WordPress ではプラグイン/テーマの開発者がカスタマイズを行えるようにするために、コアの関数に様々なアクション・フィルターフックが用意されています。ここでは WordPress で使えるアクション・フィルターフックの呼び出し元をまとめました。WordPress のバージョンは 5.1.1 です。

index.php

フロントエンドでの処理です。wp-load.php によるコアの起動後、テンプレートで呼び出した関数にフックされたアクション・フィルターが呼び出されます。

wp-blog-header.php

wp-load.php

フロントエンド、管理画面共通の処理です。wp-config.php があれば読み込み、なければ wp-admin/setup-config.php を読み込んで WordPress セットアップ画面を表示します。
ABSPATH

wp-config.php

DB_NAME, DB_USER, DB_PASSWORD, DB_HOST, DB_CHARSET, DB_COLLATE
AUTH_KEY, LOGGED_IN_KEY, NONCE_KEY, AUTH_SALT, SECURE_AUTH_SALT, LOGGED_IN_SALT, NONCE_SALT, WP_DEBUG

wp-settings.php

コアファイルの多くがこのファイルで読み込まれます。
global $wp_version, $wp_db_version, $tinymce_version, $required_php_version, $required_mysql_version, $wp_local_package
global $wpdb

wp-includes/functions.php

様々な場面で使用される関数群がここで読み込まれます。

wp_upload_dir()

apply_filters( 'upload_dir', $cache[ $key ] )
Filters the uploads directory data.
@since 2.0.0
メディアのアップロードディレクトリを変更することができます。例えばユーザーごとにディレクトリを分ける場合にはこのフィルターフックを利用します。

wp_get_mime_types()

apply_filters( 'mime_types', array( ... ) )
Filters the list of mime types and file extensions.
@since 3.5.0
メディアにアップロードできるファイルの種類を追加/制限することができます。

get_allowed_mime_types()

apply_filters( 'upload_mimes', $t, $user )
Filters list of allowed mime types and file extensions.
@since 2.0.0

wp_start_object_cache()

global $wp_filter

wp-includes/default-filters.php

デフォルトのアクション・フィルターフックが読み込まれます。
do_action( 'mu_plugin_loaded', $mu_plugin )
Fires once a single must-use plugin has loaded.
@since 5.1.0
do_action( 'muplugins_loaded' )
Fires once all must-use and network-activated plugins have loaded.
@since 2.8.0

wp-includes/vars.php

global $pagenow, $is_lynx, $is_gecko, $is_winIE, $is_macIE, $is_opera, $is_NS4, $is_safari, $is_chrome, $is_iphone, $is_IE, $is_edge, $is_apache, $is_IIS, $is_iis7, $is_nginx;
do_action( 'plugin_loaded', $plugin )
Fires once a single activated plugin has loaded.
@since 5.1.0
do_action( 'plugins_loaded' )
Fires once activated plugins have loaded.
@since 1.5.0
do_action( 'sanitize_comment_cookies' )
Fires when comment cookies are sanitized.
@since 2.0.11
$GLOBALS['wp_query']
$GLOBALS['wp_rewrite']
$GLOBALS['wp']
$GLOBALS['wp_roles']
do_action( 'setup_theme' )
Fires before the theme is loaded.
@since 2.6.0
$GLOBALS['wp_locale']

functions.php (child)

子テーマの functions.php はここで読み込まれます。

functions.php (parent)

子テーマに続いて親テーマの functions.php が読み込まれます。
do_action( 'after_theme_setup' )
Fires after the theme is loaded.
@since 3.0.0
do_action( 'init' )
Fires after WordPress has finished loading but before any headers are sent.
@since 1.5.0
wp-includes/defalt-filters.php で登録される create_initial_post_typescreate_initial_taxonomieswp_cronrest_api_init などはここで呼ばれます。
do_action( 'wp_loaded' )
This hook is fired once WP, all plugins, and the theme are fully loaded and instantiated.
@since 3.0.0

wp()

$wp->main()

$wp->parse_request()

apply_filters( 'do_parse_request', true, $this, $extra_query_vars )
Filters whether to parse the request.
@since 3.5.0
apply_filters( 'query_vars', $this->public_query_vars )
Filters the query variables whitelist before processing.
@since 1.5.0
apply_filters( 'request', $this->query_vars )
Filters the array of parsed query variables.
@since 2.1.0
do_action_ref_array( 'parse_request', array( &$this ) )
Fires once all query variables for the current request have been parsed.
@since 2.1.0

