The value you have passed as the file descriptor is not valid. It is either negative or does not represent a currently open file or socket.

So you have either closed the socket before calling write() or you have corrupted the value of 'sockfd' somewhere in your code.

It would be useful to trace all calls to close(), and the value of 'sockfd' prior to the write() calls.

Your technique of only printing error messages in debug mode seems to me complete madness, and in any case calling another function between a system call and perror() is invalid, as it may disturb the value of errno. Indeed it may have done so in this case, and the real underlying error may be different.

One thing to be aware of is that many Linux netfilter firewalls are misconfigured.

If you have something like:

-A FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT

-A FORWARD -p tcp -j REJECT --reject-with tcp-reset

then packet reordering can result in the firewall considering the packets invalid and thus generating resets which will then break otherwise healthy connections.

Reordering is particularly likely with a wireless network.

This should instead be:

-A FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT

-A FORWARD -m state --state INVALID -j DROP

-A FORWARD -p tcp -j REJECT --reject-with tcp-reset

Basically anytime you have:

... -m state --state RELATED,ESTABLISHED -j ACCEPT

it should immediately be followed by:

... -m state --state INVALID -j DROP

It's better to drop a packet then to generate a potentially protocol disrupting tcp reset. Resets are better when they're provably the correct thing to send... since this eliminates timeouts. But if there's any chance they're invalid then they can cause this sort of pain.

To check all ports:

netstat -lnp

To close an open port:

fuser -k port_no/tcp

Example:

fuser -k 8080/tcp

In both cases you can use the sudo command if needed.

Assuming you have some level of control over the protocol, I'm a big fan of sending heartbeats to verify that a connection is active. It's proven to be the most fail proof method and will often give you the quickest notification when a connection has been broken.

TCP keepalives will work, but what if the remote host is suddenly powered off? TCP can take a long time to timeout. On the other hand, if you have logic in your app that expects a heartbeat reply every x seconds, the first time you don't get them you know the connection no longer works, either by a network or a server issue on the remote side.

See Do I need to heartbeat to keep a TCP connection open? for more discussion.

The problem is extra 13 byte which server.py receives at the start. To resolve that write "l = c.recv(1024)" twice before the while loop as below.

print "Receiving..."
l = c.recv(1024) #this receives 13 bytes which is corrupting the data
l = c.recv(1024) # Now actual data starts receiving
while (l):

This resolves the issue, tried with different format and sizes of files. If anyone knows what this starting 13 bytes refers to, please reply.

A connection timeout occurs only upon starting the TCP connection. This usually happens if the remote machine does not answer. This means that the server has been shut down, you used the wrong IP/DNS name, wrong port or the network connection to the server is down.

A socket timeout is dedicated to monitor the continuous incoming data flow. If the data flow is interrupted for the specified timeout the connection is regarded as stalled/broken. Of course this only works with connections where data is received all the time.

By setting socket timeout to 1 this would require that every millisecond new data is received (assuming that you read the data block wise and the block is large enough)!

If only the incoming stream stalls for more than a millisecond you are running into a timeout.

When linger is on but the timeout is zero the TCP stack doesn't wait for pending data to be sent before closing the connection. Data could be lost due to this but by setting linger this way you're accepting this and asking that the connection be reset straight away rather than closed gracefully. This causes an RST to be sent rather than the usual FIN.

Thanks to EJP for his comment, see here for details.

I've found quite useful, another workaround for that!

If you use asynchronous methods for reading data from the network socket (I mean, use BeginReceive - EndReceive methods), whenever a connection is terminated; one of these situations appear: Either a message is sent with no data (you can see it with Socket.Available - even though BeginReceive is triggered, its value will be zero) or Socket.Connected value becomes false in this call (don't try to use EndReceive then).

I'm posting the function I used, I think you can see what I meant from it better:

private void OnRecieve(IAsyncResult parameter) 
{
    Socket sock = (Socket)parameter.AsyncState;
    if(!sock.Connected || sock.Available == 0)
    {
        // Connection is terminated, either by force or willingly
        return;
    }

    sock.EndReceive(parameter);
    sock.BeginReceive(..., ... , ... , ..., new AsyncCallback(OnRecieve), sock);

    // To handle further commands sent by client.
    // "..." zones might change in your code.
}

Here is a rough explanation of the concepts.

[ACK] is the acknowledgement that the previously sent data packet was received.

[FIN] is sent by a host when it wants to terminate the connection; the TCP protocol requires both endpoints to send the termination request (i.e. FIN).

So, suppose

• host A sends a data packet to host B
• and then host B wants to close the connection.
• Host B (depending on timing) can respond with [FIN,ACK] indicating that it received the sent packet and wants to close the session.
• Host A should then respond with a [FIN,ACK] indicating that it received the termination request (the ACK part) and that it too will close the connection (the FIN part).

However, if host A wants to close the session after sending the packet, it would only send a [FIN] packet (nothing to acknowledge) but host B would respond with [FIN,ACK] (acknowledges the request and responds with FIN).

Finally, some TCP stacks perform half-duplex termination, meaning that they can send [RST] instead of the usual [FIN,ACK]. This happens when the host actively closes the session without processing all the data that was sent to it. Linux is one operating system which does just this.

You can find a more detailed and comprehensive explanation here.

UDP is applied a lot in games or other Peer-to-peer setups because it's faster and most of the time you don't need the protocol itself to make sure everything gets to the destination in the original order (UDP does not garantee packet delivery or delivery order).

Web traffic on the other hand is over TCP. (I'm not sure here but I think it has to do with the way the HTTP protocol is built)

Edited because I failed at UDP.

Thanks to sud007 for this answer. In my case, I only need this part of the solution:

In CMD/Terminal:

$ adb kill-server

$ adb tcpip 5555
restarting in TCP mode port: 5555

$ adb connect 192.168.XXX.XXX

This bug brings more errors than unable to connect to 192.168.XXX.XXX:5555: Connection refused. In my case, I could connect to the device, but when you try to run the app. AndroidStudio stay in Installing APK forever. In this case, I needed to restart the phone too.

A limit on the number of open sockets is configurable in the /proc file system

cat /proc/sys/fs/file-max

Max for incoming connections in the OS defined by integer limits.

Linux itself allows billions of open sockets.

To use the sockets you need an application listening, e.g. a web server, and that will use a certain amount of RAM per socket.

RAM and CPU will introduce the real limits. (modern 2017, think millions not billions)

1 millions is possible, not easy. Expect to use X Gigabytes of RAM to manage 1 million sockets.

Outgoing TCP connections are limited by port numbers ~65000 per IP. You can have multiple IP addresses, but not unlimited IP addresses. This is a limit in TCP not Linux.

TCP / HTTP Listening On Ports: How Can Many Users Share the Same Port

So, what happens when a server listen for incoming connections on a TCP port? For example, let's say you have a web-server on port 80. Let's assume that your computer has the public IP address of 24.14.181.229 and the person that tries to connect to you has IP address 10.1.2.3. This person can connect to you by opening a TCP socket to 24.14.181.229:80. Simple enough.

Intuitively (and wrongly), most people assume that it looks something like this:

    Local Computer    | Remote Computer
    --------------------------------
    <local_ip>:80     | <foreign_ip>:80

    ^^ not actually what happens, but this is the conceptual model a lot of people have in mind.

This is intuitive, because from the standpoint of the client, he has an IP address, and connects to a server at IP:PORT. Since the client connects to port 80, then his port must be 80 too? This is a sensible thing to think, but actually not what happens. If that were to be correct, we could only serve one user per foreign IP address. Once a remote computer connects, then he would hog the port 80 to port 80 connection, and no one else could connect.

Three things must be understood:

1.) On a server, a process is listening on a port. Once it gets a connection, it hands it off to another thread. The communication never hogs the listening port.

2.) Connections are uniquely identified by the OS by the following 5-tuple: (local-IP, local-port, remote-IP, remote-port, protocol). If any element in the tuple is different, then this is a completely independent connection.

3.) When a client connects to a server, it picks a random, unused high-order source port. This way, a single client can have up to ~64k connections to the server for the same destination port.

So, this is really what gets created when a client connects to a server:

    Local Computer   | Remote Computer           | Role
    -----------------------------------------------------------
    0.0.0.0:80       | <none>                    | LISTENING
    127.0.0.1:80     | 10.1.2.3:<random_port>    | ESTABLISHED

Looking at What Actually Happens

First, let's use netstat to see what is happening on this computer. We will use port 500 instead of 80 (because a whole bunch of stuff is happening on port 80 as it is a common port, but functionally it does not make a difference).

    netstat -atnp | grep -i ":500 "

As expected, the output is blank. Now let's start a web server:

    sudo python3 -m http.server 500

Now, here is the output of running netstat again:

    Proto Recv-Q Send-Q Local Address           Foreign Address         State  
    tcp        0      0 0.0.0.0:500             0.0.0.0:*               LISTEN      - 

So now there is one process that is actively listening (State: LISTEN) on port 500. The local address is 0.0.0.0, which is code for "listening for all". An easy mistake to make is to listen on address 127.0.0.1, which will only accept connections from the current computer. So this is not a connection, this just means that a process requested to bind() to port IP, and that process is responsible for handling all connections to that port. This hints to the limitation that there can only be one process per computer listening on a port (there are ways to get around that using multiplexing, but this is a much more complicated topic). If a web-server is listening on port 80, it cannot share that port with other web-servers.

So now, let's connect a user to our machine:

    quicknet -m tcp -t localhost:500 -p Test payload.

This is a simple script (https://github.com/grokit/dcore/tree/master/apps/quicknet) that opens a TCP socket, sends the payload ("Test payload." in this case), waits a few seconds and disconnects. Doing netstat again while this is happening displays the following:

    Proto Recv-Q Send-Q Local Address           Foreign Address         State  
    tcp        0      0 0.0.0.0:500             0.0.0.0:*               LISTEN      -
    tcp        0      0 192.168.1.10:500        192.168.1.13:54240      ESTABLISHED -

If you connect with another client and do netstat again, you will see the following:

    Proto Recv-Q Send-Q Local Address           Foreign Address         State  
    tcp        0      0 0.0.0.0:500             0.0.0.0:*               LISTEN      -
    tcp        0      0 192.168.1.10:500        192.168.1.13:26813      ESTABLISHED -

... that is, the client used another random port for the connection. So there is never confusion between the IP addresses.

I made a small script to see not only who is listening where but also to display established connections and to which countries. Works on OSX Siera

#!/bin/bash
printf "\nchecking established connections\n\n"
for i in $(sudo lsof -i -n -P | grep TCP | grep ESTABLISHED | grep -v IPv6 | 
grep -v 127.0.0.1 | cut -d ">" -f2 | cut -d " " -f1 | cut -d ":" -f1); do
    printf "$i : " & curl freegeoip.net/xml/$i -s -S | grep CountryName | 
cut -d ">" -f2 | cut -d"<" -f1
done

printf "\ndisplaying listening ports\n\n"

sudo lsof -i -n -P | grep TCP | grep LISTEN | cut -d " " -f 1,32-35

#EOF

Sample output
checking established connections

107.178.244.155 : United States
17.188.136.186 : United States
17.252.76.19 : United States
17.252.76.19 : United States
17.188.136.186 : United States
5.45.62.118 : Netherlands
40.101.42.66 : Ireland
151.101.1.69 : United States
173.194.69.188 : United States
104.25.170.11 : United States
5.45.62.49 : Netherlands
198.252.206.25 : United States
151.101.1.69 : United States
34.198.53.220 : United States
198.252.206.25 : United States
151.101.129.69 : United States
91.225.248.133 : Ireland
216.58.212.234 : United States

displaying listening ports

mysqld TCP *:3306 (LISTEN)
com.avast TCP 127.0.0.1:12080 (LISTEN)
com.avast TCP [::1]:12080 (LISTEN)
com.avast TCP 127.0.0.1:12110 (LISTEN)
com.avast TCP [::1]:12110 (LISTEN)
com.avast TCP 127.0.0.1:12143 (LISTEN)
com.avast TCP [::1]:12143 (LISTEN)
com.avast TCP 127.0.0.1:12995 (LISTEN)
com.avast [::1]:12995 (LISTEN)
com.avast 127.0.0.1:12993 (LISTEN)
com.avast [::1]:12993 (LISTEN)
Google TCP 127.0.0.1:34013 (LISTEN)

This may be useful to check if you are connected to north-korea! ;-)

Another possible case (but rare) could be if you have server to server communications and have set server.maxConnections to a very low value.

In node's core lib net.js it will call clientHandle.close() which will also cause error ECONNRESET:

if (self.maxConnections && self._connections >= self.maxConnections) {
  clientHandle.close(); // causes ECONNRESET on the other end
  return;
}

ipGlobalProperties.GetActiveTcpConnections() doesn't return connections in Listen State.

Port can be used for listening, but with no one connected to it the method described above will not work.

For me easiest way was adding static route on office router based on destination network. Just route traffic to some unresponsive host (e.g. your computer) and you will get request timeout.

Best thing for me was that static route can be managed over web interface and enabled/disabled easily.

If you're behind a masquerading NAT (as most home users are these days), there is a limited pool of external ports, and these must be shared among the TCP connections. Therefore masquerading NATs tend to assume a connection has been terminated if no data has been sent for a certain time period.

This and other such issues (anywhere in between the two endpoints) can mean the connection will no longer "work" if you try to send data after a reasonble idle period. However, you may not discover this until you try to send data.

Using keepalives both reduces the chance of the connection being interrupted somewhere down the line, and also lets you find out about a broken connection sooner.

in case of the IPv4 protocol, the server with one IP address that listens on one port only can handle 2^32 IP addresses x 2^16 ports so 2^48 unique sockets. If you speak about a server as a physical machine, and you are able to utilize all 2^16 ports, then there could be maximum of 2^48 x 2^16 = 2^64 unique TCP/IP sockets for one IP address. Please note that some ports are reserved for the OS, so this number will be lower. To sum up:

1 IP and 1 port --> 2^48 sockets

1 IP and all ports --> 2^64 sockets

all unique IPv4 sockets in the universe --> 2^96 sockets

There is a limit, yes. See ulimit.

Also you need to consider the TIMED_WAIT state. Once a TCP socket is closed (by default) the port remains occupied in TIMED_WAIT status for 2 minutes. This value is tunable. This will also "run you out of sockets" even though they are closed.

Run netstat to see the TIMED_WAIT stuff in action.

P.S. The reason for TIMED_WAIT is to handle the case of packets arriving after the socket is closed. This can happen because packets are delayed or the other side just doesn't know that the socket has been closed yet. This allows the OS to silently drop those packets without a chance of "infecting" a different, unrelated socket connection.

In theory SMTP can be handled by either TCP, UDP, or some 3rd party protocol.

As defined in RFC 821, RFC 2821, and RFC 5321:

SMTP is independent of the particular transmission subsystem and requires only a reliable ordered data stream channel.

In addition, the Internet Assigned Numbers Authority has allocated port 25 for both TCP and UDP for use by SMTP.

In practice however, most if not all organizations and applications only choose to implement the TCP protocol. For example, in Microsoft's port listing port 25 is only listed for TCP and not UDP.

The big difference between TCP and UDP that makes TCP ideal here is that TCP checks to make sure that every packet is received and re-sends them if they are not whereas UDP will simply send packets and not check for receipt. This makes UDP ideal for things like streaming video where every single packet isn't as important as keeping a continuous flow of packets from the server to the client.

Considering SMTP, it makes more sense to use TCP over UDP. SMTP is a mail transport protocol, and in mail every single packet is important. If you lose several packets in the middle of the message the recipient might not even receive the message and if they do they might be missing key information. This makes TCP more appropriate because it ensures that every packet is delivered.

The following configs works on Cent OS 6 or earlier

As stated above first have to disable selinux.

Step 1 nano /etc/sysconfig/selinux

Make sure the file has this configurations

SELINUX=disabled

SELINUXTYPE=targeted

Then restart the system

Step 2

iptables -A INPUT -m state --state NEW -p tcp --dport 8080 -j ACCEPT

Step 3

sudo service iptables save

For Cent OS 7

step 1

firewall-cmd --zone=public --permanent --add-port=8080/tcp

Step 2

firewall-cmd --reload

WebSocket is basically an application protocol (with reference to the ISO/OSI network stack), message-oriented, which makes use of TCP as transport layer.

The idea behind the WebSocket protocol consists of reusing the established TCP connection between a Client and Server. After the HTTP handshake the Client and Server start speaking WebSocket protocol by exchanging WebSocket envelopes. HTTP handshaking is used to overcome any barrier (e.g. firewalls) between a Client and a Server offering some services (usually port 80 is accessible from anywhere, by anyone). Client and Server can switch over speaking HTTP in any moment, making use of the same TCP connection (which is never released).

Behind the scenes WebSocket rebuilds the TCP frames in consistent envelopes/messages. The full-duplex channel is used by the Server to push updates towards the Client in an asynchronous way: the channel is open and the Client can call any futures/callbacks/promises to manage any asynchronous WebSocket received message.

To put it simply, WebSocket is a high level protocol (like HTTP itself) built on TCP (reliable transport layer, on per frame basis) that makes possible to build effective real-time application with JS Clients (previously Comet and long-polling techniques were used to pull updates from the Server before WebSockets were implemented. See Stackoverflow post: Differences between websockets and long polling for turn based game server ).

All the 'use UDP' answers assume an open network and 'stuff it as much as you can' approach. Good for old-style closed-garden dedicated audio/video networks, which are a vanishing sort.

In the actual world, your transmission will go through firewalls (that will drop multicast and sometimes udp), the network is shared with others more important ($$$) apps, so you want to punish abusers with window scaling.

For any non-trivial application (I.E. the application must receive and handle different kinds of messages with different lengths), the solution to your particular problem isn't necessarily just a programming solution - it's a convention, I.E. a protocol.

In order to determine how many bytes you should pass to your read call, you should establish a common prefix, or header, that your application receives. That way, when a socket first has reads available, you can make decisions about what to expect.

A binary example might look like this:

#include <stdint.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <arpa/inet.h>

enum MessageType {
    MESSAGE_FOO,
    MESSAGE_BAR,
};

struct MessageHeader {
    uint32_t type;
    uint32_t length;
};

/**
 * Attempts to continue reading a `socket` until `bytes` number
 * of bytes are read. Returns truthy on success, falsy on failure.
 *
 * Similar to @grieve's ReadXBytes.
 */
int readExpected(int socket, void *destination, size_t bytes)
{
    /*
    * Can't increment a void pointer, as incrementing
    * is done by the width of the pointed-to type -
    * and void doesn't have a width
    *
    * You can in GCC but it's not very portable
    */
    char *destinationBytes = destination;
    while (bytes) {
        ssize_t readBytes = read(socket, destinationBytes, bytes);
        if (readBytes < 1)
            return 0;
        destinationBytes += readBytes;
        bytes -= readBytes;
    }
    return 1;
}

int main(int argc, char **argv)
{
    int selectedFd;

    // use `select` or `poll` to wait on sockets
    // received a message on `selectedFd`, start reading

    char *fooMessage;
    struct {
        uint32_t a;
        uint32_t b;
    } barMessage;

    struct MessageHeader received;
    if (!readExpected (selectedFd, &received, sizeof(received))) {
        // handle error
    }
    // handle network/host byte order differences maybe
    received.type = ntohl(received.type);
    received.length = ntohl(received.length);

    switch (received.type) {
        case MESSAGE_FOO:
            // "foo" sends an ASCII string or something
            fooMessage = calloc(received.length + 1, 1);
            if (readExpected (selectedFd, fooMessage, received.length))
                puts(fooMessage);
            free(fooMessage);
            break;
        case MESSAGE_BAR:
            // "bar" sends a message of a fixed size
            if (readExpected (selectedFd, &barMessage, sizeof(barMessage))) {
                barMessage.a = ntohl(barMessage.a);
                barMessage.b = ntohl(barMessage.b);
                printf("a + b = %d\n", barMessage.a + barMessage.b);
            }
            break;
        default:
            puts("Malformed type received");
            // kick the client out probably
    }
}

You can likely already see one disadvantage of using a binary format - for each attribute greater than a char you read, you will have to ensure its byte order is correct using the ntohl or ntohs functions.

An alternative is to use byte-encoded messages, such as simple ASCII or UTF-8 strings, which avoid byte-order issues entirely but require extra effort to parse and validate.

There are two final considerations for network data in C.

The first is that some C types do not have fixed widths. For example, the humble int is defined as the word size of the processor, so 32 bit processors will produce 32 bit ints, while 64 bit processors will produces 64 bit ints. Good, portable code should have network data use fixed-width types, like those defined in stdint.h.

The second is struct padding. A struct with different-widthed members will add data in between some members to maintain memory alignment, making the struct faster to use in the program but sometimes producing confusing results.

#include <stdio.h>
#include <stdint.h>

int main()
{
    struct A {
        char a;
        uint32_t b;
    } A;

    printf("sizeof(A): %ld\n", sizeof(A));
}

In this example, its actual width won't be 1 char + 4 uint32_t = 5 bytes, it'll be 8:

mharrison@mharrison-KATANA:~$ gcc -o padding padding.c
mharrison@mharrison-KATANA:~$ ./padding 
sizeof(A): 8

This is because 3 bytes are added after char a to make sure uint32_t b is memory-aligned.

So if you write a struct A, then attempt to read a char and a uint32_t on the other side, you'll get char a, and a uint32_t where the first three bytes are garbage and the last byte is the first byte of the actual integer you wrote.

Either document your data format explicitly as C struct types or, better yet, document any padding bytes they might contain.

I think you're looking for Hping (http://www.hping.org/), which has a Windows version.

"The interface is inspired to the ping(8) unix command, but hping isn't only able to send ICMP echo requests. It supports TCP, UDP, ICMP..."

It's also very useful if you want to see where along a route that a TCP port is being blocked (like by a firewall), where ICMP might not be.

A single listening port can accept more than one connection simultaneously.

There is a '64K' limit that is often cited, but that is per client per server port, and needs clarifying.

