simple_fb_connect.module in Simple FB Connect 7.2

Simple Facebook Login Module for Drupal Sites.

File

simple_fb_connect.module

<?php

/**
 * @file
 * Simple Facebook Login Module for Drupal Sites.
 */
define("SIMPLE_FB_CONNECT_DEFAULT_DIMENSIONS_STRING", "1024x1024");
define("SIMPLE_FB_CONNECT_DEFAULT_WIDTH", 1024);
define("SIMPLE_FB_CONNECT_DEFAULT_HEIGHT", 1024);
use Facebook\FacebookRedirectLoginHelper;
use Facebook\FacebookRequest;
use Facebook\FacebookRequestException;
use Facebook\FacebookSession;
use Facebook\GraphObject;

/**
 * Implements hook_menu().
 */
function simple_fb_connect_menu() {
  $items['user/simple-fb-connect'] = array(
    'title' => 'Facebook login',
    'page callback' => 'simple_fb_connect_redirect_to_fb',
    'access callback' => 'user_is_anonymous',
    'type' => MENU_LOCAL_TASK,
  );
  $items['user/simple-fb-connect/return'] = array(
    'title' => 'Facebook login',
    'page callback' => 'simple_fb_connect_return_from_fb',
    'access callback' => 'user_is_anonymous',
    'type' => MENU_CALLBACK,
  );
  $items['admin/config/people/simple-fb-connect'] = array(
    'title' => 'Simple FB Connect Settings',
    'page callback' => 'drupal_get_form',
    'page arguments' => array(
      'simple_fb_connect_api_keys_settings',
    ),
    'access arguments' => array(
      'administer simple fb',
    ),
    'file' => 'simple_fb_connect.admin.inc',
  );
  return $items;
}

/**
 * Implements hook_permission().
 */
function simple_fb_connect_permission() {
  $items = array();
  $items['administer simple fb'] = array(
    'title' => "Administer Simple Facebook Connect Module settings",
  );
  return $items;
}

/**
 * Implements hook_libraries_info().
 */
function simple_fb_connect_libraries_info() {
  $libraries['facebook-php-sdk-v4'] = array(
    'name' => 'Facebook PHP SDK v4',
    'vendor url' => 'https://github.com/facebook/facebook-php-sdk-v4',
    'download url' => 'https://github.com/facebook/facebook-php-sdk-v4/releases',
    'version arguments' => array(
      'file' => 'README.md',
      // Pattern to search for: Stable-4.0.23.
      'pattern' => '@Stable-(\\d*\\.\\d*\\.\\d*)@',
    ),
    'xautoload' => function ($adapter) {
      $adapter
        ->add('Facebook', 'src');
    },
  );
  return $libraries;
}

/**
 * Implemets hook_user_logout().
 *
 * Module configuration allows site builders to define if the user should be
 * logged out also from Facebook after Drupal logout. Facebook logout is done
 * by redirecting the user to an URL generated by Facebook SDK. Facebook returns
 * the user back to our Drupal site immediately after the user has been logged
 * out from Facebook.
 *
 * We can't redirect the user out from the Drupal site from hook_user_logout()
 * because the hooks are executed just before the Drupal session is terminated.
 * Drupal user_logout performs an internal redirect to home page as the final
 * step of the logout flow so we can set a persistent variable here in
 * hook_user_logout() and then check in hook_drupal_goto_alter() implementation
 * if it has been set and redirect the user to Facebook from there.
 */
function simple_fb_connect_user_logout($account) {
  global $base_url;

  // Validate configuration.
  if (simple_fb_connect_initialize()) {

    // Check if we have a FacebookSession for the current user.
    $fb_session = simple_fb_connect_get_session();
    if ($fb_session && variable_get('simple_fb_connect_logout_action')) {

      // Generate the FB logout URL and store it in a persistent variable.
      $login_helper = new FacebookRedirectLoginHelper('');
      $fb_logout_url =& drupal_static('simple_fb_connect_fb_logout_url');
      $fb_logout_url = $login_helper
        ->getLogoutUrl($fb_session, $base_url . '/');
    }
  }
}

/**
 * Implemets hook_drupal_goto_alter().
 *
 * Redirect the user to Facebook logout URL after Drupal logout.
 * The persistent variable is set in hook_user_logout() implementation.
 */
function simple_fb_connect_drupal_goto_alter(&$path, &$options, &$http_response_code) {
  $fb_logout_url =& drupal_static('simple_fb_connect_fb_logout_url');
  if (empty($path) && $fb_logout_url) {
    $path = $fb_logout_url;
  }
  drupal_static_reset('simple_fb_connect_fb_logout_url');
}

