* Facebook support

5 files changed, 715 insertions, 0 deletions

diff --git a/lib/facebook-graph-sdk/src/Facebook/Helpers/FacebookCanvasHelper.php b/lib/facebook-graph-sdk/src/Facebook/Helpers/FacebookCanvasHelper.php
new file mode 100644
index 0000000..8068526
--- /dev/null
+++ b/lib/facebook-graph-sdk/src/Facebook/Helpers/FacebookCanvasHelper.php
@@ -0,0 +1,52 @@
+<?php
+/**
+ * Copyright 2014 Facebook, Inc.
+ *
+ * You are hereby granted a non-exclusive, worldwide, royalty-free license to
+ * use, copy, modify, and distribute this software in source code or binary
+ * form for use in connection with the web services and APIs provided by
+ * Facebook.
+ *
+ * As with any software that integrates with the Facebook platform, your use
+ * of this software is subject to the Facebook Developer Principles and
+ * Policies [http://developers.facebook.com/policy/]. This copyright notice
+ * shall be included in all copies or substantial portions of the software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ */
+namespace Facebook\Helpers;
+
+/**
+ * Class FacebookCanvasLoginHelper
+ *
+ * @package Facebook
+ */
+class FacebookCanvasHelper extends FacebookSignedRequestFromInputHelper
+{
+    /**
+     * Returns the app data value.
+     *
+     * @return mixed|null
+     */
+    public function getAppData()
+    {
+        return $this->signedRequest ? $this->signedRequest->get('app_data') : null;
+    }
+
+    /**
+     * Get raw signed request from POST.
+     *
+     * @return string|null
+     */
+    public function getRawSignedRequest()
+    {
+        return $this->getRawSignedRequestFromPost() ?: null;
+    }
+}
diff --git a/lib/facebook-graph-sdk/src/Facebook/Helpers/FacebookJavaScriptHelper.php b/lib/facebook-graph-sdk/src/Facebook/Helpers/FacebookJavaScriptHelper.php
new file mode 100644
index 0000000..5d406b5
--- /dev/null
+++ b/lib/facebook-graph-sdk/src/Facebook/Helpers/FacebookJavaScriptHelper.php
@@ -0,0 +1,42 @@
+<?php
+/**
+ * Copyright 2014 Facebook, Inc.
+ *
+ * You are hereby granted a non-exclusive, worldwide, royalty-free license to
+ * use, copy, modify, and distribute this software in source code or binary
+ * form for use in connection with the web services and APIs provided by
+ * Facebook.
+ *
+ * As with any software that integrates with the Facebook platform, your use
+ * of this software is subject to the Facebook Developer Principles and
+ * Policies [http://developers.facebook.com/policy/]. This copyright notice
+ * shall be included in all copies or substantial portions of the software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ */
+namespace Facebook\Helpers;
+
+/**
+ * Class FacebookJavaScriptLoginHelper
+ *
+ * @package Facebook
+ */
+class FacebookJavaScriptHelper extends FacebookSignedRequestFromInputHelper
+{
+    /**
+     * Get raw signed request from the cookie.
+     *
+     * @return string|null
+     */
+    public function getRawSignedRequest()
+    {
+        return $this->getRawSignedRequestFromCookie();
+    }
+}
diff --git a/lib/facebook-graph-sdk/src/Facebook/Helpers/FacebookPageTabHelper.php b/lib/facebook-graph-sdk/src/Facebook/Helpers/FacebookPageTabHelper.php
new file mode 100644
index 0000000..ee43f5e
--- /dev/null
+++ b/lib/facebook-graph-sdk/src/Facebook/Helpers/FacebookPageTabHelper.php
@@ -0,0 +1,95 @@
+<?php
+/**
+ * Copyright 2014 Facebook, Inc.
+ *
+ * You are hereby granted a non-exclusive, worldwide, royalty-free license to
+ * use, copy, modify, and distribute this software in source code or binary
+ * form for use in connection with the web services and APIs provided by
+ * Facebook.
+ *
+ * As with any software that integrates with the Facebook platform, your use
+ * of this software is subject to the Facebook Developer Principles and
+ * Policies [http://developers.facebook.com/policy/]. This copyright notice
+ * shall be included in all copies or substantial portions of the software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ */
+namespace Facebook\Helpers;
+
+use Facebook\FacebookApp;
+use Facebook\FacebookClient;
+
+/**
+ * Class FacebookPageTabHelper
+ *
+ * @package Facebook
+ */
+class FacebookPageTabHelper extends FacebookCanvasHelper
+{
+    /**
+     * @var array|null
+     */
+    protected $pageData;
+
+    /**
+     * Initialize the helper and process available signed request data.