$wp->send_headers()

apply_filters( 'wp_headers', $headers, $this )
Filters the HTTP headers before they’re sent to the browser.
@since 2.8.0
do_action_ref_array( 'send_headers', array( &$this ) )
Fires once the requested HTTP headers for caching, content type, etc. have been sent.
@since 2.1.0

$wp->query_posts()

$wp->build_query_string()

apply_filters( 'query_string', $this->query_string )
Filters the query string before parsing.
@since 1.5.0

$wp_the_query->query( $this->query_vars )

$wp_query->get_posts()

$wp_query->parse_query()

do_action_ref_array( 'parse_query', array( &$this ) )
Fires after the main query vars have been parsed.
@since 1.5.0
do_action_ref_array( 'pre_get_posts', array( &$this ) )
Fires after the query variable object is created, but before the actual query is run.
@since 2.0.0
クエリ変数オブジェクトが生成されたときに呼び出されます。クエリ変数は用意されているのでその中身を見ることはできますが、実際にクエリは実行されていないので、投稿情報はもっていません。

if ( ! $q[‘suppress_filters’] )

apply_filters_ref_array( 'posts_search', array( $search, &$this ) )
Filters the search SQL that is used in the WHERE clause of WP_Query.
@since 3.0.0

if ( ! empty( $q[‘s’] ) )

apply_filters( 'posts_search_orderby', $search_orderby, $this )
Filters the ORDER BY used when ordering search results.
@since 3.7.0
apply_filters_ref_array( 'posts_where', array( $where, &$this ) )
Filters the WHERE clause of the query.
@since 1.5.0
apply_filters_ref_array( 'posts_join', array( $join, &$this ) )
Filters the JOIN clause of the query.
@since 1.5.0
apply_filters_ref_array( 'comment_feed_join', array( $cjoin, &$this ) )
Filters the JOIN clause of the comments feed query before sending.
@since 2.2.0
apply_filters_ref_array( 'comment_feed_where', array( $cwhere, &$this ) )
Filters the WHERE clause of the comments feed query before sending.
@since 2.2.0
apply_filters_ref_array( 'comment_feed_groupby', array( $cgroupby, &$this ) )
Filters the GROUP BY clause of the comments feed query before sending.
@since 2.2.0
apply_filters_ref_array( 'comment_feed_orderby', array( 'comment_date_gmt DESC', &$this ) )
Filters the ORDER BY clause of the comments feed query before sending.
@since 2.8.0
apply_filters_ref_array( 'comment_feed_limits', array( 'LIMIT ' . get_option( 'posts_per_rss' ), &$this ) )
Filters the LIMIT clause of the comments feed query before sending.
@since 2.8.0
apply_filters_ref_array( 'posts_where_paged', array( $where, &$this ) )
Filters the WHERE clause of the query.
@since 1.5.0
apply_filters_ref_array( 'posts_groupby', array( $groupby, &$this ) )
Filters the GROUP BY clause of the query.
@since 2.0.0
apply_filters_ref_array( 'posts_join_paged', array( $join, &$this ) )
Filters the JOIN clause of the query.
@since 1.5.0
apply_filters_ref_array( 'posts_orderby', array( $orderby, &$this ) )
Filters the ORDER BY clause of the query.
@since 1.5.1
apply_filters_ref_array( 'posts_distinct', array( $distinct, &$this ) )
Filters the DISTINCT clause of the query.
since 2.1.0
apply_filters_ref_array( 'post_limits', array( $limits, &$this ) )
Filters the LIMIT clause of the query.
@since 2.1.0
apply_filters_ref_array( 'posts_fields', array( $fields, &$this ) )
Filters the SELECT clause of the query.
@since 2.1.0
apply_filters_ref_array( 'posts_clauses', array( compact( $pieces ), &$this ) )
Filters all query clauses at once, for convenience.
@since 3.1.0
do_action( 'posts_selection', $where . $groupby . $orderby . $limits . $join )
Fires to announce the query’s current selection parameters.
@since 2.3.0
データベースから投稿を取得するための選択クエリが準備できたときに呼び出されます。投稿情報はまだ取得されていないため、グローバル変数 $post はセットされていません。

if ( ! $q[‘suppress_filters’] )