/**
 * Page callback for /user/simple-fb-connect.
 *
 * Redirects the user to FB for authentication.
 */
function simple_fb_connect_redirect_to_fb() {

  // Validate configuration.
  if (!simple_fb_connect_initialize()) {
    drupal_goto('user');
  }

  // FacebookRedirectLoginHelper requires session to be started.
  drupal_session_start();

  // Generate the URL where FB will return the user after authentication.
  $return_url = simple_fb_connect_get_return_url();
  $login_helper = new FacebookRedirectLoginHelper($return_url);

  // Allow other modules to modify FB permission scope.
  $scope = simple_fb_connect_get_scope();

  // Save the post login URL to session variables.
  simple_fb_connect_save_post_login_url();

  // Generate the URL where the user will be redirected for FB login.
  // If the user did not have email permission granted on previous attempt,
  // we use the re-request URL requesting only the email address.
  $api_version = simple_fb_connect_get_api_version();
  $login_url = $login_helper
    ->getLoginUrl($scope, $api_version);
  if (isset($_SESSION['simple_fb_connect']['reprompt'])) {
    $scope = array(
      'public_profile',
      'email',
    );
    $login_url = $login_helper
      ->getReRequestUrl($scope, $api_version);
  }

  // Redirect the user to Facebook for login.
  drupal_goto($login_url);

  // We should never reach this point because the user was redirected.
  return MENU_ACCESS_DENIED;
}

/**
 * Page callback for /user/simple-fb-connect/return.
 *
 * Facebook returns the user here after user has authenticated in FB.
 */
function simple_fb_connect_return_from_fb() {

  // Validate configuration.
  if (!simple_fb_connect_initialize()) {
    drupal_goto('user');
  }

  // FB SDK can start FacebookSession from the page where FB returned the user.
  $return_url = simple_fb_connect_get_return_url();
  $login_helper = new FacebookRedirectLoginHelper($return_url);
  if (!simple_fb_connect_save_session($login_helper)) {
    drupal_set_message(t("Facebook login failed."), "error");
    drupal_goto('user');
  }

  // Get a validated FacebookSession object.
  if (!($fb_session = simple_fb_connect_get_session())) {
    drupal_set_message(t("Facebook login failed."), "error");
    simple_fb_connect_destroy_session();
    drupal_goto('user');
  }

  // Check that user authorized our app to access user's email address.
  if (!simple_fb_connect_check_permission($fb_session, 'email')) {
    $site_name = variable_get('site_name');
    if ($site_name) {
      drupal_set_message(t("Facebook login failed. @site_name requires permission to get your email address from Facebook. Please try again and give the permission.", array(
        '@site_name' => $site_name,
      )), "error");
    }
    else {
      drupal_set_message(t("Facebook login failed. This site requires permission to get your email address from Facebook. Please try again and give the permission."), "error");
    }

    // Preserve the post login URL from the previous attempt.
    $post_login_url = simple_fb_connect_get_post_login_url();
    simple_fb_connect_destroy_session();

    // Set the email permission reprompt flag and save post-login URL.
    $_SESSION['simple_fb_connect']['reprompt'] = TRUE;
    $_SESSION['simple_fb_connect']['post_login_url'] = $post_login_url;
    drupal_goto('user');
  }

  // Get the user's Facebook profile from Facebook API.
  if (!($fb_profile = simple_fb_connect_get_fb_profile($fb_session))) {
    drupal_set_message(t("Facebook login failed."), "error");
    simple_fb_connect_destroy_session();
    drupal_goto('user');
  }

  // Get user's email address from the profile. It is possible that FB profile
  // does not have email address (user can sign up with a phone number only).
  if (!($email = simple_fb_connect_get_email($fb_profile))) {
    drupal_set_message(t('Facebook login failed. This site requires an email address. Please add one in your Facebook profile.'), 'error');
    simple_fb_connect_destroy_session();
    drupal_goto('user');
  }

  // Check if we have an existing Drupal user with the same email address and try to log in.
  if ($drupal_user = user_load_by_mail($email)) {
    if (simple_fb_connect_login_user($drupal_user)) {
      $post_login_url = simple_fb_connect_get_post_login_url();
      simple_fb_connect_go_to_redirect_url($post_login_url, $drupal_user);
    }
    else {
      simple_fb_connect_destroy_session();
      drupal_goto('user');
    }
  }

  // If there was no existing user, try to create a new user and try to log in.
  if ($drupal_user = simple_fb_connect_create_user($fb_profile, $fb_session)) {
    if (simple_fb_connect_login_user($drupal_user)) {

