just the HTTP request (the scope you have when doing request.setAttribute(String,Object), i.e. you can access the variable in other filtrers.

Disadvantages:

You can use this method only when the thread which process the filter is the same as the one which process the HTTP request (this is the case in all Java-based servers I know). Consequently, this will not work when
- doing a HTTP redirect (because the browser does a new HTTP request and there is no way to guarantee that it will be processed by the same thread)
- processing data in separate threads, e.g. when using java.util.stream.Stream.parallel, java.util.concurrent.Future, java.lang.Thread.
You must be able to modify the request processor/application

Some side notes:

The server has a Thread pool to process the HTTP requests. Since this is pool:
1. a Thread from this thread pool will process many HTTP requests, but only one at a time (so you need either to cleanup you variable after usage or to define it for each HTTP request = pay attention to code such as if (value!=null) { THREAD_VARIABLE.set(value);} because you will reuse the value from the previous HTTP request when value is null : side effects are guaranteed).
2. There is no guarantee that two requests will be processed by the same thread (it may be the case but you have no guarantee). If you need to keep user data from one request to another request, it would be better to use HttpSession.setAttribute()
The JEE @RequestScoped internally uses a ThreadLocal, but using the ThreadLocal is more versatile: you can use it in non JEE/CDI containers (e.g. in multithreaded JRE applications)

Neither BindingResult nor plain target object for bean name available as request attr

Make sure that your Spring form mentions the modelAttribute="<Model Name".

Example:

@Controller
@RequestMapping("/greeting.html")
public class GreetingController {

 @ModelAttribute("greeting")
 public Greeting getGreetingObject() {
  return new Greeting();
 }

 /**
  * GET
  * 
  * 
  */
 @RequestMapping(method = RequestMethod.GET)
 public String handleRequest() {
  return "greeting";
 }

 /**
  * POST
  * 
  * 
  */
 @RequestMapping(method = RequestMethod.POST)
 public ModelAndView processSubmit(@ModelAttribute("greeting") Greeting greeting, BindingResult result){
  ModelAndView mv = new ModelAndView();
  mv.addObject("greeting", greeting);  
  return mv;
 }
}

In your JSP :

<form:form  modelAttribute="greeting" method="POST" action="greeting.html">

How to set a parameter in a HttpServletRequest?

If you really want to do this, create an HttpServletRequestWrapper.

public class AddableHttpRequest extends HttpServletRequestWrapper {

   private HashMap params = new HashMap();

   public AddableingHttpRequest(HttpServletRequest request) {
           super(request);
   }

   public String getParameter(String name) {
           // if we added one, return that one
           if ( params.get( name ) != null ) {
                 return params.get( name );
           }
           // otherwise return what's in the original request
           HttpServletRequest req = (HttpServletRequest) super.getRequest();
           return validate( name, req.getParameter( name ) );
   }

   public void addParameter( String name, String value ) {
           params.put( name, value );
   }

}

How to differ sessions in browser-tabs?

The window.name Javascript property, is the only thing that will persist across tab activity, but can remain independent (instead of URL guff).

Internal vs. Private Access Modifiers

Internal will allow you to reference, say, a Data Access static class (for thread safety) between multiple business logic classes, while not subscribing them to inherit that class/trip over each other in connection pools, and to ultimately avoid allowing a DAL class to promote access at the public level. This has countless backings in design and best practices.

Entity Framework makes good use of this type of access

How can I generate an MD5 hash?

import java.security.*;
import javax.xml.bind.*;

byte[] bytesOfMessage = yourString.getBytes("UTF-8");
MessageDigest md = MessageDigest.getInstance("MD5");
byte[] bytesOfDigest = md.digest(bytesOfMessage);
String digest = DatatypeConverter.printHexBinary(bytesOfDigest).toLowerCase();

How to do a HTTP HEAD request from the windows command line?

There is a Win32 port of wget that works decently.

PowerShell's Invoke-WebRequest -Method Head would work as well.

String method cannot be found in a main class method

It seem like your Resort method doesn't declare a compareTo method. This method typically belongs to the Comparable interface. Make sure your class implements it.

Additionally, the compareTo method is typically implemented as accepting an argument of the same type as the object the method gets invoked on. As such, you shouldn't be passing a String argument, but rather a Resort.

Alternatively, you can compare the names of the resorts. For example

if (resortList[mid].getResortName().compareTo(resortName)>0)

adding comment in .properties files

The property file task is for editing properties files. It contains all sorts of nice features that allow you to modify entries. For example:

<propertyfile file="build.properties">
    <entry key="build_number"
        type="int"
        operation="+"
        value="1"/>
</propertyfile>

I've incremented my build_number by one. I have no idea what the value was, but it's now one greater than what it was before.

Use the <echo> task to build a property file instead of <propertyfile>. You can easily layout the content and then use <propertyfile> to edit that content later on.

Example:

<echo file="build.properties">
# Default Configuration
source.dir=1
dir.publish=1
# Source Configuration
dir.publish.html=1
</echo>

Create separate properties files for each section. You're allowed a comment header for each type. Then, use to batch them together into one single file:

Example:

<propertyfile file="default.properties"
    comment="Default Configuration">
    <entry key="source.dir" value="1"/>
    <entry key="dir.publish" value="1"/>
<propertyfile>

<propertyfile file="source.properties"
    comment="Source Configuration">
    <entry key="dir.publish.html" value="1"/>
<propertyfile>
<concat destfile="build.properties">
    <fileset dir="${basedir}">
        <include name="default.properties"/>
        <include name="source.properties"/>
    </fileset>
</concat>

<delete>
    <fileset dir="${basedir}">
         <include name="default.properties"/>
        <include name="source.properties"/>
    </fileset>
</delete>

Postgres manually alter sequence

Use select setval('payments_id_seq', 21, true);

setval contains 3 parameters:

1st parameter is sequence_name
2nd parameter is Next nextval
3rd parameter is optional.

The use of true or false in 3rd parameter of setval is as follows:

SELECT setval('payments_id_seq', 21);           // Next nextval will return 22
SELECT setval('payments_id_seq', 21, true);     // Same as above 
SELECT setval('payments_id_seq', 21, false);    // Next nextval will return 21

The better way to avoid hard-coding of sequence name, next sequence value and to handle empty column table correctly, you can use the below way:

SELECT setval(pg_get_serial_sequence('table_name', 'id'), coalesce(max(id), 0)+1 , false) FROM table_name;

where table_name is the name of the table, id is the primary key of the table

TypeError: '<=' not supported between instances of 'str' and 'int'

input() by default takes the input in form of strings.

if (0<= vote <=24):

vote takes a string input (suppose 4,5,etc) and becomes uncomparable.

The correct way is: vote = int(input("Enter your message")will convert the input to integer (4 to 4 or 5 to 5 depending on the input)

How do I set hostname in docker-compose?

I found that the hostname was not visible to other containers when using docker run. This turns out to be a known issue (perhaps more a known feature), with part of the discussion being:

We should probably add a warning to the docs about using hostname. I think it is rarely useful.

The correct way of assigning a hostname - in terms of container networking - is to define an alias like so:

services:
  some-service:
    networks:
      some-network:
        aliases:
          - alias1
          - alias2

Unfortunately this still doesn't work with docker run. The workaround is to assign the container a name:

docker-compose run --name alias1 some-service

And alias1 can then be pinged from the other containers.

UPDATE: As @grilix points out, you should use docker-compose run --use-aliases to make the defined aliases available.

SQLite table constraint - unique on multiple columns

Be careful how you define the table for you will get different results on insert. Consider the following



CREATE TABLE IF NOT EXISTS t1 (id INTEGER PRIMARY KEY, a TEXT UNIQUE, b TEXT);
INSERT INTO t1 (a, b) VALUES
    ('Alice', 'Some title'),
    ('Bob', 'Palindromic guy'),
    ('Charles', 'chucky cheese'),
    ('Alice', 'Some other title') 
    ON CONFLICT(a) DO UPDATE SET b=excluded.b;
CREATE TABLE IF NOT EXISTS t2 (id INTEGER PRIMARY KEY, a TEXT UNIQUE, b TEXT, UNIQUE(a) ON CONFLICT REPLACE);
INSERT INTO t2 (a, b) VALUES
    ('Alice', 'Some title'),
    ('Bob', 'Palindromic guy'),
    ('Charles', 'chucky cheese'),
    ('Alice', 'Some other title');

$ sqlite3 test.sqlite
SQLite version 3.28.0 2019-04-16 19:49:53
Enter ".help" for usage hints.
sqlite> CREATE TABLE IF NOT EXISTS t1 (id INTEGER PRIMARY KEY, a TEXT UNIQUE, b TEXT);
sqlite> INSERT INTO t1 (a, b) VALUES
   ...>     ('Alice', 'Some title'),
   ...>     ('Bob', 'Palindromic guy'),
   ...>     ('Charles', 'chucky cheese'),
   ...>     ('Alice', 'Some other title') 
   ...>     ON CONFLICT(a) DO UPDATE SET b=excluded.b;
sqlite> CREATE TABLE IF NOT EXISTS t2 (id INTEGER PRIMARY KEY, a TEXT UNIQUE, b TEXT, UNIQUE(a) ON CONFLICT REPLACE);
sqlite> INSERT INTO t2 (a, b) VALUES
   ...>     ('Alice', 'Some title'),
   ...>     ('Bob', 'Palindromic guy'),
   ...>     ('Charles', 'chucky cheese'),
   ...>     ('Alice', 'Some other title');
sqlite> .mode col
sqlite> .headers on
sqlite> select * from t1;
id          a           b               
----------  ----------  ----------------
1           Alice       Some other title
2           Bob         Palindromic guy 
3           Charles     chucky cheese   
sqlite> select * from t2;
id          a           b              
----------  ----------  ---------------
2           Bob         Palindromic guy
3           Charles     chucky cheese  
4           Alice       Some other titl
sqlite>

While the insert/update effect is the same, the id changes based on the table definition type (see the second table where 'Alice' now has id = 4; the first table is doing more of what I expect it to do, keep the PRIMARY KEY the same). Be aware of this effect.

How to insert a column in a specific position in oracle without dropping and recreating the table?

Amit-

I don't believe you can add a column anywhere but at the end of the table once the table is created. One solution might be to try this:

CREATE TABLE MY_TEMP_TABLE AS
SELECT *
FROM TABLE_TO_CHANGE;

Drop the table you want to add columns to:

DROP TABLE TABLE_TO_CHANGE;

It's at the point you could rebuild the existing table from scratch adding in the columns where you wish. Let's assume for this exercise you want to add the columns named "COL2 and COL3".

Now insert the data back into the new table:

INSERT INTO TABLE_TO_CHANGE (COL1, COL2, COL3, COL4) 
SELECT COL1, 'Foo', 'Bar', COL4
FROM MY_TEMP_TABLE;

When the data is inserted into your "new-old" table, you can drop the temp table.

DROP TABLE MY_TEMP_TABLE;

This is often what I do when I want to add columns in a specific location. Obviously if this is a production on-line system, then it's probably not practical, but just one potential idea.

-CJ

Request header field Access-Control-Allow-Headers is not allowed by itself in preflight response

To add to the other answers. I had the same problem and this is the code i used in my express server to allow REST calls:

app.all('*', function(req, res, next) {
  res.header('Access-Control-Allow-Origin', 'URLs to trust of allow');
  res.header('Access-Control-Allow-Methods', 'GET, POST, OPTIONS, PUT, PATCH, DELETE');
  res.header('Access-Control-Allow-Headers', 'Content-Type');
  if ('OPTIONS' == req.method) {
  res.sendStatus(200);
  } else {
    next();
  }
});

What this code basically does is intercepts all the requests and adds the CORS headers, then continue with my normal routes. When there is a OPTIONS request it responds only with the CORS headers.

EDIT: I was using this fix for two separate nodejs express servers on the same machine. In the end I fixed the problem with a simple proxy server.

Face recognition Library

Update

OpenCV 2.4.2 now comes with the very new cv::FaceRecognizer. Please see the very detailed documentation at:

http://docs.opencv.org/2.4/modules/contrib/doc/facerec/index.html

Original Post

I have released libfacerec, a modern face recognition library for the OpenCV C++ API (BSD license). libfacerec has no additional dependencies and implements the Eigenfaces method, Fisherfaces method and Local Binary Patterns Histograms. Parts of the library are going to be included in OpenCV 2.4.

The latest revision of the libfacerec is available at:

https://github.com/bytefish/libfacerec

The library was written for OpenCV 2.3.1 with the upcoming OpenCV 2.4 in mind, so I don't support OpenCV versions earlier than 2.3.1. This project comes as a CMake project with a well-documented API, there's also a tutorial on gender classification. You can see a HTML version of the documentation at:

http://www.bytefish.de/dev/libfacerec/

If you want to understand how those algorithms work, you might want to read my Guide To Face Recognition (includes Python and GNU Octave/MATLAB examples):

http://www.bytefish.de/blog/face_recognition_with_opencv2

There's also a Python and GNU Octave/MATLAB implementation of the algorithms in my github repository. Both projects in facerec also include several cross validation methods for evaluating algorithms:

https://github.com/bytefish/facerec

The relevant publications are:

Turk, M., and Pentland, A. Eigenfaces for recognition.. Journal of Cognitive Neuroscience 3 (1991), 71–86.
Belhumeur, P. N., Hespanha, J., and Kriegman, D. Eigenfaces vs. Fisherfaces: Recognition using class specific linear projection.. IEEE Transactions on Pattern Analysis and Machine Intelligence 19, 7 (1997), 711–720.
Ahonen, T., Hadid, A., and Pietikainen, M. Face Recognition with Local Binary Patterns.. Computer Vision - ECCV 2004 (2004), 469–481.

How do I bind a WPF DataGrid to a variable number of columns?

I've continued my research and have not found any reasonable way to do this. The Columns property on the DataGrid isn't something I can bind against, in fact it's read only.

Bryan suggested something might be done with AutoGenerateColumns so I had a look. It uses simple .Net reflection to look at the properties of the objects in ItemsSource and generates a column for each one. Perhaps I could generate a type on the fly with a property for each column but this is getting way off track.

Since this problem is so easily sovled in code I will stick with a simple extension method I call whenever the data context is updated with new columns:

public static void GenerateColumns(this DataGrid dataGrid, IEnumerable<ColumnSchema> columns)
{
    dataGrid.Columns.Clear();

    int index = 0;
    foreach (var column in columns)
    {
        dataGrid.Columns.Add(new DataGridTextColumn
        {
            Header = column.Name,
            Binding = new Binding(string.Format("[{0}]", index++))
        });
    }
}

// E.g. myGrid.GenerateColumns(schema);

Write a file on iOS

Swift

func saveFile() {
    let paths = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)
    let documentsDirectory = paths[0] as! String
    let fileName = "\(documentsDirectory)/textFile.txt"
    let content = "Hello World"
    content.writeToFile(fileName, atomically: false, encoding: NSUTF8StringEncoding, error: nil)
}

func loadFile() {
    let paths = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)
    let documentsDirectory = paths[0] as! String
    let fileName = "\(documentsDirectory)/textFile.txt"
    let content: String = String(contentsOfFile: fileName, encoding: NSUTF8StringEncoding, error: nil)!
    println(content)
}

Swift 2

func saveFile() {
    let paths = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)
    let documentsDirectory = paths[0]
    let fileName = "\(documentsDirectory)/textFile.txt"
    let content = "Hello World"
    do{
        try content.writeToFile(fileName, atomically: false, encoding: NSUTF8StringEncoding)
    }catch _ {

    }

}

func loadFile()->String {
    let paths = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)
    let documentsDirectory = paths[0] 
    let fileName = "\(documentsDirectory)/textFile.txt"
    let content: String
    do{
       content = try String(contentsOfFile: fileName, encoding: NSUTF8StringEncoding)
    }catch _{
        content=""
    }
    return content;
}

Swift 3

func saveFile() {
    let paths = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)
    let documentsDirectory = paths[0]
    let fileName = "\(documentsDirectory)/textFile.txt"
    let content = "Hello World"
    do{
        try content.write(toFile: fileName, atomically: false, encoding: String.Encoding.utf8)
    }catch _ {

    }

}

func loadFile()->String {
    let paths = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)
    let documentsDirectory = paths[0]
    let fileName = "\(documentsDirectory)/textFile.txt"
    let content: String
    do{
        content = try String(contentsOfFile: fileName, encoding: String.Encoding.utf8)
    } catch _{
        content=""
    }
    return content;
}

Using regular expression in css?

As complement of this answer you can use $ to get the end matches and * to get matches anywhere in the value name.

Matches anywhere: .col-md, .left-col, .col, .tricolor, etc.

[class*="col"]

Matches at the beginning: .col-md, .col-sm-6, etc.

[class^="col-"]

Matches at the ending: .left-col, .right-col, etc.

[class$="-col"]

How I can get web page's content and save it into the string variable

Webclient client = new Webclient();
string content = client.DownloadString(url);

Pass the URL of page who you want to get. You can parse the result using htmlagilitypack.

Javascript - Get Image height

Try this:

var curHeight;
var curWidth;

function getImgSize(imgSrc)
{
var newImg = new Image();
newImg.src = imgSrc;
curHeight = newImg.height;
curWidth = newImg.width;

}

How to measure time in milliseconds using ANSI C?

