ServiceStack.Auth.AuthenticateService.Post C# (CSharp) Method

        public object Post(Authenticate request)
        {
            AssertAuthProviders();

            if (ValidateFn != null)
            {
                var validationResponse = ValidateFn(this, HttpMethods.Get, request);
                if (validationResponse != null) return validationResponse;
            }

            if (request.RememberMe.HasValue)
            {
                var opt = request.RememberMe.GetValueOrDefault(false)
                    ? SessionOptions.Permanent
                    : SessionOptions.Temporary;

                base.Request.AddSessionOptions(opt);
            }

            var provider = request.provider ?? AuthProviders[0].Provider;
            if (provider == CredentialsAliasProvider)
                provider = CredentialsProvider;

            var oAuthConfig = GetAuthProvider(provider);
            if (oAuthConfig == null)
                throw HttpError.NotFound("No configuration was added for OAuth provider '{0}'".Fmt(provider));

            if (request.provider == LogoutAction)
                return oAuthConfig.Logout(this, request);

            var session = this.GetSession();

            var isHtml = base.Request.ResponseContentType.MatchesContentType(MimeTypes.Html);
            try
            {
                var response = Authenticate(request, provider, session, oAuthConfig);

                // The above Authenticate call may end an existing session and create a new one so we need
                // to refresh the current session reference.
                session = this.GetSession();

                var referrerUrl = request.Continue
                    ?? session.ReferrerUrl
                    ?? this.Request.GetHeader("Referer")
                    ?? oAuthConfig.CallbackUrl;

                var alreadyAuthenticated = response == null;
                response = response ?? new AuthenticateResponse {
                    UserId = session.UserAuthId,
                    UserName = session.UserAuthName,
                    SessionId = session.Id,
                    ReferrerUrl = referrerUrl,
                };

                if (isHtml)
                {
                    if (alreadyAuthenticated)
                        return this.Redirect(referrerUrl.AddHashParam("s", "0"));

                    if (!(response is IHttpResult) && !String.IsNullOrEmpty(referrerUrl))
                    {
                        return new HttpResult(response) {
                            Location = referrerUrl
                        };
                    }
                }

                return response;
            }
            catch (HttpError ex)
            {
                var errorReferrerUrl = this.Request.GetHeader("Referer");
                if (isHtml && errorReferrerUrl != null)
                {
                    errorReferrerUrl = errorReferrerUrl.SetQueryParam("error", ex.Message);
                    return HttpResult.Redirect(errorReferrerUrl);
                }

                throw;
            }
        }