apply_filters_ref_array( 'posts_where_request', array( $where, &$this ) )
Filters the WHERE clause of the query.
For use by caching plugins.
@since 2.5.0
apply_filters_ref_array( 'posts_groupby_request', array( $groupby, &$this ) )
Filters the GROUP BY clause of the query.
For use by caching plugins.
@since 2.5.0
apply_filters_ref_array( 'posts_join_request', array( $join, &$this ) )
Filters the JOIN clause of the query.
For use by caching plugins.
@since 2.5.0
apply_filters_ref_array( 'posts_orderby_request', array( $orderby, &$this ) )
Filters the ORDER BY clause of the query.
For use by caching plugins.
@since 2.5.0
apply_filters_ref_array( 'posts_distinct_request', array( $distinct, &$this ) )
Filters the DISTINCT clause of the query.
For use by caching plugins.
@since 2.5.0
apply_filters_ref_array( 'posts_fields_request', array( $fields, &$this ) )
Filters the SELECT clause of the query.
For use by caching plugins.
@since 2.5.0
apply_filters_ref_array( 'post_limits_request', array( $limits, &$this ) )
Filters the LIMIT clause of the query.
For use by caching plugins.
@since 2.5.0
apply_filters_ref_array( 'posts_clauses_request', array( compact( $pieces ), &$this ) )
Filters all query clauses at once, for convenience.
For use by caching plugins.
@since 3.1.0
apply_filters_ref_array( 'posts_request', array( $this->request, &$this ) )
Filters the completed SQL query before sending.
@since 2.0.0
apply_filters_ref_array( 'posts_pre_query', array( null, &$this ) )
Filters the posts array before the query takes place.Return a non-null value to bypass WordPress’s default post queries.
Filtering functions that require pagination information are encouraged to set the `found_posts` and `max_num_pages` properties of the WP_Query object, passed to the filter by reference. If WP_Query does not perform a database query, it will not have enough information to generate these values itself.
@since 4.6.0

$wp->handle_404()

apply_filters( 'pre_handle_404', false, $wp_query )
Filters whether to short-circuit default header status handling.
@since 4.5.0

$wp->register_globals()

$GLOBALS['query_string'], $GLOBALS['posts'], $GLOBALS['post'], $GLOBALS['request']
do_action_ref_array( 'wp', array( &$this ) )
Fires once the WordPress environment has been set up.
@since 2.1.0

wp-includes/template-loader.php

do_action( 'template_redirect' )
Fires before determining which template to load.
@since 1.5.0
do_action( 'do_robots' )
Fired when the template loader determines a robots.txt request.
@since 2.1.0
wp-includes/default-filters.php で登録された、wp-includes/functions.php で定義されている do_robots 関数が呼び出されます。

do_robots()

do_action( 'do_robotstxt' )
Fires when displaying the robots.txt file.
@since 2.1.0
apply_filters( 'robots_txt', $output, $public )
Filters the robots.txt output.
@since 3.0.0
apply_filters( 'exit_on_http_head', true )
Filters whether to allow ‘HEAD’ requests to generate content.
@since 3.5.0

if ( is_robots() )

do_action( 'do_robots' )
Fired when the template loader determines a robots.txt request.
@since 2.1.0
apply_filters( 'template_include', $template )
Filters the path of the current template before including it.
@since 3.0.0

include( $template )

get_header( $name = null )

do_action( 'get_header', $name )
Fires before the header template file is loaded.
@since 2.8.0

get_template_part( $slug, $name = null )

do_action( "get_template_part_{$slug}", $slug, $name )
Fires before the specified template part file is loaded.

get_search_form( $echo = true )

do_action( 'pre_get_search_form' )
Fires before the search form is retrieved, at the start of get_search_form().
@since 3.6.0
apply_filters( 'search_form_format', $format )
Filters the HTML format of the search form.
@since 3.6.0
apply_filters( 'get_search_form', $form )
Filters the HTML output of the search form.
@since 2.7.0

wp_loginout( $redirect = ”, $echo = true )

apply_filters( 'loginout', $link )
Filters the HTML output for the Log In/Log Out link.
@since 1.5.0

wp_logout_url( $redirect = ” )

apply_filters( 'logout_url', $logout_url, $redirect )
Filters the logout URL.
@since 2.8.0

wp_login_url( $redirect = ”, $force_reauth = false )

apply_filters( 'login_url', $login_url, $redirect, $force_reauth )
Filters the login URL.
@since 4.2.0