The best precision you can possibly get is through the use of the x86-only "rdtsc" instruction, which can provide clock-level resolution (ne must of course take into account the cost of the rdtsc call itself, which can be measured easily on application startup).

The main catch here is measuring the number of clocks per second, which shouldn't be too hard.

Text border using css (border around text)

Sure. You could use CSS3 text-shadow :

text-shadow: 0 0 2px #fff;

However it wont show in all browsers right away. Using a script library like Modernizr will help getting it right in most browsers though.

Unable to Resolve Module in React Native App

react-native start --reset-cache solved the issue. https://github.com/facebook/react-native/issues/1924

Laravel 5 - How to access image uploaded in storage within View?

If you are like me and you somehow have full file paths (I did some glob() pattern matching on required photos so I do pretty much end up with full file paths), and your storage setup is well linked (i.e. such that your paths have the string storage/app/public/), then you can use my little dirty hack below :p)

 public static function hackoutFileFromStorageFolder($fullfilePath) {
        if (strpos($fullfilePath, 'storage/app/public/')) {
           $fileParts = explode('storage/app/public/', $fullfilePath);
           if( count($fileParts) > 1){
               return $fileParts[1];
           }
        }

        return '';
    }

curl: (6) Could not resolve host: google.com; Name or service not known

Issues were:

IPV6 enabled
Wrong DNS server

Here is how I fixed it:

IPV6 Disabling

Open Terminal
Type su and enter to log in as the super user
Enter the root password
Type cd /etc/modprobe.d/ to change directory to /etc/modprobe.d/
Type vi disableipv6.conf to create a new file there
Press Esc + i to insert data to file
Type install ipv6 /bin/true on the file to avoid loading IPV6 related modules
Type Esc + : and then wq for save and exit
Type reboot to restart fedora
After reboot open terminal and type lsmod | grep ipv6
If no result, it means you properly disabled IPV6

Add Google DNS server

Open Terminal
Type su and enter to log in as the super user
Enter the root password
Type cat /etc/resolv.conf to check what DNS server your Fedora using. Mostly this will be your Modem IP address.
Now we have to Find a powerful DNS server. Luckily there is a open DNS server maintain by Google.
Go to this page and find out what are the "Google Public DNS IP addresses"
Today those are 8.8.8.8 and 8.8.4.4. But in future those may change.
Type vi /etc/resolv.conf to edit the resolv.conf file
Press Esc + i for insert data to file
Comment all the things in the file by inserting # at the begin of the each line. Do not delete anything because can be useful in future.
Type below two lines in the file

nameserver 8.8.8.8
nameserver 8.8.4.4

-Type Esc + : and then wq for save and exit
Now you are done and everything works fine (Not necessary to restart).
But every time when you restart the computer your /etc/resolv.conf will be replaced by default. So I'll let you find a way to avoid that.

Here is my blog post about this: http://codeketchup.blogspot.sg/2014/07/how-to-fix-curl-6-could-not-resolve.html

Using if-else in JSP

Instead of if-else condition use if in both conditions. it will work that way but not sure why.

iPad Multitasking support requires these orientations

as Michael said,

Check the "Requires full screen" of the target of xcodeproj, if you don't need to support multitasking.

or Check the following device orientations

Portrait
Upside Down
Landscape Left
Landscape Right

In this case, we need to support launch storyboard.

Spring @Transactional read-only propagation

Calling readOnly=false from readOnly=true doesn't work since the previous transaction continues.

In your example, the handle() method on your service layer is starting a new read-write transaction. If the handle method in turn calls service methods that annotated read-only, the read-only will take no effect as they will participate in the existing read-write transaction instead.

If it is essential for those methods to be read-only, then you can annotate them with Propagation.REQUIRES_NEW, and they will then start a new read-only transaction rather than participate in the existing read-write transaction.

Here is a worked example, CircuitStateRepository is a spring-data JPA repository.

BeanS calls a transactional=read-only Bean1, which does a lookup and calls transactional=read-write Bean2 which saves a new object.

Bean1 starts a read-only tx.

31 09:39:44.199 [pool-1-thread-1] DEBUG o.s.orm.jpa.JpaTransactionManager - Creating new transaction with name [nz.co.vodafone.wcim.business.Bean1.startSomething]: PROPAGATION_REQUIRED,ISOLATION_DEFAULT,readOnly; ''

Bean 2 pariticipates in it.

31 09:39:44.230 [pool-1-thread-1] DEBUG o.s.orm.jpa.JpaTransactionManager - Participating in existing transaction

Nothing is committed to the database.

Now change Bean2 @Transactional annotation to add propagation=Propagation.REQUIRES_NEW

Bean1 starts a read-only tx.

31 09:31:36.418 [pool-1-thread-1] DEBUG o.s.orm.jpa.JpaTransactionManager - Creating new transaction with name [nz.co.vodafone.wcim.business.Bean1.startSomething]: PROPAGATION_REQUIRED,ISOLATION_DEFAULT,readOnly; ''
Bean2 starts a new read-write tx

31 09:31:36.449 [pool-1-thread-1] DEBUG o.s.orm.jpa.JpaTransactionManager - Suspending current transaction, creating new transaction with name [nz.co.vodafone.wcim.business.Bean2.createSomething]

And the changes made by Bean2 are now committed to the database.

Here's the example, tested with spring-data, hibernate and oracle.

@Named
public class BeanS {    
    @Inject
    Bean1 bean1;

    @Scheduled(fixedRate = 20000)
    public void runSomething() {
        bean1.startSomething();
    }
}

@Named
@Transactional(readOnly = true)
public class Bean1 {    
    Logger log = LoggerFactory.getLogger(Bean1.class);

    @Inject
    private CircuitStateRepository csr;

    @Inject
    private Bean2 bean2;

    public void startSomething() {    
        Iterable<CircuitState> s = csr.findAll();
        CircuitState c = s.iterator().next();
        log.info("GOT CIRCUIT {}", c.getCircuitId());
        bean2.createSomething(c.getCircuitId());    
    }
}

@Named
@Transactional(readOnly = false)
public class Bean2 {    
    @Inject
    CircuitStateRepository csr;

    public void createSomething(String circuitId) {
        CircuitState c = new CircuitState(circuitId + "-New-" + new DateTime().toString("hhmmss"), new DateTime());

        csr.save(c);
     }
}

Determine when a ViewPager changes pages

For ViewPager2,

viewPager.registerOnPageChangeCallback(object : ViewPager2.OnPageChangeCallback() {
  override fun onPageSelected(position: Int) {
    super.onPageSelected(position)
  }
})

where OnPageChangeCallback is a static class with three methods:

onPageScrolled(int position, float positionOffset, @Px int positionOffsetPixels),
onPageSelected(int position), 
onPageScrollStateChanged(@ScrollState int state)

Markdown and including multiple files

Asciidoc is actually a markdown on steroids. Overall, Asciidoc and Markdown will look very similar and it is rather easy to switch. A huge benefit of Asciidoc over markdown is that it supports includes already, for other Asciidoc files but also for any format you like. You can even partly include files based on line numbers or tags inside your included files.

Including other files is really a life saver when you write docs.

You can for instance have an asciidoc file with such content:

// [source,perl]
// ----
// include::script.pl[]
// ----

and maintain your sample in script.pl

And I am sure you will wonder so yes, Github also supports asciidoc.

How is the default submit button on an HTML form determined?

Another solution I've used is to just have one button in the form, and fake the other buttons.

Here's an example:

<form>
  <label for="amount">Amount of items</label>
  <input id="amount" type="text" name="amount" />
  <span id="checkStock" class="buttonish">Check stock</span>
  <button type="submit" name="action" value="order">Place order</button>
</form>

I then style the span elements to look like a button. A JS listener observes the span and performs the desired operation once clicked.

Not necessarily right for all situations, but at least it's pretty easy to do.

Hide all warnings in ipython

For jupyter lab this should work (@Alasja)

from IPython.display import HTML
HTML('''<script>
var code_show_err = false; 
var code_toggle_err = function() {
 var stderrNodes = document.querySelectorAll('[data-mime-type="application/vnd.jupyter.stderr"]')
 var stderr = Array.from(stderrNodes)
 if (code_show_err){
     stderr.forEach(ele => ele.style.display = 'block');
 } else {
     stderr.forEach(ele => ele.style.display = 'none');
 }
 code_show_err = !code_show_err
} 
document.addEventListener('DOMContentLoaded', code_toggle_err);
</script>
To toggle on/off output_stderr, click <a onclick="javascript:code_toggle_err()">here</a>.''')

How do I manually configure a DataSource in Java?

Basically in JDBC most of these properties are not configurable in the API like that, rather they depend on implementation. The way JDBC handles this is by allowing the connection URL to be different per vendor.

So what you do is register the driver so that the JDBC system can know what to do with the URL:

 DriverManager.registerDriver((Driver) Class.forName("com.mysql.jdbc.Driver").newInstance());

Then you form the URL:

 String url = "jdbc:mysql://[host][,failoverhost...][:port]/[database][?propertyName1][=propertyValue1][&propertyName2][=propertyValue2]"

And finally, use it to get a connection:

 Connection c = DriverManager.getConnection(url);

In more sophisticated JDBC, you get involved with connection pools and the like, and application servers often have their own way of registering drivers in JNDI and you look up a DataSource from there, and call getConnection on it.

In terms of what properties MySQL supports, see here.

EDIT: One more thought, technically just having a line of code which does Class.forName("com.mysql.jdbc.Driver") should be enough, as the class should have its own static initializer which registers a version, but sometimes a JDBC driver doesn't, so if you aren't sure, there is little harm in registering a second one, it just creates a duplicate object in memeory.

Blue and Purple Default links, how to remove?

<a href="https://www." style="color: inherit;"target="_blank">

For CSS inline style, this worked best for me.

Insert data into a view (SQL Server)

Looks like you are running afoul of this rule for updating views from Books Online: "INSERT statements must specify values for any columns in the underlying table that do not allow null values and have no DEFAULT definitions."

Find max and second max salary for a employee table MySQL

Try below Query, was working for me to find Nth highest number salary. Just replace your number with nth_No

Select DISTINCT TOP 1 salary
from 
(Select DISTINCT TOP *nth_No* salary
from Employee
ORDER BY Salary DESC)
Result
ORDER BY Salary

Random color generator

Random color generation with brightness control:

function getRandColor(brightness){

    // Six levels of brightness from 0 to 5, 0 being the darkest
    var rgb = [Math.random() * 256, Math.random() * 256, Math.random() * 256];
    var mix = [brightness*51, brightness*51, brightness*51]; //51 => 255/5
    var mixedrgb = [rgb[0] + mix[0], rgb[1] + mix[1], rgb[2] + mix[2]].map(function(x){ return Math.round(x/2.0)})
    return "rgb(" + mixedrgb.join(",") + ")";
}

How to use Session attributes in Spring-mvc

When I trying to my login (which is a bootstrap modal), I used the @sessionattributes annotation. But problem was when the view is a redirect ("redirect:/home"), values I entered to session shows in the url. Some Internet sources suggest to follow http://docs.spring.io/spring/docs/4.3.x/spring-framework-reference/htmlsingle/#mvc-redirecting But I used the HttpSession instead. This session will be there until you close the browsers. Here is sample code

        @RequestMapping(value = "/login")
        @ResponseBody
        public BooleanResponse login(HttpSession session,HttpServletRequest request){
            //HttpServletRequest used to take data to the controller
            String username = request.getParameter("username");
            String password = request.getParameter("password");

           //Here you set your values to the session
           session.setAttribute("username", username);
           session.setAttribute("email", email);

          //your code goes here
}

You don't change specific thing on view side.

<c:out value="${username}"></c:out>
<c:out value="${email}"></c:out>

After login add above codes to anyplace in you web site. If session correctly set, you will see the values there. Make sure you correctly added the jstl tags and El- expressions (Here is link to set jstl tags https://menukablog.wordpress.com/2016/05/10/add-jstl-tab-library-to-you-project-correctly/)

Uncaught SyntaxError: Unexpected token with JSON.parse

In my case there is following character problems in my JSON string

\r
\t
\r\n
\n
:
"

I have replaced them with another characters or symbols, and then revert back again from coding.

Running Java gives "Error: could not open `C:\Program Files\Java\jre6\lib\amd64\jvm.cfg'"

I thought I will share how I resolved the same issue "Error Could not open lib\amd64\jvm.cfg". I found the Java run time Jre7 is missing amd64 folder under lib. However, I have 1.7.0_25 JDK which is having jre folder and also having amd64.

I moved the original contents of jre7 folder to a backup file and copied everything from 1.7.0_25\jre.

Now I am not getting this error anymore and able to proceed with scene builder.

How can I search for a commit message on GitHub?

This works well from within Eclipse, until GitHub adds the feature:

Enter image description here

EGit/User Guide, Searching for commits

2D array values C++

int iArray[2][2] = {{1, 2}, {3, 4}};

Think of a 2D array as an array of arrays.

Short description of the scoping rules?

Python resolves your variables with -- generally -- three namespaces available.

At any time during execution, there are at least three nested scopes whose namespaces are directly accessible: the innermost scope, which is searched first, contains the local names; the namespaces of any enclosing functions, which are searched starting with the nearest enclosing scope; the middle scope, searched next, contains the current module's global names; and the outermost scope (searched last) is the namespace containing built-in names.

There are two functions: globals and locals which show you the contents two of these namespaces.

Namespaces are created by packages, modules, classes, object construction and functions. There aren't any other flavors of namespaces.

In this case, the call to a function named x has to be resolved in the local name space or the global namespace.

Local in this case, is the body of the method function Foo.spam.

Global is -- well -- global.

The rule is to search the nested local spaces created by method functions (and nested function definitions), then search global. That's it.

There are no other scopes. The for statement (and other compound statements like if and try) don't create new nested scopes. Only definitions (packages, modules, functions, classes and object instances.)

Inside a class definition, the names are part of the class namespace. code2, for instance, must be qualified by the class name. Generally Foo.code2. However, self.code2 will also work because Python objects look at the containing class as a fall-back.

An object (an instance of a class) has instance variables. These names are in the object's namespace. They must be qualified by the object. (variable.instance.)

From within a class method, you have locals and globals. You say self.variable to pick the instance as the namespace. You'll note that self is an argument to every class member function, making it part of the local namespace.

See Python Scope Rules, Python Scope, Variable Scope.

How to write an XPath query to match two attributes?

or //div[@id='id-74385'][@class='guest clearfix']

How to check if any Checkbox is checked in Angular

I've a sample for multiple data with their subnode 3 list , each list has attribute and child attribute:

var list1 = {
    name: "Role A",
    name_selected: false,
    subs: [{
        sub: "Read",
        id: 1,
        selected: false
    }, {
        sub: "Write",
        id: 2,
        selected: false
    }, {
        sub: "Update",
        id: 3,
        selected: false
    }],
};
var list2 = {
    name: "Role B",
    name_selected: false,
    subs: [{
        sub: "Read",
        id: 1,
        selected: false
    }, {
        sub: "Write",
        id: 2,
        selected: false
    }],
};
var list3 = {
    name: "Role B",
    name_selected: false,
    subs: [{
        sub: "Read",
        id: 1,
        selected: false
    }, {
        sub: "Update",
        id: 3,
        selected: false
    }],
};

Add these to Array :

newArr.push(list1);
newArr.push(list2);
newArr.push(list3);
$scope.itemDisplayed = newArr;

Show them in html:

<li ng-repeat="item in itemDisplayed" class="ng-scope has-pretty-child">
    <div>
        <ul>
            <input type="checkbox" class="checkall" ng-model="item.name_selected" ng-click="toggleAll(item)" />
            <span>{{item.name}}</span>
            <div>
                <li ng-repeat="sub in item.subs" class="ng-scope has-pretty-child">
                    <input type="checkbox" kv-pretty-check="" ng-model="sub.selected" ng-change="optionToggled(item,item.subs)"><span>{{sub.sub}}</span>
                </li>
            </div>
        </ul>
    </div>
</li>

And here is the solution to check them:

$scope.toggleAll = function(item) {
    var toogleStatus = !item.name_selected;
    console.log(toogleStatus);
    angular.forEach(item, function() {
        angular.forEach(item.subs, function(sub) {
            sub.selected = toogleStatus;
        });
    });
};

$scope.optionToggled = function(item, subs) {
    item.name_selected = subs.every(function(itm) {
        return itm.selected;
    })
}

jsfiddle demo

Android simple alert dialog

No my friend its very simple, try using this:

AlertDialog alertDialog = new AlertDialog.Builder(AlertDialogActivity.this).create();
alertDialog.setTitle("Alert Dialog");
alertDialog.setMessage("Welcome to dear user.");
alertDialog.setIcon(R.drawable.welcome);

alertDialog.setButton(AlertDialog.BUTTON_POSITIVE, "OK", new DialogInterface.OnClickListener() {
    public void onClick(DialogInterface dialog, int which) {
        Toast.makeText(getApplicationContext(), "You clicked on OK", Toast.LENGTH_SHORT).show();
    }
});

alertDialog.show();

This tutorial shows how you can create custom dialog using xml and then show them as an alert dialog.