+     *
+     * @param FacebookApp    $app          The FacebookApp entity.
+     * @param FacebookClient $client       The client to make HTTP requests.
+     * @param string|null    $graphVersion The version of Graph to use.
+     */
+    public function __construct(FacebookApp $app, FacebookClient $client, $graphVersion = null)
+    {
+        parent::__construct($app, $client, $graphVersion);
+
+        if (!$this->signedRequest) {
+            return;
+        }
+
+        $this->pageData = $this->signedRequest->get('page');
+    }
+
+    /**
+     * Returns a value from the page data.
+     *
+     * @param string     $key
+     * @param mixed|null $default
+     *
+     * @return mixed|null
+     */
+    public function getPageData($key, $default = null)
+    {
+        if (isset($this->pageData[$key])) {
+            return $this->pageData[$key];
+        }
+
+        return $default;
+    }
+
+    /**
+     * Returns true if the user is an admin.
+     *
+     * @return boolean
+     */
+    public function isAdmin()
+    {
+        return $this->getPageData('admin') === true;
+    }
+
+    /**
+     * Returns the page id if available.
+     *
+     * @return string|null
+     */
+    public function getPageId()
+    {
+        return $this->getPageData('id');
+    }
+}
diff --git a/lib/facebook-graph-sdk/src/Facebook/Helpers/FacebookRedirectLoginHelper.php b/lib/facebook-graph-sdk/src/Facebook/Helpers/FacebookRedirectLoginHelper.php
new file mode 100644
index 0000000..144a5b4
--- /dev/null
+++ b/lib/facebook-graph-sdk/src/Facebook/Helpers/FacebookRedirectLoginHelper.php
@@ -0,0 +1,360 @@
+<?php
+/**
+ * Copyright 2014 Facebook, Inc.
+ *
+ * You are hereby granted a non-exclusive, worldwide, royalty-free license to
+ * use, copy, modify, and distribute this software in source code or binary
+ * form for use in connection with the web services and APIs provided by
+ * Facebook.
+ *
+ * As with any software that integrates with the Facebook platform, your use
+ * of this software is subject to the Facebook Developer Principles and
+ * Policies [http://developers.facebook.com/policy/]. This copyright notice
+ * shall be included in all copies or substantial portions of the software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ */
+namespace Facebook\Helpers;
+
+use Facebook\Authentication\AccessToken;
+use Facebook\Authentication\OAuth2Client;
+use Facebook\Url\UrlDetectionInterface;
+use Facebook\Url\FacebookUrlDetectionHandler;
+use Facebook\Url\FacebookUrlManipulator;
+use Facebook\PersistentData\PersistentDataInterface;
+use Facebook\PersistentData\FacebookSessionPersistentDataHandler;
+use Facebook\PseudoRandomString\PseudoRandomStringGeneratorInterface;
+use Facebook\PseudoRandomString\McryptPseudoRandomStringGenerator;
+use Facebook\PseudoRandomString\OpenSslPseudoRandomStringGenerator;
+use Facebook\PseudoRandomString\UrandomPseudoRandomStringGenerator;
+use Facebook\Exceptions\FacebookSDKException;
+
+/**
+ * Class FacebookRedirectLoginHelper
+ *
+ * @package Facebook
+ */
+class FacebookRedirectLoginHelper
+{
+    /**
+     * @const int The length of CSRF string to validate the login link.
+     */
+    const CSRF_LENGTH = 32;
+
+    /**
+     * @var OAuth2Client The OAuth 2.0 client service.
+     */
+    protected $oAuth2Client;
+
+    /**
+     * @var UrlDetectionInterface The URL detection handler.
+     */
+    protected $urlDetectionHandler;
+
+    /**
+     * @var PersistentDataInterface The persistent data handler.
+     */
+    protected $persistentDataHandler;
+
+    /**
+     * @var PseudoRandomStringGeneratorInterface The cryptographically secure pseudo-random string generator.
+     */
+    protected $pseudoRandomStringGenerator;
+
+    /**
+     * @param OAuth2Client                              $oAuth2Client          The OAuth 2.0 client service.
+     * @param PersistentDataInterface|null              $persistentDataHandler The persistent data handler.
+     * @param UrlDetectionInterface|null                $urlHandler            The URL detection handler.
+     * @param PseudoRandomStringGeneratorInterface|null $prsg                  The cryptographically secure pseudo-random string generator.
