1. 8 core/core.api.php hooks
  2. 4.6 includes/module.inc hooks
  3. 4.7 includes/module.inc hooks
  4. 5 includes/module.inc hooks
  5. 6 includes/module.inc hooks
  6. 7 includes/module.inc hooks

Allow modules to interact with the Drupal core.

Drupal's module system is based on the concept of "hooks". A hook is a PHP function that is named foo_bar(), where "foo" is the name of the module (whose filename is thus foo.module) and "bar" is the name of the hook. Each hook has a defined set of parameters and a specified result type.

To extend Drupal, a module need simply implement a hook. When Drupal wishes to allow intervention from modules, it determines which modules implement a hook and call that hook in all enabled modules that implement it.

The available hooks to implement are explained here in the Hooks section of the developer documentation. The string "hook" is used as a placeholder for the module name is the hook definitions. For example, if the module file is called example.module, then hook_help() as implemented by that module would be defined as example_help().


includes/module.inc, line 95
API for loading and interacting with Drupal modules.


Namesort descending Location Description
hook_access developer/hooks/node.php Define access restrictions.
hook_auth developer/hooks/authentication.php Verify authentication of a user.
hook_block developer/hooks/core.php Declare a block or set of blocks.
hook_comment developer/hooks/core.php Act on comments.
hook_cron developer/hooks/core.php Perform periodic actions.
hook_db_rewrite_sql developer/hooks/core.php Add JOIN and WHERE statements to queries and decide whether the primary_field shall be made DISTINCT. For node objects, primary field is always called nid. For taxonomy terms, it is tid and for vocabularies it is vid. For comments, it is cid. Primary…
hook_delete developer/hooks/node.php Respond to node deletion.
hook_elements developer/hooks/core.php Allows modules to declare their own form element types and specify their default values.
hook_exit developer/hooks/core.php Perform cleanup tasks.
hook_file_download developer/hooks/core.php Allow file downloads.
hook_filter developer/hooks/core.php Define content filters.
hook_filter_tips developer/hooks/core.php Provide tips for using filters.
hook_footer developer/hooks/core.php Insert closing HTML.
hook_form developer/hooks/node.php Display a node editing form.
hook_form_alter developer/hooks/core.php Perform alterations before a form is rendered. One popular use of this hook is to add form elements to the node form.
hook_help developer/hooks/core.php Provide online user help.
hook_info developer/hooks/authentication.php Declare authentication scheme information.
hook_init developer/hooks/core.php Perform setup tasks.
hook_insert developer/hooks/node.php Respond to node insertion.
hook_install developer/hooks/install.php Install the current version of the database schema.
hook_link developer/hooks/core.php Define internal Drupal links.
hook_load developer/hooks/node.php Load node-type-specific information.
hook_menu developer/hooks/core.php Define menu items and page callbacks.
hook_nodeapi developer/hooks/core.php Act on nodes defined by other modules.
hook_node_grants developer/hooks/core.php Grant access to nodes.
hook_node_info developer/hooks/node.php Define the human-readable name of a node type.
hook_perm developer/hooks/core.php Define user permissions.
hook_ping developer/hooks/core.php Ping another server.
hook_prepare developer/hooks/node.php This is a hook used by node modules. It is called after load but before the node is shown on the add/edit form.
hook_search developer/hooks/core.php Define a custom search routine.
hook_search_preprocess developer/hooks/core.php Preprocess text for the search index.
hook_settings developer/hooks/core.php Declare administrative settings for a module.
hook_submit developer/hooks/node.php This is a hook used by node modules. It is called after validation has succeeded and before insert/update. It is used to for actions which must happen only if the node is to be saved. Usually, $node is changed in some way and then the actual saving of…
hook_taxonomy developer/hooks/core.php Act on taxonomy changes.
hook_update developer/hooks/node.php Respond to node updating.
hook_update_index developer/hooks/core.php Update Drupal's full-text index for this module.
hook_update_N developer/hooks/install.php Perform a single update. For each patch which requires a database change add a new hook_update_N() which will be called by update.php.
hook_user developer/hooks/core.php Act on user account actions.
hook_validate developer/hooks/node.php Verify a node editing form.
hook_view developer/hooks/node.php Display a node.
hook_xmlrpc developer/hooks/core.php Register XML-RPC callbacks.
module_hook includes/module.inc Determine whether a module implements a hook.
module_implements includes/module.inc Determine which modules are implementing a hook.
module_invoke includes/module.inc Invoke a hook in a particular module.
module_invoke_all includes/module.inc Invoke a hook in all enabled modules that implement it.