Each TCP/IP packet has basically four fields for addressing. These are:

source_ip source_port destination_ip destination_port
<----- client ------> <--------- server ------------>

Inside the TCP stack, these four fields are used as a compound key to match up packets to connections (e.g. file descriptors).

If a client has many connections to the same port on the same destination, then three of those fields will be the same - only source_port varies to differentiate the different connections. Ports are 16-bit numbers, therefore the maximum number of connections any given client can have to any given host port is 64K.

However, multiple clients can each have up to 64K connections to some server's port, and if the server has multiple ports or either is multi-homed then you can multiply that further.

So the real limit is file descriptors. Each individual socket connection is given a file descriptor, so the limit is really the number of file descriptors that the system has been configured to allow and resources to handle. The maximum limit is typically up over 300K, but is configurable e.g. with sysctl.

The realistic limits being boasted about for normal boxes are around 80K for example single threaded Jabber messaging servers.

1. Connect device via USB and make sure debugging is working, then run:

   adb tcpip 5555
   adb connect <DEVICE_IP_ADDRESS>:5555
   

2. Disconnect USB and proceed with wireless debugging.

3. When you're done and want to switch back to USB debugging, run:

   adb -s <DEVICE_IP_ADDRESS>:5555
   

To find the IP address of your device, go to Settings > Wi-Fi > Advanced > IP Address on your device or run adb shell netcfg.

No root required. Only one device can be debugged at a time.

See this XDA post.

The adb command is located in the platform-tools folder of the Android SDK.

another solution, in development environment of course, is killing process using it, for example

def serve():
    server = HTTPServer(('', PORT_NUMBER), BaseHTTPRequestHandler)
    print 'Started httpserver on port ' , PORT_NUMBER
    server.serve_forever()
try:
    serve()
except Exception, e:
    print "probably port is used. killing processes using given port %d, %s"%(PORT_NUMBER,e)
    os.system("xterm -e 'sudo fuser -kuv %d/tcp'" % PORT_NUMBER)
    serve()
    raise e

Pax is correct about the reasons for TIME_WAIT, and why you should be careful about lowering the default setting.

A better solution is to vary the port numbers used for the originating end of your sockets. Once you do this, you won't really care about time wait for individual sockets.

For listening sockets, you can use SO_REUSEADDR to allow the listening socket to bind despite the TIME_WAIT sockets sitting around.

HTTP 2.0 is a binary protocol that multiplexes numerous streams going over a single (normally TLS-encrypted) TCP connection.

The contents of each stream are HTTP 1.1 requests and responses, just encoded and packed up differently. HTTP2 adds a number of features to manage the streams, but leaves old semantics untouched.

"""
tcp_disconnect.py
Echo network data test program in python. This easily translates to C & Java.

A server program might want to confirm that a tcp client is still connected 
before it sends a data. That is, detect if its connected without reading from socket.
This will demonstrate how to detect a TCP client disconnect without reading data.

The method to do this:
1) select on socket as poll (no wait)
2) if no recv data waiting, then client still connected
3) if recv data waiting, the read one char using PEEK flag 
4) if PEEK data len=0, then client has disconnected, otherwise its connected.
Note, the peek flag will read data without removing it from tcp queue.

To see it in action: 0) run this program on one computer 1) from another computer, 
connect via telnet port 12345, 2) type a line of data 3) wait to see it echo, 
4) type another line, 5) disconnect quickly, 6) watch the program will detect the 
disconnect and exit.

John Masinter, 17-Dec-2008
"""

import socket
import time
import select

HOST = ''       # all local interfaces
PORT = 12345    # port to listen

# listen for new TCP connections
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
s.bind((HOST, PORT))
s.listen(1)
# accept new conneciton
conn, addr = s.accept()
print 'Connected by', addr
# loop reading/echoing, until client disconnects
try:
    conn.send("Send me data, and I will echo it back after a short delay.\n")
    while 1:
        data = conn.recv(1024)                          # recv all data queued
        if not data: break                              # client disconnected
        time.sleep(3)                                   # simulate time consuming work
        # below will detect if client disconnects during sleep
        r, w, e = select.select([conn], [], [], 0)      # more data waiting?
        print "select: r=%s w=%s e=%s" % (r,w,e)        # debug output to command line
        if r:                                           # yes, data avail to read.
            t = conn.recv(1024, socket.MSG_PEEK)        # read without remove from queue
            print "peek: len=%d, data=%s" % (len(t),t)  # debug output
            if len(t)==0:                               # length of data peeked 0?
                print "Client disconnected."            # client disconnected
                break                                   # quit program
        conn.send("-->"+data)                           # echo only if still connected
finally:
    conn.close()

Here is another choice: Chaosreader

So I need to debug an application which posts xml to a 3rd party application. I found a brilliant little perl script which does all the hard work – you just chuck it a tcpdump output file, and it does all the manipulation and outputs everything you need...

The script is called chaosreader0.94. See http://www.darknet.org.uk/2007/11/chaosreader-trace-tcpudp-sessions-from-tcpdump/

It worked like a treat, I did the following:

tcpdump host www.blah.com -s 9000 -w outputfile; perl chaosreader0.94 outputfile

Acked Unseen sample

Hi guys! Just some observations from what I just found in my capture:

On many occasions, the packet capture reports “ACKed segment that wasn't captured” on the client side, which alerts of the condition that the client PC has sent a data packet, the server acknowledges receipt of that packet, but the packet capture made on the client does not include the packet sent by the client

Initially, I thought it indicates a failure of the PC to record into the capture a packet it sends because “e.g., machine which is running Wireshark is slow” (https://osqa-ask.wireshark.org/questions/25593/tcp-previous-segment-not-captured-is-that-a-connectivity-issue)
However, then I noticed every time I see this “ACKed segment that wasn't captured” alert I can see a record of an “invalid” packet sent by the client PC

• In the capture example above, frame 67795 sends an ACK for 10384

• Even though wireshark reports Bogus IP length (0), frame 67795 is reported to have length 13194

• Frame 67800 sends an ACK for 23524
• 10384+13194 = 23578
• 23578 – 23524 = 54
• 54 is in fact length of the Ethernet / IP / TCP headers (14 for Ethernt, 20 for IP, 20 for TCP)
• So in fact, the frame 67796 does represent a large TCP packets (13194 bytes) which operating system tried to put on the wore
  • NIC driver will fragment it into smaller 1500 bytes pieces in order to transmit over the network
  • But Wireshark running on my PC fails to understand it is a valid packet and parse it. I believe Wireshark running on 2012 Windows server reads these captures correctly
• So after all, these “Bogus IP length” and “ACKed segment that wasn't captured” alerts were in fact false positives in my case

I'm guessing that it's too late for an answer, and this might not be a good one, but here you go...

What about putting it inside of a while loop with a timer on it of some sort. I'm more of a Perl guy than Solaris, but depending on the shell you're using, you should be able to do something like:

TIME = 'date +%s' + 15
while TIME != `date +%s'
do whatever

And then just add a flag in the while loop, so that if it times out before completing, you can cite the timeout as reason for failure.

I suspect that the telnet has a timeout switch as well, but just off the top of my head, I think the above will work.

It's fatal. The remote server has sent you a RST packet, which indicates an immediate dropping of the connection, rather than the usual handshake. This bypasses the normal half-closed state transition. I like this description:

"Connection reset by peer" is the TCP/IP equivalent of slamming the phone back on the hook. It's more polite than merely not replying, leaving one hanging. But it's not the FIN-ACK expected of the truly polite TCP/IP converseur.

What exactly are the rules for requesting retransmission of lost data?

The receiver does not request the retransmission. The sender waits for an ACK for the byte-range sent to the client and when not received, resends the packets, after a particular interval. This is ARQ (Automatic Repeat reQuest). There are several ways in which this is implemented.

Stop-and-wait ARQ
Go-Back-N ARQ
Selective Repeat ARQ

are detailed in the RFC 3366.

At what time frequency are the retransmission requests performed?

The retransmissions-times and the number of attempts isn't enforced by the standard. It is implemented differently by different operating systems, but the methodology is fixed. (One of the ways to fingerprint OSs perhaps?)

The timeouts are measured in terms of the RTT (Round Trip Time) times. But this isn't needed very often due to Fast-retransmit which kicks in when 3 Duplicate ACKs are received.

Is there an upper bound on the number?

Yes there is. After a certain number of retries, the host is considered to be "down" and the sender gives up and tears down the TCP connection.

Is there functionality for the client to indicate to the server to forget about the whole TCP segment for which part went missing when the IP packet went missing?

The whole point is reliable communication. If you wanted the client to forget about some part, you wouldn't be using TCP in the first place. (UDP perhaps?)

There are lot of factors , first see whether server returns the result, then check between server and client.

rectify them from server side first,then check the writing condition between server and client !

server side rectify the time outs between the datalayer and server from client side rectify the time out and number of available connections !

If You need to access SQL server on hostgator remotely using SSMS, you need to white list your IP in hostgator. Usually it takes 1 hour to open port for the whitelisted IP

You can also check for socket output stream error while writing to client socket.

out.println(output);
if(out.checkError())
{
    throw new Exception("Error transmitting data.");
}

TLDR;

• TCP - stream-oriented, requires a connection, reliable, slow
• UDP - message-oriented, connectionless, unreliable, fast

Before we start, remember that all disadvantages of something are a continuation of its advantages. There only a right tool for a job, no panacea. TCP/UDP coexist for decades, and for a reason.

TCP

It was designed to be extremely reliable and it does its job very well. It's so complex because it accomplishes a hard task: providing a reliable transport over the unreliable IP protocol.

Since all TCP's complex logic is encapsulated into the network stack, you are free from doing lots of laborious, error-prone low-level stuff in the application layer.

When you send data over TCP, you write a stream of bytes to the socket at the sender side where it gets broken into packets, passed down the stack and sent over the wire. On the receiver side packets get reassembled again into a continous stream of bytes.

Maintaining this nice abstraction has a cost in terms of complexity and performance. If the 1st packet from the byte stream is lost, the receiver will delay processing of subsequent packets even those have already arrived (the so-called "head of line blocking").

In addition, in order to be reliable, TCP implements this:

• TCP requires an established connection, which requires 3 round-trips ("infamous" 3-way handshake)
• TCP has a feature called "slow start" when it gradually ramps up the transmission rate after establishing a connection to allow a receiver to keep up with data rate
• Every sent packet has to be acknowledged or else a sender will stop sending more data
• And on and on and on...

All this is exacerbated in slow unreliable wireless networks because TCP was designed for wired networks where delays are predictable and packet loss is not so common. In addition, like many people already mentioned, for some things TCP just doesn't work at all (DHCP). However, where relevant, TCP still does its work exceptionally well.

Using a mail analogy a TCP session is similar to telling a story to your secretary who breaks it into mails and sends over a crappy mail service to a publisher. On the other side another secretary assembles mails into a single piece of text. Some mails get lost, some get corrupted, so a very complex procedure is required for reliable delivery and your 10-page story can take a long time to reach your publisher.

UDP

UDP, on the other hand, is message-oriented, so a receiver writes a message (packet) to the socket and then it gets transmitted to a receiver as-is, without any splitting/assembling in the transport layer.

Compared to TCP, its specification is very straightforward. Essentially, all it does for you is adding a checksum to the packet so a receiver can detect its corruption. Everything else must be implemented by you, a software developer. Now read the voluminous TCP spec and try thinking of re-implementing even a small subset of it.

Some people went this way and got very decent results, to the point that HTTP/3 uses QUIC - a protocol based on UDP. However, this is more of an exception. Common applications of UDP are audio/video streaming and conferencing applications like Skype, Zoom or Google Hangout where loosing packets is not so important compared to a delay introduced by TCP.

Here are some examples for:

1) Simple
2) Fork
3) Threads

based server:

http://www.martinbroadhurst.com/server-examples.html

You can use the setsockopt function to set a timeout on receive operations:

SO_RCVTIMEO

Sets the timeout value that specifies the maximum amount of time an input function waits until it completes. It accepts a timeval structure with the number of seconds and microseconds specifying the limit on how long to wait for an input operation to complete. If a receive operation has blocked for this much time without receiving additional data, it shall return with a partial count or errno set to [EAGAIN] or [EWOULDBLOCK] if no data is received. The default for this option is zero, which indicates that a receive operation shall not time out. This option takes a timeval structure. Note that not all implementations allow this option to be set.

// LINUX
struct timeval tv;
tv.tv_sec = timeout_in_seconds;
tv.tv_usec = 0;
setsockopt(sockfd, SOL_SOCKET, SO_RCVTIMEO, (const char*)&tv, sizeof tv);

// WINDOWS
DWORD timeout = timeout_in_seconds * 1000;
setsockopt(socket, SOL_SOCKET, SO_RCVTIMEO, (const char*)&timeout, sizeof timeout);

// MAC OS X (identical to Linux)
struct timeval tv;
tv.tv_sec = timeout_in_seconds;
tv.tv_usec = 0;
setsockopt(sockfd, SOL_SOCKET, SO_RCVTIMEO, (const char*)&tv, sizeof tv);

Reportedly on Windows this should be done before calling bind. I have verified by experiment that it can be done either before or after bind on Linux and OS X.

If it's a server socket, you should call listen() on your socket, and then getsockname() to find the port number on which it is listening:

struct sockaddr_in sin;
socklen_t len = sizeof(sin);
if (getsockname(sock, (struct sockaddr *)&sin, &len) == -1)
    perror("getsockname");
else
    printf("port number %d\n", ntohs(sin.sin_port));

As for the IP address, if you use INADDR_ANY then the server socket can accept connections to any of the machine's IP addresses and the server socket itself does not have a specific IP address. For example if your machine has two IP addresses then you might get two incoming connections on this server socket, each with a different local IP address. You can use getsockname() on the socket for a specific connection (which you get from accept()) in order to find out which local IP address is being used on that connection.

Reading quickly through the source it seems that you're not far off. The following link should help (I did something similar but for FTP). For a file send from server to client, you start off with a file instance and an array of bytes. You then read the File into the byte array and write the byte array to the OutputStream which corresponds with the InputStream on the client's side.

http://www.rgagnon.com/javadetails/java-0542.html

Edit: Here's a working ultra-minimalistic file sender and receiver. Make sure you understand what the code is doing on both sides.

package filesendtest;

import java.io.*;
import java.net.*;

class TCPServer {

    private final static String fileToSend = "C:\\test1.pdf";

    public static void main(String args[]) {

        while (true) {
            ServerSocket welcomeSocket = null;
            Socket connectionSocket = null;
            BufferedOutputStream outToClient = null;

            try {
                welcomeSocket = new ServerSocket(3248);
                connectionSocket = welcomeSocket.accept();
                outToClient = new BufferedOutputStream(connectionSocket.getOutputStream());
            } catch (IOException ex) {
                // Do exception handling
            }

            if (outToClient != null) {
                File myFile = new File( fileToSend );
                byte[] mybytearray = new byte[(int) myFile.length()];

                FileInputStream fis = null;

                try {
                    fis = new FileInputStream(myFile);
                } catch (FileNotFoundException ex) {
                    // Do exception handling
                }
                BufferedInputStream bis = new BufferedInputStream(fis);

                try {
                    bis.read(mybytearray, 0, mybytearray.length);
                    outToClient.write(mybytearray, 0, mybytearray.length);
                    outToClient.flush();
                    outToClient.close();
                    connectionSocket.close();

                    // File sent, exit the main method
                    return;
                } catch (IOException ex) {
                    // Do exception handling
                }
            }
        }
    }
}

package filesendtest;

import java.io.*;
import java.io.ByteArrayOutputStream;
import java.net.*;

class TCPClient {

    private final static String serverIP = "127.0.0.1";
    private final static int serverPort = 3248;
    private final static String fileOutput = "C:\\testout.pdf";

    public static void main(String args[]) {
        byte[] aByte = new byte[1];
        int bytesRead;

        Socket clientSocket = null;
        InputStream is = null;

        try {
            clientSocket = new Socket( serverIP , serverPort );
            is = clientSocket.getInputStream();
        } catch (IOException ex) {
            // Do exception handling
        }

        ByteArrayOutputStream baos = new ByteArrayOutputStream();

        if (is != null) {

            FileOutputStream fos = null;
            BufferedOutputStream bos = null;
            try {
                fos = new FileOutputStream( fileOutput );
                bos = new BufferedOutputStream(fos);
                bytesRead = is.read(aByte, 0, aByte.length);

                do {
                        baos.write(aByte);
                        bytesRead = is.read(aByte);
                } while (bytesRead != -1);

                bos.write(baos.toByteArray());
                bos.flush();
                bos.close();
                clientSocket.close();
            } catch (IOException ex) {
                // Do exception handling
            }
        }
    }
}

Related

Byte array of unknown length in java

Edit: The following could be used to fingerprint small files before and after transfer (use SHA if you feel it's necessary):

public static String md5String(File file) {
    try {
        InputStream fin = new FileInputStream(file);
        java.security.MessageDigest md5er = MessageDigest.getInstance("MD5");
        byte[] buffer = new byte[1024];
        int read;
        do {
            read = fin.read(buffer);
            if (read > 0) {
                md5er.update(buffer, 0, read);
            }
        } while (read != -1);
        fin.close();
        byte[] digest = md5er.digest();
        if (digest == null) {
            return null;
        }
        String strDigest = "0x";
        for (int i = 0; i < digest.length; i++) {
            strDigest += Integer.toString((digest[i] & 0xff)
                    + 0x100, 16).substring(1).toUpperCase();
        }
        return strDigest;
    } catch (Exception e) {
        return null;
    }
}

If you need to quickly blast a message across the net between two IP's that haven't even talked yet, then a UDP is going to arrive at least 3 times faster, usually 5 times faster.

netem leverages functionality already built into Linux and userspace utilities to simulate networks. This is actually what Mark's answer refers to, by a different name.

The examples on their homepage already show how you can achieve what you've asked for:

Examples

Emulating wide area network delays

This is the simplest example, it just adds a fixed amount of delay to all packets going out of the local Ethernet.

# tc qdisc add dev eth0 root netem delay 100ms

Now a simple ping test to host on the local network should show an increase of 100 milliseconds. The delay is limited by the clock resolution of the kernel (Hz). On most 2.4 systems, the system clock runs at 100 Hz which allows delays in increments of 10 ms. On 2.6, the value is a configuration parameter from 1000 to 100 Hz.

Later examples just change parameters without reloading the qdisc

Real wide area networks show variability so it is possible to add random variation.

# tc qdisc change dev eth0 root netem delay 100ms 10ms

This causes the added delay to be 100 ± 10 ms. Network delay variation isn't purely random, so to emulate that there is a correlation value as well.

# tc qdisc change dev eth0 root netem delay 100ms 10ms 25%

This causes the added delay to be 100 ± 10 ms with the next random element depending 25% on the last one. This isn't true statistical correlation, but an approximation.

Delay distribution

Typically, the delay in a network is not uniform. It is more common to use a something like a normal distribution to describe the variation in delay. The netem discipline can take a table to specify a non-uniform distribution.

# tc qdisc change dev eth0 root netem delay 100ms 20ms distribution normal

The actual tables (normal, pareto, paretonormal) are generated as part of the iproute2 compilation and placed in /usr/lib/tc; so it is possible with some effort to make your own distribution based on experimental data.

Packet loss

Random packet loss is specified in the 'tc' command in percent. The smallest possible non-zero value is:

2^-32 = 0.0000000232%

# tc qdisc change dev eth0 root netem loss 0.1%

This causes 1/10th of a percent (i.e. 1 out of 1000) packets to be randomly dropped.

An optional correlation may also be added. This causes the random number generator to be less random and can be used to emulate packet burst losses.

# tc qdisc change dev eth0 root netem loss 0.3% 25%

This will cause 0.3% of packets to be lost, and each successive probability depends by a quarter on the last one.

Prob_n = 0.25 × Prob_n-1 + 0.75 × Random

Note that you should use tc qdisc add if you have no rules for that interface or tc qdisc change if you already have rules for that interface. Attempting to use tc qdisc change on an interface with no rules will give the error RTNETLINK answers: No such file or directory.

How many thousands of users?

I've run some TCP/IP client/server connection tests in the past on Windows 2003 Server and managed more than 70,000 connections on a reasonably low spec VM. (see here for details: http://www.lenholgate.com/blog/2005/10/the-64000-connection-question.html). I would be extremely surprised if Windows 2008 Server is limited to less than 2003 Server and, IMHO, the posting that Cloud links to is too vague to be much use. This kind of question comes up a lot, I blogged about why I don't really think that it's something that you should actually worry about here: http://www.serverframework.com/asynchronousevents/2010/12/one-million-tcp-connections.html.

Personally I'd test it and see. Even if there is no inherent limit in the Windows 2008 Server version that you intend to use there will still be practical limits based on memory, processor speed and server design.

If you want to run some 'generic' tests you can use my multi-client connection test and the associated echo server. Detailed here: http://www.lenholgate.com/blog/2005/11/windows-tcpip-server-performance.html and here: http://www.lenholgate.com/blog/2005/11/simple-echo-servers.html. These are what I used to run my own tests for my server framework and these are what allowed me to create 70,000 active connections on a Windows 2003 Server VM with 760MB of memory.

Edited to add details from the comment below...

If you're already thinking of multiple servers I'd take the following approach.

1. Use the free tools that I link to and prove to yourself that you can create a reasonable number of connections onto your target OS (beware of the Windows limits on dynamic ports which may cause your client connections to fail, search for MAX_USER_PORT).

2. during development regularly test your actual server with test clients that can create connections and actually 'do something' on the server. This will help to prevent you building the server in ways that restrict its scalability. See here: http://www.serverframework.com/asynchronousevents/2010/10/how-to-support-10000-or-more-concurrent-tcp-connections-part-2-perf-tests-from-day-0.html

They work almost the same as today. However, be sure you include [] around your IP.