+     */
+    public function __construct(OAuth2Client $oAuth2Client, PersistentDataInterface $persistentDataHandler = null, UrlDetectionInterface $urlHandler = null, PseudoRandomStringGeneratorInterface $prsg = null)
+    {
+        $this->oAuth2Client = $oAuth2Client;
+        $this->persistentDataHandler = $persistentDataHandler ?: new FacebookSessionPersistentDataHandler();
+        $this->urlDetectionHandler = $urlHandler ?: new FacebookUrlDetectionHandler();
+        $this->pseudoRandomStringGenerator = $prsg ?: $this->detectPseudoRandomStringGenerator();
+    }
+
+    /**
+     * Returns the persistent data handler.
+     *
+     * @return PersistentDataInterface
+     */
+    public function getPersistentDataHandler()
+    {
+        return $this->persistentDataHandler;
+    }
+
+    /**
+     * Returns the URL detection handler.
+     *
+     * @return UrlDetectionInterface
+     */
+    public function getUrlDetectionHandler()
+    {
+        return $this->urlDetectionHandler;
+    }
+
+    /**
+     * Returns the cryptographically secure pseudo-random string generator.
+     *
+     * @return PseudoRandomStringGeneratorInterface
+     */
+    public function getPseudoRandomStringGenerator()
+    {
+        return $this->pseudoRandomStringGenerator;
+    }
+
+    /**
+     * Detects which pseudo-random string generator to use.
+     *
+     * @return PseudoRandomStringGeneratorInterface
+     *
+     * @throws FacebookSDKException
+     */
+    public function detectPseudoRandomStringGenerator()
+    {
+        // Since openssl_random_pseudo_bytes() can sometimes return non-cryptographically
+        // secure pseudo-random strings (in rare cases), we check for mcrypt_create_iv() first.
+        if (function_exists('mcrypt_create_iv')) {
+            return new McryptPseudoRandomStringGenerator();
+        }
+
+        if (function_exists('openssl_random_pseudo_bytes')) {
+            return new OpenSslPseudoRandomStringGenerator();
+        }
+
+        if (!ini_get('open_basedir') && is_readable('/dev/urandom')) {
+            return new UrandomPseudoRandomStringGenerator();
+        }
+
+        throw new FacebookSDKException('Unable to detect a cryptographically secure pseudo-random string generator.');
+    }
+
+    /**
+     * Stores CSRF state and returns a URL to which the user should be sent to in order to continue the login process with Facebook.
+     *
+     * @param string $redirectUrl The URL Facebook should redirect users to after login.
+     * @param array  $scope       List of permissions to request during login.
+     * @param array  $params      An array of parameters to generate URL.
+     * @param string $separator   The separator to use in http_build_query().
+     *
+     * @return string
+     */
+    private function makeUrl($redirectUrl, array $scope, array $params = [], $separator = '&')
+    {
+        $state = $this->pseudoRandomStringGenerator->getPseudoRandomString(static::CSRF_LENGTH);
+        $this->persistentDataHandler->set('state', $state);
+
+        return $this->oAuth2Client->getAuthorizationUrl($redirectUrl, $state, $scope, $params, $separator);
+    }
+
+    /**
+     * Returns the URL to send the user in order to login to Facebook.
+     *
+     * @param string $redirectUrl The URL Facebook should redirect users to after login.
+     * @param array  $scope       List of permissions to request during login.
+     * @param string $separator   The separator to use in http_build_query().
+     *
+     * @return string
+     */
+    public function getLoginUrl($redirectUrl, array $scope = [], $separator = '&')
+    {
+        return $this->makeUrl($redirectUrl, $scope, [], $separator);
+    }
+
+    /**
+     * Returns the URL to send the user in order to log out of Facebook.
+     *
+     * @param AccessToken|string $accessToken The access token that will be logged out.
+     * @param string             $next        The url Facebook should redirect the user to after a successful logout.
+     * @param string             $separator   The separator to use in http_build_query().
+     *
+     * @return string
+     *
+     * @throws FacebookSDKException
+     */
+    public function getLogoutUrl($accessToken, $next, $separator = '&')
+    {
+        if (!$accessToken instanceof AccessToken) {
+            $accessToken = new AccessToken($accessToken);
+        }
+
+        if ($accessToken->isAppAccessToken()) {
+            throw new FacebookSDKException('Cannot generate a logout URL with an app access token.', 722);
+        }
+
+        $params = [
+            'next' => $next,
+            'access_token' => $accessToken->getValue(),
+        ];
+
+        return 'https://www.facebook.com/logout.php?' . http_build_query($params, null, $separator);
+    }
+
+    /**
+     * Returns the URL to send the user in order to login to Facebook with permission(s) to be re-asked.
