Facebook.FacebookClient.TryParseSignedRequest C# (CSharp) Method

        public virtual bool TryParseSignedRequest(string signedRequestValue, out object signedRequest)
        {
            return TryParseSignedRequest(AppSecret, signedRequestValue, out signedRequest);
        }

        private void context_AuthenticateRequest(object sender, EventArgs e)
        {
            var httpApplication = (HttpApplication)sender;
            var context = httpApplication.Context;

            foreach (var regex in ExcludePathsRegEx)
            {
                if(new Regex(regex).IsMatch(context.Request.Path))
                    return;
            }

            var applicationId = ConfigurationManager.AppSettings["facebookApplicationId"];
            var applicationSecret = ConfigurationManager.AppSettings["facebookApplicationSecret"];

            var client = new FacebookClient();

            //Read the signed request added by the Javascript SDK login
            var signedRequestCookie = context.Request.Cookies[string.Concat("fbsr_", applicationId)];

            dynamic signedRequest;

            if (signedRequestCookie == null)
                return;

            if (!client.TryParseSignedRequest(applicationSecret, signedRequestCookie.Value, out signedRequest))
                return;

            if (signedRequest == null)
                return;

            if (signedRequest.expires != null)
            {
                int expires = signedRequest.expires;
                return;
            }

            string userId = signedRequest.user_id;

            if (string.IsNullOrEmpty(userId))
                return;

            User user;

            try
            {
                user = User.Load(client, userId);

                if (user == null)
                    return;
            }
            catch (FacebookOAuthException ex)
            {
                return;
            }

            context.User = new GenericPrincipal(user, null);
        }