fb_url_rewrite.inc in Drupal for Facebook 6.2

Performs custom url rewriting for Drupal for Facebook.

Historically, these modules prefixed all facebook callbacks with values that could be parsed from the url. In particular we learned which application was being used. And in advanced cases, mostly for iframe apps, we learned the "page type" and session key as well.

Now, we learn these by inspecting 'fb_sig' params (canvas pages) and cookies (facebook connect). So most users will not need these functions. They are available here for compatability and to support those more advanced cases where they may still be necessary.

If your application needs these, include this file in your settings.php. I.e. the end of your settings.php might look like:

include 'sites/all/modules/fb/fb_url_rewrite.inc'; // This on only if necessary. include 'sites/all/modules/fb/fb_settings.inc'; // Always include this.

File

fb_url_rewrite.inc

<?php

/**
 * @file
 * Performs custom url rewriting for Drupal for Facebook.
 *
 * Historically, these modules prefixed all facebook callbacks with values
 * that could be parsed from the url.  In particular we learned which
 * application was being used.  And in advanced cases, mostly for iframe apps,
 * we learned the "page type" and session key as well.
 *
 * Now, we learn these by inspecting 'fb_sig' params (canvas pages) and
 * cookies (facebook connect).  So most users will not need these functions.
 * They are available here for compatability and to support those more
 * advanced cases where they may still be necessary.
 *
 * If your application needs these, include this file in your settings.php.
 * I.e. the end of your settings.php might look like:
 *
 * include 'sites/all/modules/fb/fb_url_rewrite.inc'; // This on only if necessary.
 * include 'sites/all/modules/fb/fb_settings.inc'; // Always include this.
 */

/**
 * Returns a list of the values which we prepend to paths when rewriting urls.
 */
function _fb_settings_url_rewrite_prefixes() {
  static $prefixes;
  if (!isset($prefixes)) {
    $prefixes = array(
      FB_SETTINGS_CB,
      FB_SETTINGS_CB_TYPE,
      FB_SETTINGS_CB_SESSION,
    );
  }
  return $prefixes;
}

/**
 * Parse a setting from the URL.  This may be called before
 * custom_url_rewrite, so we can't count on fb_settings() to return the value.
 * For internal use only (see fb_session.inc).
 */
function _fb_settings_parse($key) {
  if (isset($_GET['q'])) {
    $path = $_GET['q'];
    $pos = strpos($path, $key . '/');
    if ($pos !== FALSE) {

      // Too soon for arg() function.
      $args = explode('/', $path);
      $i = 0;
      while (isset($args[$i]) && isset($args[$i + 1])) {
        if ($args[$i] == $key) {

          // Found the value we're interested in.
          return $args[$i + 1];
        }
        $i = $i + 2;
      }
    }
  }
}

//// URL Management

// We define our custom_url rewrite function here, and not in
// fb_canvas.module, because custom_url_rewrite_inbound() must be defined
// *before* drupal_init_path(), which is called during DRUPAL_BOOTSTRAP_PATH,
// *before modules are loaded.  Set $conf['fb_url_rewrite'] = FALSE in
// *settings.php to disable this behavior.  That is safe for sites
// *implementing facebook connect, but not canvas pages or profile tabs.
// Enable by default.
if (!isset($conf['fb_url_rewrite'])) {
  $conf['fb_url_rewrite'] = TRUE;
}

/**
 * Define custom_url_rewrite_inbound() if not defined already.
 */
if (!function_exists('custom_url_rewrite_inbound') && $conf['fb_url_rewrite']) {
  function custom_url_rewrite_inbound(&$result, $path, $path_language) {
    fb_url_inbound_alter($result, $path, $path_language);
  }
}

/**
 * Define custom_url_rewrite_outbound() if not defined already.
 */
if (!function_exists('custom_url_rewrite_outbound') && $conf['fb_url_rewrite']) {
  function custom_url_rewrite_outbound(&$path, &$options, $original_path) {
    if (function_exists('fb_canvas_url_outbound_alter')) {
      fb_canvas_url_outbound_alter($path, $options, $original_path);
    }
    fb_url_outbound_alter($path, $options, $original_path);
  }
}

/**
 * Implementation of hook_url_outbound_alter().
 */
function fb_url_outbound_alter(&$path, &$options, $original_path) {

  //dpm(func_get_args(), 'fb_settings_url_rewrite_outbound'); // debug
  $pre = '';

  // Prefix each known value to the URL
  foreach (_fb_settings_url_rewrite_prefixes() as $prefix) {
    if ($value = fb_settings($prefix)) {
      $pre .= $prefix . '/' . $value . '/';
    }
  }
  $path = $pre . $path;
  return $path;
}

/**
 * Implementation of hook_url_inbound_alter().
 *
 * Rewrite URLs for facebook canvas pages, and connect callbacks.
 * 
 */
function fb_url_inbound_alter(&$result, $path, $path_language) {

  //dpm(func_get_args(), 'fb_settings_url_rewrite_outbound'); // debug

  // See if this is a request for us.
  if (strpos($path, FB_SETTINGS_CB . '/') === 0) {

    // Too soon for arg() function.
    $args = explode('/', $path);
    while (count($args) && in_array($args[0], _fb_settings_url_rewrite_prefixes())) {
      $key = array_shift($args);
      $value = array_shift($args);
      $app_nid = fb_settings($key, $value);

      // Store for use later.
    }
    if ($app_label = fb_settings(FB_SETTINGS_CB)) {
      if (count($args)) {
        $path = implode('/', $args);

        // remaining args
        $alias = drupal_lookup_path('source', $path, $path_language);

        //can't use drupal_get_normal_path, it calls custom_url_rewrite_inbound
        if ($alias) {
          $path = $alias;
        }
      }
      else {

        // frontpage
        $path = variable_get('site_frontpage', 'node');
        $alias = drupal_lookup_path('source', $path, $path_language);
        if ($alias) {
          $path = $alias;
        }
        $_REQUEST['destination'] = $path;

        //required workaround for compatibility with Global Redirect module, best practice?
      }
    }
  }
  else {

    //resolve aliases for non-fb-callbacks
    $alias = drupal_lookup_path('source', $path, $path_language);
    if ($alias) {
      $path = $alias;
    }
  }
  $result = $path;
}

Functions

Name	Description
fb_url_inbound_alter	Implementation of hook_url_inbound_alter().
fb_url_outbound_alter	Implementation of hook_url_outbound_alter().
_fb_settings_parse	Parse a setting from the URL. This may be called before custom_url_rewrite, so we can't count on fb_settings() to return the value. For internal use only (see fb_session.inc).
_fb_settings_url_rewrite_prefixes	Returns a list of the values which we prepend to paths when rewriting urls.