wp_registration_url()

apply_filters( 'register_url', site_url( 'wp-login.php?action=register', 'login' ) )
Returns the URL that allows the user to register on the site.
@since 3.6.0

wp_login_form( $args = array() )

apply_filters( 'login_form_defaults', $defaults )
Filters the default login form output arguments.
@since 3.0.0
apply_filters( 'login_form_top', '', $args )
Filters content to display at the top of the login form.
@since 3.0.0
apply_filters( 'login_form_middle', '', $args )
Filters content to display in the middle of the login form.
@since 3.0.0
apply_filters( 'login_form_bottom', '', $args )
Filters content to display at the bottom of the login form.
@since 3.0.0

wp_lostpassword_url( $redirect = ” )

apply_filters( 'lostpassword_url', $lostpassword_url, $redirect )
Filters the Lost Password URL.
@since 2.8.0

wp_register( $before = ‘<li>’, $after = ‘</li>’, $echo = true )

apply_filters( 'register', $link )
Filters the HTML link to the Registration or Admin page.
@since 1.5.0

wp_meta()

do_action( 'wp_meta' )
Fires before displaying echoed content in the sidebar.
@since 1.5.0

get_sidebar()

do_action( 'get_sidebar', $name )
Fires before the sidebar template file is loaded.
@since 2.8.0

get_footer( $name = null )

do_action( 'get_footer', $name )
Fires before the footer template file is loaded.
@since 2.8.0

wp-admin/index.php

管理画面のトップ(ダッシュボード)での処理です。wp-load.php によるコアの起動後、管理画面の処理に必要な各種 API が呼び出されます。ここにフックされているアクション・フィルターフックを用いることで、細かなカスタマイズが可能になります。

wp-admin/admin.php

WP_ADMIN, WP_NETWORK_ADMIN, WP_USER_ADMIN, WP_BLOG_ADMIN, WP_LOAD_IMPORTERS

wp-load.php

nocache_headers()

do_action( 'after_db_upgrade' )
Fires on the next page load after a successful DB upgrade.
@since 2.8.0

wp-admin/includes/admin.php

admin での多くの API が読み込まれます。

wp-admin/includes/admin-filters.php

wp-admin/includes/bookmark.php

wp-admin/includes/comment.php

wp-admin/includes/file.php

wp-admin/includes/image.php

wp-admin/includes/media.php

wp-admin/includes/import.php

wp-admin/includes/misc.php

wp-admin/includes/options.php

wp-admin/includes/plugin.php

wp-admin/includes/post.php

wp-admin/includes/class-wp-screen.php

wp-admin/includes/screen.php

wp-admin/includes/taxonomy.php

wp-admin/includes/template.php

wp-admin/includes/class-wp-list-table.php

apply_filters( "views_{$this->screen->id}", $views )
Filters the list of available list table views.
@since 3.5.0
投稿等の一覧画面での見出し下の「すべて」「所有」「公開済み」「下書き」「ゴミ箱」などの表示/非表示を制御することができます。
apply_filters( "bulk_actions-{$this->screen->id}", $this->_actions )
Filters the list table Bulk Actions drop-down.
@since 3.5.0
apply_filters( 'disable_months_dropdown', false, $post_type )
Filters whether to remove the ‘Months’ drop-down from the post list table.
@since 4.2.0
apply_filters( 'months_dropdown_results', $months, $post_type )
Filters the ‘Months’ drop-down results.
@since 3.7.0
apply_filters( "{$option}", $per_page )
Filters the number of items to be displayed on each page of the list table.
@since 2.9.0
apply_filters( 'list_table_primary_column', $default, $this->screen->id )
Filters the name of the primary column for the current list table.
@since 4.3.0
apply_filters( "manage_{$this->screen->id}_sortable_columns", $sortable_columns )
Filters the list table sortable columns for a specific screen.
@since 3.5.0

wp-admin/includes/class-wp-list-table-compat.php

wp-admin/includes/list-table.php

wp-admin/includes/theme.php

wp-admin/includes/user.php

wp-admin/includes/class-wp-site-icon.php

wp-admin/includes/update.php

auth_redirect()

set_screen_options()

wp_enqueue_script( 'common' )

