FB post

Facebook class

Class FacebookController () 
{
    public function actionPost() {
        $req     = Yii::$app->controller->action->id;
        $message = Yii::$app->request->post('message');
        // store the message in $_SESSION
        $this->authenticate($req);
    }
    
    private function authenticate($req) {
        $fb_cred = Yii::$app->params['fb_credential'];
        $fb      = new Facebook\Facebook([
            'app_id' => $fb_cred['app_id'], // Replace {app-id} with your app id
            'app_secret' => $fb_cred['app_secret'],
            'default_graph_version' => 'v2.2',
        ]);
        $helper  = $fb->getRedirectLoginHelper();

        $permissions = ['email', 'user_about_me', 'user_birthday', 'user_friends', 'read_custom_friendlists', 'publish_actions', 'user_posts']; // Optional permissions
        
        $callBackUrl = Url::to(['facebook/callback?type=' . $req], true);
        //path-to-Facebook-post-script-that-you-want-to-call-back-to
        $loginUrl = $helper->getLoginUrl($callBackUrl, $permissions);
        // header("Location:$loginUrl");
        //exit();
        return $this->redirect($loginUrl);
    }

    public function actionCallback() {
        $fb_cred = Yii::$app->params['fb_credential'];
        $fb      = new Facebook\Facebook([
            'app_id' => $fb_cred['app_id'], // Replace {app-id} with your app id
            'app_secret' => $fb_cred['app_secret'],
            'default_graph_version' => 'v2.2',
        ]);

        $helper = $fb->getRedirectLoginHelper();

        try {
            $accessToken = $helper->getAccessToken();
        } catch (Facebook\Exceptions\FacebookResponseException $e) {
            // When Graph returns an error
            echo 'Graph returned an error: ' . $e->getMessage();
            exit;
        } catch (Facebook\Exceptions\FacebookSDKException $e) {
            // When validation fails or other local issues
            echo 'Facebook SDK returned an error: ' . $e->getMessage();
            exit;
        }
        $oAuth2Client = $fb->getOAuth2Client();

        $tokenMetadata = $oAuth2Client->debugToken($accessToken);
        $tokenMetadata->validateAppId($fb_cred['app_id']); // Replace {app-id} with your app id
        $tokenMetadata->validateExpiration();

        if (!$accessToken->isLongLived()) {
            try {
                $accessToken = $oAuth2Client->getLongLivedAccessToken($accessToken);
            } catch (Facebook\Exceptions\FacebookSDKException $e) {
                echo "<p>Error getting long-lived access token: " . $helper->getMessage() . "</p>\n\n";
                exit;
            }
        }
        Yii::$app->session->set('fb_access_token', $accessToken);
        $req = Yii::$app->request->get('type');

        if (!empty($req)) {
            if ($req == 'post') {
                //retrive message to be posted from session that we set earlier
                $message = Yii::$app->session->get('message');
                $this->post($fb, $accessToken, $message);
            } 
        }
    }
    private function post($fb, $accessToken, $message) {
        $params = ['message' => $message];
        try {
            $response = $fb->post('/me/feed', $params, $accessToken);

            if ($response->getHttpStatusCode() == '200') {
                $successString = 'Successfully posted on your timeline';
            } else {
                $errorString = 'Failed to post on your timeline';
            }
        } catch (Facebook\Exceptions\FacebookResponseException $e) {
            $errorString = 'Graph returned an error: ' . $e->getMessage();
        } catch (Facebook\Exceptions\FacebookSDKException $e) {
            $errorString = 'Facebook SDK returned an error: ' . $e->getMessage();
        }
        
    }
}