[javascript] How to enable CORS in AngularJs

I have created a demo using JavaScript for Flickr photo search API. Now I am converting it to the AngularJs. I have searched on internet and found below configuration.

Configuration:

myApp.config(function($httpProvider) {
  $httpProvider.defaults.useXDomain = true;
  delete $httpProvider.defaults.headers.common['X-Requested-With'];
});

Service:

myApp.service('dataService', function($http) {
    delete $http.defaults.headers.common['X-Requested-With'];
    this.flickrPhotoSearch = function() {
        return $http({
            method: 'GET',
            url: 'http://api.flickr.com/services/rest/?method=flickr.photos.search&api_key=3f807259749363aaa29c76012fa93945&tags=india&format=json&callback=?',
            dataType: 'jsonp',
            headers: {'Authorization': 'Token token=xxxxYYYYZzzz'}
         });
     }
});

Controller:

myApp.controller('flickrController', function($scope, dataService) {
        $scope.data = null;
        dataService.flickrPhotoSearch().then(function(dataResponse) {
            $scope.data = dataResponse;
            console.log($scope.data);
        });
    });

But still I got the same error. Here are some links I tried:

XMLHttpRequest cannot load URL. Origin not allowed by Access-Control-Allow-Origin

http://goo.gl/JuS5B1

I encountered a similar problem like this, problem was with the backend . I was using node server(Express). I had a get request from the frontend(angular) as shown below

   onGetUser(){
        return this.http.get("http://localhost:3000/user").pipe(map(
            (response:Response)=>{
                const user =response.json();
                return user;
            }
        )) 
    }

But it gave the following error

This is the backend code written using express without the headers

app.get('/user',async(req,res)=>{
     const user=await getuser();
     res.send(user);
 })

After adding a header to the method problem was solved

app.get('/user',async(req,res)=>{
    res.header("Access-Control-Allow-Origin", "*");
    const user=await getuser();
    res.send(user);
})

You can get more details about Enabling CORS on Node JS

Try using the resource service to consume flickr jsonp:

var MyApp = angular.module('MyApp', ['ng', 'ngResource']);

MyApp.factory('flickrPhotos', function ($resource) {
    return $resource('http://api.flickr.com/services/feeds/photos_public.gne', { format: 'json', jsoncallback: 'JSON_CALLBACK' }, { 'load': { 'method': 'JSONP' } });
});

MyApp.directive('masonry', function ($parse) {
    return {
        restrict: 'AC',
        link: function (scope, elem, attrs) {
            elem.masonry({ itemSelector: '.masonry-item', columnWidth: $parse(attrs.masonry)(scope) });
        }
    };        
});

MyApp.directive('masonryItem', function () {
    return {
        restrict: 'AC',
        link: function (scope, elem, attrs) {
            elem.imagesLoaded(function () {
               elem.parents('.masonry').masonry('reload');
            });
        }
    };        
});

MyApp.controller('MasonryCtrl', function ($scope, flickrPhotos) {
    $scope.photos = flickrPhotos.load({ tags: 'dogs' });
});

Template:

<div class="masonry: 240;" ng-controller="MasonryCtrl">
    <div class="masonry-item" ng-repeat="item in photos.items">
        <img ng-src="{{ item.media.m }}" />
    </div>
</div>

This issue occurs because of web application security model policy that is Same Origin Policy Under the policy, a web browser permits scripts contained in a first web page to access data in a second web page, but only if both web pages have the same origin. That means requester must match the exact host, protocol, and port of requesting site.

We have multiple options to over come this CORS header issue.

1. Using Proxy - In this solution we will run a proxy such that when request goes through the proxy it will appear like it is some same origin. If you are using the nodeJS you can use cors-anywhere to do the proxy stuff. https://www.npmjs.com/package/cors-anywhere.

   Example:-

   var host = process.env.HOST || '0.0.0.0';
   var port = process.env.PORT || 8080;
   var cors_proxy = require('cors-anywhere');
   cors_proxy.createServer({
       originWhitelist: [], // Allow all origins
       requireHeader: ['origin', 'x-requested-with'],
       removeHeaders: ['cookie', 'cookie2']
   }).listen(port, host, function() {
       console.log('Running CORS Anywhere on ' + host + ':' + port);
   });
   

2. JSONP - JSONP is a method for sending JSON data without worrying about cross-domain issues.It does not use the XMLHttpRequest object.It uses the <script> tag instead. https://www.w3schools.com/js/js_json_jsonp.asp

3. Server Side - On server side we need to enable cross-origin requests. First we will get the Preflighted requests (OPTIONS) and we need to allow the request that is status code 200 (ok).

   Preflighted requests first send an HTTP OPTIONS request header to the resource on the other domain, in order to determine whether the actual request is safe to send. Cross-site requests are preflighted like this since they may have implications to user data. In particular, a request is preflighted if it uses methods other than GET or POST. Also, if POST is used to send request data with a Content-Type other than application/x-www-form-urlencoded, multipart/form-data, or text/plain, e.g. if the POST request sends an XML payload to the server using application/xml or text/xml, then the request is preflighted. It sets custom headers in the request (e.g. the request uses a header such as X-PINGOTHER)

   If you are using the spring just adding the bellow code will resolves the issue. Here I have disabled the csrf token that doesn't matter enable/disable according to your requirement.