wp-admin/menu.php

管理者ページでのメニューがここでセットされます。
@global array $menu

wp-admin/includes/menu.php

do_action( 'admin_menu', '' )
Fires before the administration menu loads in the admin.
@since 1.5.0
管理ページでメニューが読み込まれる前に発火します。メニュー項目を変更する場合はこのアクションを利用してグローバル変数 $menu に変更を加えてください。
apply_filters( 'custom_menu_order', false )
Filters whether to enable custom ordering of the administration menu.
@since 2.8.0
do_action( 'admin_init' )
Fires as an admin screen or script is being initialized.
@since 2.5.0
管理画面とスクリプトが初期化されたタイミングで発火します。このアクションは admin-ajax.php / admin-post.php でも発火します。

set_current_screen

if ( isset( $plugin_page ) )

if ( $page_hook )

do_action( "load-{$page_hook}" )
Fires before a particular screen is loaded.
The load-* hook fires in a number of contexts. This hook is for plugin screens where a callback is provided when the screen is registered.
@since 2.1.0

wp-admin/admin-header.php

do_action( $page_hook )
Used to call the registered callback for a plugin screen.
@since 1.5.0

else

do_action( "load-{$plugin_page}" )
Fires before a particular screen is loaded.
The load-* hook fires in a number of contexts. This hook is for plugin screens where the file to load is directly included, rather than the use of a function.
@since 1.5.0

wp-admin/admin-header.php

include( WP_PLUGIN_DIR . “/$plugin_page” )

wp-admin/admin-footer.php

else

do_action( "load-{$pagenow}" )
Fires before a particular screen is loaded.
The load-* hook fires in a number of contexts. This hook is for core screens.
@since 2.1.0
do_action( "admin_action_{$action}" )
Fires when an ‘action’ request variable is sent.
The dynamic portion of the hook name, `$action`, refers to the action derived from the `GET` or `POST` request.
@since 2.6.0

wp-admin/includes/dashboard.php

wp_dashboard_setup 等の定義

wp_dashboard_setup()

global $wp_registered_widgets, $wp_registered_widget_controls, $wp_dashboard_control_callbacks;
do_action( 'wp_dashboard_setup' )
Fires after core widgets for the admin dashboard have been registered.
@since 2.5.0
apply_filters( 'wp_dashboard_widgets', array() )
Filters the list of widgets to load for the admin dashboard.
@since 2.5.0

wp_add_dashboard_widget

登録されるウィジェットごとに呼び出されます。ウィジェットを完全に非表示にするには、$widget_id ごとに wp_add_dashboard_widget( $widget_id, $widget_name, $callback, $control_callback = null, $callback_args = null ) に空の無名関数を $callback に渡して上書きし、さらに remove_meta_box を呼び出します。

add_meta_box

do_action( 'do_meta_boxes', $screen->id, 'normal', '' )
Fires after meta boxes have been added.
do_action( 'do_meta_boxes', $screen->id, 'side', '' )
wp_enqueue_script( 'dashboard' )
wp_enqueue_script( 'plugin-install' )
wp_enqueue_script( 'updates' )
wp_enqueue_script( 'media-upload' )

add_thickbox()

wp_enqueue_script( 'jquery-touch-punch' )

get_current_screen()

wp-admin/admin-header.php

global $title, $hook_suffix, $current_screen, $wp_locale, $pagenow, $update_title, $total_update_count, $parent_file;
apply_filters( 'admin_title', $admin_title, $title )
Filters the title tag content for an admin page.
@since 3.1.0
do_action( 'admin_enqueue_scripts', $hook_suffix )
Enqueue scripts for all admin pages.
@since 2.8.0
do_action( "admin_print_styles-{$hook_suffix}" )
Fires when styles are printed for a specific admin page based on $hook_suffix.
@since 2.6.0
do_action( 'admin_print_styles' )
Fires when styles are printed for all admin pages.
@since 2.6.0
do_action( "admin_print_scripts-{$hook_suffix}" )
Fires when scripts are printed for a specific admin page based on $hook_suffix.
@since 2.1.0
do_action( 'admin_print_scripts' )
Fires when scripts are printed for all admin pages.
@since 2.1.0
do_action( "admin_head-{$hook_suffix}" )
Fires in head article for a specific admin page.
@since 2.1.0
do_action( 'admin_head' )
Fires in head article for all admin pages.
@since 2.1.0
apply_filters( 'admin_body_class', '' )
Filters the CSS classes for the body tag in the admin.
@since 2.3.0

