Why Context.User.Identity.Name is empty from Xamarin? - xamarin

Question

I can't figure out why when I try to connect from Xamarin Context.User.Indetity.Name is empty. Is there anything special I need to do? I logged in to the server and the user has a connection stablished. After that I use the following code:
var Connection = new HubConnection(Url);
_hub = Connection.CreateHubProxy(hubName);
_hub.On(srvEvent, onData);
await Connection.Start();
But I never get the username. What am I doing wrong?
Here's the code for the server:
var name = Context.User.Identity.Name;
Connections.Add(name, Context.ConnectionId);
return base.OnConnected();
It works when it comes from the web app, not from the xamarin app.
Thanks!

Answer 1

Here is the code I was telling you about.
I'm using an external OAuth2 server for authentication, so I must pass the access token to SignalR somehow, because SignalR uses web sockets for the messages back and forth I can't pass the access token in the header because this is not supported by web sockets.
I'm passing that access token as a query string parameter this way (Javascript client)
$.connection.hub.qs = "access_token=" + mytoken;
Then on my SignalR I added a middleware that takes that query string and adds it to the header as an Authorization header using Bearer Token. This is done this way in my startup class
app.UseAuthQSTokenExtractor();
The code for the middleware is this one
namespace Owin
{
public static class AuthorizationQSTokenExtractorExtension
{
public static void UseAuthQSTokenExtractor(this IAppBuilder app)
{
app.Use<AuthorizationQsTokenExtractorMiddleware>();
}
}
}
namespace Chat.Middleware
{
public class AuthorizationQsTokenExtractorMiddleware : OwinMiddleware
{
public AuthorizationQsTokenExtractorMiddleware(OwinMiddleware next)
: base(next)
{
}
public override async Task Invoke(IOwinContext context)
{
Debug.WriteLine("signalr-auth-middleware");
string bearerToken = context.Request.Query.Get("access_token");
Debug.WriteLine("signar-bearer: " + bearerToken);
if (bearerToken != null)
{
TokenHelper.DecodeAndWrite(bearerToken);
string[] authorization = { "Bearer " + bearerToken };
context.Request.Headers.Add("Authorization", authorization);
}
await Next.Invoke(context);
}
}
My startup class then looks like this
app.UseCors(CorsOptions.AllowAll);
app.UseAuthQSTokenExtractor();
JwtSecurityTokenHandler.InboundClaimTypeMap = new Dictionary<string, string>();
app.UseIdentityServerBearerTokenAuthentication(
new IdentityServerBearerTokenAuthenticationOptions
{
Authority = ConfigurationManager.AppSettings["api:idserver"],
RequiredScopes = new[]
{
"chat-hub"
}
});
var hubConfiguration = new HubConfiguration ();
hubConfiguration.EnableDetailedErrors = true;
app.RunSignalR(hubConfiguration);
You can see in the code above where I tell SignalR to use the Oauth2 Server, that code is this one
app.UseIdentityServerBearerTokenAuthentication(
new IdentityServerBearerTokenAuthenticationOptions
{
Authority = ConfigurationManager.AppSettings["api:idserver"],
RequiredScopes = new[]
{
"chat-hub"
}
});
After all this is set up I have access to my Context.User.Identity.Name and if you want to get the others IdentityClaim you can do this
var identity = Context.User.Identity as ClaimsIdentity;
Which I'm using that code above to get the subjectId (userid) like this
public static string[] GetIdentityClaimsIssSub(HubCallerContext Context)
{
var identity = Context.User.Identity as ClaimsIdentity;
if (identity == null)
return null;
var issuerFromIdentity = identity.FindFirst("iss");
var subFromIdentity = identity.FindFirst("sub");
if (issuerFromIdentity == null || subFromIdentity == null)
return null;
return new string[] { issuerFromIdentity.Value, subFromIdentity.Value };
}
I hope it helps