No Access-Control-Allow-Origin header in Angular 2 app

Question

For this project  I m just learning and practicing Angular 2  I have no server-side and am making API requests to  barchart ondemand api    I m wondering if it is possible to bypass the cors issue  I m still fairly new to all this  so baby-step instructions are really appreciated  I m using http   localhost 8080   Error message   api key commented out    XMLHttpRequest cannot load http   marketdata websol barchart com getHistory json key MY API KEY amp symbol GOOG amp type daily amp startDate 20150311000000  Response to preflight request doesn t pass access control check  No  Access-Control-Allow-Origin  header is present on the requested resource  Origin  http   localhost 8080  is therefore not allowed access   StockInformationService   import  Injectable  from  angular2 core   import  Http  Headers  from  angular2 http   import  Observable  from  rxjs Rx     Injectable   export class StockInformationService       private apiRoot    http   marketdata websol barchart com getHistory json key MY API KEY amp         constructor  private  http  Http          getData symbol  string   Observable lt any gt               Tried adding headers with no luck         const headers   new Headers            headers append  Access-Control-Allow-Headers    Content-Type            headers append  Access-Control-Allow-Methods    GET            headers append  Access-Control-Allow-Origin                  return this  http get this apiRoot    symbol     symbol     amp type daily amp startDate 20150311000000    headers  headers                map response   gt  response json               App Component   import  Component  from  angular2 core   import  VolumeComponent  from        components volume volume   import  StockInformationService  from        core stock-information service     Component       selector   app-shell       template  require    app-shell html        directives   VolumeComponent       providers   StockInformationService     export class AppShell       constructor private  stockInformationService  StockInformationService             In my template  on button click  make api request     requestData symbol  string            this  stockInformationService getData symbol               subscribe                  data   gt                        console log data                                     error   gt  console log  Error      error                            In my console  the requestData Error  Error   object Object

User · Answer

You can read more about that from here  http   www html5rocks com en tutorials cors    Your resource methods won t get hit  so their headers will never get set  The reason is that there is what s called a preflight request before the actual request  which is an OPTIONS request  So the error comes from the fact that the preflight request doesn t produce the necessary headers  check that you will need to add following in your  htaccess file   Header set Access-Control-Allow-Origin

User · Answer

Most of the time this happens due to the invalid response type from server   Make sure the following 2 to avoid this issue     You don t need to set any CORS headers in Angular side  it very well know how to deal with it  Angular expects the return data to be in json format  so make sure the return type is JSON even for the OPTIONS request  You Handle CORS in server side by using CORS header which is very self explanatory or you can google how to set CORS headers or middlewares

User · Answer

If you are creating a mock-up with SoapUI a  free testing tool for REST and SOAP request and response  for Angular 2  application you should remember to set inside your http header request    Access-Control-Allow-Origin        I add two images for helping your insert  The first shows the header you should add  If you want to add the header before you have to click the plus button it s green      The second image shows the insert the    The value   permits to accept all the request from different hosts     After this work my Angular application removed this annoying error in my console     A big recourse that helped me to understand for creating my first mock up is this video  It will help you for creating a new mock-up inside SoapUi s environment without a server-side

User · Answer

this is server configuration  set up config addAllowedHeader       in the CorsConfiguration

User · Answer

Simply you can set in php file as  header  Access-Control-Allow-Origin       header  Content-Type  application json  charset UTF-8

User · Answer

This a problem with the CORS configuration on the server  It is not clear what server are you using  but if you are using Node express you can solve it with the following code     Add headers app use function  req  res  next            Website you wish to allow to connect     res setHeader  Access-Control-Allow-Origin    http   localhost 8888            Request methods you wish to allow     res setHeader  Access-Control-Allow-Methods    GET  POST  OPTIONS  PUT  PATCH  DELETE            Request headers you wish to allow     res setHeader  Access-Control-Allow-Headers    X-Requested-With content-type            Set to true if you need the website to include cookies in the requests sent        to the API  e g  in case you use sessions      res setHeader  Access-Control-Allow-Credentials   true           Pass to next layer of middleware     next          that code was an answer of  jvandemo to a very similar question

User · Answer

I also had the same issue while using http   www mocky io  what i did is to add in mock io response header  Access-Control-Allow-Origin    To add it there just need to click on advanced options   Once this is done  my application was able to retrieve the data from external domain

User · Answer

Unfortunately  that s not an Angular2 error  that s an error your browser is running into  i e  outside of your app    That CORS header will have to be added to that endpoint on the server before you can make ANY requests

User · Answer

I have spent lot of time for solution and got it worked finally by making changes in the server side Check the website https   docs microsoft com en-us aspnet core security cors  It worked for me when I enabled corse in the server side We were using Asp Net core in API and the below code worked  1  Added Addcors in ConfigureServices of Startup cs  public void ConfigureServices IServiceCollection services                services AddCors            services AddMvc            2  Added UseCors in Configure method as below   public void Configure IApplicationBuilder app  IHostingEnvironment env                app UseCors builder   gt builder AllowAnyOrigin             app UseMvc

User · Answer

I had the same problem when I was practising Angular5  Then I came across https   spring io guides gs rest-service-cors  which helped me to resolve the issue   I have kept  CrossOrigin exposedHeaders  Access-Control-Allow-Origin   on my request mapping method  We can also configure this globally in spring boot application

User · Answer

Another simple way  without installing anything   HTTP function  authenticate credentials     let body   new URLSearchParams    body set  username   credentials username   body set  password   credentials password    return this http post  rest myEndpoint  body     subscribe    data   gt  this loginResult   data    error   gt        console log error               gt         function to execute after successfull api call              Create a proxy conf json file       rest      target    http   endpoint com 8080 package     pathRewrite          rest          secure   false      then ng serve --proxy-config proxy conf json  or   open package json and replace    scripts      start    ng serve --proxy-config proxy conf json          and then npm start  That s it   Check here https   webpack github io docs webpack-dev-server html for more options

User · Answer

I also encountered the same problem and passed the following way to solve this problem   step 1     npm install --save-dev http-proxy-middleware   step 2   add a proxy when i fetch web api  if you use lite-server you can add a file bs-config js      file  bs-config js var proxyMiddleware   require  http-proxy-middleware     module exports         server            middleware                1  proxyMiddleware   example-api                     target   http   api example com                   changeOrigin  true                  pathRewrite                       news-at-api     api                                                        hope this helps

User · Answer

I got the same error and here how I solved it  by adding the following to your spring controller    CrossOrigin origins     http   localhost 3000

[angular] No 'Access-Control-Allow-Origin' header in Angular 2 app

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