For example : http://[1fff:0:a88:85a3::ac1f]:8001/index.html

Wikipedia has a pretty good article about IPv6: http://en.wikipedia.org/wiki/IPv6#Addressing

To answer to your second question. You can just hit the IP address of the machine that your flask app is running, e.g. 192.168.1.100 in a browser on different machine on the same network and you are there. Though, you will not be able to access it if you are on a different network. Firewalls or VLans can cause you problems with reaching your application. If that computer has a public IP, then you can hit that IP from anywhere on the planet and you will be able to reach the app. Usually this might impose some configuration, since most of the public servers are behind some sort of router or firewall.

Try run HTTP over UDP with node-httpp:

https://github.com/InstantWebP2P/node-httpp

If []byte is ASCII byte numbers then first convert the []byte to string and use the strconv package Atoi method which convert string to int.

package main
import (
    "fmt"
    "strconv"
)

func main() {
    byteNumber := []byte("14")
    byteToInt, _ := strconv.Atoi(string(byteNumber))
    fmt.Println(byteToInt)
}

go playground - https://play.golang.org/p/gEzxva8-BGP

Have no fear, because a brave group of Ops Programmers have solved the situation with a brand spanking new nginx_tcp_proxy_module

Written in August 2012, so if you are from the future you should do your homework.

Prerequisites

Assumes you are using CentOS:

• Remove current instance of NGINX (suggest using dev server for this)
• If possible, save your old NGINX config files so you can re-use them (that includes your init.d/nginx script)
• yum install pcre pcre-devel openssl openssl-devel and any other necessary libs for building NGINX
• Get the nginx_tcp_proxy_module from GitHub here https://github.com/yaoweibin/nginx_tcp_proxy_module and remember the folder where you placed it (make sure it is not zipped)

Build Your New NGINX

Again, assumes CentOS:

• cd /usr/local/
• wget 'http://nginx.org/download/nginx-1.2.1.tar.gz'
• tar -xzvf nginx-1.2.1.tar.gz
• cd nginx-1.2.1/
• patch -p1 < /path/to/nginx_tcp_proxy_module/tcp.patch
• ./configure --add-module=/path/to/nginx_tcp_proxy_module --with-http_ssl_module (you can add more modules if you need them)
• make
• make install

Optional:

• sudo /sbin/chkconfig nginx on

Set Up Nginx

Remember to copy over your old configuration files first if you want to re-use them.

Important: you will need to create a tcp {} directive at the highest level in your conf. Make sure it is not inside your http {} directive.

The example config below shows a single upstream websocket server, and two proxies for both SSL and Non-SSL.

tcp {
    upstream websockets {
        ## webbit websocket server in background
        server 127.0.0.1:5501;
        
        ## server 127.0.0.1:5502; ## add another server if you like!

        check interval=3000 rise=2 fall=5 timeout=1000;
    }   

    server {
        server_name _;
        listen 7070;

        timeout 43200000;
        websocket_connect_timeout 43200000;
        proxy_connect_timeout 43200000;

        so_keepalive on;
        tcp_nodelay on;

        websocket_pass websockets;
        websocket_buffer 1k;
    }

    server {
        server_name _;
        listen 7080;

        ssl on;
        ssl_certificate      /path/to/cert.pem;
        ssl_certificate_key  /path/to/key.key;

        timeout 43200000;
        websocket_connect_timeout 43200000;
        proxy_connect_timeout 43200000;

        so_keepalive on;
        tcp_nodelay on;

        websocket_pass websockets;
        websocket_buffer 1k;
    }
}

A connected socket is assigned to a new (dedicated) port

That's a common intuition, but it's incorrect. A connected socket is not assigned to a new/dedicated port. The only actual constraint that the TCP stack must satisfy is that the tuple of (local_address, local_port, remote_address, remote_port) must be unique for each socket connection. Thus the server can have many TCP sockets using the same local port, as long as each of the sockets on the port is connected to a different remote location.

See the "Socket Pair" paragraph at: http://books.google.com/books?id=ptSC4LpwGA0C&lpg=PA52&dq=socket%20pair%20tuple&pg=PA52#v=onepage&q=socket%20pair%20tuple&f=false

Maybe SO_REUSEADDR helps here? http://www.unixguide.net/network/socketfaq/4.5.shtml

When you create a TCP connection, you ask to connect to a specific TCP address, which is a combination of an IP address (v4 or v6, depending on the protocol you're using) and a port.

When a server listens for connections, it can inform the kernel that it would like to listen to a specific IP address and port, i.e., one TCP address, or on the same port on each of the host's IP addresses (usually specified with IP address 0.0.0.0), which is effectively listening on a lot of different "TCP addresses" (e.g., 192.168.1.10:8000, 127.0.0.1:8000, etc.)

No, you can't have two applications listening on the same "TCP address," because when a message comes in, how would the kernel know to which application to give the message?

However, you in most operating systems you can set up several IP addresses on a single interface (e.g., if you have 192.168.1.10 on an interface, you could also set up 192.168.1.11, if nobody else on the network is using it), and in those cases you could have separate applications listening on port 8000 on each of those two IP addresses.

It should be 65535.

Except for some internal logging, Close == Dispose.

Dispose calls tcpClient.Client.Shutdown( SocketShutdown.Both ), but its eats any errors. Maybe if you call it directly, you can get some useful exception information.

The absolute limitation on TCP packet size is 64K (65535 bytes), but in practicality this is far larger than the size of any packet you will see, because the lower layers (e.g. ethernet) have lower packet sizes.

The MTU (Maximum Transmission Unit) for Ethernet, for instance, is 1500 bytes. Some types of networks (like Token Ring) have larger MTUs, and some types have smaller MTUs, but the values are fixed for each physical technology.

Open a port in your server with netcat and start listening:

nc -lvp port number

And on the machine you are reading the serial port, send it with netcat as root:

nc <IP address> portnumber < /dev/ttyACM0

If you want to store the data on the server you can redirect the data to a text file.

First create a file where you are saving the data:

touch data.txt

And then start saving data

nc -lvp port number > data.txt

1. Open "Start" (Windows Button)
2. Search for "Turn Windows features On or Off"
3. Check "Telnet client" and check "Telnet server".

Network communication for video games is almost always done over UDP.

Speed is of utmost importance and it doesn't really matter if updates are missed since each update contains the complete current state of what the player can see.

i got this error because I closed ServerSocket inside a for loop that try to accept number of clients inside it (I did not finished accepting all clints)

so be careful where to close your Socket

JMeter's built-in proxy may be used to record all HTTP request/response information.

Firefox "Live HTTP headers" plugin may be used to see what is happening on the browser side when sending/receiving request.

Firefox "Tamper data" plugin may be useful when you need to intercept and modify request.

I thought I'd share the function I put together. Hopefully it can save you time.

It was originally used to track timing of a text-based script, so the output is in text form. But you can easily modify it to HTML if you prefer.

It will do all the calculations for you for how much time has been spent since the start of the script and in each step. It formats all the output with 3 decimals of precision. (Down to milliseconds.)

Once you copy it to the top of your script, all you do is put the recordTime function calls after each piece you want to time.

Copy this to the top of your script file:

$tRecordStart = microtime(true);
header("Content-Type: text/plain");
recordTime("Start");

function recordTime ($sName) {
  global $tRecordStart;
  static $tStartQ;
  $tS = microtime(true);
  $tElapsedSecs = $tS - $tRecordStart;
  $tElapsedSecsQ = $tS - $tStartQ;
  $sElapsedSecs = str_pad(number_format($tElapsedSecs, 3), 10, " ", STR_PAD_LEFT);
  $sElapsedSecsQ = number_format($tElapsedSecsQ, 3);
  echo "//".$sElapsedSecs." - ".$sName;
  if (!empty($tStartQ)) echo " In ".$sElapsedSecsQ."s";
  echo "\n";
  $tStartQ = $tS;
}

To track the time that passes, just do:

recordTime("What We Just Did")

For example:

recordTime("Something Else")
//Do really long operation.
recordTime("Really Long Operation")
//Do a short operation.
recordTime("A Short Operation")
//In a while loop.
for ($i = 0; $i < 300; $i ++) {
  recordTime("Loop Cycle ".$i)
}

Gives output like this:

//     0.000 - Start
//     0.001 - Something Else In 0.001s
//    10.779 - Really Long Operation In 10.778s
//    11.986 - A Short Operation In 1.207s
//    11.987 - Loop Cycle 0 In 0.001s
//    11.987 - Loop Cycle 1 In 0.000s
...
//    12.007 - Loop Cycle 299 In 0.000s

Hope this helps someone!

POD in C++11 was basically split into two different axes here: triviality and layout. Triviality is about the relationship between an object's conceptual value and the bits of data within its storage. Layout is about... well, the layout of an object's subobjects. Only class types have layout, while all types have triviality relationships.

So here is what the triviality axis is about:

1. Non-trivially copyable: The value of objects of such types may be more than just the binary data that are stored directly within the object.

   For example, unique_ptr<T> stores a T*; that is the totality of the binary data within the object. But that's not the totality of the value of a unique_ptr<T>. A unique_ptr<T> stores either a nullptr or a pointer to an object whose lifetime is managed by the unique_ptr<T> instance. That management is part of the value of a unique_ptr<T>. And that value is not part of the binary data of the object; it is created by the various member functions of that object.

   For example, to assign nullptr to a unique_ptr<T> is to do more than just change the bits stored in the object. Such an assignment must destroy any object managed by the unique_ptr. To manipulate the internal storage of a unique_ptr without going through its member functions would damage this mechanism, to change its internal T* without destroying the object it currently manages, would violate the conceptual value that the object possesses.

2. Trivially copyable: The value of such objects are exactly and only the contents of their binary storage. This is what makes it reasonable to allow copying that binary storage to be equivalent to copying the object itself.

   The specific rules that define trivial copyability (trivial destructor, trivial/deleted copy/move constructors/assignment) are what is required for a type to be binary-value-only. An object's destructor can participate in defining the "value" of an object, as in the case with unique_ptr. If that destructor is trivial, then it doesn't participate in defining the object's value.

   Specialized copy/move operations also can participate in an object's value. unique_ptr's move constructor modifies the source of the move operation by null-ing it out. This is what ensures that the value of a unique_ptr is unique. Trivial copy/move operations mean that such object value shenanigans are not being played, so the object's value can only be the binary data it stores.

3. Trivial: This object is considered to have a functional value for any bits that it stores. Trivially copyable defines the meaning of the data store of an object as being just that data. But such types can still control how data gets there (to some extent). Such a type can have default member initializers and/or a default constructor that ensures that a particular member always has a particular value. And thus, the conceptual value of the object can be restricted to a subset of the binary data that it could store.

   Performing default initialization on a type that has a trivial default constructor will leave that object with completely uninitialized values. As such, a type with a trivial default constructor is logically valid with any binary data in its data storage.

The layout axis is really quite simple. Compilers are given a lot of leeway in deciding how the subobjects of a class are stored within the class's storage. However, there are some cases where this leeway is not necessary, and having more rigid ordering guarantees is useful.

Such types are standard layout types. And the C++ standard doesn't even really do much with saying what that layout is specifically. It basically says three things about standard layout types:

1. The first subobject is at the same address as the object itself.

2. You can use offsetof to get a byte offset from the outer object to one of its member subobjects.

3. unions get to play some games with accessing subobjects through an inactive member of a union if the active member is (at least partially) using the same layout as the inactive one being accessed.

Compilers generally permit standard layout objects to map to struct types with the same members in C. But there is no statement of that in the C++ standard; that's just what compilers feel like doing.

POD is basically a useless term at this point. It is just the intersection of trivial copyability (the value is only its binary data) and standard layout (the order of its subobjects is more well-defined). One can infer from such things that the type is C-like and could map to similar C objects. But the standard has no statements to that effect.

can you please elaborate following rules:

I'll try:

a) standard-layout classes must have all non-static data members with the same access control

That's simple: all non-static data members must all be public, private, or protected. You can't have some public and some private.

The reasoning for them goes to the reasoning for having a distinction between "standard layout" and "not standard layout" at all. Namely, to give the compiler the freedom to choose how to put things into memory. It's not just about vtable pointers.

Back when they standardized C++ in 98, they had to basically predict how people would implement it. While they had quite a bit of implementation experience with various flavors of C++, they weren't certain about things. So they decided to be cautious: give the compilers as much freedom as possible.

That's why the definition of POD in C++98 is so strict. It gave C++ compilers great latitude on member layout for most classes. Basically, POD types were intended to be special cases, something you specifically wrote for a reason.

When C++11 was being worked on, they had a lot more experience with compilers. And they realized that... C++ compiler writers are really lazy. They had all this freedom, but they didn't do anything with it.

The rules of standard layout are more or less codifying common practice: most compilers didn't really have to change much if anything at all to implement them (outside of maybe some stuff for the corresponding type traits).

Now, when it came to public/private, things are different. The freedom to reorder which members are public vs. private actually can matter to the compiler, particularly in debugging builds. And since the point of standard layout is that there is compatibility with other languages, you can't have the layout be different in debug vs. release.

Then there's the fact that it doesn't really hurt the user. If you're making an encapsulated class, odds are good that all of your data members will be private anyway. You generally don't expose public data members on fully encapsulated types. So this would only be a problem for those few users who do want to do that, who want that division.

So it's no big loss.

b) only one class in the whole inheritance tree can have non-static data members,

The reason for this one comes back to why they standardized standard layout again: common practice.

There's no common practice when it comes to having two members of an inheritance tree that actually store things. Some put the base class before the derived, others do it the other way. Which way do you order the members if they come from two base classes? And so on. Compilers diverge greatly on these questions.

Also, thanks to the zero/one/infinity rule, once you say you can have two classes with members, you can say as many as you want. This requires adding a lot of layout rules for how to handle this. You have to say how multiple inheritance works, which classes put their data before other classes, etc. That's a lot of rules, for very little material gain.

You can't make everything that doesn't have virtual functions and a default constructor standard layout.

and the first non-static data member cannot be of a base class type (this could break aliasing rules).

I can't really speak to this one. I'm not educated enough in C++'s aliasing rules to really understand it. But it has something to do with the fact that the base member will share the same address as the base class itself. That is:

struct Base {};
struct Derived : Base { Base b; };

Derived d;
static_cast<Base*>(&d) == &d.b;

And that's probably against C++'s aliasing rules. In some way.

However, consider this: how useful could having the ability to do this ever actually be? Since only one class can have non-static data members, then Derived must be that class (since it has a Base as a member). So Base must be empty (of data). And if Base is empty, as well as a base class... why have a data member of it at all?

Since Base is empty, it has no state. So any non-static member functions will do what they do based on their parameters, not their this pointer.

So again: no big loss.

I was looking for a similar solution, trying to find SQL that work work in PostgreSQL as well as HSQLDB. (HSQLDB was what made this difficult.) Using your example as a basis, this is the format that I found elsewhere.

sql = "INSERT INTO hundred (name,name_slug,status)"
sql += " ( SELECT " + hundred + ", '" + hundred_slug + "', " + status
sql += " FROM hundred"
sql += " WHERE name = " + hundred + " AND name_slug = '" + hundred_slug + "' AND status = " + status
sql += " HAVING COUNT(*) = 0 );"

Try /public_html/stats/* ?

But since the files in git status reported as to be commited that means you've already added them manually. In which case, of course, it's a bit too late to ignore. You can git rm --cache them (IIRC).

204:

No Content.” This code means that the server has successfully processed the request, but is not going to return any content

https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/204

You can use monitorEvents function.

Just inspect your element (right mouse click ? Inspect on visible element or go to Elements tab in Chrome Developer Tools and select wanted element) then go to Console tab and write:

monitorEvents($0)

Now when you move mouse over this element, focus or click it, the name of the fired event will be displayed with its data.

To stop getting this data just write this to console:

unmonitorEvents($0)

$0 is just the last DOM element selected by Chrome Developer Tools. You can pass any other DOM object there (for example result of getElementById or querySelector).

You can also specify event "type" as second parameter to narrow monitored events to some predefined set. For example:

monitorEvents(document.body, 'mouse')

List of this available types is here.

I made a small gif that illustrates how this feature works:

Apache commons to the rescue again.

assertTrue(CollectionUtils.isEqualCollection(coll1, coll2));

Works like a charm. I don't know why but I found that with collections the following assertEquals(coll1, coll2) doesn't always work. In the case where it failed for me I had two collections backed by Sets. Neither hamcrest nor junit would say the collections were equal even though I knew for sure that they were. Using CollectionUtils it works perfectly.

Importing file2 in file1.py makes the global (i.e., module level) names bound in file2 available to following code in file1 -- the only such name is SomeClass. It does not do the reverse: names defined in file1 are not made available to code in file2 when file1 imports file2. This would be the case even if you imported the right way (import file2, as @nate correctly recommends) rather than in the horrible, horrible way you're doing it (if everybody under the Sun forgot the very existence of the construct from ... import *, life would be so much better for everybody).

Apparently you want to make global names defined in file1 available to code in file2 and vice versa. This is known as a "cyclical dependency" and is a terrible idea (in Python, or anywhere else for that matter).

So, rather than showing you the incredibly fragile, often unmaintainable hacks to achieve (some semblance of) a cyclical dependency in Python, I'd much rather discuss the many excellent way in which you can avoid such terrible structure.

For example, you could put global names that need to be available to both modules in a third module (e.g. file3.py, to continue your naming streak;-) and import that third module into each of the other two (import file3 in both file1 and file2, and then use file3.foo etc, that is, qualified names, for the purpose of accessing or setting those global names from either or both of the other modules, not barenames).

Of course, more and more specific help could be offered if you clarified (by editing your Q) exactly why you think you need a cyclical dependency (just one easy prediction: no matter what makes you think you need a cyclical dependency, you're wrong;-).

I was trying to test an extjs application and after sucessfully setting a testingAuthenticationToken this suddenly stopped working with no obvious cause.

I couldn't get the above answers to work so my solution was to skip out this bit of spring in the test environment. I introduced a seam around spring like this:

public class SpringUserAccessor implements UserAccessor
{
    @Override
    public User getUser()
    {
        SecurityContext context = SecurityContextHolder.getContext();
        Authentication authentication = context.getAuthentication();
        return (User) authentication.getPrincipal();
    }
}

User is a custom type here.

I'm then wrapping it in a class which just has an option for the test code to switch spring out.

public class CurrentUserAccessor
{
    private static UserAccessor _accessor;

    public CurrentUserAccessor()
    {
        _accessor = new SpringUserAccessor();
    }

    public User getUser()
    {
        return _accessor.getUser();
    }

    public static void UseTestingAccessor(User user)
    {
        _accessor = new TestUserAccessor(user);
    }
}

The test version just looks like this:

public class TestUserAccessor implements UserAccessor
{
    private static User _user;

    public TestUserAccessor(User user)
    {
        _user = user;
    }

    @Override
    public User getUser()
    {
        return _user;
    }
}

In the calling code I'm still using a proper user loaded from the database:

    User user = (User) _userService.loadUserByUsername(username);
    CurrentUserAccessor.UseTestingAccessor(user);

Obviously this wont be suitable if you actually need to use the security but I'm running with a no-security setup for the testing deployment. I thought someone else might run into a similar situation. This is a pattern I've used for mocking out static dependencies before. The other alternative is you can maintain the staticness of the wrapper class but I prefer this one as the dependencies of the code are more explicit since you have to pass CurrentUserAccessor into classes where it is required.

Are'nt you creating the pdf file but not actually writing the byte array back? Therefore you cannot open the PDF.

out = new FileOutputStream("D:/ABC_XYZ/1.pdf");
out.Write(b, 0, b.Length);
out.Position = 0;
out.Close();

This is in addition to correctly reading in the PDF to byte array.

Here is an example of one of our stored procedures that executes multiple stored procedures within it:

ALTER PROCEDURE [dbo].[AssetLibrary_AssetDelete]
(
    @AssetID AS uniqueidentifier
)
AS

SET NOCOUNT ON

SET TRANSACTION ISOLATION LEVEL READ COMMITTED

EXEC AssetLibrary_AssetDeleteAttributes @AssetID
EXEC AssetLibrary_AssetDeleteComponents @AssetID
EXEC AssetLibrary_AssetDeleteAgreements @AssetID
EXEC AssetLibrary_AssetDeleteMaintenance @AssetID

DELETE FROM
    AssetLibrary_Asset
WHERE
    AssetLibrary_Asset.AssetID = @AssetID

RETURN (@@ERROR)

First get the instance of SharedPreferences using

SharedPreferences userDetails = context.getSharedPreferences("userdetails", MODE_PRIVATE);

Now to save the values in the SharedPreferences

Editor edit = userDetails.edit();
edit.putString("username", username.getText().toString().trim());
edit.putString("password", password.getText().toString().trim());
edit.apply();

Above lines will write username and password to preference

Now to to retrieve saved values from preference, you can follow below lines of code

String userName = userDetails.getString("username", "");
String password = userDetails.getString("password", "");

(NOTE: SAVING PASSWORD IN THE APP IS NOT RECOMMENDED. YOU SHOULD EITHER ENCRYPT THE PASSWORD BEFORE SAVING OR SKIP THE SAVING THE PASSWORD)

I am gonna explain with a simple example code which takes a compare function as parameter to another sorting function. Lets say I have a bubble sort function that takes a custom compare function and uses it instead of a fixed if statement.

Compare Function

bool compare(int a, int b) {
    return a > b;
}

Now , the Bubble sort that takes another function as its parameter to perform comparison

Bubble sort function

void bubble_sort(int arr[], int n, bool (&cmp)(int a, int b)) {

    for (int i = 0;i < n - 1;i++) {
        for (int j = 0;j < (n - 1 - i);j++) {
            
            if (cmp(arr[j], arr[j + 1])) {
                swap(arr[j], arr[j + 1]);
            }
        }
    }
}

Finally , the main which calls the Bubble sort function by passing the boolean compare function as argument.

int main()
{
    int i, n = 10, key = 11;
    int arr[10] = { 20, 22, 18, 8, 12, 3, 6, 12, 11, 15 };

    bubble_sort(arr, n, compare);
    cout<<"Sorted Order"<<endl;
    for (int i = 0;i < n;i++) {
        cout << arr[i] << " ";
    }
}

Output:

Sorted Order
3 6 8 11 12 12 15 18 20 22

Fail module works great! Thanks.