wp-admin/menu-header.php

apply_filters( 'submenu_file', $submenu_file, $parent_file )
@since 4.4.0
Filters the file of an admin menu sub-menu item.
do_action( 'adminmenu' )
Fires after the admin menu has been output.
@since 2.3.0
do_action( 'in_admin_header' )
Fires at the beginning of the content article in an admin page.
@since 3.0.0
do_action( 'admin_notices' )
Prints admin screen notices.
@since 3.1.0
do_action( 'all_admin_notices' )
Prints generic admin screen notices.
@since 3.1.0
do_action( 'welcome_panel' )
Add content to the welcome panel on the admin dashboard.
To remove the default welcome panel, use remove_action():
remove_action( ‘welcome_panel’, ‘wp_welcome_panel’ );
@since 3.5.0

wp_dashboard()

wp-admin/admin-footer.php

do_action( 'in_admin_footer' )
Fires after the opening tag for the admin footer.
@since 2.5.0
apply_filters( 'admin_footer_text', '<span id="footer-thankyou">' . $text . '</span>' )
Filters the “Thank you” text displayed in the admin footer.
@since 2.8.0
apply_filters( 'update_footer', '' )
Filters the version/update text displayed in the admin footer.
@since 2.3.0
do_action( 'admin_footer', '' )
Prints scripts or data before the default footer scripts.
@since 1.2.0
do_action( "admin_print_footer_scripts-{$hook_suffix}" )
Prints scripts and data queued for the footer.
@since 4.6.0
do_action( 'admin_print_footer_scripts' )
Prints any scripts and data queued for the footer.
@since 2.8.0
do_action( "admin_footer-{$hook_suffix}" )
Prints scripts or data after the default footer scripts.
@since 2.8.0

wp-admin/edit.php

管理ページの投稿/固定ページ/カスタム投稿タイプ一覧画面での処理です。wp-admin/admin.php による管理ページの初期化後に投稿/固定ページ/カスタム投稿タイプ一覧を表示するためのテーブルが用意されます。

wp-admin/admin.php

global $post_type, $post_type_object

_get_list_table( ‘WP_Posts_List_Table’ )

WP_List_Table を継承した WP_Posts_List_Table クラスがインスタンス化されます。これで投稿/固定ページ/カスタム投稿タイプ一覧のテーブルが表示されます。
apply_filters( 'edit_posts_per_page', $per_page, $post_type )
apply_filters( 'disable_categories_dropdown', false, $post_type )
Filters whether to remove the ‘Categories’ drop-down from the post list table.
@since 4.6.0
do_action( 'restrict_manage_posts', $this->screen->post_type, $which )
Fires before the Filter button on the Posts and Pages list tables.
@since 2.1.0
do_action( 'manage_posts_extra_tablenav', $which )
Fires immediately following the closing “actions” div in the tablenav for the posts list table.
@since 4.4.0
apply_filters( "manage_taxonomies_for_{$post_type}_columns", $taxonomies, $post_type )
Filters the taxonomy columns in the Posts list table.
@since 3.5.0

if ( ‘page’ === $post_type )

apply_filters( 'manage_pages_columns', $posts_columns )
Filters the columns displayed in the Pages list table.
@since 2.5.0
固定ページの一覧テーブルにカラムを追加したい場合は、ここで $posts_columns['eyecatch'] = __( 'Eyecatch' ); のように配列の固有なキーにカラム名を追加します。

else

apply_filters( 'manage_posts_columns', $posts_columns, $post_type )
Filters the columns displayed in the Posts list table.
@since 1.5.0
投稿の一覧テーブルにカラムを追加したい場合は、ここで $posts_columns['eyecatch'] = __( 'Eyecatch' ); のように配列の固有なキーにカラム名を追加します。
apply_filters( "manage_{$post_type}_posts_columns", $posts_columns )
Filters the columns displayed in the Posts list table for a specific post type.
@since 3.0.0
カスタム投稿タイプの一覧テーブルにカラムを追加したい場合は、ここで $posts_columns['eyecatch'] = __( 'Eyecatch' ); のように配列の固有なキーにカラム名を追加します。
apply_filters( 'the_title', $parent->post_title, $parent->ID )
apply_filters( 'post_date_column_status', $status, $post, 'date', $mode )
Filters the status text of the post.
@since 4.8.0
apply_filters( 'post_date_column_time', $t_time, $post, 'date', $mode )
Filters the published time of the post.
@since 2.5.1

