user_access

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• Drupal 4.7
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Definition

user_access($string, $account = NULL, $reset = FALSE)
modules/user/user.module, line 481

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.

$reset (optional) Resets the user's permissions cache, which will result in a recalculation of the user's permissions. This is necessary to support dynamically added user roles.

Return value

Boolean TRUE if the current user has the requested permission.

Code

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

  if ($reset) {
    $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])) {
    $result = db_query("SELECT p.perm FROM {role} r INNER JOIN {permission} p ON p.rid = r.rid WHERE r.rid IN (". db_placeholders($account->roles) .")", array_keys($account->roles));

    $perms = array();
    while ($row = db_fetch_object($result)) {
      $perms += array_flip(explode(', ', $row->perm));
    }
    $perm[$account->uid] = $perms;
  }

  return isset($perm[$account->uid][$string]);
}
?>