Handling of non breaking space: <p> </p> vs. <p> </p>

In HTML, elements containing nothing but normal whitespace characters are considered empty. A paragraph that contains just a normal space character will have zero height. A non-breaking space is a special kind of whitespace character that isn't considered to be insignificant, so it can be used as content for a non-empty paragraph.

Even if you consider CSS margins on paragraphs, since an "empty" paragraph has zero height, its vertical margins will collapse. This causes it to have no height and no margins, making it appear as if it were never there at all.

C/C++ macro string concatenation

You don't need that sort of solution for string literals, since they are concatenated at the language level, and it wouldn't work anyway because "s""1" isn't a valid preprocessor token.

[Edit: In response to the incorrect "Just for the record" comment below that unfortunately received several upvotes, I will reiterate the statement above and observe that the program fragment

#define PPCAT_NX(A, B) A ## B
PPCAT_NX("s", "1")

produces this error message from the preprocessing phase of gcc: error: pasting ""s"" and ""1"" does not give a valid preprocessing token

]

However, for general token pasting, try this:

/*
 * Concatenate preprocessor tokens A and B without expanding macro definitions
 * (however, if invoked from a macro, macro arguments are expanded).
 */
#define PPCAT_NX(A, B) A ## B

/*
 * Concatenate preprocessor tokens A and B after macro-expanding them.
 */
#define PPCAT(A, B) PPCAT_NX(A, B)

Then, e.g., both PPCAT_NX(s, 1) and PPCAT(s, 1) produce the identifier s1, unless s is defined as a macro, in which case PPCAT(s, 1) produces <macro value of s>1.

Continuing on the theme are these macros:

/*
 * Turn A into a string literal without expanding macro definitions
 * (however, if invoked from a macro, macro arguments are expanded).
 */
#define STRINGIZE_NX(A) #A

/*
 * Turn A into a string literal after macro-expanding it.
 */
#define STRINGIZE(A) STRINGIZE_NX(A)

Then,

#define T1 s
#define T2 1
STRINGIZE(PPCAT(T1, T2)) // produces "s1"

By contrast,

STRINGIZE(PPCAT_NX(T1, T2)) // produces "T1T2"
STRINGIZE_NX(PPCAT_NX(T1, T2)) // produces "PPCAT_NX(T1, T2)"

#define T1T2 visit the zoo
STRINGIZE(PPCAT_NX(T1, T2)) // produces "visit the zoo"
STRINGIZE_NX(PPCAT(T1, T2)) // produces "PPCAT(T1, T2)"

How to disable Python warnings?

warnings are output via stderr and the simple solution is to append '2> /dev/null' to the CLI. this makes a lot of sense to many users such as those with centos 6 that are stuck with python 2.6 dependencies (like yum) and various modules are being pushed to the edge of extinction in their coverage.

this is especially true for cryptography involving SNI et cetera. one can update 2.6 for HTTPS handling using the proc at: https://urllib3.readthedocs.io/en/latest/user-guide.html#ssl-py2

the warning is still in place, but everything you want is back-ported. the re-direct of stderr will leave you with clean terminal/shell output although the stdout content itself does not change.

responding to FriendFX. sentence one (1) responds directly to the problem with an universal solution. sentence two (2) takes into account the cited anchor re 'disable warnings' which is python 2.6 specific and notes that RHEL/centos 6 users cannot directly do without 2.6. although no specific warnings were cited, para two (2) answers the 2.6 question I most frequently get re the short-comings in the cryptography module and how one can "modernize" (i.e., upgrade, backport, fix) python's HTTPS/TLS performance. para three (3) merely explains the outcome of using the re-direct and upgrading the module/dependencies.

How to convert integer into date object python?

Here is what I believe answers the question (Python 3, with type hints):

from datetime import date


def int2date(argdate: int) -> date:
    """
    If you have date as an integer, use this method to obtain a datetime.date object.

    Parameters
    ----------
    argdate : int
      Date as a regular integer value (example: 20160618)

    Returns
    -------
    dateandtime.date
      A date object which corresponds to the given value `argdate`.
    """
    year = int(argdate / 10000)
    month = int((argdate % 10000) / 100)
    day = int(argdate % 100)

    return date(year, month, day)


print(int2date(20160618))

The code above produces the expected 2016-06-18.

What is the "-->" operator in C/C++?

Actually, x is post-decrementing and with that condition is being checked. It's not -->, it's (x--) > 0

Note: value of x is changed after the condition is checked, because it post-decrementing. Some similar cases can also occur, for example:

-->    x-->0
++>    x++>0
-->=   x-->=0
++>=   x++>=0

Switch case in C# - a constant value is expected

You can only match to constants in switch statements.

Example:

switch (variable1)
{
    case 1: // A hard-coded value
        // Code
        break;
    default:
        // Code
        break;
}

Successful!

switch (variable1)
{
    case variable2:
        // Code
        break;
    default:
        // Code
        break;
}

CS0150 A constant value is expected.

Convert Java string to Time, NOT Date

String to Time (using an arbitrary time):

String myTime = "10:00:00"; 
Time startingTime = new Time (myTime);

String to Time (using currentTime):

String currentTime = getCurrentTime(); 
Time startingTime = new Time (currentTime);

Time to String:

private String getCurrentTime() {    
    SimpleDateFormat dateFormat = new SimpleDateFormat("kkmmss");
    String currentTime = dateFormat.format(System.currentTimeMillis());
    return currentTime;
}

Where is the Global.asax.cs file?

It don't create normally; you need to add it by yourself.

After adding Global.asax by

Right clicking your website -> Add New Item -> Global Application Class -> Add

You need to add a class

Right clicking App_Code -> Add New Item -> Class -> name it Global.cs -> Add

Inherit the newly generated by System.Web.HttpApplication and copy all the method created Global.asax to Global.cs and also add an inherit attribute to the Global.asax file.

Your Global.asax will look like this: -

<%@ Application Language="C#" Inherits="Global" %>

Your Global.cs in App_Code will look like this: -

public class Global : System.Web.HttpApplication
{
    public Global()
    {
        //
        // TODO: Add constructor logic here
        //
    }

    void Application_Start(object sender, EventArgs e)
    {
        // Code that runs on application startup

    }
    /// Many other events like begin request...e.t.c, e.t.c
}

Connect to SQL Server 2012 Database with C# (Visual Studio 2012)

Try:

SqlConnection myConnection = new SqlConnection("Database=testDB;Server=Paul-PC\\SQLEXPRESS;Integrated Security=True;connect timeout = 30");

Convert int to char in java

Make sure the integer value is ASCII value of an alphabet/character.

If not then make it.

for e.g. if int i=1

then add 64 to it so that it becomes 65 = ASCII value of 'A' Then use

char x = (char)i;

print x

// 'A' will be printed

shell init issue when click tab, what's wrong with getcwd?

Yes, cd; and cd - would work. The reason It can see is that, directory is being deleted from any other terminal or any other program and recreate it. So i-node entry is modified so program can not access old i-node entry.

Jquery in React is not defined

Just a note: if you use arrow functions you don't need the const that = this part. It might look like this:

fetch('http://jsonplaceholder.typicode.com/posts') 
  .then((response) => { return response.json(); }) 
  .then((myJson) => { 
     this.setState({data: myJson}); // for example
});

Java compile error: "reached end of file while parsing }"

You need to enclose your class in { and }. A few extra pointers: According to the Java coding conventions, you should

Put your { on the same line as the method declaration:
Name your classes using CamelCase (with initial capital letter)
Name your methods using camelCase (with small initial letter)

Here's how I would write it:

public class ModMyMod extends BaseMod {

    public String version() {
         return "1.2_02";
    }

    public void addRecipes(CraftingManager recipes) {
       recipes.addRecipe(new ItemStack(Item.diamond), new Object[] {
          "#", Character.valueOf('#'), Block.dirt
       });
    }
}

Difference between string and StringBuilder in C#

System.String is a mutable object, meaning it cannot be modified after it’s been created. Please refer to Difference between string and StringBuilder in C#? for better understanding.

How to debug Spring Boot application with Eclipse?

With eclipse or any other IDE, just right click on your main spring boot application and click "debug as java application"

How to refresh token with Google API client?

Google has made some changes since this question was originally posted.

Here is my currently working example.

    public function update_token($token){

    try {

        $client = new Google_Client();
        $client->setAccessType("offline"); 
        $client->setAuthConfig(APPPATH . 'vendor' . DIRECTORY_SEPARATOR . 'google' . DIRECTORY_SEPARATOR . 'client_secrets.json');  
        $client->setIncludeGrantedScopes(true); 
        $client->addScope(Google_Service_Calendar::CALENDAR); 
        $client->setAccessToken($token);

        if ($client->isAccessTokenExpired()) {
            $refresh_token = $client->getRefreshToken();
            if(!empty($refresh_token)){
                $client->fetchAccessTokenWithRefreshToken($refresh_token);      
                $token = $client->getAccessToken();
                $token['refresh_token'] = json_decode($refresh_token);
                $token = json_encode($token);
            }
        }

        return $token;

    } catch (Exception $e) { 
        $error = json_decode($e->getMessage());
        if(isset($error->error->message)){
            log_message('error', $error->error->message);
        }
    }


}

How to create a shared library with cmake?

Always specify the minimum required version of cmake

cmake_minimum_required(VERSION 3.9)

You should declare a project. cmake says it is mandatory and it will define convenient variables PROJECT_NAME, PROJECT_VERSION and PROJECT_DESCRIPTION (this latter variable necessitate cmake 3.9):

project(mylib VERSION 1.0.1 DESCRIPTION "mylib description")

Declare a new library target. Please avoid the use of file(GLOB ...). This feature does not provide attended mastery of the compilation process. If you are lazy, copy-paste output of ls -1 sources/*.cpp :

add_library(mylib SHARED
    sources/animation.cpp
    sources/buffers.cpp
    [...]
)

Set VERSION property (optional but it is a good practice):

set_target_properties(mylib PROPERTIES VERSION ${PROJECT_VERSION})

You can also set SOVERSION to a major number of VERSION. So libmylib.so.1 will be a symlink to libmylib.so.1.0.0.

set_target_properties(mylib PROPERTIES SOVERSION 1)

Declare public API of your library. This API will be installed for the third-party application. It is a good practice to isolate it in your project tree (like placing it include/ directory). Notice that, private headers should not be installed and I strongly suggest to place them with the source files.

set_target_properties(mylib PROPERTIES PUBLIC_HEADER include/mylib.h)

If you work with subdirectories, it is not very convenient to include relative paths like "../include/mylib.h". So, pass a top directory in included directories:

target_include_directories(mylib PRIVATE .)

target_include_directories(mylib PRIVATE include)
target_include_directories(mylib PRIVATE src)

Create an install rule for your library. I suggest to use variables CMAKE_INSTALL_*DIR defined in GNUInstallDirs:

include(GNUInstallDirs)

And declare files to install:

install(TARGETS mylib
    LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
    PUBLIC_HEADER DESTINATION ${CMAKE_INSTALL_INCLUDEDIR})

You may also export a pkg-config file. This file allows a third-party application to easily import your library:

with Makefile, see pkg-config
with Autotools, see PKG_CHECK_MODULES
with cmake, see pkg_check_modules

Create a template file named mylib.pc.in (see pc(5) manpage for more information):

prefix=@CMAKE_INSTALL_PREFIX@
exec_prefix=@CMAKE_INSTALL_PREFIX@
libdir=${exec_prefix}/@CMAKE_INSTALL_LIBDIR@
includedir=${prefix}/@CMAKE_INSTALL_INCLUDEDIR@

Name: @PROJECT_NAME@
Description: @PROJECT_DESCRIPTION@
Version: @PROJECT_VERSION@

Requires:
Libs: -L${libdir} -lmylib
Cflags: -I${includedir}

In your CMakeLists.txt, add a rule to expand @ macros (@ONLY ask to cmake to not expand variables of the form ${VAR}):

configure_file(mylib.pc.in mylib.pc @ONLY)

And finally, install generated file:

install(FILES ${CMAKE_BINARY_DIR}/mylib.pc DESTINATION ${CMAKE_INSTALL_DATAROOTDIR}/pkgconfig)

You may also use cmake EXPORT feature. However, this feature is only compatible with cmake and I find it difficult to use.

Finally the entire CMakeLists.txt should looks like:

cmake_minimum_required(VERSION 3.9)
project(mylib VERSION 1.0.1 DESCRIPTION "mylib description")
include(GNUInstallDirs)
add_library(mylib SHARED src/mylib.c)
set_target_properties(mylib PROPERTIES
    VERSION ${PROJECT_VERSION}
    SOVERSION 1
    PUBLIC_HEADER api/mylib.h)
configure_file(mylib.pc.in mylib.pc @ONLY)
target_include_directories(mylib PRIVATE .)
install(TARGETS mylib
    LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
    PUBLIC_HEADER DESTINATION ${CMAKE_INSTALL_INCLUDEDIR})
install(FILES ${CMAKE_BINARY_DIR}/mylib.pc
    DESTINATION ${CMAKE_INSTALL_DATAROOTDIR}/pkgconfig)

What is the best way to get the count/length/size of an iterator?

You will always have to iterate. Yet you can use Java 8, 9 to do the counting without looping explicitely:

Iterable<Integer> newIterable = () -> iter;
long count = StreamSupport.stream(newIterable.spliterator(), false).count();

Here is a test:

public static void main(String[] args) throws IOException {
    Iterator<Integer> iter = Arrays.asList(1, 2, 3, 4, 5).iterator();
    Iterable<Integer> newIterable = () -> iter;
    long count = StreamSupport.stream(newIterable.spliterator(), false).count();
    System.out.println(count);
}

This prints:

Interesting enough you can parallelize the count operation here by changing the parallel flag on this call:

long count = StreamSupport.stream(newIterable.spliterator(), *true*).count();

Disabling enter key for form

this is in pure javascript

_x000D_

        document.addEventListener('keypress', function (e) {_x000D_
            if (e.keyCode === 13 || e.which === 13) {_x000D_
                e.preventDefault();_x000D_
                return false;_x000D_
            }_x000D_
            _x000D_
        });

_x000D_

how to display a javascript var in html body

_x000D_

<script type="text/javascript">_x000D_
        function get_param(param) {_x000D_
   var search = window.location.search.substring(1);_x000D_
   var compareKeyValuePair = function(pair) {_x000D_
      var key_value = pair.split('=');_x000D_
      var decodedKey = decodeURIComponent(key_value[0]);_x000D_
      var decodedValue = decodeURIComponent(key_value[1]);_x000D_
      if(decodedKey == param) return decodedValue;_x000D_
      return null;_x000D_
   };_x000D_
_x000D_
   var comparisonResult = null;_x000D_
_x000D_
   if(search.indexOf('&') > -1) {_x000D_
      var params = search.split('&');_x000D_
      for(var i = 0; i < params.length; i++) {_x000D_
         comparisonResult = compareKeyValuePair(params[i]); _x000D_
         if(comparisonResult !== null) {_x000D_
            break;_x000D_
         }_x000D_
      }_x000D_
   } else {_x000D_
      comparisonResult = compareKeyValuePair(search);_x000D_
   }_x000D_
_x000D_
   return comparisonResult;_x000D_
}_x000D_
_x000D_
var parcelNumber = get_param('parcelNumber'); //abc_x000D_
var registryId  = get_param('registryId'); //abc_x000D_
var registrySectionId = get_param('registrySectionId'); //abc_x000D_
var apartmentNumber = get_param('apartmentNumber'); //abc_x000D_
_x000D_
        _x000D_
    </script>

_x000D_

then in the page i call the values like so:

_x000D_

 <td class="tinfodd"> <script  type="text/javascript">_x000D_
                                                    document.write(registrySectionId)_x000D_
                                                    </script></td>

_x000D_

Preventing scroll bars from being hidden for MacOS trackpad users in WebKit/Blink

Another good way of dealing with Lion's hidden scroll bars is to display a prompt to scroll down. It doesn't work with small scroll areas such as text fields but well with large scroll areas and keeps the overall style of the site. One site doing this is http://versusio.com, just check this example page and wait 1.5 seconds to see the prompt:

http://versusio.com/en/samsung-galaxy-nexus-32gb-vs-apple-iphone-4s-64gb

The implementation isn't hard but you have to take care, that you don't display the prompt when the user has already scrolled.

You need jQuery + Underscore and

$(window).scroll to check if the user already scrolled by himself,

_.delay() to trigger a delay before you display the prompt -- the prompt shouldn't be to obtrusive

$('#prompt_div').fadeIn('slow') to fade in your prompt and of course

$('#prompt_div').fadeOut('slow') to fade out when the user scrolled after he saw the prompt

In addition, you can bind Google Analytics events to track user's scrolling behavior.

Pure CSS animation visibility with delay

you can't animate every property,

here's a reference to which are the animatable properties

visibility is animatable while display isn't...

in your case you could also animate opacity or height depending of the kind of effect you want to render_

fiddle with opacity animation

Difference between using "chmod a+x" and "chmod 755"

chmod a+x modifies the argument's mode while chmod 755 sets it. Try both variants on something that has full or no permissions and you will notice the difference.