+     *
+     * @param string $redirectUrl The URL Facebook should redirect users to after login.
+     * @param array  $scope       List of permissions to request during login.
+     * @param string $separator   The separator to use in http_build_query().
+     *
+     * @return string
+     */
+    public function getReRequestUrl($redirectUrl, array $scope = [], $separator = '&')
+    {
+        $params = ['auth_type' => 'rerequest'];
+
+        return $this->makeUrl($redirectUrl, $scope, $params, $separator);
+    }
+
+    /**
+     * Returns the URL to send the user in order to login to Facebook with user to be re-authenticated.
+     *
+     * @param string $redirectUrl The URL Facebook should redirect users to after login.
+     * @param array  $scope       List of permissions to request during login.
+     * @param string $separator   The separator to use in http_build_query().
+     *
+     * @return string
+     */
+    public function getReAuthenticationUrl($redirectUrl, array $scope = [], $separator = '&')
+    {
+        $params = ['auth_type' => 'reauthenticate'];
+
+        return $this->makeUrl($redirectUrl, $scope, $params, $separator);
+    }
+
+    /**
+     * Takes a valid code from a login redirect, and returns an AccessToken entity.
+     *
+     * @param string|null $redirectUrl The redirect URL.
+     *
+     * @return AccessToken|null
+     *
+     * @throws FacebookSDKException
+     */
+    public function getAccessToken($redirectUrl = null)
+    {
+        if (!$code = $this->getCode()) {
+            return null;
+        }
+
+        $this->validateCsrf();
+
+        $redirectUrl = $redirectUrl ?: $this->urlDetectionHandler->getCurrentUrl();
+        // At minimum we need to remove the state param
+        $redirectUrl = FacebookUrlManipulator::removeParamsFromUrl($redirectUrl, ['state']);
+
+        return $this->oAuth2Client->getAccessTokenFromCode($code, $redirectUrl);
+    }
+
+    /**
+     * Validate the request against a cross-site request forgery.
+     *
+     * @throws FacebookSDKException
+     */
+    protected function validateCsrf()
+    {
+        $state = $this->getState();
+        $savedState = $this->persistentDataHandler->get('state');
+
+        if (!$state || !$savedState) {
+            throw new FacebookSDKException('Cross-site request forgery validation failed. Required param "state" missing.');
+        }
+
+        $savedLen = strlen($savedState);
+        $givenLen = strlen($state);
+
+        if ($savedLen !== $givenLen) {
+            throw new FacebookSDKException('Cross-site request forgery validation failed. The "state" param from the URL and session do not match.');
+        }
+
+        $result = 0;
+        for ($i = 0; $i < $savedLen; $i++) {
+            $result |= ord($state[$i]) ^ ord($savedState[$i]);
+        }
+
+        if ($result !== 0) {
+            throw new FacebookSDKException('Cross-site request forgery validation failed. The "state" param from the URL and session do not match.');
+        }
+    }
+
+    /**
+     * Return the code.
+     *
+     * @return string|null
+     */
+    protected function getCode()
+    {
+        return $this->getInput('code');
+    }
+
+    /**
+     * Return the state.
+     *
+     * @return string|null
+     */
+    protected function getState()
+    {
+        return $this->getInput('state');
+    }
+
+    /**
+     * Return the error code.
+     *
+     * @return string|null
+     */
+    public function getErrorCode()
+    {
+        return $this->getInput('error_code');
+    }
+
+    /**
+     * Returns the error.
+     *
+     * @return string|null
+     */
+    public function getError()
+    {
+        return $this->getInput('error');
+    }
+
+    /**
+     * Returns the error reason.
+     *
+     * @return string|null
+     */
+    public function getErrorReason()
+    {
+        return $this->getInput('error_reason');
+    }
+
+    /**
+     * Returns the error description.
+     *
+     * @return string|null
+     */
+    public function getErrorDescription()
+    {
+        return $this->getInput('error_description');
+    }
+
+    /**
+     * Returns a value from a GET param.
+     *
+     * @param string $key
+     *
+     * @return string|null
+     */
+    private function getInput($key)
+    {
+        return isset($_GET[$key]) ? $_GET[$key] : null;
+    }
+}
diff --git a/lib/facebook-graph-sdk/src/Facebook/Helpers/FacebookSignedRequestFromInputHelper.php b/lib/facebook-graph-sdk/src/Facebook/Helpers/FacebookSignedRequestFromInputHelper.php
new file mode 100644
index 0000000..aafa246
--- /dev/null
+++ b/lib/facebook-graph-sdk/src/Facebook/Helpers/FacebookSignedRequestFromInputHelper.php
@@ -0,0 +1,166 @@
+<?php
+/**
+ * Copyright 2014 Facebook, Inc.
