Always receiving 'invalid_client' error when POSTing to /Token endpoint with ASP Identity 2

Question

About a month ago I had a project working perfectly with ASP Identity OAuth. I'd send a POST request to the /Token endpoint with grant_type, username, and password, and all was dandy.

I recently started a new project based off of Visual Studio 2013 RC2's SPA template. It's a bit different than the old template. Authentication is set up to pretty basic defaults,

OAuthOptions = new OAuthAuthorizationServerOptions
{
    TokenEndpointPath = new PathString("/Token"),
    //AuthorizeEndpointPath = new PathString("/Account/Authorize"), 
    Provider = new ApplicationOAuthProvider(PublicClientId),
    AccessTokenExpireTimeSpan = TimeSpan.FromDays(14),
    AllowInsecureHttp = true
};

Nothing significant changed from the default template. I can register accounts successfully through a Web API controller method I have implemented;

    // POST: /Account/Register
    [HttpPost]
    [AllowAnonymous]
    public async Task<IHttpActionResult> Register(RegisterBindingModel model)
    {
        if (ModelState.IsValid)
        {
            var user = new TunrUser() { UserName = model.Email, Email = model.Email, DisplayName = model.DisplayName };
            var result = await UserManager.CreateAsync(user, model.Password);
            if (result.Succeeded)
            {
                return Created(new Uri("/api/Users/" + user.Id,UriKind.Relative), user.toViewModel());
            }
            else
            {
                return BadRequest(result.Errors.First());
            }
        }
        return BadRequest(ModelState);
    }

However, no matter what I POST to the /Token endpoint, I always get the same response.

{"error":"invalid_client"}

Normally I pass the following request body

grant_type=password&username=user%40domain.com&password=userpassword

But this results in the same error. This worked in the previous VS2013 SPA template / Identity. What's changed?

Thank you!

Answer 1

You have to Override the ValidateClientAuthentication & GrantResourceOwnerCredentials in the OAuthAuthorizationServerProvider.

See example here: http://www.tugberkugurlu.com/archive/simple-oauth-server-implementing-a-simple-oauth-server-with-katana-oauth-authorization-server-components-part-1