aspnetcore/breaking-changes/5/signalr-usesignalr-useconnections-removed.md
In ASP.NET Core 3.0, SignalR adopted endpoint routing. As part of that change, the xref:Microsoft.AspNetCore.Builder.SignalRAppBuilderExtensions.UseSignalR%2A, xref:Microsoft.AspNetCore.Builder.ConnectionsAppBuilderExtensions.UseConnections%2A, and some related methods were marked as obsolete. In ASP.NET Core 5.0, those obsolete methods were removed. For the full list of methods, see Affected APIs.
For discussion on this issue, see dotnet/aspnetcore#20082.
5.0 Preview 3
SignalR hubs and connection handlers could be registered in the middleware pipeline using the UseSignalR or UseConnections methods.
SignalR hubs and connection handlers should be registered within xref:Microsoft.AspNetCore.Builder.EndpointRoutingApplicationBuilderExtensions.UseEndpoints%2A using the xref:Microsoft.AspNetCore.SignalR.HubRouteBuilder.MapHub%2A and xref:Microsoft.AspNetCore.Http.Connections.ConnectionsRouteBuilder.MapConnectionHandler%2A extension methods on xref:Microsoft.AspNetCore.Routing.IEndpointRouteBuilder.
The old methods had custom routing logic that didn't interact with other routing components in ASP.NET Core. In ASP.NET Core 3.0, a new general-purpose routing system, called endpoint routing, was introduced. Endpoint routing enabled SignalR to interact with other routing components. Switching to this model allows users to realize the full benefits of endpoint routing. Consequently, the old methods have been removed.
Remove code that calls UseSignalR or UseConnections from your project's Startup.Configure method. Replace it with calls to MapHub or MapConnectionHandler, respectively, within the body of a call to UseEndpoints. For example:
Old code:
app.UseSignalR(routes =>
{
routes.MapHub<SomeHub>("/path");
});
New code:
app.UseEndpoints(endpoints =>
{
endpoints.MapHub<SomeHub>("/path");
});
In general, your previous MapHub and MapConnectionHandler calls can be transferred directly from the body of UseSignalR and UseConnections to UseEndpoints with little-to-no change needed.