How to enable Access-Control-Allow-Origin for angular 5/nodejs?

Question

Read many ways for including of \'Access-Control-Allow-Origin\' and none worked for me.

I use @angular/common/http module and external url as data source. by the att

Answer 1

You mentioned webpack-dev-server, which of course can handle CORS since it's using express behind the scenes. In your webpack config

devServer: {
  headers: {
    "Access-Control-Allow-Origin": "*",
    "Access-Control-Allow-Methods": "GET, POST, PUT, DELETE, PATCH, OPTIONS",
    "Access-Control-Allow-Headers": "X-Requested-With, content-type, Authorization"
  }
},

Answer 2

**Set headers to allow CORS origin in Express **

=> Add code in the server.js file or mail file.

app.use(function(req, res, next) {
   res.header("Access-Control-Allow-Origin", "*");
   res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
  next();
 });

CORS (Cross-Origin Resource Sharing) is an HTML5 feature that allows one site to access another site’s resources despite being under different domain names.

The W3C specification for CORS actually does a pretty good job of providing some simple examples of the response headers, such as the key header, Access-Control-Allow-Origin, and other headers that you must use to enable CORS on your web server.

Answer 3

Access-Control-Allow-Origin

Is response header not request header. You must add this header to your resfull (server)

Answer 4

If you are using .NET Api then add this to your WebApiConfig.cs file

    public static void Register(HttpConfiguration config)
    {
        var enableCorsAttribute = new EnableCorsAttribute("*",
                                           "Origin, Content-Type, Accept",
                                           "GET, PUT, POST, DELETE, OPTIONS");
        config.EnableCors(enableCorsAttribute);
        // Web API configuration and services
        // Configure Web API to use only bearer token authentication.
        config.SuppressDefaultHostAuthentication();
        config.Filters.Add(new HostAuthenticationFilter(OAuthDefaults.AuthenticationType));

        // Web API routes
        config.MapHttpAttributeRoutes();

        config.Routes.MapHttpRoute(
            name: "DefaultApi",
            routeTemplate: "api/v1/{controller}/{id}",
            defaults: new { id = RouteParameter.Optional }
        );
    }
}