Determine whether the current user may perform the given operation on the specified node.

Parameters

$op: The operation to be performed on the node. Possible values are:

• "view"
• "update"
• "delete"
• "create"

$node: The node object (or node array) on which the operation is to be performed, or node type (e.g. 'forum') for "create" operation.

$account: Optional, a user object representing the user for whom the operation is to be performed. Determines access for a user other than the current user.

Return value

TRUE if the operation may be performed, or FALSE otherwise.

Related topics

File

drupal-6.x/modules/node/node.module, line 2018

The core that allows content to be submitted to the site. Modules and scripts may programmatically submit nodes using the usual form API pattern.

Code

function node_access($op, $node, $account = NULL) {
  global $user;

  if (!$node || !in_array($op, array('view', 'update', 'delete', 'create'), TRUE)) {
    // If there was no node to check against, or the $op was not one of the
    // supported ones, we return access denied.
    return FALSE;
  }
  // Convert the node to an object if necessary:
  if ($op != 'create') {
    $node = (object) $node;
  }
  // If no user object is supplied, the access check is for the current user.
  if (empty($account)) {
    $account = $user;
  }
  // If the node is in a restricted format, disallow editing.
  if ($op == 'update' && !filter_access($node->format)) {
    return FALSE;
  }

  if (user_access('administer nodes', $account)) {
    return TRUE;
  }

  if (!user_access('access content', $account)) {
    return FALSE;
  }

  // Can't use node_invoke(), because the access hook takes the $op parameter
  // before the $node parameter.
  $module = node_get_types('module', $node);
  if ($module == 'node') {
    $module = 'node_content'; // Avoid function name collisions.
  }
  $access = module_invoke($module, 'access', $op, $node, $account);
  if (!is_null($access)) {
    return $access;
  }

  // If the module did not override the access rights, use those set in the
  // node_access table.
  if ($op != 'create' && $node->nid && $node->status) {
    $grants = array();
    foreach (node_access_grants($op, $account) as $realm => $gids) {
      foreach ($gids as $gid) {
        $grants[] = "(gid = $gid AND realm = '$realm')";
      }
    }

    $grants_sql = '';
    if (count($grants)) {
      $grants_sql = 'AND (' . implode(' OR ', $grants) . ')';
    }

    $sql = "SELECT 1 FROM {node_access} WHERE (nid = 0 OR nid = %d) $grants_sql AND grant_$op >= 1";
    $result = db_query_range($sql, $node->nid, 0, 1);
    return (bool) db_result($result);
  }

  // Let authors view their own nodes.
  if ($op == 'view' && $account->uid == $node->uid && $account->uid != 0) {
    return TRUE;
  }

  return FALSE;
}