user_access

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• Drupal 4.7
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Definition

user_access($string, $account = NULL)
modules/user/user.module, line 361

Description

Determine whether the user has a given privilege.

All permission checks in Drupal should go through this function. This way, we guarantee consistent behavior, and ensure that the superuser can perform all actions.

Parameters

$string The permission, such as "administer nodes", being checked for.

$account (optional) The account to check, if not given use currently logged in user.

Return value

boolean TRUE if the current user has the requested permission.

Code

<?php
function user_access($string, $account = NULL) {
  global $user;
  static $perm = array();

  if (is_null($account)) {
    $account = $user;
  }

  // User #1 has all privileges:
  if ($account->uid == 1) {
    return TRUE;
  }

  // To reduce the number of SQL queries, we cache the user's permissions
  // in a static variable.
  if (!isset($perm[$account->uid])) {
    $rids = array_keys($account->roles);
    $placeholders = implode(',', array_fill(0, count($rids), '%d'));
    $result = db_query("SELECT DISTINCT(p.perm) FROM {role} r INNER JOIN {permission} p ON p.rid = r.rid WHERE r.rid IN ($placeholders)", $rids);
    $perm[$account->uid] = '';
    while ($row = db_fetch_object($result)) {
      $perm[$account->uid] .= "$row->perm, ";
    }
  }

  if (isset($perm[$account->uid])) {
    return strpos($perm[$account->uid], "$string, ") !== FALSE;
  }

  return FALSE;
}
?>