I had to define my fact before checking it, otherwise I'd get an undefined variable error.

And I had issues when doing setting the fact with quotes and without spaces.

This worked:

set_fact: flag="failed"

This threw errors:

set_fact: flag = failed 

You can also use let data = String(decoding: myStr, as: UTF8.self) here is a resource about converting data to string

Use Form.Activate() or Form.Focus() methods.

You can have multiple CSS declarations for the same properties by separating them with commas:

.abc, .xyz {
   margin-left: 20px;
}

It seems to me removeProp is not working properly in Chrome : jsfiddle

        $('#badBut1').click(function () {
        checkit('Before');
        if( $('#chk').prop('checked') )
        {
          $('#chk').removeProp('checked');
        }else{
            $('#chk').prop('checked', true);
        }
        checkit('After');
    });
    $('#But1').click(function () {
        checkit('Before');
        if( $('#chk').prop('checked') )
        {
          $('#chk').removeClass('checked').prop('checked',false);
        }else{
            $('#chk').addClass('checked').prop('checked', true);
        }
        checkit('After');
    });

    $('#But2').click(function () {
        var chk1 = $('#chk').is(':checked');
        console.log("Value : " + chk1);
    });

    $('#chk').on( 'change',function () {
        checkit('Result');
    });
    function checkit(moment) {
        var chk1 = $('#chk').is(':checked');
        console.log(moment+", value = " + chk1);
    };

The Date object is used to work with dates and times.

Date objects are created with new Date().

var date= new Date();

 function myFunction() {
        var currentTime = new Date();
        Logger.log(currentTime);
    }

Use !empty instead of isset. isset return true for $_POST because $_POST array is superglobal and always exists (set).

Or better use $_SERVER['REQUEST_METHOD'] == 'POST'

I've also been successful with this URL structure:

Base URL:

https://calendar.google.com/calendar/r/eventedit?

And let's say this is my event details:

Title: Event Title
Description: Example of some description. See more at https://stackoverflow.com/questions/10488831/link-to-add-to-google-calendar
Location: 123 Some Place
Date: February 22, 2020
Start Time: 10:00am
End Time: 11:30am
Timezone: America/New York (GMT -5)

I'd convert my details into these parameters (URL encoded):

text=Event%20Title
details=Example%20of%20some%20description.%20See%20more%20at%20https%3A%2F%2Fstackoverflow.com%2Fquestions%2F10488831%2Flink-to-add-to-google-calendar
location=123%20Some%20Place%2C%20City
dates=20200222T100000/20200222T113000
ctz=America%2FNew_York

Example link:

https://calendar.google.com/calendar/r/eventedit?text=Event%20Title&details=Example%20of%20some%20description.%20See%20more%20at%20https%3A%2F%2Fstackoverflow.com%2Fquestions%2F10488831%2Flink-to-add-to-google-calendar&location=123%20Some%20Place%2C%20City&dates=20200222T100000/20200222T113000&ctz=America%2FNew_York

Please note that since I've specified a timezone with the "ctz" parameter, I used the local times for the start and end dates. Alternatively, you can use UTC dates and exclude the timezone parameter, like this:

dates=20200222T150000Z/20200222T163000Z

Example link:

https://calendar.google.com/calendar/r/eventedit?text=Event%20Title&details=Example%20of%20some%20description.%20See%20more%20at%20https%3A%2F%2Fstackoverflow.com%2Fquestions%2F10488831%2Flink-to-add-to-google-calendar&location=123%20Some%20Place%2C%20City&dates=20200222T150000Z/20200222T163000Z

Please note if you are downloading from the FTP to your local, you will need to use the following:

with open( filename, 'wb' ) as file :
        ftp.retrbinary('RETR %s' % filename, file.write)

Otherwise, the script will at your local file storage rather than the FTP.

I spent a few hours making the mistake myself.

Script below:

import ftplib

# Open the FTP connection
ftp = ftplib.FTP()
ftp.cwd('/where/files-are/located')


filenames = ftp.nlst()

for filename in filenames:

    with open( filename, 'wb' ) as file :
        ftp.retrbinary('RETR %s' % filename, file.write)

        file.close()

ftp.quit()

I had the same issue. But it can run properly with switching from company's internal network to visitor network.

You can also change the position of the body/html to fixed:

body,
html {
  position: fixed;
}

$(document).ready(function(){
  var dir = "test/"; // folder location
  var fileextension = ".jpg"; // image format
  var i = "1";

  $(function imageloop(){
    $("<img />").attr('src', dir + i + fileextension ).appendTo(".testing");
    if (i==13){
      alert('loaded');
    }
    else{
      i++;
      imageloop();
    };
  });   
});

For this script, I have named my image files in a folder as 1.jpg, 2.jpg, 3.jpg, ... to 13.jpg.

You can change directory and file names as you wish.

If your set command supports the /p switch, then you can pipe input that way.

set /p VAR1=<test.txt
set /? |find "/P"

The /P switch allows you to set the value of a variable to a line of input entered by the user. Displays the specified promptString before reading the line of input. The promptString can be empty.

This has the added benefit of working for un-registered file types (which the accepted answer does not).

It doesn't look like DD-MMM-YYYY is supported by default (at least, with dash as separator). However, using the AS clause, you should be able to do something like:

SELECT CONVERT(VARCHAR(11), SYSDATETIME(), 106) AS [DD-MON-YYYY]

See here: http://www.sql-server-helper.com/sql-server-2008/sql-server-2008-date-format.aspx

I had the exact same issue, after rightly have configured in Mac OSX host a SharedFolder with Auto-Mount enabled. On the Guest OS, it is also required to install VirtualBox Guest Additions. For the case of Windows, it is:

VBoxWindowsAdditions.exe

Right after this installation, i could perfectly view the shared folder content under This PC and Network ("\VBOXSVR\Installers").

Assuming the MyEjbProject is not another Maven Project you own or want to build with maven, you could use system dependencies to link to the existing jar file of the project like so

<project>
   ...
   <dependencies>
      <dependency>
         <groupId>yourgroup</groupId>
         <artifactId>myejbproject</artifactId>
         <version>2.0</version>
         <scope>system</scope>
         <systemPath>path/to/myejbproject.jar</systemPath>
      </dependency>
   </dependencies>
   ...
</project>

That said it is usually the better (and preferred way) to install the package to the repository either by making it a maven project and building it or installing it the way you already seem to do.

If they are, however, dependent on each other, you can always create a separate parent project (has to be a "pom" project) declaring the two other projects as its "modules". (The child projects would not have to declare the third project as their parent). As a consequence you'd get a new directory for the new parent project, where you'd also quite probably put the two independent projects like this:

parent
|- pom.xml
|- MyEJBProject
|   `- pom.xml
`- MyWarProject
    `- pom.xml

The parent project would get a "modules" section to name all the child modules. The aggregator would then use the dependencies in the child modules to actually find out the order in which the projects are to be built)

<project>
   ...
   <artifactId>myparentproject</artifactId>
   <groupId>...</groupId>
   <version>...</version>

   <packaging>pom</packaging>
   ...
   <modules>
     <module>MyEJBModule</module>
     <module>MyWarModule</module>
   </modules>
   ...
</project>

That way the projects can relate to each other but (once they are installed in the local repository) still be used independently as artifacts in other projects

Finally, if your projects are not in related directories, you might try to give them as relative modules:

filesystem
 |- mywarproject
 |   `pom.xml
 |- myejbproject
 |   `pom.xml
 `- parent
     `pom.xml

now you could just do this (worked in maven 2, just tried it):

<!--parent-->
<project>
  <modules>
    <module>../mywarproject</module>
    <module>../myejbproject</module>
  </modules>
</project>

This is not a question about make, it is a question about the semantic of the #include directive.

The problem is, that there is no file at the path "../StdCUtil/StdCUtil/split.h". This is the path that results when the compiler combines the include path "../StdCUtil" with the relative path from the #include directive "StdCUtil/split.h".

To fix this, just use -I.. instead of -I../StdCUtil.

It is simple. take a look at this

https://codepen.io/anon/pen/mepogj?editors=001

basically you want to deal with states of your component so you check the currently active one. you will need to include

getInitialState: function(){}
//and 
isActive: function(){}

check out the code on the link

If you're using lodash:

_.endsWith('abc', 'c'); // true

If not using lodash, you can borrow from its source.

The easiest way is to use the library commands

import commands
print commands.getstatusoutput('echo "test" | wc')

You must set proxy server for gradle at some time, you can try to change the proxy server ip address in gradle.properties which is under .gradle document

Alternatively, in situations where I want to return a number of things from a method I will sometimes use a callback mechanism instead of a container. This works very well in situations where I cannot specify ahead of time just how many objects will be generated.

With your particular problem, it would look something like this:

public class ResultsConsumer implements ResultsGenerator.ResultsCallback
{
    public void handleResult( String name, Object value )
    {
        ... 
    }
}

public class ResultsGenerator
{
    public interface ResultsCallback
    {
        void handleResult( String aName, Object aValue );
    }

    public void generateResults( ResultsGenerator.ResultsCallback aCallback )
    {
        Object value = null;
        String name = null;

        ...

        aCallback.handleResult( name, value );
    }
}

I can't guarantee it's the simplest, but I like MarkerWithLabel. As shown in the basic example, CSS styles define the label's appearance and options in the JavaScript define the content and placement.

 .labels {
   color: red;
   background-color: white;
   font-family: "Lucida Grande", "Arial", sans-serif;
   font-size: 10px;
   font-weight: bold;
   text-align: center;
   width: 60px;     
   border: 2px solid black;
   white-space: nowrap;
 }

JavaScript:

 var marker = new MarkerWithLabel({
   position: homeLatLng,
   draggable: true,
   map: map,
   labelContent: "$425K",
   labelAnchor: new google.maps.Point(22, 0),
   labelClass: "labels", // the CSS class for the label
   labelStyle: {opacity: 0.75}
 });

The only part that may be confusing is the labelAnchor. By default, the label's top left corner will line up to the marker pushpin's endpoint. Setting the labelAnchor's x-value to half the width defined in the CSS width property will center the label. You can make the label float above the marker pushpin with an anchor point like new google.maps.Point(22, 50).

In case access to the links above are blocked, I copied and pasted the packed source of MarkerWithLabel into this JSFiddle demo. I hope JSFiddle is allowed in China :|

I encountered a similar problem when I was using the below to obtain connection factory ConnectionFactory factory = new
ActiveMQConnectionFactory("admin","admin","tcp://:61616");

Its resolved when I changed it to the below

ConnectionFactory factory = new ActiveMQConnectionFactory("tcp://:61616");

The below then showed that my Q size was increasing.. http://:8161/admin/queues.jsp

use this command php artisan migrate --path=/database/migrations/my_migration.php it worked for me..

JSONArray jsonArray = new JSONArray();

for (loop) {
    JSONObject jsonObj= new JSONObject();
    jsonObj.put("srcOfPhoto", srcOfPhoto);
    jsonObj.put("username", "name"+count);
    jsonObj.put("userid", "userid"+count);

    jsonArray.put(jsonObj.valueToString());
}

JSONObject parameters = new JSONObject();

parameters.put("action", "remove");

parameters.put("datatable", jsonArray );

parameters.put(Constant.MSG_TYPE , Constant.SUCCESS);

Why were you using an Hashmap if what you wanted was to put it into a JSONObject?

EDIT: As per http://www.json.org/javadoc/org/json/JSONArray.html

EDIT2: On the JSONObject method used, I'm following the code available at: https://github.com/stleary/JSON-java/blob/master/JSONObject.java#L2327 , that method is not deprecated.

We're storing a string representation of the JSONObject, not the JSONObject itself

You may append the 3 bytes to the file before exporting, it works for me . Before doing that system only work in Windows and HP -UX but failed in Linux.

FileOutputStream fStream = new FileOutputStream( f );
final byte[] bom = new byte[] { (byte) 0xEF, (byte) 0xBB, (byte) 0xBF };
OutputStreamWriter writer = new OutputStreamWriter( fStream, "UTF8" );
fStream.write( bom );

Have a UTF-8 BOM (3 bytes, hex EF BB BF) at the start of the file. Otherwise Excel will interpret the data according to your locale's default encoding (e.g. cp1252) instead of utf-8

Generating CSV file for Excel, how to have a newline inside a value

{ getApplicationContext.finish();   }

Try this method..

From Oracle 11gR2, the LISTAGG clause should do the trick:

SELECT question_id,
       LISTAGG(element_id, ',') WITHIN GROUP (ORDER BY element_id)
FROM YOUR_TABLE
GROUP BY question_id;

Beware if the resulting string is too big (more than 4000 chars for a VARCHAR2, for instance): from version 12cR2, we can use ON OVERFLOW TRUNCATE/ERROR to deal with this issue.

Postgresql have limit.

Oracle's code:

select *
from
  tbl
where rownum <= 1000;

same in Postgresql's code:

select *
from
  tbl
limit 1000

Use str = ""+a+b+c;

Here the first + is String concat, so the result will be a String. Note where the "" lies is important.

Or (maybe) better, use a StringBuilder.

Adding the async keyword is just syntactic sugar to simplify the creation of a state machine. In essence, the compiler takes your code;

public async Task MethodName()
{
     return null;
}

And turns it into;

public Task MethodName()
{
     return Task.FromResult<object>(null);
}

If your code has any await keywords, the compiler must take your method and turn it into a class to represent the state machine required to execute it. At each await keyword, the state of variables and the stack will be preserved in the fields of the class, the class will add itself as a completion hook to the task you are waiting on, then return.

When that task completes, your task will be executed again. So some extra code is added to the top of the method to restore the state of variables and jump into the next slab of your code.

See What does async & await generate? for a gory example.

This process has a lot in common with the way the compiler handles iterator methods with yield statements.

you can use command

date | awk '{print $4}'| cut -d ':' -f3

as you mentioned using only the date|awk '{print $4}' pipeline gives you something like this

20:18:19

so as we can see if we want to extract some part of this string then we need a delimiter , for our case it is :, so we decide to chop on the basis of :. Now this delimiter will chop the string into three parts i.e. 20 ,18 and 19 , as we want the second one we use -f2 in our command. to sum up ,

cut : chops some string based on delimeter.

-d : delimeter (here :)

-f2 : the chopped off token that we want.

matcher.find() does not find all matches, only the next match.

Solution for Java 9+

long matches = matcher.results().count();

Solution for Java 8 and older

You'll have to do the following. (Starting from Java 9, there is a nicer solution)

int count = 0;
while (matcher.find())
    count++;

Btw, matcher.groupCount() is something completely different.

Complete example:

import java.util.regex.*;

class Test {
    public static void main(String[] args) {
        String hello = "HelloxxxHelloxxxHello";
        Pattern pattern = Pattern.compile("Hello");
        Matcher matcher = pattern.matcher(hello);

        int count = 0;
        while (matcher.find())
            count++;

        System.out.println(count);    // prints 3
    }
}

Handling overlapping matches

When counting matches of aa in aaaa the above snippet will give you 2.

aaaa
aa
  aa

To get 3 matches, i.e. this behavior:

aaaa
aa
 aa
  aa

You have to search for a match at index <start of last match> + 1 as follows:

String hello = "aaaa";
Pattern pattern = Pattern.compile("aa");
Matcher matcher = pattern.matcher(hello);

int count = 0;
int i = 0;
while (matcher.find(i)) {
    count++;
    i = matcher.start() + 1;
}

System.out.println(count);    // prints 3

You can also use binding

<TextBlock Text="{Binding MyText}"/>

And set MyText like this:

Public string MyText
{
    get{return string.Format("My Text \n Your Text");}
}

To get getActiveNetworkInfo() to work you need to add the following to the manifest.

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

I just found a new trick to center a box in the middle of the screen even if you don't have fixed dimensions. Let's say you would like a box 60% width / 60% height. The way to make it centered is by creating 2 boxes: a "container" box that position left: 50% top :50%, and a "text" box inside with reverse position left: -50%; top :-50%;

It works and it's cross browser compatible.

Check out the code below, you probably get a better explanation:

jQuery('.close a, .bg', '#message').on('click', function() {_x000D_
  jQuery('#message').fadeOut();_x000D_
  return false;_x000D_
});

html, body {_x000D_
  min-height: 100%;_x000D_
}_x000D_
_x000D_
#message {_x000D_
  height: 100%;_x000D_
  left: 0;_x000D_
  position: fixed;_x000D_
  top: 0;_x000D_
  width: 100%;_x000D_
}_x000D_
_x000D_
#message .container {_x000D_
  height: 60%;_x000D_
  left: 50%;_x000D_
  position: absolute;_x000D_
  top: 50%;_x000D_
  z-index: 10;_x000D_
  width: 60%;_x000D_
}_x000D_
_x000D_
#message .container .text {_x000D_
  background: #fff;_x000D_
  height: 100%;_x000D_
  left: -50%;_x000D_
  position: absolute;_x000D_
  top: -50%;_x000D_
  width: 100%;_x000D_
}_x000D_
_x000D_
#message .bg {_x000D_
  background: rgba(0, 0, 0, 0.5);_x000D_
  height: 100%;_x000D_
  left: 0;_x000D_
  position: absolute;_x000D_
  top: 0;_x000D_
  width: 100%;_x000D_
  z-index: 9;_x000D_
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>_x000D_
<div id="message">_x000D_
  <div class="container">_x000D_
    <div class="text">_x000D_
      <h2>Warning</h2>_x000D_
      <p>The message</p>_x000D_
      <p class="close"><a href="#">Close Window</a></p>_x000D_
    </div>_x000D_
  </div>_x000D_
  <div class="bg"></div>_x000D_
</div>

Here it is:

s = "123"
try:
  i = int(s)
except ValueError as verr:
  pass # do job to handle: s does not contain anything convertible to int
except Exception as ex:
  pass # do job to handle: Exception occurred while converting to int

This is my solution which works fairly well:

private Location bestLocation = null;
private Looper looper;
private boolean networkEnabled = false, gpsEnabled = false;

private synchronized void setLooper(Looper looper) {
    this.looper = looper;
}

private synchronized void stopLooper() {
    if (looper == null) return;
    looper.quit();
}

@Override
protected void runTask() {
    final LocationManager locationManager = (LocationManager) service
            .getSystemService(Context.LOCATION_SERVICE);
    final SharedPreferences prefs = getPreferences();
    final int maxPollingTime = Integer.parseInt(prefs.getString(
            POLLING_KEY, "0"));
    final int desiredAccuracy = Integer.parseInt(prefs.getString(
            DESIRED_KEY, "0"));
    final int acceptedAccuracy = Integer.parseInt(prefs.getString(
            ACCEPTED_KEY, "0"));
    final int maxAge = Integer.parseInt(prefs.getString(AGE_KEY, "0"));
    final String whichProvider = prefs.getString(PROVIDER_KEY, "any");
    final boolean canUseGps = whichProvider.equals("gps")
            || whichProvider.equals("any");
    final boolean canUseNetwork = whichProvider.equals("network")
            || whichProvider.equals("any");
    if (canUseNetwork)
        networkEnabled = locationManager
                .isProviderEnabled(LocationManager.NETWORK_PROVIDER);
    if (canUseGps)
        gpsEnabled = locationManager
                .isProviderEnabled(LocationManager.GPS_PROVIDER);
    // If any provider is enabled now and we displayed a notification clear it.
    if (gpsEnabled || networkEnabled) removeErrorNotification();
    if (gpsEnabled)
        updateBestLocation(locationManager
                .getLastKnownLocation(LocationManager.GPS_PROVIDER));
    if (networkEnabled)
        updateBestLocation(locationManager
                .getLastKnownLocation(LocationManager.NETWORK_PROVIDER));
    if (desiredAccuracy == 0
            || getLocationQuality(desiredAccuracy, acceptedAccuracy,
                    maxAge, bestLocation) != LocationQuality.GOOD) {
        // Define a listener that responds to location updates
        LocationListener locationListener = new LocationListener() {

            public void onLocationChanged(Location location) {
                updateBestLocation(location);
                if (desiredAccuracy != 0
                        && getLocationQuality(desiredAccuracy,
                                acceptedAccuracy, maxAge, bestLocation)
                                == LocationQuality.GOOD)
                    stopLooper();
            }

            public void onProviderEnabled(String provider) {
                if (isSameProvider(provider,
                        LocationManager.NETWORK_PROVIDER))networkEnabled =true;
                else if (isSameProvider(provider,
                        LocationManager.GPS_PROVIDER)) gpsEnabled = true;
                // The user has enabled a location, remove any error
                // notification
                if (canUseGps && gpsEnabled || canUseNetwork
                        && networkEnabled) removeErrorNotification();
            }

            public void onProviderDisabled(String provider) {
                if (isSameProvider(provider,
                        LocationManager.NETWORK_PROVIDER))networkEnabled=false;
                else if (isSameProvider(provider,
                        LocationManager.GPS_PROVIDER)) gpsEnabled = false;
                if (!gpsEnabled && !networkEnabled) {
                    showErrorNotification();
                    stopLooper();
                }
            }

            public void onStatusChanged(String provider, int status,
                    Bundle extras) {
                Log.i(LOG_TAG, "Provider " + provider + " statusChanged");
                if (isSameProvider(provider,
                        LocationManager.NETWORK_PROVIDER)) networkEnabled = 
                        status == LocationProvider.AVAILABLE
                        || status == LocationProvider.TEMPORARILY_UNAVAILABLE;
                else if (isSameProvider(provider,
                        LocationManager.GPS_PROVIDER))
                    gpsEnabled = status == LocationProvider.AVAILABLE
                      || status == LocationProvider.TEMPORARILY_UNAVAILABLE;
                // None of them are available, stop listening
                if (!networkEnabled && !gpsEnabled) {
                    showErrorNotification();
                    stopLooper();
                }
                // The user has enabled a location, remove any error
                // notification
                else if (canUseGps && gpsEnabled || canUseNetwork
                        && networkEnabled) removeErrorNotification();
            }
        };
        if (networkEnabled || gpsEnabled) {
            Looper.prepare();
            setLooper(Looper.myLooper());
            // Register the listener with the Location Manager to receive
            // location updates
            if (canUseGps)
                locationManager.requestLocationUpdates(
                        LocationManager.GPS_PROVIDER, 1000, 1,
                        locationListener, Looper.myLooper());
            if (canUseNetwork)
                locationManager.requestLocationUpdates(
                        LocationManager.NETWORK_PROVIDER, 1000, 1,
                        locationListener, Looper.myLooper());
            Timer t = new Timer();
            t.schedule(new TimerTask() {

