Determines whether the current user may perform the operation on the node.

Parameters

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

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

$node: The node object 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, FALSE otherwise.

Related topics

File

modules/node/node.module, line 2981

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) {
  $rights = &drupal_static(__FUNCTION__, array());

  if (!$node || !in_array($op, array('view', 'update', 'delete', 'create'), TRUE)) {
    // If there was no node to check against, or the $op was not one of the
    // supported ones, we return access denied.
    return FALSE;
  }
  // If no user object is supplied, the access check is for the current user.
  if (empty($account)) {
    $account = $GLOBALS['user'];
  }

  // $node may be either an object or a node type. Since node types cannot be
  // an integer, use either nid or type as the static cache id.

  $cid = is_object($node) ? $node->nid : $node;

  // If we've already checked access for this node, user and op, return from
  // cache.
  if (isset($rights[$account->uid][$cid][$op])) {
    return $rights[$account->uid][$cid][$op];
  }

  if (user_access('bypass node access', $account)) {
    $rights[$account->uid][$cid][$op] = TRUE;
    return TRUE;
  }
  if (!user_access('access content', $account)) {
    $rights[$account->uid][$cid][$op] = FALSE;
    return FALSE;
  }

  // We grant access to the node if both of the following conditions are met:
  // - No modules say to deny access.
  // - At least one module says to grant access.
  // If no module specified either allow or deny, we fall back to the
  // node_access table.
  $access = module_invoke_all('node_access', $node, $op, $account);
  if (in_array(NODE_ACCESS_DENY, $access, TRUE)) {
    $rights[$account->uid][$cid][$op] = FALSE;
    return FALSE;
  }
  elseif (in_array(NODE_ACCESS_ALLOW, $access, TRUE)) {
    $rights[$account->uid][$cid][$op] = TRUE;
    return TRUE;
  }

  // Check if authors can view their own unpublished nodes.
  if ($op == 'view' && !$node->status && user_access('view own unpublished content', $account) && $account->uid == $node->uid && $account->uid != 0) {
    $rights[$account->uid][$cid][$op] = TRUE;
    return TRUE;
  }

  // If the module did not override the access rights, use those set in the
  // node_access table.
  if ($op != 'create' && $node->nid) {
    if (module_implements('node_grants')) {
      $query = db_select('node_access');
      $query->addExpression('1');
      $query->condition('grant_' . $op, 1, '>=');
      $nids = db_or()->condition('nid', $node->nid);
      if ($node->status) {
        $nids->condition('nid', 0);
      }
      $query->condition($nids);
      $query->range(0, 1);

      $grants = db_or();
      foreach (node_access_grants($op, $account) as $realm => $gids) {
        foreach ($gids as $gid) {
          $grants->condition(db_and()->condition('gid', $gid)->condition('realm', $realm));
        }
      }
      if (count($grants) > 0) {
        $query->condition($grants);
      }
      $result = (bool) $query->execute()->fetchField();
      $rights[$account->uid][$cid][$op] = $result;
      return $result;
    }
    elseif (is_object($node) && $op == 'view' && $node->status) {
      // If no modules implement hook_node_grants(), the default behavior is to
      // allow all users to view published nodes, so reflect that here.
      $rights[$account->uid][$cid][$op] = TRUE;
      return TRUE;
    }
  }

  return FALSE;
}