Web API 身份验证 不记名令牌验证 Bearer Token Authentication

public static OAuthBearerAuthenticationOptions OAuthBearerOptions { get; private set; }

        /// <summary>
        /// 构造函数
        /// </summary>
        static Startup()
        {
            OAuthBearerOptions = new OAuthBearerAuthenticationOptions();
        }    

            // 使用不记名身份验证
            app.UseOAuthBearerAuthentication(OAuthBearerOptions);

            config.SuppressDefaultHostAuthentication();
            config.Filters.Add(new HostAuthenticationFilter("Bearer"));

        [HttpPost]
        public async Task<String> Authenticate(string userName, string password)
        {
            if (string.IsNullOrEmpty(userAccount) || string.IsNullOrEmpty(password))
            {
                return string.Empty;
            }

            // 用户查找失败
            User user = await UserManager.FindAsync(userName, password);            
            if (user == null)
            {
                return string.Empty;
            }

            // 身份验证票证包括角色或者可以换成用户名
            var identity = new ClaimsIdentity(Startup.OAuthBearerOptions.AuthenticationType);
            identity.AddClaim(new Claim(ClaimTypes.NameIdentifier, user.Id.ToString()));
            if (UserManager.SupportsUserRole)
            {
                IList<string> roles = await UserManager.GetRolesAsync(user.Id).ConfigureAwait(false);
                foreach (string roleName in roles)
                {
                    identity.AddClaim(new Claim(ClaimTypes.Role, roleName, ClaimValueTypes.String));
                }
            }
            AuthenticationTicket ticket = new AuthenticationTicket(identity, new AuthenticationProperties());
            var currentUtc = DateTime.UtcNow;
            ticket.Properties.IssuedUtc = currentUtc;
            ticket.Properties.ExpiresUtc = currentUtc.Add(TimeSpan.FromDays(1));

            // 返回值
            return Startup.OAuthBearerOptions.AccessTokenFormat.Protect(ticket);
        }

[Authorize(Roles = "Admin")]
public class UsersController : ApiController
{
}