How to jump to top of browser page

_x000D_

// When the user scrolls down 20px from the top of the document, show the button_x000D_
window.onscroll = function() {scrollFunction()};_x000D_
_x000D_
function scrollFunction() {_x000D_
    if (document.body.scrollTop > 20 || document.documentElement.scrollTop > 20) {_x000D_
        document.getElementById("myBtn").style.display = "block";_x000D_
    } else {_x000D_
        document.getElementById("myBtn").style.display = "none";_x000D_
    }_x000D_
   _x000D_
}_x000D_
_x000D_
// When the user clicks on the button, scroll to the top of the document_x000D_
function topFunction() {_x000D_
 _x000D_
     $('html, body').animate({scrollTop:0}, 'slow');_x000D_
}

_x000D_

body {_x000D_
  font-family: Arial, Helvetica, sans-serif;_x000D_
  font-size: 20px;_x000D_
}_x000D_
_x000D_
#myBtn {_x000D_
  display: none;_x000D_
  position: fixed;_x000D_
  bottom: 20px;_x000D_
  right: 30px;_x000D_
  z-index: 99;_x000D_
  font-size: 18px;_x000D_
  border: none;_x000D_
  outline: none;_x000D_
  background-color: red;_x000D_
  color: white;_x000D_
  cursor: pointer;_x000D_
  padding: 15px;_x000D_
  border-radius: 4px;_x000D_
}_x000D_
_x000D_
#myBtn:hover {_x000D_
  background-color: #555;_x000D_
}

_x000D_

<script src="https://code.jquery.com/jquery-1.10.2.js"></script>_x000D_
_x000D_
<button onclick="topFunction()" id="myBtn" title="Go to top">Top</button>_x000D_
_x000D_
<div style="background-color:black;color:white;padding:30px">Scroll Down</div>_x000D_
<div style="background-color:lightgrey;padding:30px 30px 2500px">This example demonstrates how to create a "scroll to top" button that becomes visible when the user starts to scroll the page.</div>

_x000D_

Centering Bootstrap input fields

For bootstrap 4 use offset-4, see below.

<div class="mx-auto">        
        <form class="mx-auto" action="/campgrounds" method="POST">
            <div class="form-group row">                
                <div class="col-sm-4 offset-4">
                    <input class="form-control" type="text" name="name" placeholder="name">
                </div>
            </div>
            <div class="form-group row">               
                <div class="col-sm-4 offset-4">
                    <input class="form-control" type="text" name="picture" placeholder="image url">
                </div>
            </div>
            <div class="form-group row">
                    <div class="col-sm-4 offset-4">
                        <input class="form-control" type="text" name="description" placeholder="description">
                    </div>
                </div>
            <button class="btn btn-primary" type="submit">Submit!</button>
            <a class="btn btn-secondary"  href="/campgrounds">Go Back</a>
        </form>      
    </div>

How to check if cursor exists (open status)

Just Small change to what Gary W mentioned, adding 'SELECT':

IF (SELECT CURSOR_STATUS('global','myCursor')) >= -1
BEGIN
 DEALLOCATE myCursor
END

http://social.msdn.microsoft.com/Forums/en/sqlgetstarted/thread/eb268010-75fd-4c04-9fe8-0bc33ccf9357

How to embed PDF file with responsive width

<html>
<head>
<style type="text/css">
#wrapper{ width:100%; float:left; height:auto; border:1px solid #5694cf;}
</style>
</head>
<div id="wrapper">
<object data="http://partners.adobe.com/public/developer/en/acrobat/PDFOpenParameters.pdf" width="100%" height="100%">
<p>Your web browser doesn't have a PDF Plugin. Instead you can <a href="http://partners.adobe.com/public/developer/en/acrobat/PDFOpenParameters.pdf"> Click
here to download the PDF</a></p>
</object>
</div>
</html>

Where to put Gradle configuration (i.e. credentials) that should not be committed?

For those of you who are building on a MacOS, and don't like leaving your password in clear text on your machine, you can use the keychain tool to store the credentials and then inject it into the build. Credits go to Viktor Eriksson. https://pilloxa.gitlab.io/posts/safer-passwords-in-gradle/

Setting up Eclipse with JRE Path

You should specify where Eclipse should find your JDK in the file eclipse.ini. Specifically, the following parameter (note that it is 2 separate lines in the ini file):

-vm
C:\Java\JDK\1.8\bin\javaw.exe

or wherever your javaw.exe happens to be.

Note: The format of the ini file is very particular; make sure to consult https://wiki.eclipse.org/Eclipse.ini to ensure you get it exactly right

How to clear the Entry widget after a button is pressed in Tkinter?

real gets the value ent.get() which is just a string. It has no idea where it came from, and no way to affect the widget.

Instead of real.delete(), call .delete() on the entry widget itself:

def res(ent, real, secret):
    if secret == eval(real):
        showinfo(message='that is right!')
    ent.delete(0, END)

def guess():
    ...
    btn = Button(ge, text="Enter", command=lambda: res(ent, ent.get(), secret))

What is the question mark for in a Typescript parameter name

This is to make the variable of Optional type. Otherwise declared variables shows "undefined" if this variable is not used.

export interface ISearchResult {  
  title: string;  
  listTitle:string;
  entityName?: string,
  lookupName?:string,
  lookupId?:string  
}

Any way to clear python's IDLE window?

os.system('clear') works on linux. If you are running windows try os.system('CLS') instead.

You need to import os first like this:

import os

Return multiple values in JavaScript?

Other than returning an array or an object as others have recommended, you can also use a collector function (similar to the one found in The Little Schemer):

function a(collector){
  collector(12,13);
}

var x,y;
a(function(a,b){
  x=a;
  y=b;
});

I made a jsperf test to see which one of the three methods is faster. Array is fastest and collector is slowest.

http://jsperf.com/returning-multiple-values-2

Parse query string in JavaScript

Following on from my comment to the answer @bobby posted, here is the code I would use:

    function parseQuery(str)
        {
        if(typeof str != "string" || str.length == 0) return {};
        var s = str.split("&");
        var s_length = s.length;
        var bit, query = {}, first, second;
        for(var i = 0; i < s_length; i++)
            {
            bit = s[i].split("=");
            first = decodeURIComponent(bit[0]);
            if(first.length == 0) continue;
            second = decodeURIComponent(bit[1]);
            if(typeof query[first] == "undefined") query[first] = second;
            else if(query[first] instanceof Array) query[first].push(second);
            else query[first] = [query[first], second]; 
            }
        return query;
        }

This code takes in the querystring provided (as 'str') and returns an object. The string is split on all occurances of &, resulting in an array. the array is then travsersed and each item in it is split by "=". This results in sub arrays wherein the 0th element is the parameter and the 1st element is the value (or undefined if no = sign). These are mapped to object properties, so for example the string "hello=1&another=2&something" is turned into:

{
hello: "1",
another: "2",
something: undefined
}

In addition, this code notices repeating reoccurances such as "hello=1&hello=2" and converts the result into an array, eg:

{
hello: ["1", "2"]
}

You'll also notice it deals with cases in whih the = sign is not used. It also ignores if there is an equal sign straight after an & symbol.

A bit overkill for the original question, but a reusable solution if you ever need to work with querystrings in javascript :)

Where do I find the definition of size_t?

In minimalistic programs where a size_t definition was not loaded "by chance" in some include but I still need it in some context (for example to access std::vector<double>), then I use that context to extract the correct type. For example typedef std::vector<double>::size_type size_t.

(Surround with namespace {...} if necessary to make the scope limited.)

Transparent ARGB hex value

Adding to the other answers and doing nothing more of what @Maleta explained in a comment on https://stackoverflow.com/a/28481374/1626594, doing alpha*255 then round then to hex. Here's a quick converter http://jsfiddle.net/8ajxdLap/4/

_x000D_

function rgb2hex(rgb) {_x000D_
  var rgbm = rgb.match(/^rgba?[\s+]?\([\s+]?(\d+)[\s+]?,[\s+]?(\d+)[\s+]?,[\s+]?(\d+)[\s+]?,[\s+]?((?:[0-9]*[.])?[0-9]+)[\s+]?\)/i);_x000D_
  if (rgbm && rgbm.length === 5) {_x000D_
    return "#" +_x000D_
      ('0' + Math.round(parseFloat(rgbm[4], 10) * 255).toString(16).toUpperCase()).slice(-2) +_x000D_
      ("0" + parseInt(rgbm[1], 10).toString(16).toUpperCase()).slice(-2) +_x000D_
      ("0" + parseInt(rgbm[2], 10).toString(16).toUpperCase()).slice(-2) +_x000D_
      ("0" + parseInt(rgbm[3], 10).toString(16).toUpperCase()).slice(-2);_x000D_
  } else {_x000D_
    var rgbm = rgb.match(/^rgba?[\s+]?\([\s+]?(\d+)[\s+]?,[\s+]?(\d+)[\s+]?,[\s+]?(\d+)[\s+]?/i);_x000D_
    if (rgbm && rgbm.length === 4) {_x000D_
      return "#" +_x000D_
        ("0" + parseInt(rgbm[1], 10).toString(16).toUpperCase()).slice(-2) +_x000D_
        ("0" + parseInt(rgbm[2], 10).toString(16).toUpperCase()).slice(-2) +_x000D_
        ("0" + parseInt(rgbm[3], 10).toString(16).toUpperCase()).slice(-2);_x000D_
    } else {_x000D_
      return "cant parse that";_x000D_
    }_x000D_
  }_x000D_
}_x000D_
_x000D_
$('button').click(function() {_x000D_
  var hex = rgb2hex($('#in_tb').val());_x000D_
  $('#in_tb_result').html(hex);_x000D_
});

_x000D_

body {_x000D_
  padding: 20px;_x000D_
}

_x000D_

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
Convert RGB/RGBA to hex #RRGGBB/#AARRGGBB:<br>_x000D_
<br>_x000D_
<input id="in_tb" type="text" value="rgba(200, 90, 34, 0.75)"> <button>Convert</button><br>_x000D_
<br> Result: <span id="in_tb_result"></span>

_x000D_

Post request in Laravel - Error - 419 Sorry, your session/ 419 your page has expired

I also had a problem like this and I've discovered that the session files were locked for writing. So, I don't know if you are running your Laravel via stuff like vagrant or Docker, but I advise you to try to change the rights of the session directory (and files of course) (When you run Laravel in a VM you should change the rights locally and in the VM (like, when you share the files via NFS)

Like this:

chmod -R 777 storage/framework/sessions
chmod -R 777 storage/logs

I know, a 777 permission is the worst disaster that you can ever imagine. But they are handy for troubleshooting.

To be sure that I never forgot this I made a bash script. (Called it lalog, just because I wanted to clear the log files and set permissions)

Note: Make sure that you use this on the session directory. In config/session.php there is a files key declared with the location. In my case:

<?php
//...........
'files' => storage_path('framework/sessions'),
//...........

Location: /usr/bin/lalog (This is a file, not a directory)
Execute in shell as lalog

#!/bin/bash
rm -rf /home/username/Projects/x/storage/logs/laravel.log
echo "Laravel log removed"
touch /home/username/Projects/x/storage/logs/laravel.log
echo "Laravel log created"
chmod -R 777 /home/username/Projects/x/storage/
echo "CHMOD 777 on Storage dir"

Warning! This will allow write access for everyone, so be carefull with it! Also, maybe there is some usefull information in the log file of Laravel. (be sure to look in that log file before running my bash script)

Also, I know that it's already mentioned. But, be totally sure that you always

Allow cookies in the browser, so the token can be set in the cookies
Check if you are using the @csrf in your blade file

The form should be something like this

<form method="POST" action="{{ route('login') }}">
@csrf
.......
</form>

Disabling radio buttons with jQuery

Remove your "each" and just use:

$('input[name=ticketID]').attr("disabled",true);

That simple. It works

Add new line in text file with Windows batch file

DISCLAIMER: The below solution does not preserve trailing tabs.

If you know the exact number of lines in the text file, try the following method:

@ECHO OFF
SET origfile=original file
SET tempfile=temporary file
SET insertbefore=4
SET totallines=200
<%origfile% (FOR /L %%i IN (1,1,%totallines%) DO (
  SETLOCAL EnableDelayedExpansion
  SET /P L=
  IF %%i==%insertbefore% ECHO(
  ECHO(!L!
  ENDLOCAL
)
) >%tempfile%
COPY /Y %tempfile% %origfile% >NUL
DEL %tempfile%

The loop reads lines from the original file one by one and outputs them. The output is redirected to a temporary file. When a certain line is reached, an empty line is output before it.

After finishing, the original file is deleted and the temporary one gets assigned the original name.

UPDATE

If the number of lines is unknown beforehand, you can use the following method to obtain it:

FOR /F %%C IN ('FIND /C /V "" ^<%origfile%') DO SET totallines=%%C

(This line simply replaces the SET totallines=200 line in the above script.)

The method has one tiny flaw: if the file ends with an empty line, the result will be the actual number of lines minus one. If you need a workaround (or just want to play safe), you can use the method described in this answer.

How do I make a Mac Terminal pop-up/alert? Applescript?

Use osascript. For example:

osascript -e 'tell app "Finder" to display dialog "Hello World"'

Replacing “Finder” with whatever app you desire. Note if that app is backgrounded, the dialog will appear in the background too. To always show in the foreground, use “System Events” as the app:

osascript -e 'tell app "System Events" to display dialog "Hello World"'

Spring JPA and persistence.xml

This may be old, but if anyone has the same problem try changing unitname to just name in the PersistenceContext annotation:

From

@PersistenceContext(unitName="educationPU")

@PersistenceContext(name="educationPU")

How to check if a file exists in a shell script

Internally, the rm command must test for file existence anyway,
so why add another test? Just issue

rm filename

and it will be gone after that, whether it was there or not.
Use rm -f is you don't want any messages about non-existent files.

If you need to take some action if the file does NOT exist, then you must test for that yourself. Based on your example code, this is not the case in this instance.

Replace console output in Python

An easy solution is just writing "\r" before the string and not adding a newline; if the string never gets shorter this is sufficient...

sys.stdout.write("\rDoing thing %i" % i)
sys.stdout.flush()

Slightly more sophisticated is a progress bar... this is something I am using:

def startProgress(title):
    global progress_x
    sys.stdout.write(title + ": [" + "-"*40 + "]" + chr(8)*41)
    sys.stdout.flush()
    progress_x = 0

def progress(x):
    global progress_x
    x = int(x * 40 // 100)
    sys.stdout.write("#" * (x - progress_x))
    sys.stdout.flush()
    progress_x = x

def endProgress():
    sys.stdout.write("#" * (40 - progress_x) + "]\n")
    sys.stdout.flush()

You call startProgress passing the description of the operation, then progress(x) where x is the percentage and finally endProgress()

What is the preferred Bash shebang?

/bin/sh is usually a link to the system's default shell, which is often bash but on, e.g., Debian systems is the lighter weight dash. Either way, the original Bourne shell is sh, so if your script uses some bash (2nd generation, "Bourne Again sh") specific features ([[ ]] tests, arrays, various sugary things, etc.), then you should be more specific and use the later. This way, on systems where bash is not installed, your script won't run. I understand there may be an exciting trilogy of films about this evolution...but that could be hearsay.

Also note that when evoked as sh, bash to some extent behaves as POSIX standard sh (see also the GNU docs about this).

How to modify existing, unpushed commit messages?

If you have to change an old commit message over multiple branches (i.e., the commit with the erroneous message is present in multiple branches) you might want to use:

git filter-branch -f --msg-filter \
'sed "s/<old message>/<new message>/g"' -- --all

Git will create a temporary directory for rewriting and additionally backup old references in refs/original/.

-f will enforce the execution of the operation. This is necessary if the temporary directory is already present or if there are already references stored under refs/original. If that is not the case, you can drop this flag.
-- separates filter-branch options from revision options.
--all will make sure that all branches and tags are rewritten.

Due to the backup of your old references, you can easily go back to the state before executing the command.

Say, you want to recover your master and access it in branch old_master:

git checkout -b old_master refs/original/refs/heads/master

invalid use of non-static data member

In C++, nested classes are not connected to any instance of the outer class. If you want bar to access non-static members of foo, then bar needs to have access to an instance of foo. Maybe something like:

class bar {
  public:
    int getA(foo & f ) {return foo.a;}
};

Or maybe

class bar {
  private:
    foo & f;

  public:
    bar(foo & g)
    : f(g)
    {
    }

    int getA() { return f.a; }
};

In any case, you need to explicitly make sure you have access to an instance of foo.

sklearn error ValueError: Input contains NaN, infinity or a value too large for dtype('float64')

This is the check on which it fails:

https://github.com/scikit-learn/scikit-learn/blob/0.17.X/sklearn/utils/validation.py#L51

Which says

def _assert_all_finite(X):
    """Like assert_all_finite, but only for ndarray."""
    X = np.asanyarray(X)
    # First try an O(n) time, O(1) space solution for the common case that
    # everything is finite; fall back to O(n) space np.isfinite to prevent
    # false positives from overflow in sum method.
    if (X.dtype.char in np.typecodes['AllFloat'] and not np.isfinite(X.sum())
            and not np.isfinite(X).all()):
        raise ValueError("Input contains NaN, infinity"
                         " or a value too large for %r." % X.dtype)

So make sure that you have non NaN values in your input. And all those values are actually float values. None of the values should be Inf either.