      // Check if new users should be redirected to Drupal user form.
      $redirect_to_user_form = variable_get('simple_fb_connect_redirect_user_form', 0);
      if ($redirect_to_user_form) {
        drupal_set_message(t("Please take a moment to confirm your account details. Since you logged in with Facebook, you don't need to update your password."));
        $post_login_url = 'user/' . $drupal_user->uid . '/edit';
        simple_fb_connect_go_to_redirect_url($post_login_url, $drupal_user);
      }

      // If user wasn't redirected to user form, use the normal post login path.
      $post_login_url = simple_fb_connect_get_post_login_url();
      simple_fb_connect_go_to_redirect_url($post_login_url, $drupal_user);
    }
    else {

      // New user was successfully created but the account is blocked.
      drupal_set_message(t('You will receive an email when a site administrator activates your account.'), 'warning');
      $post_login_url = simple_fb_connect_get_post_login_url();
      simple_fb_connect_destroy_session();
      simple_fb_connect_go_to_redirect_url($post_login_url, $drupal_user);
    }
  }
  else {

    // New user could not be created.
    simple_fb_connect_destroy_session();
    drupal_goto('user');
  }

  // We should never reach this point because the user is redirected in all
  // cases to some other page. If we ever get here, return "access denied" page.
  return MENU_ACCESS_DENIED;
}

/**
 * Initializes the FB App.
 *
 * @return
 *   TRUE if initialization was OK. FALSE otherwise.
 */
function simple_fb_connect_initialize() {

  // Check that PHP version is 5.4 or higher.
  if (version_compare(phpversion(), '5.4.0', '<')) {
    drupal_set_message(t('Simple FB Connect is not configured properly.'), 'error');
    watchdog('simple_fb_connect', 'Facebook PHP SDK v4 requires PHP 5.4 or higher. Your PHP version is @version', array(
      '@version' => phpversion(),
    ), WATCHDOG_ERROR);
    return FALSE;
  }

  // Check that Facebook PHP SDK is properly installed and that the version is 4.0.x.
  $sdk = libraries_detect('facebook-php-sdk-v4');
  if (!is_array($sdk) || !$sdk['installed'] || $sdk['version'] < '4.0' || $sdk['version'] >= '4.1') {
    drupal_set_message(t('The Facebook PHP SDK is not properly installed.'), 'error');
    watchdog('simple_fb_connect', 'Facebook PHP SDK 4.0.x not found on sites/all/libraries/facebook-php-sdk-v4', array(), WATCHDOG_ERROR);
    return FALSE;
  }

  // Check that the module is configured properly.
  $app_id = variable_get('simple_fb_connect_appid', 0);
  $app_secret = variable_get('simple_fb_connect_skey', 0);
  $api_version = variable_get('simple_fb_connect_api_version', 0);
  if (!$app_id || !$app_secret || !$api_version) {
    drupal_set_message(t('Simple FB Connect not configured properly.'), 'error');
    watchdog('simple_fb_connect', 'Could not initialize FB App. Define App ID, App Secret and API Version on module settings.', array(), WATCHDOG_ERROR);
    return FALSE;
  }

  // If we have not returned FALSE, SDK is found and module has been configured.
  FacebookSession::setDefaultApplication($app_id, $app_secret);
  return TRUE;
}

/**
 * Checks that we have a valid FB session after Facebook has returned the user
 * back to our site. User's access token is saved to $_SESSION.
 *
 * @param FacebookRedirectLoginHelper $login_helper
 *   FacebookRedirectLoginHelper object.
 *
 * @return
 *   FacebookSession object if we have a valid FB session, FALSE otherwise.
 */
function simple_fb_connect_save_session(FacebookRedirectLoginHelper $login_helper) {
  try {
    $fb_session = $login_helper
      ->getSessionFromRedirect();
    if ($fb_session) {

      // Store user access token to $_SESSION.
      $_SESSION['simple_fb_connect']['user_token'] = $fb_session
        ->getToken();
      return TRUE;
    }
    else {

      // If the user cancels the dialog or return URL is invalid,
      // Facebook will not throw an exception but will return NULL.
      watchdog('simple_fb_connect', 'Could not start FB session. User cancelled the dialog in FB or return URL was not valid.', array(), WATCHDOG_ERROR);
    }
  } catch (FacebookRequestException $ex) {

    // When Facebook returns an error.
    watchdog('simple_fb_connect', 'Could not save FB session. FacebookRequestException: @message', array(
      '@message' => json_encode($ex
        ->getResponse()),
    ), WATCHDOG_ERROR);
  } catch (\Exception $ex) {

    // When validation fails or other local issues.
    watchdog('simple_fb_connect', 'Could not save FB session. Exception: @message', array(
      '@message' => $ex
        ->getMessage(),
    ), WATCHDOG_ERROR);
  }
  return FALSE;
}