if ( is_post_type_hierarchical( $post->post_type ) )

do_action( 'manage_pages_custom_column', $column_name, $post->ID )
Fires in each custom column on the Posts list table.
@since 2.5.0
固定ページで一覧テーブルのカラムを追加した場合に、ここで表示させるべき情報を echo させます。

else

do_action( 'manage_posts_custom_column', $column_name, $post->ID )
Fires in each custom column in the Posts list table.
@since 1.5.0
投稿で一覧テーブルのカラムを追加した場合に、ここで表示させるべき情報を echo させます。
do_action( "manage_{$post->post_type}_posts_custom_column", $column_name, $post->ID )
Fires for each custom column of a specific post type in the Posts list table.
@since 3.1.0
カスタム投稿タイプで一覧テーブルのカラムを追加した場合に、ここで表示させるべき情報を echo させます。

if ( is_post_type_hierarchical( $post->post_type ) )

apply_filters( 'page_row_actions', $actions, $post )
Filters the array of row action links on the Pages list table.
@since 2.8.0

else

apply_filters( 'post_row_actions', $actions, $post )
Filters the array of row action links on the Posts list table.
@since 2.8.0
apply_filters( 'quick_edit_show_taxonomy', $show_in_quick_edit, $taxonomy_name, $screen->post_type )
Filters whether the current taxonomy should be shown in the Quick Edit panel.
@since 4.2.0
apply_filters( 'quick_edit_dropdown_pages_args', $dropdown_args )
Filters the arguments used to generate the Quick Edit page-parent drop-down.
@since 2.7.0
apply_filters( 'default_page_template_title', __( 'Default Template' ), 'quick-edit' )

if ( $bulk )

do_action( 'bulk_edit_custom_box', $column_name, $screen->post_type )
Fires once for each column in Bulk Edit mode.
@since 2.7.0

else

do_action( 'quick_edit_custom_box', $column_name, $screen->post_type, '' )
Fires once for each column in Quick Edit mode.
@since 2.7.0

wp-admin/admin-header.php

wp-admin/admin-footer.php

wp-admin/post.php

管理ページの投稿/固定ページ/カスタム投稿タイプ編集画面での処理です。wp-admin/admin.php による管理ページの初期化後に投稿/固定ページ/カスタム投稿タイプの編集画面が表示されます。

wp-admin/admin.php

global $post_type, $post_type_object, $post

switch ( $action )

case ‘edit’:

apply_filters( 'replace_editor', false, $post ) === true )
Allows replacement of the editor.
@since 4.9.0

wp-admin/edit-form-advanced.php

apply_filters( 'post_updated_messages', $messages )
Filters the post updated messages.
@since 3.0.0

wp-admin/admin-header.php

do_action( 'post_edit_form_tag', $post )
Fires inside the post editor form tag.
@since 3.0.0
do_action( 'edit_form_top', $post )
Fires at the beginning of the edit form.
@since 3.7.0
apply_filters( 'enter_title_here', __( 'Enter title here' ), $post )
Filters the title field placeholder text.
@since 3.1.0
do_action( 'edit_form_before_permalink', $post )
Fires before the permalink field in the edit form.
@since 4.1.0
do_action( 'edit_form_after_title', $post )
Fires after the title field.
@since 3.5.0
do_action( 'edit_form_after_editor', $post )
Fires after the content editor.
@since 3.5.0

if ( ‘page’ == $post_type )

do_action( 'submitpage_box', $post )
Fires before meta boxes with ‘side’ context are output for the ‘page’ post type.
@since 2.5.0
do_action( 'edit_page_form', $post )
Fires after ‘normal’ context meta boxes have been output for the ‘page’ post type.
@since 1.5.0

else

do_action( 'submitpost_box', $post )
Fires before meta boxes with ‘side’ context are output for all post types other than ‘page’.
@since 2.5.0
do_action( 'edit_form_advanced', $post )
Fires after ‘normal’ context meta boxes have been output for all post types other than ‘page’.
@since 1.5.0
do_action( 'dbx_post_sidebar', $post )
Fires after all meta box sections have been output, before the closing #post-body div.
@since 2.1.0

wp-admin/admin-footer.php

wp-admin/users.php

ユーザー一覧画面での処理です。wp-admin/admin.php による管理ページの初期化後にユーザー一覧を表示するためのテーブルが用意されます。

wp-admin/admin.php

_get_list_table( ‘WP_Users_List_Table’ )