+ *
+ * You are hereby granted a non-exclusive, worldwide, royalty-free license to
+ * use, copy, modify, and distribute this software in source code or binary
+ * form for use in connection with the web services and APIs provided by
+ * Facebook.
+ *
+ * As with any software that integrates with the Facebook platform, your use
+ * of this software is subject to the Facebook Developer Principles and
+ * Policies [http://developers.facebook.com/policy/]. This copyright notice
+ * shall be included in all copies or substantial portions of the software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ */
+namespace Facebook\Helpers;
+
+use Facebook\Facebook;
+use Facebook\FacebookApp;
+use Facebook\FacebookClient;
+use Facebook\SignedRequest;
+use Facebook\Authentication\AccessToken;
+use Facebook\Authentication\OAuth2Client;
+
+/**
+ * Class FacebookSignedRequestFromInputHelper
+ *
+ * @package Facebook
+ */
+abstract class FacebookSignedRequestFromInputHelper
+{
+    /**
+     * @var SignedRequest|null The SignedRequest entity.
+     */
+    protected $signedRequest;
+
+    /**
+     * @var FacebookApp The FacebookApp entity.
+     */
+    protected $app;
+
+    /**
+     * @var OAuth2Client The OAuth 2.0 client service.
+     */
+    protected $oAuth2Client;
+
+    /**
+     * Initialize the helper and process available signed request data.
+     *
+     * @param FacebookApp    $app          The FacebookApp entity.
+     * @param FacebookClient $client       The client to make HTTP requests.
+     * @param string|null    $graphVersion The version of Graph to use.
+     */
+    public function __construct(FacebookApp $app, FacebookClient $client, $graphVersion = null)
+    {
+        $this->app = $app;
+        $graphVersion = $graphVersion ?: Facebook::DEFAULT_GRAPH_VERSION;
+        $this->oAuth2Client = new OAuth2Client($this->app, $client, $graphVersion);
+
+        $this->instantiateSignedRequest();
+    }
+
+    /**
+     * Instantiates a new SignedRequest entity.
+     *
+     * @param string|null
+     */
+    public function instantiateSignedRequest($rawSignedRequest = null)
+    {
+        $rawSignedRequest = $rawSignedRequest ?: $this->getRawSignedRequest();
+
+        if (!$rawSignedRequest) {
+            return;
+        }
+
+        $this->signedRequest = new SignedRequest($this->app, $rawSignedRequest);
+    }
+
+    /**
+     * Returns an AccessToken entity from the signed request.
+     *
+     * @return AccessToken|null
+     *
+     * @throws \Facebook\Exceptions\FacebookSDKException
+     */
+    public function getAccessToken()
+    {
+        if ($this->signedRequest && $this->signedRequest->hasOAuthData()) {
+            $code = $this->signedRequest->get('code');
+            $accessToken = $this->signedRequest->get('oauth_token');
+
+            if ($code && !$accessToken) {
+                return $this->oAuth2Client->getAccessTokenFromCode($code);
+            }
+
+            $expiresAt = $this->signedRequest->get('expires', 0);
+
+            return new AccessToken($accessToken, $expiresAt);
+        }
+
+        return null;
+    }
+
+    /**
+     * Returns the SignedRequest entity.
+     *
+     * @return SignedRequest|null
+     */
+    public function getSignedRequest()
+    {
+        return $this->signedRequest;
+    }
+
+    /**
+     * Returns the user_id if available.
+     *
+     * @return string|null
+     */
+    public function getUserId()
+    {
+        return $this->signedRequest ? $this->signedRequest->getUserId() : null;
+    }
+
+    /**
+     * Get raw signed request from input.
+     *
+     * @return string|null
+     */
+    abstract public function getRawSignedRequest();
+
+    /**
+     * Get raw signed request from POST input.
+     *
+     * @return string|null
+     */
+    public function getRawSignedRequestFromPost()
+    {
+        if (isset($_POST['signed_request'])) {
+            return $_POST['signed_request'];
+        }
+
+        return null;
+    }
+
+    /**
+     * Get raw signed request from cookie set from the Javascript SDK.
+     *
+     * @return string|null
+     */
+    public function getRawSignedRequestFromCookie()
+    {
+        if (isset($_COOKIE['fbsr_' . $this->app->getId()])) {
+            return $_COOKIE['fbsr_' . $this->app->getId()];
+        }
+
+        return null;
+    }
+}