/**
 * Loads the user's access token from $_SESSION and validates it.
 *
 * @return
 *   FacebookSession object if access token was found and session is valid. FALSE otherwise.
 */
function simple_fb_connect_get_session() {
  static $fb_session = NULL;

  // We are only executing the following code when this function is called for the first time.
  if (is_null($fb_session)) {
    if (isset($_SESSION['simple_fb_connect']['user_token'])) {
      $user_token = $_SESSION['simple_fb_connect']['user_token'];
      try {

        // Check that we are able to start a session with the token.
        $fb_session = new FacebookSession($user_token);
        $fb_session
          ->validate();
        return $fb_session;
      } catch (FacebookRequestException $ex) {

        // Session not valid, Graph API returned an exception with the reason.
        watchdog('simple_fb_connect', 'Could not load FB session. FacebookRequestException: @message', array(
          '@message' => json_encode($ex
            ->getResponse()),
        ), WATCHDOG_NOTICE);
      } catch (\Exception $ex) {

        // Graph API returned info, but it may mismatch the current app or have expired.
        watchdog('simple_fb_connect', 'Could not load FB session. Exception: @message', array(
          '@message' => $ex
            ->getMessage(),
        ), WATCHDOG_ERROR);
      }
    }

    // Return FALSE if we don't have a session at all or if the access token was not valid.
    $fb_session = FALSE;
  }
  return $fb_session;
}

/**
 * Destroys the session if user was not logged in.
 *
 * @see https://www.drupal.org/node/2829558
 */
function simple_fb_connect_destroy_session() {

  // Remove all other session keys except 'messages' which is preserved
  // so that we can display a message about a failed login.
  foreach ($_SESSION as $key => $value) {
    if ($key != 'messages') {
      unset($_SESSION[$key]);
    }
  }
}

/**
 * Makes an API call to check if user has granted given permission.
 *
 * @param Facebook\FacebookSession $fb_session
 *   FacebookSession object.
 * @param string $permission_to_check
 *   Permission to check.
 *
 * @return bool
 *   True if user has granted given permission.
 *   False otherwise.
 */
function simple_fb_connect_check_permission(FacebookSession $fb_session, $permission_to_check) {
  try {

    // Make the API call to Facebook.
    $api_version = simple_fb_connect_get_api_version();
    $request = new FacebookRequest($fb_session, 'GET', '/me/permissions', NULL, $api_version);
    $permissions = $request
      ->execute()
      ->getGraphObject()
      ->asArray();
    foreach ($permissions as $permission) {
      if ($permission->permission == $permission_to_check && $permission->status == 'granted') {
        return TRUE;
      }
    }
  } catch (FacebookRequestException $ex) {
    watchdog('simple_fb_connect', 'Error checking permission: FacebookRequestException. Error details: @message', array(
      '@message' => json_encode($ex
        ->getResponse()),
    ), WATCHDOG_WARNING);
  } catch (\Exception $ex) {
    watchdog('simple_fb_connect', 'Error checking permission: Unhandled exception. Error details: @message', array(
      '@message' => $ex
        ->getMessage(),
    ), WATCHDOG_WARNING);
  }

  // We don't have permission or we got an exception during the API call.
  return FALSE;
}

/**
 * Makes an API call to get user's Facebook profile.
 *
 * @param Facebook\FacebookSession $fb_session
 *   FacebookSession object.
 *
 * @return Facebook\GraphObject|false
 *   GraphObject representing the user.
 *   False if exception was thrown.
 */
function simple_fb_connect_get_fb_profile(FacebookSession $fb_session) {
  try {
    $api_version = simple_fb_connect_get_api_version();
    $request = new FacebookRequest($fb_session, 'GET', '/me', array(
      'fields' => 'id,name,email',
    ), $api_version);
    $object = $request
      ->execute()
      ->getGraphObject();
    return $object;
  } catch (FacebookRequestException $ex) {
    watchdog('simple_fb_connect', 'Could not load FB user profile: FacebookRequestException. Error details: @message', array(
      '@message' => json_encode($ex
        ->getResponse()),
    ), WATCHDOG_ERROR);
  } catch (\Exception $ex) {
    watchdog('simple_fb_connect', 'Could not load FB user profile: Unhandled exception. Error details: @message', array(
      '@message' => $ex
        ->getMessage(),
    ), WATCHDOG_ERROR);
  }

  // Something went wrong.
  return FALSE;
}

/**
 * Makes an API call to get user's Facebook profile picture.
 *
 * @param Facebook\FacebookSession $fb_session
 *   FacebookSession object.
 *
 * @return int|false
 *   File id (fid) of the Drupal file object if download was successful.
 *   False on errors.
 */
function simple_fb_connect_get_fb_profile_pic(FacebookSession $fb_session) {

