c# - How do you enable cross-origin requests (CORS) in ASP.NET Core MVC

Question

I'd like to enable CORS on an API built with ASP.NET Core MVC, but all the current documents refer to earlier versions of that framework.

Answer 1

The notes on the new Cors features are very light, but I was able to get it working in my solution by looking at the new classes and methods. My Web API startup.cs looks like this. You can see how you can construct your origins and policies her by using the new CorsPolicy class. And enabling CORS with the AddCors and UseCors methods.

 public void ConfigureServices(IServiceCollection services)
 {
     services.AddMvc();
     //Add Cors support to the service
     services.AddCors();

     var policy = new Microsoft.AspNet.Cors.Core.CorsPolicy();

     policy.Headers.Add("*");    
     policy.Methods.Add("*");          
     policy.Origins.Add("*");
     policy.SupportsCredentials = true;

     services.ConfigureCors(x=>x.AddPolicy("mypolicy", policy));

 }


 public void Configure(IApplicationBuilder app, IHostingEnvironment  env)
 {
     // Configure the HTTP request pipeline.

     app.UseStaticFiles();
     //Use the new policy globally
     app.UseCors("mypolicy");
     // Add MVC to the request pipeline.
     app.UseMvc();
 }

You can also reference the policy in the controllers with the new attributes like so

[EnableCors("mypolicy")]
[Route("api/[controller]")]