Getting User in web api controller using Asp.net Identity 2 - User not authenticated - asp.net-mvc

Question

I am using Asp.net Identity 2 in my new MVC 5 project. After much work I was able to implement my own custom user store etc and authenticate my users at log in. However, when I call User.Identity.Name inside my Web API controller, the name is always null and the user is not authenticated. I can see the authorization header and cookies in the request object, but no authorization seems to be occurring. If I add an "authorize" attribute, I am denied access.
EDIT:
Here is the OAuthProvider class:
public class MyOAuthProvider : OAuthAuthorizationServerProvider
{
private readonly string publicClientId;
private readonly Func<UserManager<CustomUser, int>> userManagerFactory;
public MyOAuthProvider(string publicClientId, Func<UserManager<CustomUser, int>> userManagerFactory)
{
if (publicClientId == null)
{
throw new ArgumentNullException("publicClientId");
}
if (userManagerFactory == null)
{
throw new ArgumentNullException("userManagerFactory");
}
this.publicClientId = publicClientId;
this.userManagerFactory = userManagerFactory;
}
public static AuthenticationProperties CreateProperties(CustomUser user, IEnumerable<string> roles)
{
//var roles = string.Join(",", user.Roles.Select(iur => iur.RoleId));
IDictionary<string, string> data = new Dictionary<string, string>
{
{ "userName", user.UserName },
{ "userRoles", string.Join(",", roles.ToArray()) }
};
return new AuthenticationProperties(data);
}
public override async Task GrantResourceOwnerCredentials(OAuthGrantResourceOwnerCredentialsContext context)
{
using (var userManager = this.userManagerFactory())
{
var user = await userManager.FindAsync(context.UserName, context.Password);
if (user == null)
{
context.SetError("invalid_grant", "The user name or password is incorrect.");
return;
}
ClaimsIdentity oAuthIdentity = await userManager.CreateIdentityAsync(user, context.Options.AuthenticationType);
ClaimsIdentity cookiesIdentity = await userManager.CreateIdentityAsync(user, CookieAuthenticationDefaults.AuthenticationType);
var roles = userManager.GetRoles(user.Id).ToArray();
AuthenticationProperties properties = CreateProperties(user, roles);
AuthenticationTicket ticket = new AuthenticationTicket(oAuthIdentity, properties);
context.Validated(ticket);
context.Request.Context.Authentication.SignIn(cookiesIdentity);
}
}
public override Task TokenEndpoint(OAuthTokenEndpointContext context)
{
foreach (var property in context.Properties.Dictionary)
{
context.AdditionalResponseParameters.Add(property.Key, property.Value);
}
return Task.FromResult<object>(null);
}
public override Task ValidateClientAuthentication(OAuthValidateClientAuthenticationContext context)
{
// Resource owner password credentials does not provide a client ID.
if (context.ClientId == null)
{
context.Validated();
}
return Task.FromResult<object>(null);
}
public override Task ValidateClientRedirectUri(OAuthValidateClientRedirectUriContext context)
{
if (context.ClientId == this.publicClientId)
{
var expectedRootUri = new Uri(context.Request.Uri, "/");
if (expectedRootUri.AbsoluteUri == context.RedirectUri)
{
context.Validated();
}
}
return Task.FromResult<object>(null);
}
}
What might I be doing wrong?