                @Override
                public void run() {
                    stopLooper();
                }
            }, maxPollingTime * 1000);
            Looper.loop();
            t.cancel();
            setLooper(null);
            locationManager.removeUpdates(locationListener);
        } else // No provider is enabled, show a notification
        showErrorNotification();
    }
    if (getLocationQuality(desiredAccuracy, acceptedAccuracy, maxAge,
            bestLocation) != LocationQuality.BAD) {
        sendUpdate(new Event(EVENT_TYPE, locationToString(desiredAccuracy,
                acceptedAccuracy, maxAge, bestLocation)));
    } else Log.w(LOG_TAG, "LocationCollector failed to get a location");
}

private synchronized void showErrorNotification() {
    if (notifId != 0) return;
    ServiceHandler handler = service.getHandler();
    NotificationInfo ni = NotificationInfo.createSingleNotification(
            R.string.locationcollector_notif_ticker,
            R.string.locationcollector_notif_title,
            R.string.locationcollector_notif_text,
            android.R.drawable.stat_notify_error);
    Intent intent = new Intent(
            android.provider.Settings.ACTION_LOCATION_SOURCE_SETTINGS);
    ni.pendingIntent = PendingIntent.getActivity(service, 0, intent,
            PendingIntent.FLAG_UPDATE_CURRENT);
    Message msg = handler.obtainMessage(ServiceHandler.SHOW_NOTIFICATION);
    msg.obj = ni;
    handler.sendMessage(msg);
    notifId = ni.id;
}

private void removeErrorNotification() {
    if (notifId == 0) return;
    ServiceHandler handler = service.getHandler();
    if (handler != null) {
        Message msg = handler.obtainMessage(
                ServiceHandler.CLEAR_NOTIFICATION, notifId, 0);
        handler.sendMessage(msg);
        notifId = 0;
    }
}

@Override
public void interrupt() {
    stopLooper();
    super.interrupt();
}

private String locationToString(int desiredAccuracy, int acceptedAccuracy,
        int maxAge, Location location) {
    StringBuilder sb = new StringBuilder();
    sb.append(String.format(
            "qual=%s time=%d prov=%s acc=%.1f lat=%f long=%f",
            getLocationQuality(desiredAccuracy, acceptedAccuracy, maxAge,
                    location), location.getTime() / 1000, // Millis to
                                                            // seconds
            location.getProvider(), location.getAccuracy(), location
                    .getLatitude(), location.getLongitude()));
    if (location.hasAltitude())
        sb.append(String.format(" alt=%.1f", location.getAltitude()));
    if (location.hasBearing())
        sb.append(String.format(" bearing=%.2f", location.getBearing()));
    return sb.toString();
}

private enum LocationQuality {
    BAD, ACCEPTED, GOOD;

    public String toString() {
        if (this == GOOD) return "Good";
        else if (this == ACCEPTED) return "Accepted";
        else return "Bad";
    }
}

private LocationQuality getLocationQuality(int desiredAccuracy,
        int acceptedAccuracy, int maxAge, Location location) {
    if (location == null) return LocationQuality.BAD;
    if (!location.hasAccuracy()) return LocationQuality.BAD;
    long currentTime = System.currentTimeMillis();
    if (currentTime - location.getTime() < maxAge * 1000
            && location.getAccuracy() <= desiredAccuracy)
        return LocationQuality.GOOD;
    if (acceptedAccuracy == -1
            || location.getAccuracy() <= acceptedAccuracy)
        return LocationQuality.ACCEPTED;
    return LocationQuality.BAD;
}

private synchronized void updateBestLocation(Location location) {
    bestLocation = getBestLocation(location, bestLocation);
}

protected Location getBestLocation(Location location,
        Location currentBestLocation) {
    if (currentBestLocation == null) {
        // A new location is always better than no location
        return location;
    }
    if (location == null) return currentBestLocation;
    // Check whether the new location fix is newer or older
    long timeDelta = location.getTime() - currentBestLocation.getTime();
    boolean isSignificantlyNewer = timeDelta > TWO_MINUTES;
    boolean isSignificantlyOlder = timeDelta < -TWO_MINUTES;
    boolean isNewer = timeDelta > 0;
    // If it's been more than two minutes since the current location, use
    // the new location
    // because the user has likely moved
    if (isSignificantlyNewer) {
        return location;
        // If the new location is more than two minutes older, it must be
        // worse
    } else if (isSignificantlyOlder) {
        return currentBestLocation;
    }
    // Check whether the new location fix is more or less accurate
    int accuracyDelta = (int) (location.getAccuracy() - currentBestLocation
            .getAccuracy());
    boolean isLessAccurate = accuracyDelta > 0;
    boolean isMoreAccurate = accuracyDelta < 0;
    boolean isSignificantlyLessAccurate = accuracyDelta > 200;
    // Check if the old and new location are from the same provider
    boolean isFromSameProvider = isSameProvider(location.getProvider(),
            currentBestLocation.getProvider());
    // Determine location quality using a combination of timeliness and
    // accuracy
    if (isMoreAccurate) {
        return location;
    } else if (isNewer && !isLessAccurate) {
        return location;
    } else if (isNewer && !isSignificantlyLessAccurate
            && isFromSameProvider) {
        return location;
    }
    return bestLocation;
}

/** Checks whether two providers are the same */
private boolean isSameProvider(String provider1, String provider2) {
    if (provider1 == null) return provider2 == null;
    return provider1.equals(provider2);
}

Worked for me:

$(".filter-mobile").click(function() {
   if ($("#menuProdutos").height() > 0) {
      $("#menuProdutos").animate({
         height: 0
      }, 200);
   } else {
      $("#menuProdutos").animate({
         height: 500
      }, 200);
   }
});

The report definition is not valid or supported by this version of Reporting Services. This could be the result of publishing a report definition of a later version of Reporting Services, or that the report definition contains XML that is not well-formed or the XML is not valid based on the Report Definition schema.

I got this error when I used ReportSync to upload some .rdl files to SQL Server Report Services. In my case, the issue was that these .rdl files had some Text Box containing characters like ©, — (Em dash), – (En dash) characters, etc. When uploading .rdl files using ReportSync, I had to encode these characters (©, —, –, etc.) and use Placeholder Properties to set the Markup type to HTML in order to get rid of this error.

I wouldn't get this error If I manually uploaded each of the .rdl files one-by-one using SQL Server Reporting Services. But I have a lot of .rdl files and uploading each one individually would be time-consuming, which is why I use ReportSync to mass upload all .rdl files.

Sorry, if my answer doesn't seem relevant, but I hope this helps anyone else getting this error message when dealing with SSRS .rdl files.

The usual way is to use UPDATE:

UPDATE mytable
   SET new_column = <expr containing old_column>

You should be able to do this is a single transaction.

With the latest version of Adobe Reader, Adobe Reader XI, it seems that you can save the form.

From their webpage: Type your responses right on the PDF form, or click through and fill in the form fields. Then save and submit

For large lists, we can do it the iter-way:

product_iter_object = itertools.imap(operator.mul, [1,2,3,4], [2,3,4,5])

product_iter_object.next() gives each of the element in the output list.

The output would be the length of the shorter of the two input lists.

Most drivers support forward only resultset - so method like last, beforeFirst etc are not supported.

The first approach is suitable if you are also getting the data in the same loop - otherwise the resultSet has already been iterated and can not be used again.

In most cases the requirement is to get the number of rows a query would return without fetching the rows. Iterating through the result set to find the row count is almost same as processing the data. It is better to do another count(*) query instead.

Are you using Hibernate's Query object, or JPA? For JPA, it should work fine:

String jpql = "from A where name in (:names)";
Query q = em.createQuery(jpql);
q.setParameter("names", l);

For Hibernate's, you'll need to use the setParameterList:

String hql = "from A where name in (:names)";
Query q = s.createQuery(hql);
q.setParameterList("names", l);

With a Spring Boot one can do the following:

application.properties

values[0]=abc
values[1]=def

Configuration class

import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;

import java.util.ArrayList;
import java.util.List;

@Component
@ConfigurationProperties
public class Configuration {

    List<String> values = new ArrayList<>();

    public List<String> getValues() {
        return values;
    }

}

This is needed, without this class or without the values in class it is not working.

Spring Boot Application class

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

import java.util.List;

@SpringBootApplication
public class SpringBootConsoleApplication implements CommandLineRunner {

    private static Logger LOG = LoggerFactory.getLogger(SpringBootConsoleApplication.class);

    // notice #{} is used instead of ${}
    @Value("#{configuration.values}")
    List<String> values;

    public static void main(String[] args) {
        SpringApplication.run(SpringBootConsoleApplication.class, args);
    }

    @Override
    public void run(String... args) {
        LOG.info("values: {}", values);
    }

}

Similar to Underscore library there is another library called as 'lodash' that has one method "orderBy" which takes in the parameter to determine in which order to sort it. You can use it like

_.orderBy('collection', 'propertyName', 'desc')

For some reason, it's not documented on the website docs.

I'm getting OpenJDK 8 from the official Debian repositories, rather than some random PPA or non-free Oracle binary. Here's how I did it:

sudo apt-get install debian-keyring debian-archive-keyring

Make /etc/apt/sources.list.d/debian-jessie-backports.list:

deb http://httpredir.debian.org/debian/ jessie-backports main

Make /etc/apt/preferences.d/debian-jessie-backports:

Package: *
Pin: release o=Debian,a=jessie-backports
Pin-Priority: -200

Then finally do the install:

sudo apt-get update
sudo apt-get -t jessie-backports install openjdk-8-jdk

I'm the one supporting CairoPlot and I'm very proud it came up here. Surely matplotlib is great, but I believe CairoPlot is better looking. So, for presentations and websites, it's a very good choice.

Today I released version 1.1. If interested, check it out at CairoPlot v1.1

EDIT: After a long and cold winter, CairoPlot is being developed again. Check out the new version on GitHub.

sp_msforeachdb 'use ?;select name,''?'' from sys.procedures where object_definition(object_id) like ''%text%'''

This will search in all stored procedure of all databases. This will also work for long procedures.

@IBAction func back(_ sender: Any) {
        self.dismiss(animated: false, completion: nil)
    }

You can use gererics to work for any class

public class FileUtils<T> {
public String createReport(String filePath, List<T> t) {
    if (t.isEmpty()) {
        return null;
    }

    List<String> reportData = new ArrayList<String>();

    addDataToReport(t.get(0), reportData, 0);

    for (T k : t) {
        addDataToReport(k, reportData, 1);
    }
    return !dumpReport(filePath, reportData) ? null : filePath;
}

public static Boolean dumpReport(String filePath, List<String> lines) {
    Boolean isFileCreated = false;

    
    String[] dirs = filePath.split(File.separator);
    String baseDir = "";
    for (int i = 0; i < dirs.length - 1; i++) {
        baseDir += " " + dirs[i];
    }
    baseDir = baseDir.replace(" ", "/");
    
    File base = new File(baseDir);
    base.mkdirs();

    File file = new File(filePath);
    try {
        if (!file.exists())
            file.createNewFile();
    } catch (Exception e) {
        e.printStackTrace();
        return isFileCreated;
    }

    try (BufferedWriter writer = new BufferedWriter(
            new OutputStreamWriter(new FileOutputStream(file), System.getProperty("file.encoding")))) {
        for (String line : lines) {
            writer.write(line + System.lineSeparator());
        }
    } catch (IOException e) {
        e.printStackTrace();
        return false;
    }
    return true;
}

void addDataToReport(T t, List<String> reportData, int index) {
    String[] jsonObjectAsArray = new Gson().toJson(t).replace("{", "").replace("}", "").split(",\"");
    StringBuilder row = new StringBuilder();

    for (int i = 0; i < jsonObjectAsArray.length; i++) {
        String str = jsonObjectAsArray[i];
        str = str.replaceFirst(":", "_").split("_")[index];

        if (i == 0) {
            if (str != null) {
                row.append(str.replace("\"", ""));
            } else {
                row.append("N/A");
            }
        } else {
            if (str != null) {
                row.append(", " + str.replace("\"", ""));
            } else {
                row.append(", N/A");
            }
        }
    }
    reportData.add(row.toString());
}

Binary install it the simple way!

I can't believe no one has suggested this already - use the binary-only option for pip. For example, for mysqlclient:

pip install --only-binary :all: mysqlclient

Many packages don't create a build for every single release which forces your pip to build from source. If you're happy to use the latest pre-compiled binary version, use --only-binary :all: to allow pip to use an older binary version.

try this

$("label").html(your value); or $("label").text(your value);

You can only close a window using javascript that was opened using javascript, i.e. when the window was opened using :

window.open

then

window.close

will work. Or else not.

According to the URI standard the path is for hierarchical parameters and the query is for non-hierarchical parameters. Ofc. it can be very subjective what is hierarchical for you.

In situations where multiple URIs are assigned to the same resource I like to put the parameters - necessary for identification - into the path and the parameters - necessary to build the representation - into the query. (For me this way it is easier to route.)

For example:

• /users/123 and /users/123?fields="name, age"
• /users and /users?name="John"&age=30

For map reduce I like to use the following approaches:

• /users?name="John"&age=30
• /users/name:John/age:30

So it is really up to you (and your server side router) how you construct your URIs.

note: Just to mention these parameters are query parameters. So what you are really doing is defining a simple query language. By complex queries (which contain operators like and, or, greater than, etc.) I suggest you to use an already existing query language. The capabilities of URI templates are very limited...

I want to point out one behavior of BackgroundWorker class that wasn't mentioned yet. You can make a normal Thread to run in background by setting the Thread.IsBackground property.

Background threads are identical to foreground threads, except that background threads do not prevent a process from terminating. [1]

You can test this behavoir by calling the following method in the constructor of your form window.

void TestBackgroundThread()
{
    var thread = new Thread((ThreadStart)delegate()
    {
        long count = 0;
        while (true)
        {
            count++;
            Debug.WriteLine("Thread loop count: " + count);
        }
    });

    // Choose one option:
    thread.IsBackground = true; // <--- This will make the thread run in background
    thread.IsBackground = false; // <--- This will delay program termination

    thread.Start();
}

When the IsBackground property is set to true and you close the window, then your application will terminate normaly.

But when the IsBackground property is set to false (by default) and you close the window, then just the window will disapear but the process will still keep running.

The BackgroundWorker class utilize a Thread that runs in the background.

I wrote a revision controlled spreadsheet using VBA. It is geared more for engineering reports where you have multiple people working on a Bill Of Material or Schedule and then at some point in time you want to create a snapshot revision that shows adds, del and updates from the previous rev.

Note: it is a macro enabled workbook that you need to sign in to download from my site (you can use OpenID)

All the code is unlocked.

Rev Controlled Spreadsheet

With an HTML form like:

<input type="submit" name="btnSubmit" value="Save Changes" />
<input type="submit" name="btnDelete" value="Delete" />

The PHP code to use would look like:

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    // Something posted

    if (isset($_POST['btnDelete'])) {
        // btnDelete
    } else {
        // Assume btnSubmit
    }
}

You should always assume or default to the first submit button to appear in the form HTML source code. In practice, the various browsers reliably send the name/value of a submit button with the post data when:

1. The user literally clicks the submit button with the mouse or pointing device
2. Or there is focus on the submit button (they tabbed to it), and then the Enter key is pressed.

Other ways to submit a form exist, and some browsers/versions decide not to send the name/value of any submit buttons in some of these situations. For example, many users submit forms by pressing the Enter key when the cursor/focus is on a text field. Forms can also be submitted via JavaScript, as well as some more obscure methods.

It's important to pay attention to this detail, otherwise you can really frustrate your users when they submit a form, yet "nothing happens" and their data is lost, because your code failed to detect a form submission, because you did not anticipate the fact that the name/value of a submit button may not be sent with the post data.

Also, the above advice should be used for forms with a single submit button too because you should always assume a default submit button.

I'm aware that the Internet is filled with tons of form-handler tutorials, and almost of all them do nothing more than check for the name and value of a submit button. But, they're just plain wrong!

Try this:

Pattern p = Pattern.compile(?<=\\<(any_tag)\\>)(\\s*.*\\s*)(?=\\<\\/(any_tag)\\>);
Matcher m = p.matcher(anyString);

For example:

String str = "<TR> <TD>1Q Ene</TD> <TD>3.08%</TD> </TR>";
Pattern p = Pattern.compile("(?<=\\<TD\\>)(\\s*.*\\s*)(?=\\<\\/TD\\>)");
Matcher m = p.matcher(str);
while(m.find()){
   Log.e("Regex"," Regex result: " + m.group())       
}

Output:

10 Ene

3.08%

Double and double are identical.

For the reason, see http://www.yoda.arachsys.com/csharp/floatingpoint.html . In short: a double is not an exact type and a minute difference between "x" and "0.1" will throw it off.

Note that

<input type="text" id="car" required="true" />

is wrong, it should be one of

<input type="text" id="car" required />
<input type="text" id="car" required="" />
<input type="text" id="car" required='' />
<input type="text" id="car" required=required />
<input type="text" id="car" required="required" />
<input type="text" id="car" required='required' />

This is because the true value suggests that the false value will make the form control optional, which is not the case.

Simply choose your background color of your item and specify the opacity separatly:

div { background-color:#000; opacity:0.8; }

UPDATE:

[o for d in [{}] for o in lst if o.name != "" or d.setdefault("", o) == o]

or using filter and lambda:

flag = {}
filter(lambda o: bool(o.name) or flag.setdefault("", o) == o, lst)

Previous Answer

OK, are you stuck on using filter and lambda?

It seems like this would be better served with a dictionary comprehension,

{o.name : o for o in input}.values()

I think the reason that Python doesn't allow assignment in a lambda is similar to why it doesn't allow assignment in a comprehension and that's got something to do with the fact that these things are evaluated on the C side and thus can give us an increase in speed. At least that's my impression after reading one of Guido's essays.

My guess is this would also go against the philosophy of having one right way of doing any one thing in Python.

Here's a ready-to-go Java version from the Android source code. This is the best one I've found.

public static final Matcher WEB  = Pattern.compile(new StringBuilder()                 
.append("((?:(http|https|Http|Https|rtsp|Rtsp):")                      
.append("\\/\\/(?:(?:[a-zA-Z0-9\\$\\-\\_\\.\\+\\!\\*\\'\\(\\)")                         
.append("\\,\\;\\?\\&\\=]|(?:\\%[a-fA-F0-9]{2})){1,64}(?:\\:(?:[a-zA-Z0-9\\$\\-\\_")                         
.append("\\.\\+\\!\\*\\'\\(\\)\\,\\;\\?\\&\\=]|(?:\\%[a-fA-F0-9]{2})){1,25})?\\@)?)?")                         
.append("((?:(?:[a-zA-Z0-9][a-zA-Z0-9\\-]{0,64}\\.)+")   // named host                            
.append("(?:")   // plus top level domain                         
.append("(?:aero|arpa|asia|a[cdefgilmnoqrstuwxz])")                         
.append("|(?:biz|b[abdefghijmnorstvwyz])")                         
.append("|(?:cat|com|coop|c[acdfghiklmnoruvxyz])")                         
.append("|d[ejkmoz]")                         
.append("|(?:edu|e[cegrstu])")                         
.append("|f[ijkmor]")                         
.append("|(?:gov|g[abdefghilmnpqrstuwy])")                         
.append("|h[kmnrtu]")                         
.append("|(?:info|int|i[delmnoqrst])")                         
.append("|(?:jobs|j[emop])")                         
.append("|k[eghimnrwyz]")                         
.append("|l[abcikrstuvy]")                         
.append("|(?:mil|mobi|museum|m[acdghklmnopqrstuvwxyz])")                         
.append("|(?:name|net|n[acefgilopruz])")                         
.append("|(?:org|om)")                         
.append("|(?:pro|p[aefghklmnrstwy])")                         
.append("|qa")                         
.append("|r[eouw]")                         
.append("|s[abcdeghijklmnortuvyz]")                         
.append("|(?:tel|travel|t[cdfghjklmnoprtvwz])")                         
.append("|u[agkmsyz]")                         
.append("|v[aceginu]")                         
.append("|w[fs]")                         
.append("|y[etu]")                         
.append("|z[amw]))")                         
.append("|(?:(?:25[0-5]|2[0-4]") // or ip address                                                 
.append("[0-9]|[0-1][0-9]{2}|[1-9][0-9]|[1-9])\\.(?:25[0-5]|2[0-4][0-9]")                             
.append("|[0-1][0-9]{2}|[1-9][0-9]|[1-9]|0)\\.(?:25[0-5]|2[0-4][0-9]|[0-1]")                         
.append("[0-9]{2}|[1-9][0-9]|[1-9]|0)\\.(?:25[0-5]|2[0-4][0-9]|[0-1][0-9]{2}")                         
.append("|[1-9][0-9]|[0-9])))")                         
.append("(?:\\:\\d{1,5})?)") // plus option port number                             
.append("(\\/(?:(?:[a-zA-Z0-9\\;\\/\\?\\:\\@\\&\\=\\#\\~")  // plus option query params                         
.append("\\-\\.\\+\\!\\*\\'\\(\\)\\,\\_])|(?:\\%[a-fA-F0-9]{2}))*)?")                         
.append("(?:\\b|$)").toString()                 
).matcher("");

$this->db->where('accommodation BETWEEN '' . $sdate . '' AND '' . $edate . ''');

this is my solution

In javascript the includes() method can be used to determines whether a string contains particular word (or characters at specified position). Its case sensitive.

var str = "Hello there."; 

var check1 = str.includes("there"); //true
var check2 = str.includes("There"); //false, the method is case sensitive
var check3 = str.includes("her");   //true
var check4 = str.includes("o",4);   //true, o is at position 4 (start at 0)
var check5 = str.includes("o",6);   //false o is not at position 6

simple you can write:

<?= $form->field($model, 'hidden1')->hiddenInput(['value'=>'abc value'])->label(false); ?>

Once you have localized the dropdown element

dropdownElement = $("#dropdownElement");

Find the <option> element using the JQuery attribute selector

dropdownElement.find('option[value=foo]').remove();

I think you will have to loop over the "inserted" table, which contains all rows that were updated. You can use a WHERE loop, or a WITH statement if your primary key is a GUID. This is the simpler (for me) to write, so here is my example. We use this approach, so I know for a fact it works fine.