  // Get desired dimensions from module settings.
  $dimensions_in_text = variable_get('user_picture_dimensions', SIMPLE_FB_CONNECT_DEFAULT_DIMENSIONS_STRING);
  $dimensions = explode('x', $dimensions_in_text);
  if (count($dimensions) == 2) {
    $width = $dimensions[0];
    $height = $dimensions[1];
  }
  else {
    $width = SIMPLE_FB_CONNECT_DEFAULT_WIDTH;
    $height = SIMPLE_FB_CONNECT_DEFAULT_HEIGHT;
  }

  // Check that target directory is writeable.
  $picture_directory = file_default_scheme() . '://' . variable_get('user_picture_path', 'pictures/');
  if (!file_prepare_directory($picture_directory, FILE_CREATE_DIRECTORY)) {
    watchdog('simple_fb_connect', 'Could not save FB profile picture. Directory is not writeable: @picture_directory', array(
      '@picture_directory' => $picture_directory,
    ), WATCHDOG_ERROR);
    return FALSE;
  }

  // Call Graph API to request profile picture.
  $api_version = simple_fb_connect_get_api_version();
  try {
    $request = new FacebookRequest($fb_session, 'GET', '/me/picture', array(
      'width' => $width,
      'height' => $height,
      'redirect' => 'false',
    ), $api_version);
    $graph_object = $request
      ->execute()
      ->getGraphObject();

    // We don't download the FB default silhouettes, only real pictures.
    $is_default_picture = (bool) $graph_object
      ->getProperty('is_silhouette');
    if ($is_default_picture) {
      return FALSE;
    }

    // Save the picture locally. Use FB user_id as file name.
    $picture_url = $graph_object
      ->getProperty('url');
    $fb_user_id = $fb_session
      ->getSessionInfo()
      ->getProperty('user_id');
    $destination = file_default_scheme() . '://' . variable_get('user_picture_path', 'pictures') . '/' . check_plain($fb_user_id) . '.jpg';
    if ($file = system_retrieve_file($picture_url, $destination, TRUE, FILE_EXISTS_REPLACE)) {
      return $file->fid;
    }
    else {
      watchdog('simple_fb_connect', 'Could not save FB profile picture. Check that directory is writeable: @destination', array(
        '@destination' => $destination,
      ), WATCHDOG_ERROR);
    }
  } catch (FacebookRequestException $ex) {
    watchdog('simple_fb_connect', 'Could not load FB profile picture: FacebookRequestException. Error details: @message', array(
      '@message' => json_encode($ex
        ->getResponse()),
    ), WATCHDOG_ERROR);
  } catch (\Exception $ex) {
    watchdog('simple_fb_connect', 'Could not load FB profile picture: Unhandled exception. Error details: @message', array(
      '@message' => $ex
        ->getMessage(),
    ), WATCHDOG_ERROR);
  }

  // Something went wrong and the picture could not be loaded / saved.
  return FALSE;
}

/**
 * Returns user's email address from Facebook profile.
 *
 * @param Facebook\GraphObject $fb_profile
 *   User's Facebook profile.
 *
 * @return string|false
 *   User's email address if found.
 *   False otherwise.
 */
function simple_fb_connect_get_email(GraphObject $fb_profile) {
  if ($email = $fb_profile
    ->getProperty('email')) {
    return $email;
  }

  // Email address was not found. Log error and return FALSE.
  watchdog('simple_fb_connect', 'No email address in FB user profile', array(), WATCHDOG_ERROR);
  return FALSE;
}

/**
 * Returns an array of Facebook permissions that will be requested from the user.
 *
 * @return
 *   Array of FB permissions.
 */
function simple_fb_connect_get_scope() {
  $scope = array();

  // Check if other modules have added any permissions with our hook.
  if (count(module_implements('simple_fb_connect_scope_info')) > 0) {

    // Call modules that implement the hook, and let them change scope.
    $scope = module_invoke_all('simple_fb_connect_scope_info', array());
  }

  // Add permission request to public profile and email.
  $scope[] = 'public_profile';
  $scope[] = 'email';
  return $scope;
}

/**
 * Creates a new user account for a Facebook user.
 *
 * @param Facebook\GraphObject $fb_profile
 *   Previously loaded FB user profile object.
 * @param Facebook\FacebookSession $fb_session
 *   FacebookSession object so that we can load user profile pic.
 *
 * @return
 *   Drupal user account. FALSE on errors.
 */
function simple_fb_connect_create_user(GraphObject $fb_profile, FacebookSession $fb_session) {

