Contributions API

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().

Functions

Name	Location	Description
custom_url_rewrite_inbound	documentation/hooks/core.php	custom_url_rewrite_inbound is not a hook, it's a function you can add to settings.php to alter incoming requests so they map to a Drupal path. This function is called before modules are loaded and the menu system is initialized and it changes...
custom_url_rewrite_outbound	documentation/hooks/core.php	custom_url_rewrite_outbound is not a hook, it's a function you can add to settings.php to alter all links generated by Drupal. This function is called from url(). This function is called very frequently (100+ times per page) so performance...
hook_access	documentation/hooks/node.php	Define access restrictions.
hook_block	documentation/hooks/core.php	Declare a block or set of blocks.
hook_boot	documentation/hooks/core.php	Perform setup tasks. See also, hook_init.
hook_comment	documentation/hooks/core.php	Act on comments.
hook_cron	documentation/hooks/core.php	Perform periodic actions.
hook_db_rewrite_sql	documentation/hooks/core.php	Rewrite database queries, usually for access control.
hook_delete	documentation/hooks/node.php	Respond to node deletion.
hook_disable	documentation/hooks/install.php	Perform necessary actions before module is disabled.
hook_elements	documentation/hooks/core.php	Allows modules to declare their own Forms API element types and specify their default values.
hook_enable	documentation/hooks/install.php	Perform necessary actions after module is enabled.
hook_exit	documentation/hooks/core.php	Perform cleanup tasks.
hook_file_download	documentation/hooks/core.php	Allow file downloads.
hook_filter	documentation/hooks/core.php	Define content filters.
hook_filter_tips	documentation/hooks/core.php	Provide tips for using filters.
hook_footer	documentation/hooks/core.php	Insert closing HTML.
hook_form	documentation/hooks/node.php	Display a node editing form.
hook_forms	documentation/hooks/core.php	Map form_ids to builder functions.
hook_form_alter	documentation/hooks/core.php	Perform alterations before a form is rendered.
hook_help	documentation/hooks/core.php	Provide online user help.
hook_init	documentation/hooks/core.php	Perform setup tasks. See also, hook_boot.
hook_insert	documentation/hooks/node.php	Respond to node insertion.
hook_install	documentation/hooks/install.php	Install the current version of the database schema, and any other setup tasks.
hook_link	documentation/hooks/core.php	Define internal Drupal links.
hook_link_alter	documentation/hooks/core.php	Perform alterations before links on a node are rendered. One popular use of this hook is to add/delete links from other modules.
hook_load	documentation/hooks/node.php	Load node-type-specific information.
hook_mail	documentation/hooks/core.php	Prepare a message based on parameters. @see drupal_mail for more.
hook_mail_alter	documentation/hooks/core.php	Alter any aspect of the emails sent by Drupal. You can use this hook to add a common site footer to all outgoing emails; add extra header fields and/or modify the mails sent out in any way. HTML-izing the outgoing mails is one possibility. See also...
hook_menu	documentation/hooks/core.php	Define menu items and page callbacks.
hook_menu_alter	documentation/hooks/core.php	Alter the data being saved to the {menu_router} table after hook_menu is invoked.
hook_menu_link_alter	documentation/hooks/core.php	Alter the data being saved to the {menu_links} table by menu_link_save().
hook_nodeapi	documentation/hooks/core.php	Act on nodes defined by other modules.
hook_node_access_records	documentation/hooks/core.php	Set permissions for a node to be written to the database.
hook_node_grants	documentation/hooks/core.php	Inform the node access system what permissions the user has.
hook_node_info	documentation/hooks/node.php	Define module-provided node types.
hook_node_operations	documentation/hooks/core.php	Add mass node operations.
hook_node_type	documentation/hooks/node.php	Act on node type changes.
hook_perm	documentation/hooks/core.php	Define user permissions.
hook_ping	documentation/hooks/core.php	Ping another server.
hook_prepare	documentation/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_profile_alter	documentation/hooks/core.php	Perform alterations profile items before they are rendered. You may omit/add/re-sort/re-categorize, etc.
hook_requirements	documentation/hooks/install.php	Check installation requirements and do status reporting.
hook_schema	documentation/hooks/install.php	Define the current version of the database schema.
hook_search	documentation/hooks/core.php	Define a custom search routine.
hook_search_preprocess	documentation/hooks/core.php	Preprocess text for the search index.
hook_submit	documentation/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	documentation/hooks/core.php	Act on taxonomy changes.
hook_theme	documentation/hooks/core.php	Register a module (or theme's) theme implementations.
hook_translated_menu_link_alter	documentation/hooks/core.php	Alter a menu link after it's translated, but before it's rendered.
hook_uninstall	documentation/hooks/install.php	Remove any tables or variables that the module sets.
hook_update	documentation/hooks/node.php	Respond to node updating.
hook_update_index	documentation/hooks/core.php	Update Drupal's full-text index for this module.
hook_update_N	documentation/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	documentation/hooks/core.php	Act on user account actions.
hook_user_operations	documentation/hooks/core.php	Add mass user operations.
hook_validate	documentation/hooks/node.php	Verify a node editing form.
hook_view	documentation/hooks/node.php	Display a node.
hook_watchdog	documentation/hooks/core.php	Log an event message
hook_xmlrpc	documentation/hooks/core.php	Register XML-RPC callbacks.
module_hook	6/includes/module.inc	Determine whether a module implements a hook.
module_implements	6/includes/module.inc	Determine which modules are implementing a hook.
module_invoke	6/includes/module.inc	Invoke a hook in a particular module.
module_invoke_all	6/includes/module.inc	Invoke a hook in all enabled modules that implement it.
text_content_is_empty	contributions/cck/examples/simple_field.php	Implementation of hook_content_is_empty().
text_elements	contributions/cck/examples/example_field.php	Implementation of FAPI hook_elements().
text_field	contributions/cck/examples/simple_field.php	Implementation of hook_field().
text_field_formatter	contributions/cck/examples/simple_field.php	Implementation of hook_field_formatter().
text_field_formatter_info	contributions/cck/examples/simple_field.php	Implementation of hook_field_formatter_info().
text_field_info	contributions/cck/examples/simple_field.php	Implementation of hook_field_info().
text_field_settings	contributions/cck/examples/simple_field.php	Implementation of hook_field_settings().
text_textarea_process	contributions/cck/examples/example_field.php	Process an individual element.
text_textfield_process	contributions/cck/examples/example_field.php	Process an individual element.
text_theme	contributions/cck/examples/simple_field.php	Implementation of hook_theme().
text_widget	contributions/cck/examples/simple_field.php	Implementation of hook_widget().
text_widget_info	contributions/cck/examples/simple_field.php	Implementation of hook_widget_info().
text_widget_settings	contributions/cck/examples/simple_field.php	Implementation of hook_widget_settings().
theme_text_textfield	contributions/cck/examples/example_field.php	FAPI theme for an individual text elements.