SignalR Azure Service with stand alone Identity Server 4 returns 401 on negotiaton - asp.net-core

Question

We have a ASP.Net Core application that authenticates against a standalone Identity Server 4. The ASP.Net Core app implements a few SignalR Hubs and is working fine when we use the self hosted SignalR Service. When we try to use the Azure SignalR Service, it always returns 401 in the negotiation requests. The response header also states that
"Bearer error="invalid_token", error_description="The signature key
was not found"
I thought the JWT-Configuration is correct because it works in the self hosted mode but it looks like, our ASP.Net Core application needs information about the signature key (certificate) that our identity server uses to sign the tokens. So I tried to use the same method like our identity server, to create the certificate and resolve it. Without luck :-(
This is what our JWT-Configuration looks like right now:
services.AddAuthentication("Bearer")
.AddJwtBearer("Bearer", options => {
var appSettings = Configuration.Get<AppSettingsModel>();
options.Authority = appSettings.Authority;
options.RefreshOnIssuerKeyNotFound = true;
if (environment.IsDevelopment()) {
options.RequireHttpsMetadata = false;
}
options.TokenValidationParameters = new Microsoft.IdentityModel.Tokens.TokenValidationParameters {
ValidateAudience = false,
IssuerSigningKey = new X509SecurityKey(getSigningCredential()),
IssuerSigningKeyResolver = (string token, SecurityToken securityToken, string kid, TokenValidationParameters validationParameters) =>
new List<X509SecurityKey> { new X509SecurityKey(getSigningCredential()) }
};
options.Events = new JwtBearerEvents {
OnMessageReceived = context => {
var accessToken = "";
var headerToken = context.Request.Headers[HeaderNames.Authorization].ToString().Replace("Bearer ", "");
if (!string.IsNullOrEmpty(headerToken) && headerToken.Length > 0) {
accessToken = headerToken;
}
var queryStringToken = context.Request.Query["access_token"];
if (!string.IsNullOrEmpty(queryStringToken) && queryStringToken.ToString().Length > 0) {
accessToken = queryStringToken;
}
// If the request is for our hub...
var path = context.HttpContext.Request.Path;
if (!string.IsNullOrEmpty(accessToken) && path.StartsWithSegments("/hubs")) {
context.Token = accessToken;
}
return Task.CompletedTask;
}
};
});
Update:
We also have a extended the signalR.DefaultHttpClient in our Angular Client and after playing around a bit, I noticed the application is working fine without it:
export class CustomSignalRHttpClientService extends signalR.DefaultHttpClient {
userSubscription: any;
token: string = "";
constructor(private authService: AuthorizeService) {
super(console); // the base class wants a signalR.ILogger
this.userSubscription = this.authService.accessToken$.subscribe(token => {
this.token = token
});
}
public async send(
request: signalR.HttpRequest
): Promise<signalR.HttpResponse> {
let authHeaders = {
Authorization: `Bearer ${this.token}`
};
request.headers = { ...request.headers, ...authHeaders };
try {
const response = await super.send(request);
return response;
} catch (er) {
if (er instanceof signalR.HttpError) {
const error = er as signalR.HttpError;
if (error.statusCode == 401) {
console.log('customSignalRHttpClient -> 401 -> TokenRefresh')
//token expired - trying a refresh via refresh token
this.token = await this.authService.getAccessToken().toPromise();
authHeaders = {
Authorization: `Bearer ${this.token}`
};
request.headers = { ...request.headers, ...authHeaders };
}
} else {
throw er;
}
}
//re try the request
return super.send(request);
}
}
The problem is, when the token expires while the application is not open (computer is in sleep mode e.g.), the negotiaton process is failing again.

Answer 1

I finally found and solved the problem. The difference of the authentication between "self hosted" and "Azure SignalR Service" is in the negotiation process.
Self Hosted:
SignalR-Javascript client authenticates against our own webserver with
the same token that our Javascript (Angular) app uses. It sends the
token with the negotiation request and all coming requests of the
signalR Http-Client.
Azure SignalR Service:
SignalR-Javascript client sends a negotiation request to our own
webserver and receives a new token for all coming requests against the
Azure SignalR Service.
So our problem was in the CustomSignalRHttpClientService. We changed the Authentication header to our own API-Token for all requests, including the requests against the Azure SignalR Service -> Bad Idea.
So we learned that the Azure SignalR Service is using it's own token. That also means the token can invalidate independently with our own token. So we have to handle 401 Statuscodes in a different way.
This is our new CustomSignalRHttpClientService:
export class CustomSignalRHttpClientService extends signalR.DefaultHttpClient {
userSubscription: any;
token: string = "";
constructor(private authService: AuthorizeService, #Inject(ENV) private env: IEnvironment, private router: Router,) {
super(console); // the base class wants a signalR.ILogger
this.userSubscription = this.authService.accessToken$.subscribe(token => {
this.token = token
});
}
public async send(
request: signalR.HttpRequest
): Promise<signalR.HttpResponse> {
if (!request.url.startsWith(this.env.apiUrl)) {
return super.send(request);
}
try {
const response = await super.send(request);
return response;
} catch (er) {
if (er instanceof signalR.HttpError) {
const error = er as signalR.HttpError;
if (error.statusCode == 401 && !this.router.url.toLowerCase().includes('onboarding')) {
this.router.navigate([ApplicationPaths.Login], {
queryParams: {
[QueryParameterNames.ReturnUrl]: this.router.url
}
});
}
} else {
throw er;
}
}
//re try the request
return super.send(request);
}
}
Our login-Route handles the token refresh (if required). But it could also happen, that our own api-token is still valid, but the Azure SignalR Service token is not. Therefore we handle some reconnection logic inside the service that creates the SignalR Connections like this:
this.router.events.pipe(
filter(event => event instanceof NavigationEnd)
).subscribe(async (page: NavigationEnd) => {
if (page.url.toLocaleLowerCase().includes(ApplicationPaths.Login)) {
await this.restartAllConnections();
}
});
hope this helps somebody