ALTER TRIGGER [dbo].[RA2Newsletter] ON [dbo].[Reiseagent]
    AFTER INSERT
AS
        -- This is your primary key.  I assume INT, but initialize
        -- to minimum value for the type you are using.
        DECLARE @rAgent_ID INT = 0

        -- Looping variable.
        DECLARE @i INT = 0

        -- Count of rows affected for looping over
        DECLARE @count INT

        -- These are your old variables.
        DECLARE @rAgent_Name NVARCHAR(50)
        DECLARE @rAgent_Email NVARCHAR(50)
        DECLARE @rAgent_IP NVARCHAR(50)
        DECLARE @hotelID INT
        DECLARE @retval INT

    BEGIN 
        SET NOCOUNT ON ;

        -- Get count of affected rows
        SELECT  @Count = Count(rAgent_ID)
        FROM    inserted

        -- Loop over rows affected
        WHILE @i < @count
            BEGIN
                -- Get the next rAgent_ID
                SELECT TOP 1
                        @rAgent_ID = rAgent_ID
                FROM    inserted
                WHERE   rAgent_ID > @rAgent_ID
                ORDER BY rAgent_ID ASC

                -- Populate values for the current row
                SELECT  @rAgent_Name = rAgent_Name,
                        @rAgent_Email = rAgent_Email,
                        @rAgent_IP = rAgent_IP,
                        @hotelID = hotelID
                FROM    Inserted
                WHERE   rAgent_ID = @rAgent_ID

                -- Run your stored procedure
                EXEC insert2Newsletter '', '', @rAgent_Name, @rAgent_Email,
                    @rAgent_IP, @hotelID, 'RA', @retval 

                -- Set up next iteration
                SET @i = @i + 1
            END
    END 
GO

I sure hope this helps you out. Cheers!

If you're not in an ipython notebook (like the OP), you can also just declare the size when you declare the figure:

width = 12
height = 12
plt.figure(figsize=(width, height))

std::string replace(std::string str, const std::string& sub1, const std::string& sub2)
{
    if (sub1.empty())
        return str;

    std::size_t pos;
    while ((pos = str.find(sub1)) != std::string::npos)
        str.replace(pos, sub1.size(), sub2);

    return str;
}

Do one of the two jQuery serializers inside your form submit to get all inputs having a submitted value.

var criteria = $(this).find('input,select').filter(function () {
    return ((!!this.value) && (!!this.name));
}).serializeArray();

var formData = JSON.stringify(criteria);

serializeArray() will produce an array of names and values

0: {name: "OwnLast", value: "Bird"}
1: {name: "OwnFirst", value: "Bob"}
2: {name: "OutBldg[]", value: "PDG"}
3: {name: "OutBldg[]", value: "PDA"}

var criteria = $(this).find('input,select').filter(function () {
    return ((!!this.value) && (!!this.name));
}).serialize();

serialize() creates a text string in standard URL-encoded notation

"OwnLast=Bird&OwnFirst=Bob&OutBldg%5B%5D=PDG&OutBldg%5B%5D=PDA"

Since you are using Android < 5.0 you can't use the default adb reverse method, but Facebook has added official documentation to connect to the development server via Wi-Fi, which would support your version. Quoting the instructions for MacOS, but they also have them for Linux and Windows:

Method 2: Connect via Wi-Fi

You can also connect to the development server over Wi-Fi. You'll first need to install the app on your device using a USB cable, but once that has been done you can debug wirelessly by following these instructions. You'll need your development machine's current IP address before proceeding.

You can find the IP address in System Preferences ? Network.

Make sure your laptop and your phone are on the same Wi-Fi network. Open your React Native app on your device. You'll see a red screen with an error. This is OK. The following steps will fix that. Open the in-app Developer menu. Go to Dev Settings ? Debug server host for device. Type in your machine's IP address and the port of the local dev server (e.g. 10.0.1.1:8081). Go back to the Developer menu and select Reload JS.

Go to simplelogger.properties in ${MAVEN_HOME}/conf/logging/ and set the following properties:

org.slf4j.simpleLogger.defaultLogLevel=warn
org.slf4j.simpleLogger.log.Sisu=warn
org.slf4j.simpleLogger.warnLevelString=warn

And beware: warn, not warning

I have had numerous problems with opencv and only succeded after a gruesome 4-6 months. This is the last problem I have had, but all of the above didn't work. What worked for me was just copying and pasting the opencv_core2*.dll (and opencv_highgui2*.dll which it will ask for since you included this as well) into the release (or debug folder - I'm assuming. Haven't tested this) folder of your project, where your application file is.

Hope this helps!

you cannot set this in javascript, you have to do this with html/css:

<style type="text/css" media="print">
  @page { size: landscape; }
</style>

EDIT: See this Question and the accepted answer for more information on browser support: Is @Page { size:landscape} obsolete?

stringstream.str() returns a temporary string object that's destroyed at the end of the full expression. If you get a pointer to a C string from that (stringstream.str().c_str()), it will point to a string which is deleted where the statement ends. That's why your code prints garbage.

You could copy that temporary string object to some other string object and take the C string from that one:

const std::string tmp = stringstream.str();
const char* cstr = tmp.c_str();

Note that I made the temporary string const, because any changes to it might cause it to re-allocate and thus render cstr invalid. It is therefor safer to not to store the result of the call to str() at all and use cstr only until the end of the full expression:

use_c_str( stringstream.str().c_str() );

Of course, the latter might not be easy and copying might be too expensive. What you can do instead is to bind the temporary to a const reference. This will extend its lifetime to the lifetime of the reference:

{
  const std::string& tmp = stringstream.str();   
  const char* cstr = tmp.c_str();
}

IMO that's the best solution. Unfortunately it's not very well known.

Upload the image on your server or in images hosting site where you get image link and then add the line on your website page where you get that image the line is

<img src="paste here your image full path"/>

You got this Error because you tried to convert column DataType from String to int which is

leagal if and only if

you dont have row in that table with string content inside that column

so just make sure your previously inserted Rows is compatible with the new changes

If elem.find() is not working for you, check that you are including JQuery script before angular script....

I tried all the solutions, none worked for me (using Swift 4), this is the solution that worked for me, if anyone in future faces the same problem.

let temp = base64String.components(separatedBy: ",")
let dataDecoded : Data = Data(base64Encoded: temp[1], options: 
 .ignoreUnknownCharacters)!
let decodedimage = UIImage(data: dataDecoded)

yourImage.image = decodedimage

I don't suggest you to use syntax like you did. AngularJs lets you to have different functionalities as you want (run, config, service, factory, etc..), which are more professional.In this function you don't even have to inject that by yourself like

MainCtrl.$inject = ['$scope', '$rootScope', '$location', 'socket', ...];

you can use it, as you know.

This example stores the values you have checked and displays them in a toast. And it updates when you uncheck items http://android-coding.blogspot.ro/2011/09/listview-with-multiple-choice.html

If you are using Reactive Forms you can use this:

<button [disabled]="!contactForm.valid" type="submit" class="btn btn-lg btn primary" (click)="printSomething()">Submit</button>

This seemed to have worked for me!

Mat a_image = imread(argv[1]);

cvtColor(a_image, a_image, CV_BGR2GRAY);
GaussianBlur(a_image, a_image, Size(7,7), 1.5, 1.5);
threshold(a_image, a_image, 100, 255, CV_THRESH_BINARY);

Specifically, if you are dealing with a UserForm, then you might try the Repaint method. You might encounter an issue with DoEvents if you are using event triggers in your form. For instance, any keys pressed while a function is running will be sent by DoEvents The keyboard input will be processed before the screen is updated, so if you are changing cells on a spreadsheet by holding down one of the arrow keys on the keyboard, then the cell change event will keep firing before the main function finishes.

A UserForm will not be refreshed in some cases, because DoEvents will fire the events; however, Repaint will update the UserForm and the user will see the changes on the screen even when another event immediately follows the previous event.

In the UserForm code it is as simple as:

Me.Repaint

In a batch file solution

for /R c:\source %%f in (*.xml) do copy %%f x:\destination\

The code works as such;

for each file for in directory c:\source and subdirectories /R that match pattern (\*.xml) put the file name in variable %%f, then for each file do copy file copy %%f to destination x:\\destination\\

Just tested it here on my Windows XP computer and it worked like a treat for me. But I typed it into command prompt so I used the single %f variable name version, as described in the linked question above.

On heroku server (readonly filesystem), If you want runtime compilation of css (its not recommended but you can do it), make sure you have done settings like below -

# inside config/application.rb
config.assets.enabled = true
config.assets.prefix = Rails.root.join('tmp/assets').to_s

# If you are using sass then keep gem outside of asset group
 gem 'sass-rails',   '3.1.4'

# inside config/environments/production.rb
config.assets.compile = true

I was able to recover my files from the following location:

C:\Users\<yourusername>\Documents\SQL Server Management Studio\Backup Files\Solution1

There should be different recovery files per tab. I'd say look for the files for the date you lost them.

Finally, this is what I did:

private File getFileFromURL() {
    URL url = this.getClass().getClassLoader().getResource("/sql");
    File file = null;
    try {
        file = new File(url.toURI());
    } catch (URISyntaxException e) {
        file = new File(url.getPath());
    } finally {
        return file;
    }
}

...

File folder = getFileFromURL();
File[] listOfFiles = folder.listFiles();

I was facing the same issue. Everything was fine but in

bootstrap/cache/config.php

always had the incomplete password. Upon digging further, realized that the password had '#' character in it and that was getting dropped. As '#' is used to mark a line as a comment.

As you enter your Perl script you have all the installed modules as .pm files below the folders in @INC so a small bash script will do the job for you:

#!/bin/bash

echo -e -n "Content-type: text/plain\n\n"

inc=`perl -e '$, = "\n"; print @INC;'`

for d in $inc
do
   find $d -name '*.pm'
done

declare
strTime1 varchar2(50) := '02/08/2013 01:09:42 PM';
strTime2 varchar2(50) := '02/08/2013 11:09:00 PM';
v_date1 date := to_date(strTime1,'DD/MM/YYYY HH:MI:SS PM');
v_date2 date := to_date(strTime2,'DD/MM/YYYY HH:MI:SS PM');
difrence_In_Hours number;
difrence_In_minutes number;
difrence_In_seconds number;
begin
    difrence_In_Hours   := (v_date2 - v_date1) * 24;
    difrence_In_minutes := difrence_In_Hours * 60;
    difrence_In_seconds := difrence_In_minutes * 60;

    dbms_output.put_line(strTime1);        
    dbms_output.put_line(strTime2);
    dbms_output.put_line('*******');
    dbms_output.put_line('difrence_In_Hours  : ' || difrence_In_Hours);
    dbms_output.put_line('difrence_In_minutes: ' || difrence_In_minutes);
    dbms_output.put_line('difrence_In_seconds: ' || difrence_In_seconds);        
end ;

Hope this helps.

From https://api.jquery.com/change/:

The change event is sent to an element when its value changes. This event is limited to <input> elements, <textarea> boxes and <select> elements. For select boxes, checkboxes, and radio buttons, the event is fired immediately when the user makes a selection with the mouse, but for the other element types the event is deferred until the element loses focus.

 Fragment fr = new Fragment_class();
             FragmentManager fm = getFragmentManager();
            FragmentTransaction fragmentTransaction = fm.beginTransaction();
            fragmentTransaction.add(R.id.viewpagerId, fr);
            fragmentTransaction.commit();

Just to be precise, R.id.viewpagerId is cretaed in your current class layout, upon calling, the new fragment automatically gets infiltrated.

It's called a for-each or enhanced for statement. See the JLS §14.14.2.

It's syntactic sugar provided by the compiler for iterating over Iterables and arrays. The following are equivalent ways to iterate over a list:

List<Foo> foos = ...;
for (Foo foo : foos)
{
    foo.bar();
}

// equivalent to:
List<Foo> foos = ...;
for (Iterator<Foo> iter = foos.iterator(); iter.hasNext();)
{
    Foo foo = iter.next();
    foo.bar();
}

and these are two equivalent ways to iterate over an array:

int[] nums = ...;
for (int num : nums)
{
    System.out.println(num);
}

// equivalent to:
int[] nums = ...;
for (int i=0; i<nums.length; i++)
{
    int num = nums[i];
    System.out.println(num);
}

Further reading

• How is Java's for loop code generated by the compiler
• The For-Each Loop

You can override the default implementation of console.log()

(function () {
    var old = console.log;
    var logger = document.getElementById('log');
    console.log = function (message) {
        if (typeof message == 'object') {
            logger.innerHTML += (JSON && JSON.stringify ? JSON.stringify(message) : message) + '<br />';
        } else {
            logger.innerHTML += message + '<br />';
        }
    }
})();

Demo: Fiddle

You'll need to join twice:

SELECT home.*, away.*, g.network, g.date_start 
FROM game AS g
INNER JOIN team AS home
  ON home.importid = g.home
INNER JOIN team AS away
  ON away.importid = g.away
ORDER BY g.date_start DESC 
LIMIT 7

Try this (but once clicked, it is not reversible):

HTML:

<a id="test"><img src="normal-image.png"/></a>

CSS:

a#test {
    border: 0;
}
a#test:visited img, a#test:active img {
    background-image: url(clicked-image.png);
}

had the same problem; my issue was selinux was set to enforcing.

I kept getting the "failed to open stream: Permission denied" error even after chmoding to 777 and making sure all parent folders had execute permissions for the apache user. Turns out my issue was that selinux was set to enforcing (I'm on centos7), this is a devbox so I turned it off.

The Thing that worked for me:

1. Find out which migrations in your migration folder created the table if not add the class in your models.py.
2. If the class already exist in your models.py, try to delete that one and run python manage.py makemigrations <appname>
3. And while migrating fake that migrations as your error might say table not found to delete using python manage.py migrate <yourappname> --fake
4. Add the class again and makemigrations again python manage.py makemigrations <appname>.
5. And finally migrate again python manage.py migrate <appname>

You need use patches.

import matplotlib.pyplot as plt
import matplotlib.patches as patches

fig2 = plt.figure()
ax2 = fig2.add_subplot(111, aspect='equal')

ax2.add_patch(
     patches.Rectangle(
        (0.1, 0.1),
        0.5,
        0.5,
        fill=False      # remove background
     ) ) 
fig2.savefig('rect2.png', dpi=90, bbox_inches='tight')

You can make the border transparent. In this way it exists, but is invisible, so it doesn't push anything around:

.jobs .item {
   background: #eee;
   border: 1px solid transparent;
}

.jobs .item:hover {
   background: #e1e1e1;
   border: 1px solid #d0d0d0;
}

<div class="jobs">
  <div class="item">Item</div>
</div>

For elements that already have a border, and you don't want them to move, you can use negative margins:

.jobs .item {
    background: #eee;
    border: 1px solid #d0d0d0;
}

.jobs .item:hover {
   background: #e1e1e1;
    border: 3px solid #d0d0d0;
    margin: -2px;
}

<div class="jobs">
  <div class="item">Item</div>
</div>

Another possible trick for adding width to an existing border is to add a box-shadow with the spread attribute of the desired pixel width.

.jobs .item {
    background: #eee;
    border: 1px solid #d0d0d0;
}

.jobs .item:hover {
    background: #e1e1e1;
    box-shadow: 0 0 0 2px #d0d0d0;
}

<div class="jobs">
  <div class="item">Item</div>
</div>

Here is a nice simple solution using jQuery that works nicely:

$('.dropdown-toggle').click(function () {
    $(this).next('.dropdown-menu').slideToggle(300);
});

$('.dropdown-toggle').focusout(function () {
    $(this).next('.dropdown-menu').slideUp(300);
})

The slide animation toggle occurs on clicking and it always slides back up on losing focus.

Alter the 300 value to anything you want, the lower the number the faster the animation.

Edit:

This solution will only work for desktop views. It will need some further modification in order to display nicely for mobile.

BufferedImage img = ImageIO.read(new ByteArrayInputStream(bytes));

You don't only need the header file, you need the library that goes with it. Anyway, the include folder is not automatically loaded, you must configure your project to do so. Right-click on it : Build options > Search directories > Add. Choose your include folder, keep the path relative.

Edit For further assistance, please give details about the library you're trying to load (which provides a graphics.h file.)

I will describe what I use:

Validation: string contains more than 5 digits.

Cleaning: removing all non digits symbols, write in db only numbers. I'm lucky, because in my country (Russia) everybody has phone numbers with 10 digits. So I store in db only 10 diits. If you are writing multi-country application, then you should make a comprehensive validation.

Rendering: I write custom template tag to render it in template nicely. Or even render it like a picture - it is more safe to prevent sms spam.

I followed the solution above from Jonas and it worked well until I needed to add a second column. What I found is that when making the columns visible again Oracle does not necessarily set them visible in the order listed in the statement.

To demonstrate this follow Jonas' example above. As he showed, once the steps are complete the table is in the order that you'd expect. Things then break down when you add another column as shown below:

Example (continued from Jonas'):

Add another column which is to be inserted before column C.

ALTER TABLE t ADD (b2 INT);

Use the technique demonstrated above to move the newly added B2 column before column C.

ALTER TABLE t MODIFY (c INVISIBLE, d INVISIBLE, e INVISIBLE);
ALTER TABLE t MODIFY (c VISIBLE, d VISIBLE, e VISIBLE);

DESCRIBE t;

Name
----
A
B
B2
D
E
C

As shown above column C has moved to the end. It seems that the ALTER TABLE statement above processed the columns in the order D, E, C rather than in the order specified in the statement (perhaps in physical table order). To ensure that the column is placed where desired it is necessary to make the columns visible one by one in the desired order.

ALTER TABLE t MODIFY (c INVISIBLE, d INVISIBLE, e INVISIBLE);
ALTER TABLE t MODIFY c VISIBLE;
ALTER TABLE t MODIFY d VISIBLE;
ALTER TABLE t MODIFY e VISIBLE;

DESCRIBE t;

Name
----
A
B
B2
C
D
E

The end of the variable name is usually signified by a space or newline. But what if we don't want a space or newline after printing the variable value? The curly braces tell the shell interpreter where the end of the variable name is.

Classic Example 1) - shell variable without trailing whitespace

TIME=10

# WRONG: no such variable called 'TIMEsecs'
echo "Time taken = $TIMEsecs"

# What we want is $TIME followed by "secs" with no whitespace between the two.
echo "Time taken = ${TIME}secs"

Example 2) Java classpath with versioned jars

# WRONG - no such variable LATESTVERSION_src
CLASSPATH=hibernate-$LATESTVERSION_src.zip:hibernate_$LATEST_VERSION.jar

# RIGHT
CLASSPATH=hibernate-${LATESTVERSION}_src.zip:hibernate_$LATEST_VERSION.jar

(Fred's answer already states this but his example is a bit too abstract)

If you have names of the element and not id we can achieve the undefined check on all text elements (for example) as below and fill them with a default value say 0.0:

var aFieldsCannotBeNull=['ast_chkacc_bwr','ast_savacc_bwr'];
 jQuery.each(aFieldsCannotBeNull,function(nShowIndex,sShowKey) {
   var $_oField = jQuery("input[name='"+sShowKey+"']");
   if($_oField.val().trim().length === 0){
       $_oField.val('0.0')
    }
  })

In simple words

Amazon EBS provides block level storage .

Amazon EFS provides network-attached shared file storage.

Amazon S3 provides object storage .

CentOS (RHEL) 7, has changed the firewall to use firewall-cmd which has a notion of zones which is like a Windows version of Public, Home, and Private networks. You should look here to figure out which one you think you should use. EL7 uses public by default so that is what my examples below use.

You can check which zone you are using with firewall-cmd --list-all and change it with firewall-cmd --set-default-zone=<zone>.

You will then know what zone to allow a service (or port) on:

firewall-cmd --permanent --zone=<zone> --add-service=http

firewall-cmd --permanent --zone=<zone> --add-port=80/tcp

You can check if the port has actually be opened by running:

firewall-cmd --zone=<zone> --query-port=80/tcp

firewall-cmd --zone=<zone> --query-service=http

According to the documentation,

When making changes to the firewall settings in Permanent mode, your selection will only take effect when you reload the firewall or the system restarts.

You can reload the firewall settings with: firewall-cmd --reload.

Look at the Temporarily Suppressing Warnings section of the Python docs:

If you are using code that you know will raise a warning, such as a deprecated function, but do not want to see the warning, then it is possible to suppress the warning using the catch_warnings context manager:

import warnings

def fxn():
    warnings.warn("deprecated", DeprecationWarning)

with warnings.catch_warnings():
    warnings.simplefilter("ignore")
    fxn()

I don't condone it, but you could just suppress all warnings with this:

import warnings
warnings.filterwarnings("ignore")

Ex:

>>> import warnings
>>> def f():
...     print('before')
...     warnings.warn('you are warned!')
...     print('after')
...
>>> f()
before
<stdin>:3: UserWarning: you are warned!
after
>>> warnings.filterwarnings("ignore")
>>> f()
before
after

All the answers here are super helpful but miss one very weird bug about Jenkins. After you have edited the new job configurations, sometimes if your zoom level is too high, you may not see the save or apply button option. The button is present on the page and hidden by your zoom level, you have to zoom out until you see the button at the bottom left of your page.

Strange, I know!

Try shFlags -- Advanced command-line flag library for Unix shell scripts.

http://code.google.com/p/shflags/

It is very good and very flexible.