  // Check if Drupal account settings allow users to register.
  if (!variable_get('user_register', 1)) {
    drupal_set_message(t('Creation of new accounts on this site is disabled.'), 'error');
    watchdog('simple_fb_connect', 'Failed to create user. User registration is disabled in Drupal account settings.', array(), WATCHDOG_WARNING);
    return FALSE;
  }

  // Check if module settings allow users to register.
  if (variable_get('simple_fb_connect_login_only', 0)) {
    drupal_set_message(t('Only registered users can log in with Facebook.'), 'error');
    watchdog('simple_fb_connect', 'Failed to create user. User registration is disabled in Simple FB Connect settings.', array(), WATCHDOG_WARNING);
    return FALSE;
  }
  if ($fb_profile && $fb_session) {
    $real_name = $fb_profile
      ->getProperty('name');
    $email = $fb_profile
      ->getProperty('email');

    // Make sure username will be unique.
    $drupal_username_generated = simple_fb_connect_unique_user_name($real_name);
    if ($drupal_username_generated === FALSE) {
      watchdog('simple_fb_connect', 'Could not create new user, username contains illegal characters.', array(), WATCHDOG_ERROR);
      drupal_set_message(t("Username contains illegal characters."), 'error');
      return FALSE;
    }

    // This will generate a random password. Since the user will never see this
    // password, we can use long password to make it stronger.
    $password = user_password(32);

    // Set up the user fields.
    $fields = array(
      'name' => $drupal_username_generated,
      'mail' => $email,
      'pass' => $password,
      'status' => variable_get('user_register', 1) == 1 ? 1 : 0,
      'init' => $email,
      'roles' => array(
        DRUPAL_AUTHENTICATED_RID => 'authenticated user',
      ),
    );

    // Set user language to current UI language.
    if (drupal_multilingual()) {
      global $language;
      $fields['language'] = $language->language;
    }

    // Allow other modules to modify $fields array before the new user is saved.
    drupal_alter("simple_fb_connect_register", $fields, $fb_profile);

    // The first parameter is left blank so a new user is created.
    $account = user_save('', $fields);
    if ($account) {

      // If user pictures are enabled, try to get the profile picture from FB.
      if (variable_get('user_pictures', 0)) {
        if ($fid = simple_fb_connect_get_fb_profile_pic($fb_session)) {

          // Set owner of profile picture.
          $file = file_load($fid);
          $file->uid = $account->uid;
          file_save($file);

          // Add the file as user profile picture.
          $edit = array(
            'picture' => $file,
          );
          $account = user_save($account, $edit);
        }
      }

      // Log new user creation.
      watchdog('simple_fb_connect', 'New user created: @username', array(
        '@username' => $drupal_username_generated,
      ), WATCHDOG_NOTICE);
      drupal_set_message(t("New user account %username created.", array(
        '%username' => $drupal_username_generated,
      )));

      // Invoke a registration event if Rules module is enabled.
      if (module_exists('rules')) {
        rules_invoke_event('simple_fb_connect_registration', $account);
      }

      // Invoke user creation event if some module implements hook_simple_fb_connect_registration.
      module_invoke_all('simple_fb_connect_registration', $account);
      return $account;
    }
  }

  // Something went wrong.
  drupal_set_message(t("Error while creating a new user account."), 'error');
  watchdog('simple_fb_connect', 'Could not create new user.', array(), WATCHDOG_ERROR);
  return FALSE;
}

/**
 * Logs the given user in.
 *
 * @param $drupal_user
 *   A Drupal user object.
 *
 * @return bool
 *   True if login was successful.
 *   False if login was blocked.
 */
function simple_fb_connect_login_user($drupal_user) {

  // Prevent admin login if defined in module settings.
  if (simple_fb_connect_login_disabled_for_admin($drupal_user)) {
    drupal_set_message(t('FB login is disabled for site administrator. Please login with your local user account.'), 'error');
    return FALSE;
  }

  // Prevent login if user has one of the roles defined in module settings.
  if (simple_fb_connect_login_disabled_by_role($drupal_user)) {
    drupal_set_message(t('FB login is disabled for your role. Please login with your local user account.'), 'error');
    return FALSE;
  }

  // Check that the account is active.
  if ($drupal_user->status) {

    // Do the actual login.
    $form_state['uid'] = $drupal_user->uid;
    user_login_submit(array(), $form_state);

    // Invoke a login event if Rules module is enabled.
    if (module_exists('rules')) {
      rules_invoke_event('simple_fb_connect_login', $drupal_user);
    }

    // Invoke a login event if some module implements hook_simple_fb_connect_login.
    module_invoke_all('simple_fb_connect_login', $drupal_user);

