Signalr negotiate url fails

Question

Trying to get signalr up and running. I keep getting 2 errors back from the server:

1. GET negotitate url returns 500 Internal Server Error
2. XMLHttpRequest cannot load http://localhost:10772//signalr/negotiate ... No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:3000' is therefore not allowed access. The response had HTTP status code 500.

Screenshot provided.

Any ideas?

]1

Answer 1

OK, found it out myself. Spelling error. The name of the hub mentioned was incorrect.

changed:
var proxy = this.connection.createHubProxy('chattAppHub');

to:
var proxy = this.connection.createHubProxy('ChatAppHub');

In the backend:
[HubName("ChatAppHub")]
public class ChatAppHub : Hub ...

inside startup.cs
var hubConfiguration = new HubConfiguration(); hubConfiguration.EnableDetailedErrors = true; appBuilder.MapSignalR(hubConfiguration); appBuilder.UseCors(Microsoft.Owin.Cors.CorsOptions.AllowAll);

Answer 2

This fixed it for me:

C# Startup.cs tweak:

app.MapSignalR(new HubConfiguration{EnableJSONP = true});

JavaScript tweak:

connection.start({ jsonp: true })

We need JSONP anyways so for us it was a good solution.

Answer 3

I had the same problem, it is all about CORS. You should add Host URL in CORS config in Sturtup.cs, Have look at:

https://stackoverflow.com/a/59891997/854405