   @SpringBootApplication
   public class SupplierServicesApplication {
   
       public static void main(String[] args) {
           SpringApplication.run(SupplierServicesApplication.class, args);
       }
   
       @Bean
       public WebMvcConfigurer corsConfigurer() {
           return new WebMvcConfigurerAdapter() {
               @Override
               public void addCorsMappings(CorsRegistry registry) {
                   registry.addMapping("/**").allowedOrigins("*");
               }
           };
       }
   }
   

   If you are using the spring security use below code along with above code.

   @Configuration
   @EnableWebSecurity
   public class SupplierSecurityConfig extends WebSecurityConfigurerAdapter {
   
       @Override
       protected void configure(HttpSecurity http) throws Exception {
           http.csrf().disable().authorizeRequests().antMatchers(HttpMethod.OPTIONS, "/**").permitAll().antMatchers("/**").authenticated().and()
                   .httpBasic();
       }
   
   }
   

Apache/HTTPD tends to be around in most enterprises or if you're using Centos/etc at home. So, if you have that around, you can do a proxy very easily to add the necessary CORS headers.

I have a blog post on this here as I suffered with it quite a few times recently. But the important bit is just adding this to your /etc/httpd/conf/httpd.conf file and ensuring you are already doing "Listen 80":

<VirtualHost *:80>
    <LocationMatch "/SomePath">
       ProxyPass http://target-ip:8080/SomePath
       Header add "Access-Control-Allow-Origin" "*"
    </LocationMatch>
</VirtualHost>

This ensures that all requests to URLs under your-server-ip:80/SomePath route to http://target-ip:8080/SomePath (the API without CORS support) and that they return with the correct Access-Control-Allow-Origin header to allow them to work with your web-app.

Of course you can change the ports and target the whole server rather than SomePath if you like.

I had a similar problem and for me it boiled down to adding the following HTTP headers at the response of the receiving end:

Access-Control-Allow-Headers: Content-Type
Access-Control-Allow-Methods: GET, POST, OPTIONS
Access-Control-Allow-Origin: *

You may prefer not to use the * at the end, but only the domainname of the host sending the data. Like *.example.com

But this is only feasible when you have access to the configuration of the server.

Answered by myself.

CORS angular js + restEasy on POST

Well finally I came to this workaround: The reason it worked with IE is because IE sends directly a POST instead of first a preflight request to ask for permission. But I still don't know why the filter wasn't able to manage an OPTIONS request and sends by default headers that aren't described in the filter (seems like an override for that only case ... maybe a restEasy thing ...)

So I created an OPTIONS path in my rest service that rewrites the reponse and includes the headers in the response using response header

I'm still looking for the clean way to do it if anybody faced this before.

        var result=[];
        var app = angular.module('app', []);
        app.controller('myCtrl', function ($scope, $http) {
             var url="";// your request url    
             var request={};// your request parameters
             var headers = {
             // 'Authorization': 'Basic ' + btoa(username + ":" + password),
            'Access-Control-Allow-Origin': true,
            'Content-Type': 'application/json; charset=utf-8',
            "X-Requested-With": "XMLHttpRequest"
              }
             $http.post(url, request, {
                        headers
                 })
                 .then(function Success(response) {
                      result.push(response.data);             
                      $scope.Data = result;              
                 }, 
                  function Error(response) {
                      result.push(response.data);
                       $scope.Data = result;
                    console.log(response.statusText + " " + response.status)
               }); 
     });

And also add following code in your WebApiConfig file            
        var cors = new EnableCorsAttribute("*", "*", "*");
        config.EnableCors(cors);

This answer outlines two ways to workaround APIs that don't support CORS:

• Use a CORS Proxy
• Use JSONP if the API Supports it

One workaround is to use a CORS PROXY:

angular.module("app",[])
.run(function($rootScope,$http) { 
     var proxy = "//cors-anywhere.herokuapp.com";
     var url = "http://api.ipify.org/?format=json";
     $http.get(proxy +'/'+ url)
       .then(function(response) {
         $rootScope.response = response.data;
     }).catch(function(response) {
         $rootScope.response = 'ERROR: ' + response.status;
     })     
})

<script src="//unpkg.com/angular/angular.js"></script>
<body ng-app="app">
   Response = {{response}}
</body>

For more information, see

• GitHub: CORS Anywhere

Use JSONP if the API supports it:

 var url = "//api.ipify.org/";
 var trust = $sce.trustAsResourceUrl(url);
 $http.jsonp(trust,{params: {format:'jsonp'}})
   .then(function(response) {
     console.log(response);
     $scope.response = response.data;
 }).catch(function(response) {
     console.log(response);
     $scope.response = 'ERROR: ' + response.status;
 }) 

The DEMO on PLNKR

For more information, see

• AngularJS $http Service API Reference - $http.jsonp

we can enable CORS in the frontend by using the ngResourse module. But most importantly, we should have this piece of code while making the ajax request in the controller,

$scope.weatherAPI = $resource(YOUR API,
     {callback: "JSON_CALLBACK"}, {get: {method: 'JSONP'}});
 $scope.weatherResult = $scope.weatherAPI.get(YOUR REQUEST DATA, if any);

Also, you must add ngResourse CDN in the script part and add as a dependency in the app module.

<script src="https://code.angularjs.org/1.2.16/angular-resource.js"></script>

Then use "ngResourse" in the app module dependency section

var routerApp = angular.module("routerApp", ["ui.router", 'ngResource']);