.Net framework Owin Test Server does not work with WebSocket

Question

My project is Owin self-hosted, it provides Web API endpoints and web socket endpoints. Here is the relevant config code in the project's startup class Owin WebSocket is used here

using Owin;
using Owin.WebSocket.Extensions;
public void Configuration(IAppBuilder app)
    {
        HttpConfiguration config = new HttpConfiguration();
        config.MapHttpAttributeRoutes();
        config.Routes.MapHttpRoute(
           name: "api",
           routeTemplate: "api/{version}/{controller}"
       );
        config.EnsureInitialized();
        app.MapWebSocketRoute<WebSocket>("/api/v1/socket/test");
        app.UseWebApi(config);
    }

Works smoothly, when the app is launched I can consume the web api via "http://{host}/api/v1/test" and use the websockets by: "ws://{host}/api/v1/socket/test"

Then I decided to add some integration tests. I use Owin Test Server here. In TestServer.Create the config is identical:

        HttpConfiguration config = new HttpConfiguration();
        config.MapHttpAttributeRoutes();
        config.Routes.MapHttpRoute(
           name: "api",
           routeTemplate: "api/{version}/{controller}"
       );
        config.EnsureInitialized();
        app.MapWebSocketRoute<WebSocket>("/api/v1/socket/test");
        app.UseWebApi(config);

Test method for api

        var url = new UriBuilder()
        {
            Scheme = "http",
            Path = "/api/v1/test"
        }.Uri;;
        var result = client.GetAsync(url).Result;

Works nicely. But does not work for web socket:

       var wsUri = new UriBuilder()
        {
            Scheme = "ws",
            Path = "/api/v1/socket/test"
        }.Uri;

        //create websocket client, connect it and to server 
        var wsc = new ClientWebSocket();

        Task.Run(async () =>
        {
            await wsc.ConnectAsync(wsUri, CancellationToken.None);
            var a = wsc.State; // Here error thrown: No connection could be made because the target machine actively refused it 127.0.0.1:80
        }).GetAwaiter().GetResult();

Why No connection could be made here? It seems like the testing server can only support regular http request not websocket. But this is not the case in the main app where the identical setting and framework is used. What am I missing here? I have been fiddling with this for hours to no avail...

score 0 · Answer 1 · answered Aug 26 '20 at 11:24

Found the answer. The TestServer.Create<Startup>() only starts just the in-memory instance where the url is not available. The web socket client however relies on the url to work. So the solution is to user the overload WebApp.Start<Startup>(Settings.WebApiUrl) (it starts a web app on the url you provide)

       WebApp.Start(new StartOptions("http://localhost:8989"), startup =>
        {
            startup.MapWebSocketRoute<TestConnection>();
            startup.MapWebSocketRoute<TestConnection>("/ws", sResolver);
            startup.MapWebSocketPattern<TestConnection>("/captures/(?<capture1>.+)/(?<capture2>.+)", sResolver);
        });

Ref

.Net framework Owin Test Server does not work with WebSocket

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