Configure CORS to use with SignalR

Author: Сергей Трегуб

ProjectTemplates/ReferenceProject/Startup.cs

@@ -146,13 +146,15 @@ public void Configure(IApplicationBuilder app, ILogger<Startup> logger)
 
             // See: https://github.com/drwatson1/AspNet-Core-REST-Service/wiki#cross-origin-resource-sharing-cors-and-preflight-requests
             app.UseCors(builder => builder
-                .AllowAnyOrigin()
                 .AllowAnyMethod()
-                .AllowAnyHeader());
-
-            app
-                .UseOptionsVerbHandler()    // Options verb handler must be added after CORS. See: https://github.com/drwatson1/AspNet-Core-REST-Service/wiki#cross-origin-resource-sharing-cors-and-preflight-requests
-                .UseSwaggerWithOptions();   // Check out Configuration/MiddlewareConfig.cs/UseSwaggerWithOptions to do actual configuration. See: https://github.com/drwatson1/AspNet-Core-REST-Service/wiki#documenting-api
+                .AllowAnyHeader()
+                .AllowAnyOrigin() // <-- Comment this line out and uncomment two lines below to use with SignalR
+                /*.AllowCredentials()
+                  .SetIsOriginAllowed(origin => true)*/
+                );
+
+            app.UseOptionsVerbHandler()    // Options verb handler must be added after CORS. See: https://github.com/drwatson1/AspNet-Core-REST-Service/wiki#cross-origin-resource-sharing-cors-and-preflight-requests
+               .UseSwaggerWithOptions();   // Check out Configuration/MiddlewareConfig.cs/UseSwaggerWithOptions to do actual configuration. See: https://github.com/drwatson1/AspNet-Core-REST-Service/wiki#documenting-api
 
             app.UseEndpoints(endpoints =>
             {