FLAG TYPES: This is a list of the DEFINE_*'s that you can do. All flags take a name, default value, help-string, and optional 'short' name (one-letter name). Some flags have other arguments, which are described with the flag.

DEFINE_string: takes any input, and intreprets it as a string.

DEFINE_boolean: typically does not take any argument: say --myflag to set FLAGS_myflag to true, or --nomyflag to set FLAGS_myflag to false. Alternately, you can say --myflag=true or --myflag=t or --myflag=0 or --myflag=false or --myflag=f or --myflag=1 Passing an option has the same affect as passing the option once.

DEFINE_float: takes an input and intreprets it as a floating point number. As shell does not support floats per-se, the input is merely validated as being a valid floating point value.

DEFINE_integer: takes an input and intreprets it as an integer.

SPECIAL FLAGS: There are a few flags that have special meaning: --help (or -?) prints a list of all the flags in a human-readable fashion --flagfile=foo read flags from foo. (not implemented yet) -- as in getopt(), terminates flag-processing

EXAMPLE USAGE:

-- begin hello.sh --
 ! /bin/sh
. ./shflags
DEFINE_string name 'world' "somebody's name" n
FLAGS "$@" || exit $?
eval set -- "${FLAGS_ARGV}"
echo "Hello, ${FLAGS_name}."
-- end hello.sh --

$ ./hello.sh -n Kate
Hello, Kate.

Note: I took this text from shflags documentation

1. You can use the FindIndex() method to find the index of item.
2. Create a new list item.
3. Override indexed item with the new item.

List<Class1> list = new List<Class1>();

int index = list.FindIndex(item => item.Number == textBox6.Text);

Class1 newItem = new Class1();
newItem.Prob1 = "SomeValue";

list[index] = newItem;

Use the below command in the terminal/cmd to change the port(npm run dev is for node.js) you may have other commands to run your app most of them will work while changing the port, easier and faster. Furthermore, you can use any port number that is free in your system instead of 3002

PORT=3002 npm run dev

Most of the times when one runs the project while exiting one abruptly or unknowingly presses control + z that gives you exit out of the port always go for control + c that won't exit from port to run the server or project.

Furthermore, its time to change the port number in your code

server.listen(3002);

Python’s raw strings are just a way to tell the Python interpreter that it should interpret backslashes as literal slashes. If you read strings entered by the user, they are already past the point where they could have been raw. Also, user input is most likely read in literally, i.e. “raw”.

This means the interpreting happens somewhere else. But if you know that it happens, why not escape the backslashes for whatever is interpreting it?

s = s.replace("\\", "\\\\")

(Note that you can't do r"\" as “a raw string cannot end in a single backslash”, but I could have used r"\\" as well for the second argument.)

If that doesn’t work, your user input is for some arcane reason interpreting the backslashes, so you’ll need a way to tell it to stop that.

For me on windows it was Ctrl+¡ , indent line. It adds a tab at the beggining of each line.

The problem is how you've attached the listener:

<input type="checkbox" ...  onchange="doalert(this.id)">

Inline listeners are effectively wrapped in a function which is called with the element as this. That function then calls the doalert function, but doesn't set its this so it will default to the global object (window in a browser).

Since the window object doesn't have a checked property, this.checked always resolves to false.

If you want this within doalert to be the element, attach the listener using addEventListener:

window.onload = function() {
  var input = document.querySelector('#g01-01');
  if (input) {   
    input.addEventListener('change', doalert, false);
  }
}

Or if you wish to use an inline listener:

<input type="checkbox" ...  onchange="doalert.call(this, this.id)">

To avoid ZoneId you can do:

LocalDateTime date = LocalDateTime.of(1970, 1, 1, 0, 0);

System.out.println("Initial Epoch (TimeInMillis): " + date.toInstant(ZoneOffset.ofTotalSeconds(0)).toEpochMilli());

Getting 0 as value, that's right!

Actually what happens is when you use postfix i.e. i++, the initial value of i is used for returning rather than the incremented one. After this the value of i is increased by 1. And this happens with any statement that uses i++, i.e. first initial value of i is used in the expression and then it is incremented.

And the exact opposite happens in prefix. If you would have returned ++i, then the incremented value i.e. 11 is returned, which is because adding 1 is performed first and then it is returned.

I think the problem is that opening the file without a path will only work if your "current directory" is set correctly.

Try typing "Debug.Print CurDir" in the Immediate Window - that should show the location for your default files as set in Tools...Options.

I'm not sure I'm completely happy with it, perhaps because it's somewhat of a legacy VB command, but you could do this:

ChDir ThisWorkbook.Path

I think I'd prefer to use ThisWorkbook.Path to construct a path to the HTML file. I'm a big fan of the FileSystemObject in the Scripting Runtime (which always seems to be installed), so I'd be happier to do something like this (after setting a reference to Microsoft Scripting Runtime):

Const HTML_FILE_NAME As String = "my_input.html"

With New FileSystemObject
    With .OpenTextFile(.BuildPath(ThisWorkbook.Path, HTML_FILE_NAME), ForReading)
        ' Now we have a TextStream object that we can use to read the file
    End With
End With

You are seeing the ffffff because char is signed on your system. In C, vararg functions such as printf will promote all integers smaller than int to int. Since char is an integer (8-bit signed integer in your case), your chars are being promoted to int via sign-extension.

Since c0 and 80 have a leading 1-bit (and are negative as an 8-bit integer), they are being sign-extended while the others in your sample don't.

char    int
c0 -> ffffffc0
80 -> ffffff80
61 -> 00000061

Here's a solution:

char ch = 0xC0;
printf("%x", ch & 0xff);

This will mask out the upper bits and keep only the lower 8 bits that you want.

The following code fragment should return the size in bytes of any object passed to it, so long as it can be serialized. I got this from a colleague at Quixant to resolve a problem of writing to SRAM on a gaming platform. Hope it helps out. Credit and thanks to Carlo Vittuci.

/// <summary>
/// Calculates the lenght in bytes of an object 
/// and returns the size 
/// </summary>
/// <param name="TestObject"></param>
/// <returns></returns>
private int GetObjectSize(object TestObject)
{
    BinaryFormatter bf = new BinaryFormatter();
    MemoryStream ms = new MemoryStream();
    byte[] Array;
    bf.Serialize(ms, TestObject);
    Array = ms.ToArray();
    return Array.Length;
}

Try this. It will check to see if the file already exists in the destination folder, and if it does will check if the file is read-only. If the file is read-only it will change it to read-write, replace the file, and make it read-only again.

Const DestinationFile = "c:\destfolder\anyfile.txt"
Const SourceFile = "c:\sourcefolder\anyfile.txt"

Set fso = CreateObject("Scripting.FileSystemObject")
    'Check to see if the file already exists in the destination folder
    If fso.FileExists(DestinationFile) Then
        'Check to see if the file is read-only
        If Not fso.GetFile(DestinationFile).Attributes And 1 Then 
            'The file exists and is not read-only.  Safe to replace the file.
            fso.CopyFile SourceFile, "C:\destfolder\", True
        Else 
            'The file exists and is read-only.
            'Remove the read-only attribute
            fso.GetFile(DestinationFile).Attributes = fso.GetFile(DestinationFile).Attributes - 1
            'Replace the file
            fso.CopyFile SourceFile, "C:\destfolder\", True
            'Reapply the read-only attribute
            fso.GetFile(DestinationFile).Attributes = fso.GetFile(DestinationFile).Attributes + 1
        End If
    Else
        'The file does not exist in the destination folder.  Safe to copy file to this folder.
        fso.CopyFile SourceFile, "C:\destfolder\", True
    End If
Set fso = Nothing

I came across the same problem and adding this line to my application.properties solved the issue.

spring.autoconfigure.exclude=org.springframework.boot.autoconfigure.security.servlet.UserDetailsServiceAutoConfiguration

It's one of the Spring's Automatic stuffs which you exclude it like excluding other stuffs such as actuators. I recommend looking at this link

For my Azpen A727, the Windows driver installed correctly, so only step 3 of Mohammad's answer was necessary.

Both are fine, but only the first one will allow you to inspect the Exception itself.

Both swallow the Exception, and you should only catch exceptions to do something meaningfull. Hiding a problem is not meaningful!

Setting the underlying socket ReceiveTimeout property did the trick. You can access it like this: yourTcpClient.Client.ReceiveTimeout. You can read the docs for more information.

Now the code will only "sleep" as long as needed for some data to arrive in the socket, or it will raise an exception if no data arrives, at the beginning of a read operation, for more than 20ms. I can tweak this timeout if needed. Now I'm not paying the 20ms price in every iteration, I'm only paying it at the last read operation. Since I have the content-length of the message in the first bytes read from the server I can use it to tweak it even more and not try to read if all expected data has been already received.

I find using ReceiveTimeout much easier than implementing asynchronous read... Here is the working code:

string SendCmd(string cmd, string ip, int port)
{
  var client = new TcpClient(ip, port);
  var data = Encoding.GetEncoding(1252).GetBytes(cmd);
  var stm = client.GetStream();
  stm.Write(data, 0, data.Length);
  byte[] resp = new byte[2048];
  var memStream = new MemoryStream();
  var bytes = 0;
  client.Client.ReceiveTimeout = 20;
  do
  {
      try
      {
          bytes = stm.Read(resp, 0, resp.Length);
          memStream.Write(resp, 0, bytes);
      }
      catch (IOException ex)
      {
          // if the ReceiveTimeout is reached an IOException will be raised...
          // with an InnerException of type SocketException and ErrorCode 10060
          var socketExept = ex.InnerException as SocketException;
          if (socketExept == null || socketExept.ErrorCode != 10060)
              // if it's not the "expected" exception, let's not hide the error
              throw ex;
          // if it is the receive timeout, then reading ended
          bytes = 0;
      }
  } while (bytes > 0);
  return Encoding.GetEncoding(1252).GetString(memStream.ToArray());
}

I had the same problem. Debugging does not work with the stuff that comes with the OpenCV executable. you have to build your own binarys.
Then enable Microsoft Symbol Servers in Debug->options and settings->debug->symbols

Put a black, semitransparent, div on top of it.

start wgnplot.exe "c:\path to file to open\foo.dat"

You can do style attributes like so:

Button myButton = new Button(this, null,android.R.attr.buttonBarButtonStyle);

in place of:

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/btn"
    style="?android:attr/buttonBarButtonStyle"

    />

--no-pager to Git will tell it to not use a pager. Passing the option -F to less will tell it to not page if the output fits in a single screen.

Usage:

git --no-pager diff

Other options from the comments include:

# Set an evaporating environment variable to use 'cat' for your pager
GIT_PAGER=cat git diff

# Tells 'less' not to paginate if less than a page
export LESS="-F -X $LESS"
# ...then Git as usual
git diff

I think you need to reset scroll to its position before hashchange.

$(function(){
    //This emulates a click on the correct button on page load
    if(document.location.hash) {
        $("#buttons li a").removeClass('selected');
        s=$(document.location.hash).addClass('selected').attr("href").replace("javascript:","");
        eval(s);
    }

    //Click a button to change the hash
    $("#buttons li a").click(function() {
            var scrollLocation = $(window).scrollTop();
            $("#buttons li a").removeClass('selected');
            $(this).addClass('selected');
            document.location.hash = $(this).attr("id");
            $(window).scrollTop( scrollLocation );
    });
});

I wrote a version detector based on Hermann Ingjaldsson's answer, but more robust and which returns an object with name/version data in it. It covers the major browsers but I don't bother with the plethora of mobile ones and minor ones:

function getBrowserData(nav) {
    var data = {};

    var ua = data.uaString = nav.userAgent;
    var browserMatch = ua.match(/(opera|chrome|safari|firefox|msie|trident(?=\/))\/?\s*([\d\.]+)/i) || [];
    if (browserMatch[1]) { browserMatch[1] = browserMatch[1].toLowerCase(); }
    var operaMatch = browserMatch[1] === 'chrome';
    if (operaMatch) { operaMatch = ua.match(/\bOPR\/([\d\.]+)/); }

    if (/trident/i.test(browserMatch[1])) {
        var msieMatch = /\brv[ :]+([\d\.]+)/g.exec(ua) || [];
        data.name = 'msie';
        data.version = msieMatch[1];
    }
    else if (operaMatch) {
        data.name = 'opera';
        data.version = operaMatch[1];
    }
    else if (browserMatch[1] === 'safari') {
        var safariVersionMatch = ua.match(/version\/([\d\.]+)/i);
        data.name = 'safari';
        data.version = safariVersionMatch[1];
    }
    else {
        data.name = browserMatch[1];
        data.version = browserMatch[2];
    }

    var versionParts = [];
    if (data.version) {
        var versionPartsMatch = data.version.match(/(\d+)/g) || [];
        for (var i=0; i < versionPartsMatch.length; i++) {
            versionParts.push(versionPartsMatch[i]);
        }
        if (versionParts.length > 0) { data.majorVersion = versionParts[0]; }
    }
    data.name = data.name || '(unknown browser name)';
    data.version = {
        full: data.version || '(unknown full browser version)',
        parts: versionParts,
        major: versionParts.length > 0 ? versionParts[0] : '(unknown major browser version)'
    };

    return data;
};

It can then be used like this:

var brData = getBrowserData(window.navigator || navigator);
console.log('name: ' + brData.name);
console.log('major version: ' + brData.version.major);
// etc.

in my case this fixed the problem:

sudo apt-get install libssl-dev libcurl4-openssl-dev python-dev

as explained here

If it's not the Home edition of XP, you can use \\servername\c$

Mark Brackett's comment:

Note that you need to be an Administrator on the local machine, as the share permissions are locked down

COLUMN() and ROW() won't work this way because they are applied to the cell that is calling them. In conditional formatting, you will have to be explicit instead of implicit.

For instance, if you want to use this conditional formating on a range begining on cell A1, you can try:

`COLUMN(A1)` and `ROW(A1)`

Excel will automatically adapt the conditional formating to the current cell.

To merge a local directory into a directory within an image, do this. It will not delete files already present within the image. It will only add files that are present locally, overwriting the files in the image if a file of the same name already exists.

COPY ./files/. /files/

Instead of writing echo $cars.length write echo @($cars).length

Instead of using the outrageously convoluted data structures required by ggplot2, you can use the native R functions:

tab<-read.delim(text="
Company 2011 2013
Company1 300 350
Company2 320 430
Company3 310 420
",as.is=TRUE,sep=" ",row.names=1)

tab<-t(tab)

plot(tab[,1],type="b",ylim=c(min(tab),max(tab)),col="red",lty=1,ylab="Value",lwd=2,xlab="Year",xaxt="n")
lines(tab[,2],type="b",col="black",lty=2,lwd=2)
lines(tab[,3],type="b",col="blue",lty=3,lwd=2)
grid()
legend("topleft",legend=colnames(tab),lty=c(1,2,3),col=c("red","black","blue"),bg="white",lwd=2)
axis(1,at=c(1:nrow(tab)),labels=rownames(tab))

The error is not refering to myfunction but to start.

async function start() {
   ....

   const result = await helper.myfunction('test', 'test');
}

// My function_x000D_
const myfunction = async function(x, y) {_x000D_
  return [_x000D_
    x,_x000D_
    y,_x000D_
  ];_x000D_
}_x000D_
_x000D_
// Start function_x000D_
const start = async function(a, b) {_x000D_
  const result = await myfunction('test', 'test');_x000D_
  _x000D_
  console.log(result);_x000D_
}_x000D_
_x000D_
// Call start_x000D_
start();

I use the opportunity of this question to advise you about an known anti pattern using await which is : return await.

WRONG

async function myfunction() {_x000D_
  console.log('Inside of myfunction');_x000D_
}_x000D_
_x000D_
// Here we wait for the myfunction to finish_x000D_
// and then returns a promise that'll be waited for aswell_x000D_
// It's useless to wait the myfunction to finish before to return_x000D_
// we can simply returns a promise that will be resolved later_x000D_
_x000D_
// useless async here_x000D_
async function start() {_x000D_
  // useless await here_x000D_
  return await myfunction();_x000D_
}_x000D_
_x000D_
// Call start_x000D_
(async() => {_x000D_
  console.log('before start');_x000D_
_x000D_
  await start();_x000D_
  _x000D_
  console.log('after start');_x000D_
})();

CORRECT

async function myfunction() {_x000D_
  console.log('Inside of myfunction');_x000D_
}_x000D_
_x000D_
// Here we wait for the myfunction to finish_x000D_
// and then returns a promise that'll be waited for aswell_x000D_
// It's useless to wait the myfunction to finish before to return_x000D_
// we can simply returns a promise that will be resolved later_x000D_
_x000D_
// Also point that we don't use async keyword on the function because_x000D_
// we can simply returns the promise returned by myfunction_x000D_
function start() {_x000D_
  return myfunction();_x000D_
}_x000D_
_x000D_
// Call start_x000D_
(async() => {_x000D_
  console.log('before start');_x000D_
_x000D_
  await start();_x000D_
  _x000D_
  console.log('after start');_x000D_
})();

Also, know that there is a special case where return await is correct and important : (using try/catch)

Are there performance concerns with `return await`?

Pleas find bellow Program

class Node {
    int data;
    Node next;

    public Node(int data) {
        this.data = data;
        this.next = null;
    }
}

public class LinkedListManual {

    Node node;

    public void pushElement(int next_node) {
        Node nd = new Node(next_node);
        nd.next = node;
        node = nd;
    }

    public int getSize() {
        Node temp = node;
        int count = 0;
        while (temp != null) {
            count++;
            temp = temp.next;
        }
        return count;
    }

    public void getElement() {
        Node temp = node;
        while (temp != null) {
            System.out.println(temp.data);
            temp = temp.next;
        }
    }

    public static void main(String[] args) {
        LinkedListManual obj = new LinkedListManual();
        obj.pushElement(1);
        obj.pushElement(2);
        obj.pushElement(3);
        obj.getElement(); //get element
        System.out.println(obj.getSize());  //get size of link list
    }

}

I can think of a one liner like this to run

ping -c 1 127.0.0.1 &> /dev/null && echo success || echo fail

Replace 127.0.0.1 with IP or hostname, replace echo commands with what needs to be done in either case.

Code above will succeed, maybe try with an IP or hostname you know that is not accessible.

Like this:

ping -c 1 google.com &> /dev/null && echo success || echo fail

and this

ping -c 1 lolcatz.ninja &> /dev/null && echo success || echo fail

Problem: My VS 2015 was throwing up error after I installed SSDT. Whenever I clicked on Tools >> Extensions and Update it was throwing "Object reference not set to an instance of an object" error. When I tried to open a solution it threw some provider not set correctly.

Solution: After many hours of research trying out all the solutions previously mentioned by others didn't solve my problem. Every time the error popup was pointing to check the ActivityLog.xml. But I was ignoring it. After hours of frustration I decided to read the error carefully and looked into ActivitLog.xml and found that it was looking for "Could not load file or assembly 'System.Collections.Immutable, Version=1.1.37.0". So I just started searching for this assembly and stumbled upon this link https://sergeytihon.com/2015/12/01/how-to-restore-viual-studio-2015-after-update-1-dependency-dance/ and followed the steps there, which fixed my issue.

Went into %LOCALAPPDATA%/Local\Microsoft\VisualStudio\14.0\devenv.exe.config and searched for "System.Collections.Immutable" and change newVersion from 1.1.36.0 to 1.1.37.0

Final config should look like this

<dependentAssembly>
 <assemblyIdentity name="System.Collections.Immutable" publicKeyToken="b03f5f7f11d50a3a" culture="neutral"/>
 <bindingRedirect oldVersion="1.0.27.0-1.1.65535.65535" newVersion="1.1.37.0"/>
</dependentAssembly>

short answer, specific to OAuth2,

• HS256 user client secret to generate the token signature and same secret is required to validate the token in back-end. So you should have a copy of that secret in your back-end server to verify the signature.
• RS256 use public key encryption to sign the token.Signature(hash) will create using private key and it can verify using public key. So, no need of private key or client secret to store in back-end server, but back-end server will fetch the public key from openid configuration url in your tenant (https://[tenant]/.well-known/openid-configuration) to verify the token. KID parameter inside the access_toekn will use to detect the correct key(public) from openid-configuration.

When using Bootstrap >= 3.0 source files (SASS or LESS) you don't have to get rid of the rounded corners on everything if there is just one element that is bugging you, for example, to just get rid of the rounded corners on the navbar, use:

With SCSS:

$navbar-border-radius: 0;

With LESS:

@navbar-border-radius: 0;

However, if you do want to get rid of the rounded corners on everything, you can do what @adamwong246 mentioned and use:

$baseBorderRadius: 0;
@baseBorderRadius: 0;

Those two settings are the "root" settings from which the other settings like navbar-border-radius will inherit from unless other values are specified.