Fatal error: Call to a member function query() on null

put this line in parent construct : $this->load->database();

function  __construct() {
    parent::__construct();
    $this->load->library('lib_name');
    $model=array('model_name');
    $this->load->model($model);
    $this->load->database();
}

this way.. it should work..

ASP.NET MVC Return Json Result?

It should be :

public async Task<ActionResult> GetSomeJsonData()
{
    var model = // ... get data or build model etc.

    return Json(new { Data = model }, JsonRequestBehavior.AllowGet); 
}

or more simply:

return Json(model, JsonRequestBehavior.AllowGet);

I did notice that you are calling GetResources() from another ActionResult which wont work. If you are looking to get JSON back, you should be calling GetResources() from ajax directly...

Select * from subquery

You can select every column from that sub-query by aliasing it and adding the alias before the *:

SELECT t.*, a+b AS total_sum
FROM
(
   SELECT SUM(column1) AS a, SUM(column2) AS b
   FROM table
) t

A simple algorithm for polygon intersection

This can be a huge approximation depending on your polygons, but here's one :

Compute the center of mass for each polygon.
Compute the min or max or average distance from each point of the polygon to the center of mass.
If C1C2 (where C1/2 is the center of the first/second polygon) >= D1 + D2 (where D1/2 is the distance you computed for first/second polygon) then the two polygons "intersect".

Though, this should be very efficient as any transformation to the polygon applies in the very same way to the center of mass and the center-node distances can be computed only once.

Base64 Decoding in iOS 7+

Swift 3+

let plainString = "foo"

Encoding

let plainData = plainString.data(using: .utf8)
let base64String = plainData?.base64EncodedString()
print(base64String!) // Zm9v

Decoding

if let decodedData = Data(base64Encoded: base64String!),
   let decodedString = String(data: decodedData, encoding: .utf8) {
  print(decodedString) // foo
}

Swift < 3

let plainString = "foo"

Encoding

let plainData = plainString.dataUsingEncoding(NSUTF8StringEncoding)
let base64String = plainData?.base64EncodedStringWithOptions(NSDataBase64EncodingOptions(rawValue: 0))
print(base64String!) // Zm9v

Decoding

let decodedData = NSData(base64EncodedString: base64String!, options: NSDataBase64DecodingOptions(rawValue: 0))
let decodedString = NSString(data: decodedData, encoding: NSUTF8StringEncoding)
print(decodedString) // foo

Objective-C

NSString *plainString = @"foo";

Encoding

NSData *plainData = [plainString dataUsingEncoding:NSUTF8StringEncoding];
NSString *base64String = [plainData base64EncodedStringWithOptions:0];
NSLog(@"%@", base64String); // Zm9v

Decoding

NSData *decodedData = [[NSData alloc] initWithBase64EncodedString:base64String options:0];
NSString *decodedString = [[NSString alloc] initWithData:decodedData encoding:NSUTF8StringEncoding];
NSLog(@"%@", decodedString); // foo

Resetting Select2 value in dropdown with reset button

According to the latest version (select2 3.4.5) documented here, it would be as simple as:

 $("#my_select").select2("val", "");

Prevent scrolling of parent element when inner element scroll position reaches top/bottom?

Using native element scroll properties with the delta value from the mousewheel plugin:

$elem.on('mousewheel', function (e, delta) {
    // Restricts mouse scrolling to the scrolling range of this element.
    if (
        this.scrollTop < 1 && delta > 0 ||
        (this.clientHeight + this.scrollTop) === this.scrollHeight && delta < 0
    ) {
        e.preventDefault();
    }
});

How can I convert a character to a integer in Python, and viceversa?

ord and chr

Android: remove notification from notification bar

Use the NotificationManager to cancel your notification. You only need to provide your notification id

mNotificationManager.cancel(YOUR_NOTIFICATION_ID);

also check this link See Developer Link

Is there a better alternative than this to 'switch on type'?

I such cases I usually end up with a list of predicates and actions. Something along these lines:

class Mine {
    static List<Func<object, bool>> predicates;
    static List<Action<object>> actions;

    static Mine() {
        AddAction<A>(o => o.Hop());
        AddAction<B>(o => o.Skip());
    }

    static void AddAction<T>(Action<T> action) {
        predicates.Add(o => o is T);
        actions.Add(o => action((T)o);
    }

    static void RunAction(object o) {
        for (int i=0; o < predicates.Count; i++) {
            if (predicates[i](o)) {
                actions[i](o);
                break;
            }
        }
    }

    void Foo(object o) {
        RunAction(o);
    }
}

angular.element vs document.getElementById or jQuery selector with spin (busy) control

You should inject $document in your controller, and use it instead of original document object.

var myElement = angular.element($document[0].querySelector('#MyID'))

If you don't need the jquery style element wrap, $document[0].querySelector('#MyID') will give you the DOM object.

How to write one new line in Bitbucket markdown?

I was facing the same issue in bitbucket, and this worked for me:

line1
##<2 white spaces><enter>
line2

Extract / Identify Tables from PDF python

I'd just like to add to the very helpful answer from Kurt Pfeifle - there is now a Python wrapper for Tabula, and this seems to work very well so far: https://github.com/chezou/tabula-py

This will convert your PDF table to a Pandas data frame. You can also set the area in x,y co-ordinates which is obviously very handy for irregular data.

Developing for Android in Eclipse: R.java not regenerating

This problem also happened to me when I was trying to build the Support4Demos from the SDK source code.

After fixing some problems in the resource files (for example, "fill_parent" renamed to "match_parent") I've discovered that the problem was in the manifest file: I unchecked by trial and error the "Define an <application> tag in the AndroidManifest.xml" checkbox, saved the changes and the R.java magically reappeared. Then I re-checked the box, saved the file, and the R.java was regenerated again.

I guess I came across an Eclipse shortcoming.

Error inflating class android.support.v7.widget.Toolbar?

To fix this problem . first you must add latestandroid-support-v7-appcompat from the \sdk\extras\android\support

Close the main project.
Remove the android-support-v7-appcompat .
Restart the Eclipse.
Add the android-support-v7-appcompat .
Clean,To build the project.
Then open the main project and build all the projects.
The error still remains. Restart eclipse. That's it.

That works for me and I will strongly recommend you to use Android Studio.

Remove querystring from URL

var path = "path/to/myfile.png?foo=bar#hash";

console.log(
    path.replace(/(\?.*)|(#.*)/g, "")
);

Convert a CERT/PEM certificate to a PFX certificate

openssl pkcs12 -inkey bob_key.pem -in bob_cert.cert -export -out bob_pfx.pfx

How can I view the Git history in Visual Studio Code?

GitLens has a nice Git history browser. Install GitLens from the extensions marketplace, and then run "Show GitLens Explorer" from the command palette.

Why can't Python find shared objects that are in directories in sys.path?

You can also set LD_RUN_PATH to /usr/local/lib in your user environment when you compile pycurl in the first place. This will embed /usr/local/lib in the RPATH attribute of the C extension module .so so that it automatically knows where to find the library at run time without having to have LD_LIBRARY_PATH set at run time.

Commands out of sync; you can't run this command now

The problem is the MySQL client C library, which most MySQL APIs are built on. The problem is that the C library doesn't support simultaneous execution of queries, so all APIs built on top of that also do not. Even if you use unbuffered queries. This is one reason why the asynchronous MySQL API was written. It communicates directly with the MySQL server using TCP and the wire-protocol does support simultaneous queries.

Your solution is to either modify the algorithm so you don't need to have both in progress at once, or change them to use buffered queries, which is probably one of the original reasons for their existence in the C library (the other is to provide a kind of cursor).

How do I download code using SVN/Tortoise from Google Code?

Create a folder where you want to keep the code, and right click on it. Choose SVN Checkout... and type http://wittytwitter.googlecode.com/svn/trunk into the URL of repository field.

You can also run

svn checkout http://wittytwitter.googlecode.com/svn/trunk

from the command line in the folder you want to keep it (svn.exe has to be in your path, of course).

How to get a path to the desktop for current user in C#?

string path = Environment.GetFolderPath(Environment.SpecialFolder.Desktop);

HTML 5 Favicon - Support?

The answers provided (at the time of this post) are link only answers so I thought I would summarize the links into an answer and what I will be using.

When working to create Cross Browser Favicons (including touch icons) there are several things to consider.

The first (of course) is Internet Explorer. IE does not support PNG favicons until version 11. So our first line is a conditional comment for favicons in IE 9 and below:

<!--[if IE]><link rel="shortcut icon" href="path/to/favicon.ico"><![endif]-->

To cover the uses of the icon create it at 32x32 pixels. Notice the rel="shortcut icon" for IE to recognize the icon it needs the word shortcut which is not standard. Also we wrap the .ico favicon in a IE conditional comment because Chrome and Safari will use the .ico file if it is present, despite other options available, not what we would like.

The above covers IE up to IE 9. IE 11 accepts PNG favicons, however, IE 10 does not. Also IE 10 does not read conditional comments thus IE 10 won't show a favicon. With IE 11 and Edge available I don't see IE 10 in widespread use, so I ignore this browser.

For the rest of the browsers we are going to use the standard way to cite a favicon:

<link rel="icon" href="path/to/favicon.png">

This icon should be 196x196 pixels in size to cover all devices that may use this icon.

To cover touch icons on mobile devices we are going to use Apple's proprietary way to cite a touch icon:

<link rel="apple-touch-icon-precomposed" href="apple-touch-icon-precomposed.png">

Using rel="apple-touch-icon-precomposed" will not apply the reflective shine when bookmarked on iOS. To have iOS apply the shine use rel="apple-touch-icon". This icon should be sized to 180x180 pixels as that is the current size recommend by Apple for the latest iPhones and iPads. I have read Blackberry will also use rel="apple-touch-icon-precomposed".

As a note: Chrome for Android states:

The apple-touch-* are deprecated, and will be supported only for a short time. (Written as of beta for m31 of Chrome).

Custom Tiles for IE 11+ on Windows 8.1+

IE 11+ on Windows 8.1+ does offer a way to create pinned tiles for your site.

Microsoft recommends creating a few tiles at the following size:

Small: 128 x 128

Medium: 270 x 270

Wide: 558 x 270

Large: 558 x 558

These should be transparent images as we will define a color background next.

Once these images are created you should create an xml file called browserconfig.xml with the following code:

<?xml version="1.0" encoding="utf-8"?>
<browserconfig>
  <msapplication>
    <tile>
      <square70x70logo src="images/smalltile.png"/>
      <square150x150logo src="images/mediumtile.png"/>
      <wide310x150logo src="images/widetile.png"/>
      <square310x310logo src="images/largetile.png"/>
      <TileColor>#009900</TileColor>
    </tile>
  </msapplication>
</browserconfig>

Save this xml file in the root of your site. When a site is pinned IE will look for this file. If you want to name the xml file something different or have it in a different location add this meta tag to the head:

<meta name="msapplication-config" content="path-to-browserconfig/custom-name.xml" />

For additional information on IE 11+ custom tiles and using the XML file visit Microsoft's website.

Putting it all together:

To put it all together the above code would look like this:

<!-- For IE 9 and below. ICO should be 32x32 pixels in size -->
<!--[if IE]><link rel="shortcut icon" href="path/to/favicon.ico"><![endif]-->

<!-- Touch Icons - iOS and Android 2.1+ 180x180 pixels in size. --> 
<link rel="apple-touch-icon-precomposed" href="apple-touch-icon-precomposed.png">

<!-- Firefox, Chrome, Safari, IE 11+ and Opera. 196x196 pixels in size. -->
<link rel="icon" href="path/to/favicon.png">

Windows Phone Live Tiles

If a user is using a Windows Phone they can pin a website to the start screen of their phone. Unfortunately, when they do this it displays a screenshot of your phone, not a favicon (not even the MS specific code referenced above). To make a "Live Tile" for Windows Phone Users for your website one must use the following code:

Here are detailed instructions from Microsoft but here is a synopsis:

Step 1

Create a square image for your website, to support hi-res screens create it at 768x768 pixels in size.

Step 2

Add a hidden overlay of this image. Here is example code from Microsoft:

<div id="TileOverlay" onclick="ToggleTileOverlay()" style='background-color: Highlight; height: 100%; width: 100%; top: 0px; left: 0px; position: fixed; color: black; visibility: hidden'>
  <img src="customtile.png" width="320" height="320" />
  <div style='margin-top: 40px'>
     Add text/graphic asking user to pin to start using the menu...
  </div>
</div>

Step 3

You then can add thew following line to add a pin to start link:

<a href="javascript:ToggleTileOverlay()">Pin this site to your start screen</a>

Microsoft recommends that you detect windows phone and only show that link to those users since it won't work for other users.

Step 4

Next you add some JS to toggle the overlay visibility

<script>
function ToggleTileOverlay() {
 var newVisibility =     (document.getElementById('TileOverlay').style.visibility == 'visible') ? 'hidden' : 'visible';
 document.getElementById('TileOverlay').style.visibility =    newVisibility;
}
</script>

Note on Sizes

I am using one size as every browser will scale down the image as necessary. I could add more HTML to specify multiple sizes if desired for those with a lower bandwidth but I am already compressing the PNG files heavily using TinyPNG and I find this unnecessary for my purposes. Also, according to philippe_b's answer Chrome and Firefox have bugs that cause the browser to load all sizes of icons. Using one large icon may be better than multiple smaller ones because of this.

Further Reading

For those who would like more details see the links below:

Wikipedia Article on Favicons
The Icon Handbook
Understand the Favicon by Jonathan T. Neal
rel="shortcut icon" considered harmful by Mathias Bynens
Everything you always wanted to know about touch icons by Mathias Bynens

Django optional url parameters

Even simpler is to use:

(?P<project_id>\w+|)

The "(a|b)" means a or b, so in your case it would be one or more word characters (\w+) or nothing.

So it would look like:

url(
    r'^project_config/(?P<product>\w+)/(?P<project_id>\w+|)/$',
    'tool.views.ProjectConfig',
    name='project_config'
),

Get type name without full namespace

Try this to get type parameters for generic types:

public static string CSharpName(this Type type)
{
    var sb = new StringBuilder();
    var name = type.Name;
    if (!type.IsGenericType) return name;
    sb.Append(name.Substring(0, name.IndexOf('`')));
    sb.Append("<");
    sb.Append(string.Join(", ", type.GetGenericArguments()
                                    .Select(t => t.CSharpName())));
    sb.Append(">");
    return sb.ToString();
}

Maybe not the best solution (due to the recursion), but it works. Outputs look like:

Dictionary<String, Object>

JavaScript: Difference between .forEach() and .map()

forEach() :

return value : undefined

originalArray : not modified after the method call

newArray is not created after the end of method call.

map() :

return value : new Array populated with the results of calling a provided function on every element in the calling array

originalArray : not modified after the method call

newArray is created after the end of method call.

Since map builds a new array, using it when you aren't using the
returned array is an anti-pattern; use forEach or for-of instead.

Google Chrome Full Black Screen

All google chrome extensios crashed and then black screen on the window for my case.. tried uninstall and installed.. but no use..
Finally I restarted the computer.. It worked for me.. And i disabled adblock on google homepage. works pretty cool.

JavaScript set object key by variable

In ES6, you can do like this.

var key = "name";
var person = {[key]:"John"}; // same as var person = {"name" : "John"}
console.log(person); // should print  Object { name="John"}

_x000D_

    var key = "name";_x000D_
    var person = {[key]:"John"};_x000D_
    console.log(person); // should print  Object { name="John"}

_x000D_

Its called Computed Property Names, its implemented using bracket notation( square brackets) []

Example: { [variableName] : someValue }

Starting with ECMAScript 2015, the object initializer syntax also supports computed property names. That allows you to put an expression in brackets [], that will be computed and used as the property name.

For ES5, try something like this

var yourObject = {};

yourObject[yourKey] = "yourValue";

console.log(yourObject );

example:

var person = {};
var key = "name";

person[key] /* this is same as person.name */ = "John";

console.log(person); // should print  Object { name="John"}

_x000D_

    var person = {};_x000D_
    var key = "name";_x000D_
    _x000D_
    person[key] /* this is same as person.name */ = "John";_x000D_
    _x000D_
    console.log(person); // should print  Object { name="John"}

_x000D_

Correct way to integrate jQuery plugins in AngularJS

Yes, you are correct. If you are using a jQuery plugin, do not put the code in the controller. Instead create a directive and put the code that you would normally have inside the link function of the directive.

There are a couple of points in the documentation that you could take a look at. You can find them here:
Common Pitfalls

Using controllers correctly

Ensure that when you are referencing the script in your view, you refer it last - after the angularjs library, controllers, services and filters are referenced.

EDIT: Rather than using $(element), you can make use of angular.element(element) when using AngularJS with jQuery

ADB not responding. You can wait more,or kill "adb.exe" process manually and click 'Restart'

If you need to kill all adb processes on windows with one command, you can do it as follows:

taskkill /F /IM adb*

What does PermGen actually stand for?

Permgen stands for Permanent Generation. It is one of the JVM memory areas. It's part of Heap with fixed size by using a flag called MaxPermSize.

Why the name "PermGen" ?

