7 user.moduleuser_access($string, $account = NULL)
4.6 user.moduleuser_access($string, $account = NULL)
4.7 user.moduleuser_access($string, $account = NULL)
5 user.moduleuser_access($string, $account = NULL)
6 user.moduleuser_access($string, $account = NULL, $reset = FALSE)

Determine whether the user has a given privilege.

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.

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.

120 calls to user_access()
6 string references to 'user_access'

File

 

modules/user/user.module, line 511
Enables the user registration and login system.

 

Code

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

  if ($reset) {
    $perm = array();
  }

  if (!isset($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]);
}

Comments

EvanDonovan commented 

1) Define a permission in hook_perm() in your module, here called "coolstuff.module".

<?php
function coolstuff_perm() {
  return array('do cool stuff', 'do uncool stuff');
}
?>

2) Grant it to your users at admin/user/permissions.

3) Check it in a function.

<?php
function coolstuff_init() {
  if (user_access('do cool stuff')) {
   drupal_set_message(t('You can do cool stuff!'));
  }
  elseif (user_access('do uncool stuff')) {
    drupal_set_message(t('You can do uncool stuff.'));
  }
  elseif (!user_access('do cool stuff') && !user_access('do uncool stuff')) {
   drupal_set_message(t("You can't do stuff at all."));
  }
}
?>

I personally have never used the $account parameter, but presume it could be used as follows:

<?php
function check_coolstuff($uid) {
  $account = user_load($uid);
  if (user_access('do cool stuff', $account)) {
    drupal_set_message(t("The user @username with uid @uid has the permission to do cool stuff.", array('@username' => $account->name, '@uid' => $account->uid));
  }
}
?>

mosys commented 

Use this to forward administrators or editor to the administration page upon login:

<?php
  global $user;
  if ($user->uid == 1 || user_access('access administration pages')) {
    // Redirect admin to the administration page
    return 'admin';
  } else {
    return 'node';
  }
?>

PROMES commented 

Your example can be written even shorter since user_access() does the check for userid 1 for you.

<?php
  if (user_access('access administration pages')) {
    // Redirect admin to the administration page
    return 'admin';
  } else {
    return 'node';
  }
?>

Madbreaks commented 
<?php
return user_access('access administration pages') ? 'admin' : 'node';
?>