For a list all variables check out the variables.less or variables.scss

Password Strength Algorithm:

Password Length:
    5 Points: Less than 4 characters
    10 Points: 5 to 7 characters
    25 Points: 8 or more

Letters:
    0 Points: No letters
    10 Points: Letters are all lower case
    20 Points: Letters are upper case and lower case

Numbers:
    0 Points: No numbers
    10 Points: 1 number
    20 Points: 3 or more numbers

Characters:
    0 Points: No characters
    10 Points: 1 character
    25 Points: More than 1 character

Bonus:
    2 Points: Letters and numbers
    3 Points: Letters, numbers, and characters
    5 Points: Mixed case letters, numbers, and characters

Password Text Range:

    >= 90: Very Secure
    >= 80: Secure
    >= 70: Very Strong
    >= 60: Strong
    >= 50: Average
    >= 25: Weak
    >= 0: Very Weak

Settings Toggle to true or false, if you want to change what is checked in the password

var m_strUpperCase = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
var m_strLowerCase = "abcdefghijklmnopqrstuvwxyz";
var m_strNumber = "0123456789";
var m_strCharacters = "!@#$%^&*?_~"

Check password


function checkPassword(strPassword)
{
    // Reset combination count
    var nScore = 0;

    // Password length
    // -- Less than 4 characters
    if (strPassword.length < 5)
    {
        nScore += 5;
    }
    // -- 5 to 7 characters
    else if (strPassword.length > 4 && strPassword.length < 8)
    {
        nScore += 10;
    }
    // -- 8 or more
    else if (strPassword.length > 7)
    {
        nScore += 25;
    }

    // Letters
    var nUpperCount = countContain(strPassword, m_strUpperCase);
    var nLowerCount = countContain(strPassword, m_strLowerCase);
    var nLowerUpperCount = nUpperCount + nLowerCount;
    // -- Letters are all lower case
    if (nUpperCount == 0 && nLowerCount != 0) 
    { 
        nScore += 10; 
    }
    // -- Letters are upper case and lower case
    else if (nUpperCount != 0 && nLowerCount != 0) 
    { 
        nScore += 20; 
    }

    // Numbers
    var nNumberCount = countContain(strPassword, m_strNumber);
    // -- 1 number
    if (nNumberCount == 1)
    {
        nScore += 10;
    }
    // -- 3 or more numbers
    if (nNumberCount >= 3)
    {
        nScore += 20;
    }

    // Characters
    var nCharacterCount = countContain(strPassword, m_strCharacters);
    // -- 1 character
    if (nCharacterCount == 1)
    {
        nScore += 10;
    }   
    // -- More than 1 character
    if (nCharacterCount > 1)
    {
        nScore += 25;
    }

    // Bonus
    // -- Letters and numbers
    if (nNumberCount != 0 && nLowerUpperCount != 0)
    {
        nScore += 2;
    }
    // -- Letters, numbers, and characters
    if (nNumberCount != 0 && nLowerUpperCount != 0 && nCharacterCount != 0)
    {
        nScore += 3;
    }
    // -- Mixed case letters, numbers, and characters
    if (nNumberCount != 0 && nUpperCount != 0 && nLowerCount != 0 && nCharacterCount != 0)
    {
        nScore += 5;
    }


    return nScore;
}

// Runs password through check and then updates GUI 


function runPassword(strPassword, strFieldID) 
{
    // Check password
    var nScore = checkPassword(strPassword);


     // Get controls
        var ctlBar = document.getElementById(strFieldID + "_bar"); 
        var ctlText = document.getElementById(strFieldID + "_text");
        if (!ctlBar || !ctlText)
            return;

        // Set new width
        ctlBar.style.width = (nScore*1.25>100)?100:nScore*1.25 + "%";

    // Color and text
    // -- Very Secure
    /*if (nScore >= 90)
    {
        var strText = "Very Secure";
        var strColor = "#0ca908";
    }
    // -- Secure
    else if (nScore >= 80)
    {
        var strText = "Secure";
        vstrColor = "#7ff67c";
    }
    // -- Very Strong
    else 
    */
    if (nScore >= 80)
    {
        var strText = "Very Strong";
        var strColor = "#008000";
    }
    // -- Strong
    else if (nScore >= 60)
    {
        var strText = "Strong";
        var strColor = "#006000";
    }
    // -- Average
    else if (nScore >= 40)
    {
        var strText = "Average";
        var strColor = "#e3cb00";
    }
    // -- Weak
    else if (nScore >= 20)
    {
        var strText = "Weak";
        var strColor = "#Fe3d1a";
    }
    // -- Very Weak
    else
    {
        var strText = "Very Weak";
        var strColor = "#e71a1a";
    }

    if(strPassword.length == 0)
    {
    ctlBar.style.backgroundColor = "";
    ctlText.innerHTML =  "";
    }
else
    {
    ctlBar.style.backgroundColor = strColor;
    ctlText.innerHTML =  strText;
}
}

// Checks a string for a list of characters
function countContain(strPassword, strCheck)
{ 
    // Declare variables
    var nCount = 0;

    for (i = 0; i < strPassword.length; i++) 
    {
        if (strCheck.indexOf(strPassword.charAt(i)) > -1) 
        { 
                nCount++;
        } 
    } 

    return nCount; 
} 

You can customize by yourself according to your requirement.

You could use if type(ele) is dict or use isinstance(ele, dict) which would work if you had subclassed dict:

d = {'abc': 'abc', 'def': {'ghi': 'ghi', 'jkl': 'jkl'}}
for element in d.values():
    if isinstance(element, dict):
       for k, v in element.items():
           print(k,' ',v)

You need to swap all the back slashes to forward slashes so change

docker -v C:\my\folder:/mountlocation ...

to

docker -v C:/my/folder:/mountlocation ...

I normally call docker from a cmd script where I want the folder to mount to be relative to the script i'm calling so in that script I do this...

SETLOCAL

REM capture the path to this file so we can call on relative scrips
REM without having to be in this dir to do it.

REM capture the path to $0 ie this script
set mypath=%~dp0

REM strip last char
set PREFIXPATH=%mypath:~0,-1%

echo "PREFIXPATH=%PREFIXPATH%"
mkdir -p %PREFIXPATH%\my\folder\to\mount

REM swap \ for / in the path
REM because docker likes it that way in volume mounting
set PPATH=%PREFIXPATH:\=/%
echo "PPATH=%PPATH%"

REM pass all args to this script to the docker command line with %*
docker run --name mycontainername --rm -v %PPATH%/my/folder/to/mount:/some/mountpoint  myimage %*

ENDLOCAL

if you're using reactive forms then you can use the following way. consider the following example.

in component.html

 `<p class="mr-3"> Require Shipping: 

          <input type="radio" class="ml-2" value="true" name="requiresShipping" 
           id="requiresShipping" formControlName="requiresShipping">

                   &nbsp;  Yes  &nbsp;

          <input type="radio" class="ml-2" value="false" name="requiresShipping" 
          id="requiresShipping" formControlName="requiresShipping">

                   &nbsp;  No   &nbsp;
 </p>`

in component.ts

`
 export class ClassName implements OnInit {
      public yourForm: FormGroup
      
      constructor(
            private fromBuilder: FormBuilder
      ) {
            this.yourForm= this.fromBuilder.group({
                  requiresShipping: this.fromBuilder.control('true'),
            })
        }
 }

`

now you will get the default selected radio button.

grid is not a global, it is local to the main function. Change this:

int nonrecursivecountcells(color[ROW_SIZE][COL_SIZE], int row, int column)

to this:

int nonrecursivecountcells(color grid[ROW_SIZE][COL_SIZE], int row, int column)

Basically you forgot to give that first param a name, grid will do since it matches your code.

Try writing all the errors to a file.

error_reporting(-1); // reports all errors
ini_set("display_errors", "1"); // shows all errors
ini_set("log_errors", 1);
ini_set("error_log", "/tmp/php-error.log");

Something like that.

The standard best practice for most apps looking to do this automatically is: you don't. Instead you have the person running the container inject an external hostname/ip address as configuration, e.g. as an environment variable or config file. Allowing the user to inject this gives you the most portable design.

Why would this be so difficult? Because containers will, by design, isolate the application from the host environment. The network is namespaced to just that container by default, and details of the host are protected from the process running inside the container which may not be fully trusted.

There are different options depending on your specific situation:

If your container is running with host networking, then you can look at the routing table on the host directly to see the default route out. From this question the following works for me e.g.:

ip route get 1 | sed -n 's/^.*src \([0-9.]*\) .*$/\1/p'

An example showing this with host networking in a container looks like:

docker run --rm --net host busybox /bin/sh -c \
  "ip route get 1 | sed -n 's/^.*src \([0-9.]*\) .*$/\1/p'"

For current versions of Docker Desktop, they injected a DNS entry into the embedded VM:

getent hosts host.docker.internal | awk '{print $1}'

With the 20.10 release, the host.docker.internal alias can also work on Linux if you run your containers with an extra option:

docker run --add-host host.docker.internal:host-gateway ...

If you are running in a cloud environment, you can check the metadata service from the cloud provider, e.g. the AWS one:

curl http://169.254.169.254/latest/meta-data/local-ipv4

If you want your external/internet address, you can query a remote service like:

curl ifconfig.co

Each of these have limitations and only work in specific scenarios. The most portable option is still to run your container with the IP address injected as a configuration, e.g. here's an option running the earlier ip command on the host and injecting it as an environment variable:

export HOST_IP=$(ip route get 1 | sed -n 's/^.*src \([0-9.]*\) .*$/\1/p')
docker run --rm -e HOST_IP busybox printenv HOST_IP

Please see my answer here. As dreamwerx.myopenid.com points out, it is possible to do this with SimpleXML, but the DOM extension would be the better and more flexible way. Additionally there is a third way: using XMLWriter. It's much more simple to use than the DOM and therefore it's my preferred way of writing XML documents from scratch.

$w=new XMLWriter();
$w->openMemory();
$w->startDocument('1.0','UTF-8');
$w->startElement("root");
    $w->writeAttribute("ah", "OK");
    $w->text('Wow, it works!');
$w->endElement();
echo htmlentities($w->outputMemory(true));

By the way: DOM stands for Document Object Model; this is the standardized API into XML documents.

VAR is used for creating those variable whose value will change over the course of time in your application. It is same as VAR of swift, whereas VAL is used for creating those variable whose value will not change over the course of time in your application.It is same as LET of swift.

In addition to previously provided answers, one option is to follow the 'localhost exception' approach to create the first user if your db is already started with access control (--auth switch). In order to do that, you need to have localhost access to the server and then run:

mongo
use admin
db.createUser(
 {
     user: "user_name",
     pwd: "user_pass",
     roles: [
           { role: "userAdminAnyDatabase", db: "admin" },
           { role: "readWriteAnyDatabase", db: "admin" },
           { role: "dbAdminAnyDatabase", db: "admin" }
        ]
 })

As stated in MongoDB documentation:

The localhost exception allows you to enable access control and then create the first user in the system. With the localhost exception, after you enable access control, connect to the localhost interface and create the first user in the admin database. The first user must have privileges to create other users, such as a user with the userAdmin or userAdminAnyDatabase role. Connections using the localhost exception only have access to create the first user on the admin database.

Here is the link to that section of the docs.

docker build -t {image name} -v {host directory}:{temp build directory} .

This is another way to copy files into an image. The -v option temporarily creates a volume that us used during the build process.

This is different that other volumes because it mounts a host directory for the build only. Files can be copied using a standard cp command.

Also, like the curl and wget, it can be run in a command stack (runs in a single container) and not multiply the image size. ADD and COPY are not stackable because they run in a standalone container and subsequent commands on those files that execute in additional containers will multiply the image size:

With the options set thus:

-v /opt/mysql-staging:/tvol

The following will execute in one container:

RUN cp -r /tvol/mysql-5.7.15-linux-glibc2.5-x86_64 /u1 && \
    mv /u1/mysql-5.7.15-linux-glibc2.5-x86_64 /u1/mysql && \

    mkdir /u1/mysql/mysql-files && \
    mkdir /u1/mysql/innodb && \
    mkdir /u1/mysql/innodb/libdata && \
    mkdir /u1/mysql/innodb/innologs && \
    mkdir /u1/mysql/tmp && \

    chmod 750 /u1/mysql/mysql-files && \
    chown -R mysql /u1/mysql && \
    chgrp -R mysql /u1/mysql

A very fast implementation of the Sieve of Atkin is Dan Bernstein's primegen. This sieve is more efficient than the Sieve of Eratosthenes. His page has some benchmark information.

What Tyler Rinker says is correct:

AQ2 <- airquality
AQ2[is.na(AQ2)] <- 0

will do just this.

What you are originally doing is that you are taking from airquality all those rows (cases) that are complete. So, all the cases that do not have any NA's in them, and keep only those.

The accepted answer did not work for me on macOs Sierra (10.12.1). Had to do it recursive from /usr/local

cd /usr/local
sudo chown -R <your-username>:<your-group-name> *

Note: You can get your username with whoami and your group with id -g

The algorithm you are using, "AES", is a shorthand for "AES/ECB/NoPadding". What this means is that you are using the AES algorithm with 128-bit key size and block size, with the ECB mode of operation and no padding.

In other words: you are only able to encrypt data in blocks of 128 bits or 16 bytes. That's why you are getting that IllegalBlockSizeException exception.

If you want to encrypt data in sizes that are not multiple of 16 bytes, you are either going to have to use some kind of padding, or a cipher-stream. For instance, you could use CBC mode (a mode of operation that effectively transforms a block cipher into a stream cipher) by specifying "AES/CBC/NoPadding" as the algorithm, or PKCS5 padding by specifying "AES/ECB/PKCS5", which will automatically add some bytes at the end of your data in a very specific format to make the size of the ciphertext multiple of 16 bytes, and in a way that the decryption algorithm will understand that it has to ignore some data.

In any case, I strongly suggest that you stop right now what you are doing and go study some very introductory material on cryptography. For instance, check Crypto I on Coursera. You should understand very well the implications of choosing one mode or another, what are their strengths and, most importantly, their weaknesses. Without this knowledge, it is very easy to build systems which are very easy to break.

Update: based on your comments on the question, don't ever encrypt passwords when storing them at a database!!!!! You should never, ever do this. You must HASH the passwords, properly salted, which is completely different from encrypting. Really, please, don't do what you are trying to do... By encrypting the passwords, they can be decrypted. What this means is that you, as the database manager and who knows the secret key, you will be able to read every password stored in your database. Either you knew this and are doing something very, very bad, or you didn't know this, and should get shocked and stop it.

The answer of Flip is computationally more consistent than the Muis one.

Using double number format, you could see the roundoff problem in the Muis approach:

When you divide and subtract, a roundoff appears in the previous stored value, changing it.

However, the Flip approach preserves the stored value and reduces the number of divisions, hence, reducing the roundoff, and minimizing the error propagated to the stored value. Adding only will bring up roundoffs if there is something to add (when N is big, there is nothing to add)

Those changes are remarkable when you make a mean of big values tend their mean to zero.

I show you the results using a spreadsheet program:

Firstly, the results obtained:

The A and B columns are the n and X_n values, respectively.

The C column is the Flip approach, and the D one is the Muis approach, the result stored in the mean. The E column corresponds with the medium value used in the computation.

A graph showing the mean of even values is the next one:

As you can see, there is big differences between both approachs.

In the case of sentences with uppercase - lowercase letters, We can use BINARY REPACE

UPDATE `table_1`  SET  `field_1` =  BINARY REPLACE(`field_1`, 'find_string', 'replace_string')

State machines can be very complex for a complex problem. They are also subject to unexpected bugs. They can turn into a nightmare if someone runs into a bug or needs to change the logic in the future. They are also difficult to follow and debug without the state diagram. Structured programming is much better (for example you would probably not use a state machine at mainline level). You can use structured programming even in interrupt context (which is where state machines are usually used). See this article "Macros to simulate multi-tasking/blocking code at interrupt level" found at codeproject.com.

up above we saw some with iteration. Let's do the same thing using forEach:

var funcs = [function () {
        console.log(1)
  },
  function () {
        console.log(2)
  }
];

funcs.forEach(function (func) {
  func(); // outputs  1, then 2
});
//for (i = 0; i < funcs.length; i++) funcs[i]();

I prefer simple answers. No generators. No recursion or recursion limits. Just iteration:

def flatten(TheList):
    listIsNested = True

    while listIsNested:                 #outer loop
        keepChecking = False
        Temp = []

        for element in TheList:         #inner loop
            if isinstance(element,list):
                Temp.extend(element)
                keepChecking = True
            else:
                Temp.append(element)

        listIsNested = keepChecking     #determine if outer loop exits
        TheList = Temp[:]

    return TheList

This works with two lists: an inner for loop and an outer while loop.

The inner for loop iterates through the list. If it finds a list element, it (1) uses list.extend() to flatten that part one level of nesting and (2) switches keepChecking to True. keepchecking is used to control the outer while loop. If the outer loop gets set to true, it triggers the inner loop for another pass.

Those passes keep happening until no more nested lists are found. When a pass finally occurs where none are found, keepChecking never gets tripped to true, which means listIsNested stays false and the outer while loop exits.

The flattened list is then returned.

Test-run

flatten([1,2,3,4,[100,200,300,[1000,2000,3000]]])

[1, 2, 3, 4, 100, 200, 300, 1000, 2000, 3000]

You can't trigger the native validation UI (see edit below), but you can easily take advantage of the validation API on arbitrary input elements:

$('input').blur(function(event) {
    event.target.checkValidity();
}).bind('invalid', function(event) {
    setTimeout(function() { $(event.target).focus();}, 50);
});

The first event fires checkValidity on every input element as soon as it loses focus, if the element is invalid then the corresponding event will be fired and trapped by the second event handler. This one sets the focus back to the element, but that could be quite annoying, I assume you have a better solution for notifying about the errors. Here's a working example of my code above.

EDIT: All modern browsers support the reportValidity() method for native HTML5 validation, per this answer.

You can try this:

s = r'long\annoying\path'

If you want to know the number of visitors (as is titled in the question) and not the number of pageviews, then you'll need to create a custom report.

Terminology

Google Analytics has changed the terminology they use within the reports. Now, visits is named "sessions" and unique visitors is named "users."

User - A unique person who has visited your website. Users may visit your website multiple times, and they will only be counted once.

Session - The number of different times that a visitor came to your site.

Pageviews - The total number of pages that a user has accessed.

Creating a Custom Report

1. To create a custom report, click on the "Customization" item in the left navigation menu, and then click on "Custom Reports".

2. The "Create Custom Report" page will open.
3. Enter a name for your report.
4. In the "Metric Groups" section, enter either "Users" or "Sessions" depending on what information you want to collect (see Terminology, above).
5. In the "Dimension Drilldowns" section, enter "Page".
6. Under "Filters" enter the individual page (exact) or group of pages (using regex) that you would like to see the data for.
7. Save the report and run it.

print "bla: ", $myvar =~ tr{a}{b},"\n";

Just a small detail that I think is missing in above answers.

If your child activity can be opened from multiple parent activities then you can check if you need to do setResult or not, based on if your activity was opened by startActivity or startActivityForResult. You can achieve this by using getCallingActivity(). More info here.

It occurs when others in the project are also using the same port numbers as you are using! double click tomcat server, change port numbers to anything 8585 or whatever. The code will now begin to run!

h3 is absolutly a better solution than h2, h1 or h6 !

1. You have to use specific level : if you're in a h1, use h2, if you're in a h5, use h6 (if you're in a h6... hum, use strong or em for exemple). It not a obligation but a question of accessibility (Here, green part).

2. You don't have to give title to list... because this element it doesn't exist. So screen reader will not use something special.

Therefore, using Hn is probably one of the best solution, but surely not a specific level.

Support for TLS 1.0 and 1.1 was dropped for PyPI. If your system does not use a more recent version, it could explain your error.

Could you try reinstalling pip system-wide, to update your system dependencies to a newer version of TLS?

This seems to be related to Unable to install Python libraries

See Dominique Barton's answer:

Apparently pip is trying to access PyPI via HTTPS (which is encrypted and fine), but with an old (insecure) SSL version. Your system seems to be out of date. It might help if you update your packages.

On Debian-based systems I'd try:

apt-get update && apt-get upgrade python-pip

On Red Hat Linux-based systems:

yum update python-pip # (or python2-pip, at least on Red Hat Linux 7)

On Mac:

sudo easy_install -U pip

You can also try to update openssl separately.

You can also use static code block to instantiate the instance at class load and prevent the thread synchronization issues.

public class MySingleton {

  private static final MySingleton instance;

  static {
     instance = new MySingleton();
  }

  private MySingleton() {
  }

  public static MySingleton getInstance() {
    return instance;
  }

}

You need a section in your file:

[My Section]
path1 = D:\test1\first
path2 = D:\test2\second
path3 = D:\test2\third

Then, read the properties:

import ConfigParser

config = ConfigParser.ConfigParser()
config.readfp(open(r'abc.txt'))
path1 = config.get('My Section', 'path1')
path2 = config.get('My Section', 'path2')
path3 = config.get('My Section', 'path3')

If you didn't push the update in remote then the simple solution is remove last local commit using following command: git reset HEAD^. Then add all files and commit again.

For me the problem was that I was using a <button> instead of a <asp:LinkButton>

The using syntax has an advantage when used within templates. If you need the type abstraction, but also need to keep template parameter to be possible to be specified in future. You should write something like this.

template <typename T> struct whatever {};

template <typename T> struct rebind
{
  typedef whatever<T> type; // to make it possible to substitue the whatever in future.
};

rebind<int>::type variable;

template <typename U> struct bar { typename rebind<U>::type _var_member; }

But using syntax simplifies this use case.

template <typename T> using my_type = whatever<T>;

my_type<int> variable;
template <typename U> struct baz { my_type<U> _var_member; }

You can use

• helpers.<helper> in Rails 5+ (or ActionController::Base.helpers.<helper>)
• view_context.<helper> (Rails 4 & 3) (WARNING: this instantiates a new view instance per call)
• @template.<helper> (Rails 2)
• include helper in a singleton class and then singleton.helper
• include the helper in the controller (WARNING: will make all helper methods into controller actions)

Updated for Bootstrap 4

Bootstrap 4 now includes a position-fixed class for this purpose so there is no need for additional CSS...

<div class="container">
    <div class="row">
        <div class="col-lg-3">
            <div class="position-fixed">
                Fixed content
            </div>
        </div>
        <div class="col-lg-9">
            Normal scrollable content
        </div>
    </div>
</div>

https://www.codeply.com/go/yOF9csaptw

The good news is a transaction in SQL Server can span multiple batches (each exec is treated as a separate batch.)

You can wrap your EXEC statements in a BEGIN TRANSACTION and COMMIT but you'll need to go a step further and rollback if any errors occur.

Ideally you'd want something like this:

BEGIN TRY
    BEGIN TRANSACTION 
        exec( @sqlHeader)
        exec(@sqlTotals)
        exec(@sqlLine)
    COMMIT
END TRY
BEGIN CATCH

    IF @@TRANCOUNT > 0
        ROLLBACK
END CATCH

The BEGIN TRANSACTION and COMMIT I believe you are already familiar with. The BEGIN TRY and BEGIN CATCH blocks are basically there to catch and handle any errors that occur. If any of your EXEC statements raise an error, the code execution will jump to the CATCH block.

Your existing SQL building code should be outside the transaction (above) as you always want to keep your transactions as short as possible.