This permgen was named in early days of Java. Permgen mains keeps all the meta data of loaded classes. But the problem is that once a class is loaded it'll remain in the JVM till JVM shutdown. So name permgen is opt for that. But later, dynamic loading of classes came into picture but name was not changed. But with Java 8, they have addressed that issue as well. Now permagen was renamed as MetaSpace with dynamic memory size.

Error : java.lang.NoSuchMethodError: org.objectweb.asm.ClassWriter.<init>(I)V

There is a lot of incompatibility between different versions of cglib and lots of poor advice that can be googled on this subject (use ancient versions of cglib-nodeb, etc). After wrestling with this nonsense for 3 days with an ancient version of Spring (2.5.6)I have discovered:

if Spring is throwing exceptions about NoSuchMethodError based on Enhancer from cglib missing setInterceptDuringConstruction(boolean), check your dependencies in maven (Dependency Hierarchy tab should list all the versions of cglib your project is polluted by). You probably have a dependency that is bringing in a pre-2.2 version of cglib, which Spring Cglib2AopProxy will grab Enhancer from to do the proxying. Add 2.2+ version to your dependencies but make sure to put in exclusions for these other versions. If you don't it will just keep blowing up.
Make sure you have a high enough version of cglib in the current project's maven dependencies but beware of picking too high a version because then you'll get IncompatibleClassChangeError(s) instead.
Verify that your pom changes have made it into the project correctly by doing a maven update on the project in question and then looking at Project > preferences > Java Build Path > Libraries > Maven Dependencies. If you see the wrong cglib versions in there, time to edit the pom again.

How to get DateTime.Now() in YYYY-MM-DDThh:mm:ssTZD format using C#

Try this:

DateTime.Now.ToString("yyyy-MM-ddThh:mm:sszzz");

zzz is the timezone offset.

Find Locked Table in SQL Server

You can use sp_lock (and sp_lock2), but in SQL Server 2005 onwards this is being deprecated in favour of querying sys.dm_tran_locks:

select  
    object_name(p.object_id) as TableName, 
    resource_type, resource_description
from
    sys.dm_tran_locks l
    join sys.partitions p on l.resource_associated_entity_id = p.hobt_id

Short circuit Array.forEach like calling break

There is now an even better way to do this in ECMAScript2015 (aka ES6) using the new for of loop. For example, this code does not print the array elements after the number 5:

_x000D_

let arr = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];_x000D_
for (let el of arr) {_x000D_
  console.log(el);_x000D_
  if (el === 5) {_x000D_
    break;_x000D_
  }_x000D_
}

_x000D_

From the docs:

Both for...in and for...of statements iterate over something. The main difference between them is in what they iterate over. The for...in statement iterates over the enumerable properties of an object, in original insertion order. The for...of statement iterates over data that iterable object defines to be iterated over.

Need the index in the iteration? You can use Array.entries():

for (const [index, el] of arr.entries()) {
  if ( index === 5 ) break;
}

How/when to use ng-click to call a route?

You can use:

<a ng-href="#/about">About</a>

If you want some dynamic variable inside href you can do like this way:

<a ng-href="{{link + 123}}">Link to 123</a>

Where link is Angular scope variable.

Vue.js redirection to another page

<div id="app">
   <a :href="path" />Link</a>
</div>

<script>
      new Vue({
        el: '#app',
        data: {
          path: 'https://www.google.com/'
        }
      });
</script> enter code here

How to display the string html contents into webbrowser control?

Simple solution, I've tested is

webBrowser1.Refresh();
var str = "<html><head></head><body>" + sender.ToString() + "</body></html>";
webBrowser1.DocumentText = str;

How to block calls in android

It is possible and you don't need to code it on your own.

Just set the ringer volume to zero and vibration to none if incomingNumber equals an empty string. Thats it ...

Its just done for you with the application Nostalk from Android Market. Just give it a try ...

Centering elements in jQuery Mobile

You can make the button an anchor element, and put it in a paragraph with the attribute:

align='center'

Worked for me.

Get absolute path of initially run script

This is what I use and it works in Linux environments. I don't think this would work on a Windows machine...

//define canonicalized absolute pathname for the script
if(substr($_SERVER['SCRIPT_NAME'],0,1) == DIRECTORY_SEPARATOR) {
    //does the script name start with the directory separator?
    //if so, the path is defined from root; may have symbolic references so still use realpath()
    $script = realpath($_SERVER['SCRIPT_NAME']);
} else {
    //otherwise prefix script name with the current working directory
    //and use realpath() to resolve symbolic references
    $script = realpath(getcwd() . DIRECTORY_SEPARATOR . $_SERVER['SCRIPT_NAME']);
}

Get difference between two lists

single line version of arulmr solution

def diff(listA, listB):
    return set(listA) - set(listB) | set(listA) -set(listB)

How to restart a single container with docker-compose

It is very simple: Use the command:

docker-compose restart worker

You can set the time to wait for stop before killing the container (in seconds)

docker-compose restart -t 30 worker

Note that this will restart the container but without rebuilding it. If you want to apply your changes and then restart, take a look at the other answers.

Read file from line 2 or skip header row

with open(fname) as f:
    next(f)
    for line in f:
        #do something

How do I center align horizontal <UL> menu?

Generally speaking the way to center a black level element (like a <ul>) is using the margin:auto; property.

To align text and inline level elements within a block level element use text-align:center;. So all together something like...

ul {
    margin:auto;
}
ul li {
    text-align:center;
    list-style-position:inside; /* so that the bullet points are also centered */
}
ul li div {
    display:inline; /* so that the bullet points aren't above the content */
}

... should work.

The fringe case is Internet Explorer6... or even other IEs when not using a <!DOCTYPE>. IE6 incorrectly aligns block level elemnts using text-align. So if you're looking to support IE6 (or not using a <!DOCTYPE>) your full solution is...

div.topmenu-design {
    text-align:center;
}
div.topmenu-design ul {
    margin:auto;
}
div.topmenu-design ul li {
    text-align:center;
    list-style-position:inside; /* so that the bullet points are also centered */
}
div.topmenu-design ul li div {
    display:inline; /* so that the bullet points aren't above the content */
}

As a footnote, I think id="topmenu firstlevel" is invalid as an id attribute can't contain spaces... ? Indeed the w3c recommendation defines the id attribute as a 'name' type...

ID and NAME tokens must begin with a letter ([A-Za-z]) and may be followed by any number of letters, digits ([0-9]), hyphens ("-"), underscores ("_"), colons (":"), and periods (".").

Fill drop down list on selection of another drop down list

enter image description here

Model:

namespace MvcApplicationrazor.Models
{
    public class CountryModel
    {
        public List<State> StateModel { get; set; }
        public SelectList FilteredCity { get; set; }
    }
    public class State
    {
        public int Id { get; set; }
        public string StateName { get; set; }
    }
    public class City
    {
        public int Id { get; set; }
        public int StateId { get; set; }
        public string CityName { get; set; }
    }
}

Controller:

public ActionResult Index()
        {
            CountryModel objcountrymodel = new CountryModel();
            objcountrymodel.StateModel = new List<State>();
            objcountrymodel.StateModel = GetAllState();
            return View(objcountrymodel);
        }


        //Action result for ajax call
        [HttpPost]
        public ActionResult GetCityByStateId(int stateid)
        {
            List<City> objcity = new List<City>();
            objcity = GetAllCity().Where(m => m.StateId == stateid).ToList();
            SelectList obgcity = new SelectList(objcity, "Id", "CityName", 0);
            return Json(obgcity);
        }
        // Collection for state
        public List<State> GetAllState()
        {
            List<State> objstate = new List<State>();
            objstate.Add(new State { Id = 0, StateName = "Select State" });
            objstate.Add(new State { Id = 1, StateName = "State 1" });
            objstate.Add(new State { Id = 2, StateName = "State 2" });
            objstate.Add(new State { Id = 3, StateName = "State 3" });
            objstate.Add(new State { Id = 4, StateName = "State 4" });
            return objstate;
        }
        //collection for city
        public List<City> GetAllCity()
        {
            List<City> objcity = new List<City>();
            objcity.Add(new City { Id = 1, StateId = 1, CityName = "City1-1" });
            objcity.Add(new City { Id = 2, StateId = 2, CityName = "City2-1" });
            objcity.Add(new City { Id = 3, StateId = 4, CityName = "City4-1" });
            objcity.Add(new City { Id = 4, StateId = 1, CityName = "City1-2" });
            objcity.Add(new City { Id = 5, StateId = 1, CityName = "City1-3" });
            objcity.Add(new City { Id = 6, StateId = 4, CityName = "City4-2" });
            return objcity;
        }

View:

@model MvcApplicationrazor.Models.CountryModel
@{
    ViewBag.Title = "Index";
    Layout = "~/Views/Shared/_Layout.cshtml";
}

<script src="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8/jquery-ui.min.js"></script>
<script language="javascript" type="text/javascript">
    function GetCity(_stateId) {
        var procemessage = "<option value='0'> Please wait...</option>";
        $("#ddlcity").html(procemessage).show();
        var url = "/Test/GetCityByStateId/";

        $.ajax({
            url: url,
            data: { stateid: _stateId },
            cache: false,
            type: "POST",
            success: function (data) {
                var markup = "<option value='0'>Select City</option>";
                for (var x = 0; x < data.length; x++) {
                    markup += "<option value=" + data[x].Value + ">" + data[x].Text + "</option>";
                }
                $("#ddlcity").html(markup).show();
            },
            error: function (reponse) {
                alert("error : " + reponse);
            }
        });

    }
</script>
<h4>
 MVC Cascading Dropdown List Using Jquery</h4>
@using (Html.BeginForm())
{
    @Html.DropDownListFor(m => m.StateModel, new SelectList(Model.StateModel, "Id", "StateName"), new { @id = "ddlstate", @style = "width:200px;", @onchange = "javascript:GetCity(this.value);" })
    <br />
    <br />
    <select id="ddlcity" name="ddlcity" style="width: 200px">

    </select>

    <br /><br />
  }

Laravel orderBy on a relationship

It is possible to extend the relation with query functions:

<?php
public function comments()
{
    return $this->hasMany('Comment')->orderBy('column');
}

[edit after comment]

<?php
class User
{
    public function comments()
    {
        return $this->hasMany('Comment');
    }
}

class Controller
{
    public function index()
    {
        $column = Input::get('orderBy', 'defaultColumn');
        $comments = User::find(1)->comments()->orderBy($column)->get();

        // use $comments in the template
    }
}

default User model + simple Controller example; when getting the list of comments, just apply the orderBy() based on Input::get(). (be sure to do some input-checking ;) )

Placing a textview on top of imageview in android

Try this:

<RelativeLayout 
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/rel_layout"
android:layout_width="match_parent"
android:layout_height="match_parent" >

<ImageView
    android:id="@+id/ImageView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:src=//source of image />

<TextView
    android:id="@+id/ImageViewText"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignLeft="@id/ImageView"
    android:layout_alignTop="@id/ImageView"
    android:layout_alignRight="@id/ImageView"
    android:layout_alignBottom="@id/ImageView"
    android:text=//u r text here
    android:gravity="center"
    />

Hope this could help you.

Any way to declare an array in-line?

Another way to do that, if you want the result as a List inline, you can do it like this:

Arrays.asList(new String[] { "String1", "string2" });

Setting property 'source' to 'org.eclipse.jst.jee.server:JSFTut' did not find a matching property

I thought I'd add that for Tomcat 7.x, <Context> is not in the server.xml, but in the context.xml. Removing and re-adding the project did not seem to help my similar issue, which was a web.xml issue, which I found out by checking the context.xml which had this line in the <Context> section:

<WatchedResource>WEB-INF/web.xml</WatchedResource>

The solution in WARNING: Setting property 'source' to 'org.eclipse.jst.jee.server:appname' did not find a matching property brought me closer to my answer, as the change of publishing into a separate XML did resolve the error reported above for me, but unfortunately it generated a second error that I'm still investigating.

WARNING: [SetContextPropertiesRule]{Context} Setting property 'source' to 'org.eclipse.jst.jee.server:myproject' did not find a matching property.

Numpy - add row to array

You can also do this:

newrow = [1,2,3]
A = numpy.concatenate((A,newrow))

Server returned HTTP response code: 401 for URL: https

Try This. You need pass the authentication to let the server know its a valid user. You need to import these two packages and has to include a jersy jar. If you dont want to include jersy jar then import this package

import sun.misc.BASE64Encoder;

import com.sun.jersey.core.util.Base64;
import sun.net.www.protocol.http.HttpURLConnection;

and then,

String encodedAuthorizedUser = getAuthantication("username", "password");
URL url = new URL("Your Valid Jira URL");
HttpURLConnection httpCon = (HttpURLConnection) url.openConnection();
httpCon.setRequestProperty ("Authorization", "Basic " + encodedAuthorizedUser );

 public String getAuthantication(String username, String password) {
   String auth = new String(Base64.encode(username + ":" + password));
   return auth;
 }

Angular-cli from css to scss

Open angular.json file

1.change from

"schematics": {}

"schematics": {
           "@schematics/angular:component": {
                   "styleext": "scss"       
             }  
  }

change from (at two places)

"src/styles.css"

"src/styles.scss"

then check and rename all .css files and update component.ts files styleUrls from .css to .scss

Work with a time span in Javascript

You can use momentjs duration object

Example:

const diff = moment.duration(Date.now() - new Date(2010, 1, 1))
console.log(`${diff.years()} years ${diff.months()} months ${diff.days()} days ${diff.hours()} hours ${diff.minutes()} minutes and ${diff.seconds()} seconds`)

onclick="javascript:history.go(-1)" not working in Chrome

javascript:history.go(-1);

was used in the older browser.IE6. For other browser compatibility try

window.history.go(-1);

where -1 represent the number of pages you want to go back (-1,-2...etc) and return false is required to prevent default event.

For example :

<a href="#" onclick="window.history.go(-1); return false;"> Link </a>

psql: FATAL: Ident authentication failed for user "postgres"

Out of all the answers above nothing worked for me. I had to manually change the users password in the database and it suddenly worked.

psql -U postgres -d postgres -c "alter user produser with password 'produser';"

I used the following settings:

pg_hba.conf

local   all             all                                     peer
# IPv4 local connections:
host    all             all             127.0.0.1/32            password  
# IPv6 local connections:
host    all             all             ::1/128                 password

Connection is successful finally for the following command:

psql -U produser -d dbname -h localhost -W

Finding the mode of a list

If you want a clear approach, useful for classroom and only using lists and dictionaries by comprehension, you can do:

def mode(my_list):
    # Form a new list with the unique elements
    unique_list = sorted(list(set(my_list)))
    # Create a comprehensive dictionary with the uniques and their count
    appearance = {a:my_list.count(a) for a in unique_list} 
    # Calculate max number of appearances
    max_app = max(appearance.values())
    # Return the elements of the dictionary that appear that # of times
    return {k: v for k, v in appearance.items() if v == max_app}

Replace CRLF using powershell

This is a state-of-the-union answer as of Windows PowerShell v5.1 / PowerShell Core v6.2.0:

Andrew Savinykh's ill-fated answer, despite being the accepted one, is, as of this writing, fundamentally flawed (I do hope it gets fixed - there's enough information in the comments - and in the edit history - to do so).
Ansgar Wiecher's helpful answer works well, but requires direct use of the .NET Framework (and reads the entire file into memory, though that could be changed). Direct use of the .NET Framework is not a problem per se, but is harder to master for novices and hard to remember in general.
A future version of PowerShell Core will have a
Convert-TextFile cmdlet with a -LineEnding parameter to allow in-place updating of text files with a specific newline style, as being discussed on GitHub.

In PSv5+, PowerShell-native solutions are now possible, because Set-Content now supports the -NoNewline switch, which prevents undesired appending of a platform-native newline^[1] :

# Convert CRLFs to LFs only.
# Note:
#  * (...) around Get-Content ensures that $file is read *in full*
#    up front, so that it is possible to write back the transformed content
#    to the same file.
#  * + "`n" ensures that the file has a *trailing LF*, which Unix platforms
#     expect.
((Get-Content $file) -join "`n") + "`n" | Set-Content -NoNewline $file

The above relies on Get-Content's ability to read a text file that uses any combination of CR-only, CRLF, and LF-only newlines line by line.

Caveats:

You need to specify the output encoding to match the input file's in order to recreate it with the same encoding. The command above does NOT specify an output encoding; to do so, use -Encoding; without -Encoding:
- In Windows PowerShell, you'll get "ANSI" encoding, your system's single-byte, 8-bit legacy encoding, such as Windows-1252 on US-English systems.
- In PowerShell Core, you'll get UTF-8 encoding without a BOM.
The input file's content as well as its transformed copy must fit into memory as a whole, which can be problematic with large input files.
There's a risk of file corruption, if the process of writing back to the input file gets interrupted.

^{[1] In fact, if there are multiple strings to write, -NoNewline also doesn't place a newline between them; in the case at hand, however, this is irrelevant, because only one string is written.}

How to set the "Content-Type ... charset" in the request header using a HTML link

This is not possible from HTML on. The closest what you can get is the accept-charset attribute of the <form>. Only MSIE browser adheres that, but even then it is doing it wrong (e.g. CP1252 is actually been used when it says that it has sent ISO-8859-1). Other browsers are fully ignoring it and they are using the charset as specified in the Content-Type header of the response. Setting the character encoding right is basically fully the responsiblity of the server side. The client side should just send it back in the same charset as the server has sent the response in.