    // If Boost module is used, we need to add DRUPAL_UID cookie.
    // If this cookie is set, Boost will not serve cached pages to the user.
    // user/simple-fb-connect/* must also be added to Boost "cache all pages except those listed".
    if (module_exists('boost')) {
      boost_set_cookie($drupal_user->uid);
    }
    return TRUE;
  }

  // If we are still here, account is blocked.
  drupal_set_message(t('You could not be logged in because your account %username is not active.', array(
    '%username' => $drupal_user->name,
  )), 'warning');
  watchdog('simple_fb_connect', 'FB login for user %user prevented. Account is blocked.', array(
    '%user' => $drupal_user->name,
  ), WATCHDOG_WARNING);
  return FALSE;
}

/**
 * Checks if the admin FB login is disabled.
 *
 * @param $drupal_user
 *   Drupal user object.
 *
 * @return bool
 *   True if login is disabled for this user.
 *   False if login is not disabled for this user.
 */
function simple_fb_connect_login_disabled_for_admin($drupal_user) {

  // Prevent admin login if defined in module settings.
  if ($drupal_user->uid == 1 && variable_get('simple_fb_connect_disable_admin_login', 1)) {
    watchdog('simple_fb_connect', 'FB login for user %user prevented. FB login for site administrator (user 1) is disabled in module settings.', array(
      '%user' => $drupal_user->name,
    ), WATCHDOG_WARNING);
    return TRUE;
  }

  // User is not admin or admin login is not disabled.
  return FALSE;
}

/**
 * Checks if the user has one of the "FB login disabled" roles.
 *
 * @param $drupal_user
 *   Drupal user object.
 *
 * @return bool
 *   True if login is disabled for one of this user's role.
 *   False if login is not disabled for this user's roles.
 */
function simple_fb_connect_login_disabled_by_role($drupal_user) {

  // Get module settings.
  $roles = variable_get('simple_fb_connect_disabled_roles', array());

  // Loop through all roles the user has.
  foreach ($drupal_user->roles as $role) {

    // Check if FB login is disabled for this role. Disabled roles have value > 0.
    if (array_key_exists($role, $roles) && !empty($roles[$role])) {
      watchdog('simple_fb_connect', 'FB login for user %user prevented. FB login for role %role is disabled in module settings.', array(
        '%user' => $drupal_user->name,
        '%role' => $role,
      ), WATCHDOG_WARNING);
      return TRUE;
    }
  }

  // If we didn't return TRUE already, FB login is not disabled for any of the user's roles.
  return FALSE;
}

/**
 * Generates a unique username for Drupal site based on FB username.
 *
 * @return string|bool
 *   Unique username, if the generated username passes user_validate_name().
 *   False otherwise.
 *
 * @see user_validate_name()
 */
function simple_fb_connect_unique_user_name($fb_name) {

  // Truncate to max length.
  $fb_name = drupal_substr($fb_name, 0, USERNAME_MAX_LENGTH);

  // Add a trailing number if needed to make username unique.
  $base = $fb_name;
  $i = 1;
  $candidate = $base;
  while (is_object(user_load_by_name($candidate))) {
    $i++;

    // Calculate max length for $base and truncate if needed.
    $max_length_base = USERNAME_MAX_LENGTH - strlen((string) $i) - 1;
    $base = drupal_substr($base, 0, $max_length_base);
    $candidate = $base . " " . $i;
  }

  // Trim leading and trailing whitespace.
  $candidate = trim($candidate);

  // Remove multiple spacebars if needed.
  $candidate = preg_replace('/ {2,}/', ' ', $candidate);

  // We now have a candidate that is unique and not too long.
  // Let's check that the username passes Drupal username validation.
  if ($error = user_validate_name($candidate)) {
    return FALSE;
  }

  // Validation passed, return the username.
  return $candidate;
}

/**
 * Returns the path were user should be redirected after a successful FB login.
 *
 * @return
 *   Path where the user should be redirected after FB login.
 */
function simple_fb_connect_get_post_login_url() {
  $post_login_url = variable_get('simple_fb_connect_post_login_url', 'user');

  // If we have stored the destination to $_SESSION, use that instead.
  if (isset($_SESSION['simple_fb_connect']['post_login_url'])) {
    $post_login_url = $_SESSION['simple_fb_connect']['post_login_url'];
  }
  return $post_login_url;
}

/**
 * Saves post login URL to $_SESSION if it was explicitly defined.
 */
function simple_fb_connect_save_post_login_url() {
  $destination = drupal_get_destination();
  if (!url_is_external($destination['destination']) && $destination['destination'] != 'user/simple-fb-connect') {
    $_SESSION['simple_fb_connect']['post_login_url'] = $destination['destination'];

