IdentityServer3: Principals always null

问题

I tried to enhance my existing WebApi with IdentityServer3. So I installed the IdentityServer3.AccessTokenValidation package and added this piece of code to my Startup Configuration

app.UseIdentityServerBearerTokenAuthentication(new IdentityServerBearerTokenAuthenticationOptions
        {
            Authority = "<myIdentityServerUrl>",
            ValidationMode = ValidationMode.ValidationEndpoint,

            RequiredScopes = new[] { "api1" }
        });

(I did not apply the AuthorizeAttribute filter, so I can see what's going on). The identity server so far is the exact same as in the docs (code here). I tried to debug-call the test service and I saw that this.User (in the controllers method) was null. So I looked into the RequestContext. Now that was weird:

• RequestContext.Principals is null
• RequestContext.Request.Headers.Authorization has the correct access_token

As far as I know even if I made a mistake with the scopes or Authority -what I highly doubt- I should still get the claims. The AuthorizeAttribute would probably return an Unauthorized http message but that doesn't matter because I did not add that filter yet.

来源：https://stackoverflow.com/questions/40425587/identityserver3-principals-always-null