To the point, you should really configure the character encoding stuff entirely from the server side on. To overcome the inability to edit URIEncoding attribute, someone here on SO wrote a (complex) filter: Detect the URI encoding automatically in Tomcat. You may find it useful as well (note: I haven't tested it).

Update: Noted should be that the meta tag as given in your question is ignored when the content is been transferred over HTTP. Instead, the HTTP response Content-Type header will be used to determine the content type and character encoding. You can determine the HTTP header with for example Firebug, in the Net panel.

alt text

Comparing two NumPy arrays for equality, element-wise

(A==B).all()

test if all values of array (A==B) are True.

Note: maybe you also want to test A and B shape, such as A.shape == B.shape

Special cases and alternatives (from dbaupp's answer and yoavram's comment)

It should be noted that:

this solution can have a strange behavior in a particular case: if either A or B is empty and the other one contains a single element, then it return True. For some reason, the comparison A==B returns an empty array, for which the all operator returns True.
Another risk is if A and B don't have the same shape and aren't broadcastable, then this approach will raise an error.

In conclusion, if you have a doubt about A and B shape or simply want to be safe: use one of the specialized functions:

np.array_equal(A,B)  # test if same shape, same elements values
np.array_equiv(A,B)  # test if broadcastable shape, same elements values
np.allclose(A,B,...) # test if same shape, elements have close enough values

Launching an application (.EXE) from C#?

System.Diagnostics.Process.Start( @"C:\Windows\System32\Notepad.exe" );

Calculating Pearson correlation and significance in Python

Pearson coefficient calculation using pandas in python: I would suggest trying this approach since your data contains lists. It will be easy to interact with your data and manipulate it from the console since you can visualise your data structure and update it as you wish. You can also export the data set and save it and add new data out of the python console for later analysis. This code is simpler and contains less lines of code. I am assuming you need a few quick lines of code to screen your data for further analysis

Example:

data = {'list 1':[2,4,6,8],'list 2':[4,16,36,64]}

import pandas as pd #To Convert your lists to pandas data frames convert your lists into pandas dataframes

df = pd.DataFrame(data, columns = ['list 1','list 2'])

from scipy import stats # For in-built method to get PCC

pearson_coef, p_value = stats.pearsonr(df["list 1"], df["list 2"]) #define the columns to perform calculations on
print("Pearson Correlation Coefficient: ", pearson_coef, "and a P-value of:", p_value) # Results

However, you did not post your data for me to see the size of the data set or the transformations that might be needed before the analysis.

Action bar navigation modes are deprecated in Android L

I found these tutorials helpful while putting together an action bar (now the 'tool bar' - argh) that supports sliding tabs with Material Design:

https://www.youtube.com/watch?v=Fl0xMuo10yA

http://www.exoguru.com/android/material-design/navigation/android-sliding-tabs-with-material-design.html

You sort of have to synthesize these resources to match your particular situation. For example, you may not want to manually create the tabs in the same style that the exoguru.com tutorial did.

height style property doesn't work in div elements

Position absolute fixes it for me. I suggest also adding a semi-colon if you haven't already.

.container {
    width: 22.5%;
    size: 22.5% 22.5%;
    margin-top: 0%;
    border-radius: 10px;
    background-color: floralwhite;
    display:inline-block;
    min-height: 20%;
    position: absolute;
    height: 50%;
}

How to Execute SQL Server Stored Procedure in SQL Developer?

You need to add a ',' between the paramValue1 and paramValue2. You missed it.

EXEC proc_name 'paramValue1','paramValue2'

Why is this HTTP request not working on AWS Lambda?

Yeah, awendt answer is perfect. I'll just show my working code... I had the context.succeed('Blah'); line right after the reqPost.end(); line. Moving it to where I show below solved everything.

console.log('GW1');

var https = require('https');

exports.handler = function(event, context) {

    var body='';
    var jsonObject = JSON.stringify(event);

    // the post options
    var optionspost = {
        host: 'the_host',
        path: '/the_path',
        method: 'POST',
        headers: {
            'Content-Type': 'application/json',
        }
    };

    var reqPost = https.request(optionspost, function(res) {
        console.log("statusCode: ", res.statusCode);
        res.on('data', function (chunk) {
            body += chunk;
        });
        context.succeed('Blah');
    });

    reqPost.write(jsonObject);
    reqPost.end();
};

Angular 2 'component' is not a known element

This convoluted framework is driving me nuts. Given that you defined the custom component in the the template of another component part of the SAME module, then you do not need to use exports in the module (e.g. app.module.ts). You simply need to specify the declaration in the @NgModule directive of the aforementioned module:

// app.module.ts

import { JsonInputComponent } from './json-input/json-input.component';

@NgModule({
  declarations: [
    AppComponent,
    JsonInputComponent
  ],
  ...

You do NOT need to import the JsonInputComponent (in this example) into AppComponent (in this example) to use the JsonInputComponent custom component in AppComponent template. You simply need to prefix the custom component with the module name of which both components have been defined (e.g. app):

<form [formGroup]="reactiveForm">
  <app-json-input formControlName="result"></app-json-input>
</form>

Notice app-json-input not json-input!

Demo here: https://github.com/lovefamilychildrenhappiness/AngularCustomComponentValidation

Case Statement Equivalent in R

There is a switch statement but I can never seem to get it to work the way I think it should. Since you have not provided an example I will make one using a factor variable:

 dft <-data.frame(x = sample(letters[1:8], 20, replace=TRUE))
 levels(dft$x)
[1] "a" "b" "c" "d" "e" "f" "g" "h"

If you specify the categories you want in an order appropriate to the reassignment you can use the factor or numeric variables as an index:

c("abc", "abc", "abc", "def", "def", "def", "g", "h")[dft$x]
 [1] "def" "h"   "g"   "def" "def" "abc" "h"   "h"   "def" "abc" "abc" "abc" "h"   "h"   "abc"
[16] "def" "abc" "abc" "def" "def"

dft$y <- c("abc", "abc", "abc", "def", "def", "def", "g", "h")[dft$x] str(dft)
'data.frame':   20 obs. of  2 variables:
 $ x: Factor w/ 8 levels "a","b","c","d",..: 4 8 7 4 6 1 8 8 5 2 ...
 $ y: chr  "def" "h" "g" "def" ...

I later learned that there really are two different switch functions. It's not generic function but you should think about it as either switch.numeric or switch.character. If your first argument is an R 'factor', you get switch.numeric behavior, which is likely to cause problems, since most people see factors displayed as character and make the incorrect assumption that all functions will process them as such.

Webpack not excluding node_modules

From your config file, it seems like you're only excluding node_modules from being parsed with babel-loader, but not from being bundled.

In order to exclude node_modules and native node libraries from bundling, you need to:

Add target: 'node' to your webpack.config.js. This will exclude native node modules (path, fs, etc.) from being bundled.
Use webpack-node-externals in order to exclude other node_modules.

So your result config file should look like:

var nodeExternals = require('webpack-node-externals');
...
module.exports = {
    ...
    target: 'node', // in order to ignore built-in modules like path, fs, etc. 
    externals: [nodeExternals()], // in order to ignore all modules in node_modules folder 
    ...
};

Delete last char of string

string.Join is better, but if you really want a LINQ ForEach:

var strgroupids = string.Empty;

groupIds.ForEach(g =>
{
    if(strgroupids != string.Empty){
        strgroupids += ",";
    }

    strgroupids += g;
});

Some notes:

string.Join and foreach are both better than this, vastly slower, approach
No need to remove the last , since it's never appended
The increment operator (+=) is handy for appending to strings
.ToString() is unnecessary as it is called automatically when concatenating non-strings
When handling large strings, StringBuilder should be considered instead of concatenating strings

CSS background-image not working

@TheBigO, that's not correct. Spans can have background/images (tested in IE8 and Chrome as a sanity check).

The issue is that the a.btn-pToolName is marked as display: block. This causes webkit browsers to no longer show the background in the outer span. IE seems to render it how the OP is wanting.

OP chance the .btn-pTool class to be display: inline-block to make it work like a span/div hybrid (take the background, but not cause a break in the layout).

How to read response headers in angularjs?

According the MDN custom headers are not exposed by default. The server admin need to expose them using "Access-Control-Expose-Headers" in the same fashion they deal with "access-control-allow-origin"

See this MDN link for confirmation [https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Access-Control-Expose-Headers]

PHP : settings memory_limits > 1024M does not work

Getting a union of two arrays in JavaScript

You can try these:

function union(a, b) {
    return a.concat(b).reduce(function(prev, cur) {
        if (prev.indexOf(cur) === -1) prev.push(cur);
        return prev;
    }, []);    
}

function union(a, b) {
    return a.concat(b.filter(function(el) {
        return a.indexOf(el) === -1;
    }));
}

How to create file execute mode permissions in Git on Windows?

I have no touch and chmod command in my cmd.exe and git update-index --chmod=+x foo.sh doesn't work for me.

I finally resolve it by setting skip-worktree bit:

git update-index --skip-worktree --chmod=+x foo.sh

Operator overloading on class templates

This way works:

class A
{
    struct Wrap
    {
        A& a;
        Wrap(A& aa) aa(a) {}
        operator int() { return a.value; }
        operator std::string() { stringstream ss; ss << a.value; return ss.str(); } 
    }
    Wrap operator*() { return Wrap(*this); }
};

Programmatically scroll to a specific position in an Android ListView

If you want to jump directly to the desired position in a listView just use

listView.setSelection(int position);

and if you want to jump smoothly to the desired position in listView just use

listView.smoothScrollToPosition(int position);

Find html label associated with a given input

I am a bit surprised that nobody seems to know that you're perfectly allowed to do:

<label>Put your stuff here: <input value="Stuff"></label>

Which won't get picked up by any of the suggested answers, but will label the input correctly.

Here's some code that does take this case into account:

$.fn.getLabels = function() {
    return this.map(function() {
        var labels = $(this).parents('label');
        if (this.id) {
            labels.add('label[for="' + this.id + '"]');
        }
        return labels.get();
    });
};

Usage:

$('#myfancyinput').getLabels();

Some notes:

The code was written for clarity, not for performance. More performant alternatives may be available.
This code supports getting the labels of multiple items in one go. If that's not what you want, adapt as necessary.
This still doesn't take care of things like aria-labelledby if you were to use that (left as an exercise to the reader).
Using multiple labels is a tricky business when it comes to support in different user agents and assistive technologies, so test well and use at your own risk, etc. etc.
Yes, you could also implement this without using jQuery. :-)

No appenders could be found for logger(log4j)?

Consider the log4j JVM argument Dlog4j.configuration

In general:

Add the JVM argument that points out the log4j config file. The syntax is just like follows:

java [ options ] -jar file.jar [ arguments ]

A sample of a real command line is just like the following:

java -Dlog4j.configuration=conf/log4j.xml -jar myJarFile.jar myArg1 myArg2

For IntelliJ IDE users:

1.Run/Debug Configurations
2.Edit configurations...
3.VM options
4.Enter the same value also starting with "-D"

Tips:

1.Eclipse IDE users will find an equivalent approach

2.For the run/debug configuration editor, it's very likely that, at the beginning of the times, your particular executable file is not there. Depending on the size of the project you're currently working on, it can be unpleasant to navigate directories to find it. It's less of a hassle if you just run/execute the file (click play) once before proceeding to run/debug config no matter what the execution result is.

3.Pay attention to your working directory, relative paths, and classpath.

How to get all elements inside "div" that starts with a known text

var $list = $('#divname input[id^="q17_"]');   // get all input controls with id q17_

// once you have $list you can do whatever you want

var ControlCnt = $list.length;
// Now loop through list of controls
$list.each( function() {

    var id = $(this).prop("id");      // get id
    var cbx = '';
    if ($(this).is(':checkbox') || $(this).is(':radio')) {
        // Need to see if this control is checked
    }
    else { 
        // Nope, not a checked control - so do something else
    }

});

How do I make an HTML button not reload the page

You can use a form that includes a submit button. Then use jQuery to prevent the default behavior of a form:

_x000D_

$(document).ready(function($) {_x000D_
  $(document).on('submit', '#submit-form', function(event) {_x000D_
    event.preventDefault();_x000D_
  _x000D_
    alert('page did not reload');_x000D_
  });_x000D_
});

_x000D_

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.0/jquery.min.js"></script>_x000D_
<form id='submit-form'>_x000D_
  <button type='submit'>submit</button>_x000D_
</form>

_x000D_

How are parameters sent in an HTTP POST request?

Some of the webservices require you to place request data and metadata separately. For example a remote function may expect that the signed metadata string is included in a URI, while the data is posted in a HTTP-body.

The POST request may semantically look like this:

POST /?AuthId=YOURKEY&Action=WebServiceAction&Signature=rcLXfkPldrYm04 HTTP/1.1
Content-Type: text/tab-separated-values; charset=iso-8859-1
Content-Length: []
Host: webservices.domain.com
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Encoding: identity
User-Agent: Mozilla/3.0 (compatible; Indy Library)

name    id
John    G12N
Sarah   J87M
Bob     N33Y

This approach logically combines QueryString and Body-Post using a single Content-Type which is a "parsing-instruction" for a web-server.

Please note: HTTP/1.1 is wrapped with the #32 (space) on the left and with #10 (Line feed) on the right.

How to printf uint64_t? Fails with: "spurious trailing ‘%’ in format"

When compiling memcached under Centos 5.x i got the same problem.

The solution is to upgrade gcc and g++ to version 4.4 at least.

Make sure your CC/CXX is set (exported) to right binaries before compiling.

Unable to simultaneously satisfy constraints, will attempt to recover by breaking constraint

I am getting this same error, but only on a specific view, when I touch the first textfield, and then the next textfield down.

I am writing in SwiftUI for iOS 13.4

 Unable to simultaneously satisfy constraints.
        Probably at least one of the constraints in the following list is one you don't want. 
        Try this: 
            (1) look at each constraint and try to figure out which you don't expect; 
            (2) find the code that added the unwanted constraint or constraints and fix it. 
    (
        "<NSLayoutConstraint:0x2809b6760 'assistantHeight' TUISystemInputAssistantView:0x105710da0.height == 44   (active)>",
        "<NSLayoutConstraint:0x2809ccff0 'assistantView.bottom' TUISystemInputAssistantView:0x105710da0.bottom == _UIKBCompatInputView:0x10525ae10.top   (active)>",
        "<NSLayoutConstraint:0x2809cccd0 'assistantView.top' V:|-(0)-[TUISystemInputAssistantView:0x105710da0]   (active, names: '|':UIInputSetHostView:0x105215010 )>",
        "<NSLayoutConstraint:0x2809ca300 'inputView.top' V:|-(0)-[_UIKBCompatInputView:0x10525ae10]   (active, names: '|':UIInputSetHostView:0x105215010 )>"
    )

    Will attempt to recover by breaking constraint 
    <NSLayoutConstraint:0x2809ccff0 'assistantView.bottom' TUISystemInputAssistantView:0x105710da0.bottom == _UIKBCompatInputView:0x10525ae10.top   (active)>

    Make a symbolic breakpoint at UIViewAlertForUnsatisfiableConstraints to catch this in the debugger.
    The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in <UIKitCore/UIView.h> may also be helpful.

Export Postgresql table data using pgAdmin

Just right click on a table and select "backup". The popup will show various options, including "Format", select "plain" and you get plain SQL.

pgAdmin is just using pg_dump to create the dump, also when you want plain SQL.

It uses something like this:

pg_dump --user user --password --format=plain --table=tablename --inserts --attribute-inserts etc.

In Python, how do I iterate over a dictionary in sorted key order?

Assuming you are using CPython 2.x and have a large dictionary mydict, then using sorted(mydict) is going to be slow because sorted builds a sorted list of the keys of mydict.

In that case you might want to look at my ordereddict package which includes a C implementation of sorteddict in C. Especially if you have to go over the sorted list of keys multiple times at different stages (ie. number of elements) of the dictionaries lifetime.

http://anthon.home.xs4all.nl/Python/ordereddict/

Django set default form values

I had this other solution (I'm posting it in case someone else as me is using the following method from the model):

class onlyUserIsActiveField(forms.ModelForm):
    def __init__(self, *args, **kwargs):
        super(onlyUserIsActiveField, self).__init__(*args, **kwargs)
        self.fields['is_active'].initial = False

    class Meta:
        model = User
        fields = ['is_active']
        labels = {'is_active': 'Is Active'}
        widgets = {
            'is_active': forms.CheckboxInput( attrs={
                            'class':          'form-control bootstrap-switch',
                            'data-size':      'mini',
                            'data-on-color':  'success',
                            'data-on-text':   'Active',
                            'data-off-color': 'danger',
                            'data-off-text':  'Inactive',
                            'name':           'is_active',

            })
        }

The initial is definded on the __init__ function as self.fields['is_active'].initial = False

Access nested dictionary items via a list of keys?