    // We need to unset the GET parameter so that the user will be redirected.
    unset($_GET['destination']);
  }
}

/**
 * Redirects user after Facebook login to the desired Drupal path.
 *
 * The input parameter might contain a query parameter. This function
 * will parse the URL and handle the query parameters correctly.
 *
 * Other modules can modify the destination URL by implementing
 * hook_simple_fb_connect_redirect_url().
 *
 * @param string $post_login_url
 *   Post login URL.
 * @param $account
 *   Drupal user that was logged in via Simple FB Connect.
 */
function simple_fb_connect_go_to_redirect_url($post_login_url, $account) {

  // Extract URL parts and use them to define the post login URL.
  $url_parts = drupal_parse_url($post_login_url);
  $path = $url_parts['path'];
  $options = array(
    'query' => $url_parts['query'],
  );

  // Allow other modules to modify the destination URL.
  if (count(module_implements('simple_fb_connect_redirect_url')) > 0) {
    list($path, $options) = module_invoke_all('simple_fb_connect_redirect_url', $path, $options, $account);
  }
  drupal_goto($path, $options);
}

/**
 * Creates the return URL that works with and without clean URLs.
 *
 * @return
 *   return URL for FacebookRedirectLoginHelper.
 */
function simple_fb_connect_get_return_url() {

  // Generate the URL where FB will return the user after authentication.
  $return_url = url('user/simple-fb-connect/return', array(
    'absolute' => TRUE,
  ));

  // If clean URLs is disabled, we need to encode slashes in the query string.
  $query_pos = strpos($return_url, '?');
  if ($query_pos !== FALSE) {
    $url_string = substr($return_url, 0, $query_pos);
    $query_string = substr($return_url, $query_pos);
    $return_url = $url_string . str_replace('/', '%2F', $query_string);
  }
  return $return_url;
}

/**
 * Returns Facebook API version from module settings.
 *
 * @return string
 *   API version defined in module settings.
 */
function simple_fb_connect_get_api_version() {
  return variable_get('simple_fb_connect_api_version', 0);
}

Functions

Name	Description
simple_fb_connect_check_permission	Makes an API call to check if user has granted given permission.
simple_fb_connect_create_user	Creates a new user account for a Facebook user.
simple_fb_connect_destroy_session	Destroys the session if user was not logged in.
simple_fb_connect_drupal_goto_alter	Implemets hook_drupal_goto_alter().
simple_fb_connect_get_api_version	Returns Facebook API version from module settings.
simple_fb_connect_get_email	Returns user's email address from Facebook profile.
simple_fb_connect_get_fb_profile	Makes an API call to get user's Facebook profile.
simple_fb_connect_get_fb_profile_pic	Makes an API call to get user's Facebook profile picture.
simple_fb_connect_get_post_login_url	Returns the path were user should be redirected after a successful FB login.
simple_fb_connect_get_return_url	Creates the return URL that works with and without clean URLs.
simple_fb_connect_get_scope	Returns an array of Facebook permissions that will be requested from the user.
simple_fb_connect_get_session	Loads the user's access token from $_SESSION and validates it.
simple_fb_connect_go_to_redirect_url	Redirects user after Facebook login to the desired Drupal path.
simple_fb_connect_initialize	Initializes the FB App.
simple_fb_connect_libraries_info	Implements hook_libraries_info().
simple_fb_connect_login_disabled_by_role	Checks if the user has one of the "FB login disabled" roles.
simple_fb_connect_login_disabled_for_admin	Checks if the admin FB login is disabled.
simple_fb_connect_login_user	Logs the given user in.
simple_fb_connect_menu	Implements hook_menu().
simple_fb_connect_permission	Implements hook_permission().
simple_fb_connect_redirect_to_fb	Page callback for /user/simple-fb-connect.
simple_fb_connect_return_from_fb	Page callback for /user/simple-fb-connect/return.
simple_fb_connect_save_post_login_url	Saves post login URL to $_SESSION if it was explicitly defined.
simple_fb_connect_save_session	Checks that we have a valid FB session after Facebook has returned the user back to our site. User's access token is saved to $_SESSION.
simple_fb_connect_unique_user_name	Generates a unique username for Drupal site based on FB username.
simple_fb_connect_user_logout	Implemets hook_user_logout().

Constants

Name	Description
SIMPLE_FB_CONNECT_DEFAULT_DIMENSIONS_STRING	@file Simple Facebook Login Module for Drupal Sites.
SIMPLE_FB_CONNECT_DEFAULT_HEIGHT
SIMPLE_FB_CONNECT_DEFAULT_WIDTH