I'm working on a SignalR Core web app that uses the following stack:
- ASP.NET Core 2.1 preview 2 (2.1.0-preview2-final)
- SignalR Core 1.0 preview 2 (1.0.0-preview2-final)
- Microsoft.AspNetCore.Cors (2.1.0-preview2-final)
- Microsoft.AspNetCore.WebSockets (2.1.0-preview2-final)
The client is using SignalR NPM package (@aspnet/signalr).
The app is configured like so:
public void ConfigureServices(IServiceCollection services)
{
services.AddCors(options =>
{
options.AddPolicy(
"CorsPolicy",
builder => builder
.AllowCredentials()
.AllowAnyOrigin()
.AllowAnyMethod()
.AllowAnyHeader());
});
services.AddSignalR();
}
public void Configure(IApplicationBuilder app)
{
app.UseCors("CorsPolicy");
app.UseDefaultFiles();
app.UseStaticFiles();
app.UseWebSockets();
app.UseSignalR(routes =>
{
routes.MapHub<ClientHub>("/hubs/notifications");
});
}
When running locally in http://localhost
, the client connects using WS protocol. But when deployed in Azure App Service, it falls back to SSE.
The browser log shows:
WebSocket connection to 'wss://xxxxxx.azurewebsites.net/hubs/notifications?id=ZRniWKpMLMPIyLhS5RSyAg' failed: Error during WebSocket handshake: Unexpected response code: 503
Information: SSE connected to https://xxxxxx.azurewebsites.net/hubs/notifications?id=ig47oOdQzbasdgrlr0cHaw
The negotiate
method seems to return support to Websockets:
{"connectionId":"ZRniWKpMLMPIyLhS5RSyAg",
"availableTransports":[
{"transport":"WebSockets","transferFormats":["Text","Binary"]},
{"transport":"ServerSentEvents","transferFormats":["Text"]},
{"transport":"LongPolling","transferFormats":["Text","Binary"]}]
}
Am I missing something? Or is WSS not yet supported?