If you also want the ability to work with arbitrary json including nested lists and dicts, and nicely handle invalid lookup paths, here's my solution:

from functools import reduce


def get_furthest(s, path):
    '''
    Gets the furthest value along a given key path in a subscriptable structure.

    subscriptable, list -> any
    :param s: the subscriptable structure to examine
    :param path: the lookup path to follow
    :return: a tuple of the value at the furthest valid key, and whether the full path is valid
    '''

    def step_key(acc, key):
        s = acc[0]
        if isinstance(s, str):
            return (s, False)
        try:
            return (s[key], acc[1])
        except LookupError:
            return (s, False)

    return reduce(step_key, path, (s, True))


def get_val(s, path):
    val, successful = get_furthest(s, path)
    if successful:
        return val
    else:
        raise LookupError('Invalid lookup path: {}'.format(path))


def set_val(s, path, value):
    get_val(s, path[:-1])[path[-1]] = value

Multiple selector chaining in jQuery?

You can combine multiple selectors with a comma:

$('#Create .myClass,#Edit .myClass').plugin({options here});

Or if you're going to have a bunch of them, you could add a class to all your form elements and then search within that class. This doesn't get you the supposed speed savings of restricting the search, but I honestly wouldn't worry too much about that if I were you. Browsers do a lot of fancy things to optimize common operations behind your back -- the simple class selector might be faster.

How can I find WPF controls by name or type?

You can also find an element by name using FrameworkElement.FindName(string).

Given:

<UserControl ...>
    <TextBlock x:Name="myTextBlock" />
</UserControl>

In the code-behind file, you could write:

var myTextBlock = (TextBlock)this.FindName("myTextBlock");

Of course, because it's defined using x:Name, you could just reference the generated field, but perhaps you want to look it up dynamically rather than statically.

This approach is also available for templates, in which the named item appears multiple times (once per usage of the template).

Select max value of each group

select * from (select * from table order by value desc limit 999999999) v group by v.name

Laravel 5 call a model function in a blade view

I ran into a similar issue where I wanted to call a function defined in my controller from my view. Although it perplexed me for a while trying to figure out how to get to the controller from the view it turned out to be fairly straightforward.

I hand off an array to my views with data records that the view formats and presents to the user with jQuery DataTables (big duh). One column in the presented UI table is a set of action buttons that need to be created per row based on the content of the data in each of the rows. I guess I could have added the button definitions to the data rows as a column sent to the views but not all views needed the buttons so why? Instead, I wanted the view that needed them add them.

In the controller I pass a reference to the controller itself to the view as in

->with('callbackController', $this)

I called it callbackController as that is what I was doing. Now, inside my view I can either escape to PHP to use $callbackController to access the parent controller as in

<?php echo $callbackController->makeButtons($parameters); ?>

or just use the Blade mechanism

{!! $callbackController->makeButtons($parameters); ?>

It seems to be working fine across multiple controllers and views. I have not noticed a performance penalty using this mechanism and I have one huge table with over 50K rows.

I have not tried to pass on references to other objects (e.g., models, etc) yet but I do not see what that would not work as well

Might not be elegant but it seems to get the job done.

Make footer stick to bottom of page correctly

Use this one. It will fix it.

#ibox_footer {
    padding-top: 3px; 
    position: absolute;
    height: 20px;
    margin-bottom: 0;
    bottom: 0;
    width: 100%;
}

How can I develop for iPhone using a Windows development machine?

I use Flutter. I develop on my Windows machine and test on an Android emulator. When I'm ready to test on iOS, I run the code on macOS. From my experience, a Flutter app runs exactly the same on Android and iOS. If you don't have a Mac, you can download VirtualBox and install macOS on it. On VirtualBox, macOS runs exactly as it does on a real Mac, and you can build your app on it.

How to get complete current url for Cakephp

In the request object you have everything you need. To understand it:

debug($this->request->url);

and in your case

$here = $this->request->url;

.m2 , settings.xml in Ubuntu

.m2 directory on linux box usually would be $HOME/.m2

you could get the $HOME :

echo $HOME

or simply:

cd <enter>

to go to your home directory.

other information from maven site: http://maven.apache.org/download.html#Installation

How can I get the browser's scrollbar sizes?

Using jQuery, you can shorten Matthew Vines answer to:

function getScrollBarWidth () {
    var $outer = $('<div>').css({visibility: 'hidden', width: 100, overflow: 'scroll'}).appendTo('body'),
        widthWithScroll = $('<div>').css({width: '100%'}).appendTo($outer).outerWidth();
    $outer.remove();
    return 100 - widthWithScroll;
};

android layout with visibility GONE

Kotlin Style way to do this more simple (example):

    isVisible = false

Complete example:

    if (some_data_array.details == null){
                holder.view.some_data_array.isVisible = false}

Remove legend ggplot 2.2

from r cookbook, where bp is your ggplot:

Remove legend for a particular aesthetic (fill):

bp + guides(fill=FALSE)

It can also be done when specifying the scale:

bp + scale_fill_discrete(guide=FALSE)

This removes all legends:

bp + theme(legend.position="none")

Can (a== 1 && a ==2 && a==3) ever evaluate to true?

IT IS POSSIBLE!

_x000D_

var i = 0;_x000D_
_x000D_
with({_x000D_
  get a() {_x000D_
    return ++i;_x000D_
  }_x000D_
}) {_x000D_
  if (a == 1 && a == 2 && a == 3)_x000D_
    console.log("wohoo");_x000D_
}

_x000D_

This uses a getter inside of a with statement to let a evaluate to three different values.

... this still does not mean this should be used in real code...

Even worse, this trick will also work with the use of ===.

_x000D_

  var i = 0;_x000D_
_x000D_
  with({_x000D_
    get a() {_x000D_
      return ++i;_x000D_
    }_x000D_
  }) {_x000D_
    if (a !== a)_x000D_
      console.log("yep, this is printed.");_x000D_
  }

_x000D_

Where is Java's Array indexOf?

There are a couple of ways to accomplish this using the Arrays utility class.

If the array is not sorted and is not an array of primitives:

java.util.Arrays.asList(theArray).indexOf(o)

If the array is primitives and not sorted, one should use a solution offered by one of the other answers such as Kerem Baydogan's, Andrew McKinlay's or Mishax's. The above code will compile even if theArray is primitive (possibly emitting a warning) but you'll get totally incorrect results nonetheless.

If the array is sorted, you can make use of a binary search for performance:

java.util.Arrays.binarySearch(theArray, o)

sqldeveloper error message: Network adapter could not establish the connection error

In the connection properties window I changed my selection from "SID" to "Service Name", and copied my SID into the Service Name field. No idea why this change happened or why it worked, but it got me back on Oracle.

How can I sort one set of data to match another set of data in Excel?

You could also use INDEX MATCH, which is more "powerful" than vlookup. This would give you exactly what you are looking for:

enter image description here

Automated testing for REST Api

I collaborated with one of my coworkers to start the PyRestTest framework for this reason: https://github.com/svanoort/pyresttest

Although you can work with the tests in Python, the normal test format is in YAML.

Sample test suite for a basic REST app -- verifies that APIs respond correctly, checking HTTP status codes, though you can make it examine response bodies as well:

---
- config:
    - testset: "Tests using test app"

- test: # create entity
    - name: "Basic get"
    - url: "/api/person/"
- test: # create entity
    - name: "Get single person"
    - url: "/api/person/1/"
- test: # create entity
    - name: "Get single person"
    - url: "/api/person/1/"
    - method: 'DELETE'
- test: # create entity by PUT
    - name: "Create/update person"
    - url: "/api/person/1/"
    - method: "PUT"
    - body: '{"first_name": "Gaius","id": 1,"last_name": "Baltar","login": "gbaltar"}'
    - headers: {'Content-Type': 'application/json'}
- test: # create entity by POST
    - name: "Create person"
    - url: "/api/person/"
    - method: "POST"
    - body: '{"first_name": "Willim","last_name": "Adama","login": "theadmiral"}'
    - headers: {Content-Type: application/json}

How to redirect to previous page in Ruby On Rails?

In your edit action, store the requesting url in the session hash, which is available across multiple requests:

session[:return_to] ||= request.referer

Then redirect to it in your update action, after a successful save:

redirect_to session.delete(:return_to)

How to click a href link using Selenium

Use

driver.findElement(By.linkText("App Configuration")).click()

Other Approaches will be

JavascriptLibrary jsLib = new JavascriptLibrary(); 
jsLib.callEmbeddedSelenium(selenium, "triggerMouseEventAt", elementToClick,"click", "0,0");

((JavascriptExecutor) driver).executeScript("arguments[0].click();", elementToClick);

For detailed answer, View this post

Code coverage for Jest built on top of Jasmine

I had the same issue and I fixed it as below.

install yarn npm install --save-dev yarn
install jest-cli npm install --save-dev jest-cli
add this to the package.json "jest-coverage": "yarn run jest -- --coverage"

After you write the tests, run the command npm run jest-coverage. This will create a coverage folder in the root directory. /coverage/icov-report/index.html has the HTML view of the code coverage.

What is the connection string for localdb for version 11

This is a fairly old thread, but since I was reinstalling my Visual Studio 2015 Community today, I thought I might add some info on what to use on VS2015, or what might work in general.

To see which instances were installed by default, type sqllocaldb info inside a command prompt. On my machine, I get two instances, the first one named MSSQLLocalDB.

C:\>sqllocaldb info
MSSQLLocalDB
ProjectsV13

You can also create a new instance if you wish, using sqllocaldb create "some_instance_name", but the default one will work just fine:

// if not using a verbatim string literal, don't forget to escape backslashes
@"Server=(localdb)\MSSQLLocalDB;Integrated Security=true;"

ORA-00054: resource busy and acquire with NOWAIT specified

Step 1:

select object_name, s.sid, s.serial#, p.spid 
from v$locked_object l, dba_objects o, v$session s, v$process p
where l.object_id = o.object_id and l.session_id = s.sid and s.paddr = p.addr;

Step 2:

alter system kill session 'sid,serial#'; --`sid` and `serial#` get from step 1

More info: http://www.oracle-base.com/articles/misc/killing-oracle-sessions.php

How does JavaScript .prototype work?

This is a very simple prototype based object model that would be considered as a sample during the explanation, with no comment yet:

function Person(name){
    this.name = name;
}
Person.prototype.getName = function(){
    console.log(this.name);
}
var person = new Person("George");

There are some crucial points that we have to consider before going through the prototype concept.

1- How JavaScript functions actually work:

To take the first step we have to figure out, how JavaScript functions actually work , as a class like function using this keyword in it or just as a regular function with its arguments, what it does and what it returns.

Let's say we want to create a Person object model. but in this step I'm gonna be trying to do the same exact thing without using prototype and new keyword.

So in this step functions, objects and this keyword, are all we have.

The first question would be how this keyword could be useful without using new keyword.

So to answer that let's say we have an empty object, and two functions like:

var person = {};
function Person(name){  this.name = name;  }

function getName(){
    console.log(this.name);
}

and now without using new keyword how we could use these functions. So JavaScript has 3 different ways to do that:

a. first way is just to call the function as a regular function:

Person("George");
getName();//would print the "George" in the console

in this case, this would be the current context object, which is usually is the global window object in the browser or GLOBAL in Node.js. It means we would have, window.name in browser or GLOBAL.name in Node.js, with "George" as its value.

b. We can attach them to an object, as its properties

-The easiest way to do this is modifying the empty person object, like:

person.Person = Person;
person.getName = getName;

this way we can call them like:

person.Person("George");
person.getName();// -->"George"

and now the person object is like:

Object {Person: function, getName: function, name: "George"}

-The other way to attach a property to an object is using the prototype of that object that can be find in any JavaScript object with the name of __proto__, and I have tried to explain it a bit on the summary part. So we could get the similar result by doing:

person.__proto__.Person = Person;
person.__proto__.getName = getName;

But this way what we actually are doing is modifying the Object.prototype, because whenever we create a JavaScript object using literals ({ ... }), it gets created based on Object.prototype, which means it gets attached to the newly created object as an attribute named __proto__ , so if we change it, as we have done on our previous code snippet, all the JavaScript objects would get changed, not a good practice. So what could be the better practice now:

person.__proto__ = {
    Person: Person,
    getName: getName
};

and now other objects are in peace, but it still doesn't seem to be a good practice. So we have still one more solutions, but to use this solution we should get back to that line of code where person object got created (var person = {};) then change it like:

var propertiesObject = {
    Person: Person,
    getName: getName
};
var person = Object.create(propertiesObject);

what it does is creating a new JavaScript Object and attach the propertiesObject to the __proto__ attribute. So to make sure you can do:

console.log(person.__proto__===propertiesObject); //true

But the tricky point here is you have access to all the properties defined in __proto__ on the first level of the person object(read the summary part for more detail).

as you see using any of these two way this would exactly point to the person object.

c. JavaScript has another way to provide the function with `this`, which is using call or apply to invoke the function.

The apply() method calls a function with a given this value and arguments provided as an array (or an array-like object).

and

The call() method calls a function with a given this value and arguments provided individually.

this way which is my favorite, we can easily call our functions like:

Person.call(person, "George");

//apply is more useful when params count is not fixed
Person.apply(person, ["George"]);

getName.call(person);   
getName.apply(person);

these 3 methods are the important initial steps to figure out the .prototype functionality.

2- How does the `new` keyword work?

this is the second step to understand the .prototype functionality.this is what I use to simulate the process:

function Person(name){  this.name = name;  }
my_person_prototype = { getName: function(){ console.log(this.name); } };

in this part I'm gonna be trying to take all the steps which JavaScript takes, without using the new keyword and prototype, when you use new keyword. so when we do new Person("George"), Person function serves as a constructor, These are what JavaScript does, one by one:

a. first of all it makes an empty object, basically an empty hash like:

var newObject = {};

b. the next step that JavaScript takes is to attach the all prototype objects to the newly created object

we have my_person_prototype here similar to the prototype object.

for(var key in my_person_prototype){
    newObject[key] = my_person_prototype[key];
}

It is not the way that JavaScript actually attaches the properties that are defined in the prototype. The actual way is related to the prototype chain concept.

a. & b. Instead of these two steps you can have the exact same result by doing:

var newObject = Object.create(my_person_prototype);
//here you can check out the __proto__ attribute
console.log(newObject.__proto__ === my_person_prototype); //true
//and also check if you have access to your desired properties
console.log(typeof newObject.getName);//"function"

now we can call the getName function in our my_person_prototype:

newObject.getName();

c. then it gives that object to the constructor,

we can do this with our sample like:

Person.call(newObject, "George");

Person.apply(newObject, ["George"]);

then the constructor can do whatever it wants, because this inside of that constructor is the object that was just created.

now the end result before simulating the other steps: Object {name: "George"}

Summary:

Basically, when you use the new keyword on a function, you are calling on that and that function serves as a constructor, so when you say:

new FunctionName()

JavaScript internally makes an object, an empty hash and then it gives that object to the constructor, then the constructor can do whatever it wants, because this inside of that constructor is the object that was just created and then it gives you that object of course if you haven't used the return statement in your function or if you've put a return undefined; at the end of your function body.

So when JavaScript goes to look up a property on an object, the first thing it does, is it looks it up on that object. And then there is a secret property [[prototype]] which we usually have it like __proto__ and that property is what JavaScript looks at next. And when it looks through the __proto__, as far as it is again another JavaScript object, it has its own __proto__ attribute, it goes up and up until it gets to the point where the next __proto__ is null. The point is the only object in JavaScript that its __proto__ attribute is null is Object.prototype object:

console.log(Object.prototype.__proto__===null);//true

and that's how inheritance works in JavaScript.

The prototype chain

In other words, when you have a prototype property on a function and you call a new on that, after JavaScript finishes looking at that newly created object for properties, it will go look at the function's .prototype and also it is possible that this object has its own internal prototype. and so on.

Programs & Examples On #Getparameter

Spring Data and Native Query with pagination

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Android Camera Preview Stretched

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HTTP Status 500 - org.apache.jasper.JasperException: java.lang.NullPointerException

Creating java date object from year,month,day

oracle.jdbc.driver.OracleDriver ClassNotFoundException

Getting request payload from POST request in Java servlet

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how to convert object to string in java

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Could not connect to SMTP host: localhost, port: 25; nested exception is: java.net.ConnectException: Connection refused: connect

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HTTP Status 405 - HTTP method POST is not supported by this URL java servlet

HTML Submit-button: Different value / button-text?

Error inflating when extending a class

Convenient way to parse incoming multipart/form-data parameters in a Servlet

How can I avoid Java code in JSP files, using JSP 2?

Undefined reference to vtable

What is a vtable?

Where/when is a vtable generated?

How to fix the error?

Is there a max size for POST parameter content?

How to draw an overlay on a SurfaceView used by Camera on Android?

How to upload files to server using JSP/Servlet?

doGet and doPost in Servlets

Introduction

GET

POST

See also:

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java.lang.IllegalStateException: Cannot (forward | sendRedirect | create session) after response has been committed

Parsing query strings on Android

What's the best way to get the current URL in Spring MVC?

Modify request parameter with servlet filter

Neither BindingResult nor plain target object for bean name available as request attr

How to set a parameter in a HttpServletRequest?

How to differ sessions in browser-tabs?

Internal vs. Private Access Modifiers

How can I generate an MD5 hash?

How to do a HTTP HEAD request from the windows command line?

What is a `vtable`?

Where/when is a `vtable` generated?

Handling of non breaking space: <p> </p> vs. <p> </p>