OG User Roles: Hooks

hook_og_user_roles_gid

As of release 5.x-2.5.
Description
Hook to allow other modules to supply a Group Node ID to identify the group a user is in.
Parameters
No input parameters.
Return value
Returns a single Group Node ID which should be defined by your module as the current group context for the current user.
Sample code

/**
 * implementation of hook_og_user_roles_gid();
 *
 * @param No input parameters
 * @return $gid numeric value containing the current group node ID
 */
function filenode_og_user_roles_gid() {
  if (arg(0) == 'og' && arg(1) == 'files') {
    if (is_numeric(arg(2))) {
      $gid = arg(2);
    } elseif (is_numeric(arg(3))) { // E.g. og/files/create-subdir/104
      $gid = arg(3);
    }
  }
  if ($gid) return $gid;
}

Reference
http://drupal.org/node/176390