WP_List_Table を継承した WP_Users_List_Table クラスがインスタンス化されます。これでユーザー一覧のテーブルが表示されます。

wp-admin/screen.php

apply_filters( "manage_{$screen->id}_columns", array() )
Filters the column headers for a list table on a specific screen.
@since 3.0.0
ユーザー一覧テーブルにカラムを追加する場合は、ユニークなキー名、値がカラム名になるように配列に追加します。
apply_filters( 'users_list_table_query_args', $args )
Filters the query arguments used to retrieve users for the current users list table.
@since 4.4.0
apply_filters( 'user_row_actions', $actions, $user_object )
Filters the action links displayed under each user in the Users list table.
@since 2.8.0
apply_filters( 'manage_users_custom_column', '', $column_name, $user_object->ID )
Filters the display output of custom columns in the Users list table.
@since 2.8.0
ユーザー一覧テーブルにカラムを追加する場合は、ここで出力内容を返します。
apply_filters( 'get_role_list', $role_list, $user_object )
Filters the returned array of roles for a user.
@since 4.4.0

wp-admin/admin-header.php

wp-admin/admin-footer.php

wp-admin/user-new.php

新規ユーザー追加画面での処理です。

wp-admin/admin.php

wp-admin/admin-header.php

if ( current_user_can( ‘create_users’ ) )

do_action( 'user_new_form_tag' )
Fires inside the adduser form tag.
@since 3.0.0
do_action( 'user_new_form', 'add-new-user' )
Fires at the end of the new user form.
@since 3.7.0

wp-admin/admin-footer.php

wp-admin/user-edit.php

ユーザー編集画面での処理です。

wp-admin/admin.php

wp_enqueue_script( 'user-profile' )

switch ( $action )

case ‘update’:

edit_user( $user_id )

wp_insert_user( $user )

apply_filters( 'wp_pre_insert_user_data', $data, $update, $update ? (int) $ID : null )
Filters user data before the record is created or updated.
@since 4.9.0
apply_filters( 'insert_user_meta', $meta, $user, $update )
Filters a user’s meta values and keys immediately after the user is created or updated and before any user meta is inserted or updated.
@since 4.4.0
ユーザーに追加の属性を付与したい場合には、user_new_form / show_user_profile / edit_user_profile で入力欄等を用意し、このフィルターの $meta 配列にキーと値を追加します。

if ( $update )

do_action( 'profile_update', $user_id, $old_user_data )
Fires immediately after an existing user is updated.
@since 2.0.0

else

do_action( 'user_register', $user_id )
Fires immediately after a new user is registered.
@since 1.5.0

if ( IS_PROFILE_PAGE )

do_action( 'show_user_profile', $profileuser )
* Fires after the ‘About Yourself’ settings table on the ‘Your Profile’ editing screen. The action only fires if the current user is editing their own profile.
@since 2.0.0
ユーザーに属性を追加したい場合はここでフォーム入力欄を用意します。

else

do_action( 'edit_user_profile', $profileuser )
Fires after the ‘About the User’ settings table on the ‘Edit User’ screen.
@since 2.0.0
ユーザーに属性を追加したい場合はここでフォーム入力欄を用意します。

wp-admin/admin-footer.php

wp-login.php

ログイン画面での処理です。ログイン画面のカスタマイズを行う場合はここで呼び出されるアクション・フィルターフックを利用します。

wp-load.php

nocache_headers()

do_action( 'login_init' )
Fires when the login form is initialized.
@since 3.2.0
do_action( "login_form_{$action}" )
Fires before a specified login form action.
@since 2.8.0
apply_filters( 'login_link_separator', ' | ' )
Filters the separator used between login form navigation links.
@since 4.9.0
apply_filters( 'login_redirect', $redirect_to, $requested_redirect_to, $user )
Filters the login redirect URL.
@since 3.0.0

login_header()

apply_filters( 'login_title', $login_title, $title )
Filters the title tag content for login page.
@since 4.9.0
do_action( 'login_enqueue_scripts' )
Enqueue scripts and styles for the login page.
@since 3.1.0
do_action( 'login_head' )
Fires in the login page header after scripts are enqueued.
@since 2.1.0
apply_filters( 'login_headerurl', $login_header_url )
Filters link URL of the header logo above login form.
@since 2.1.0
apply_filters( 'login_headertitle', $login_header_title )
Filters the title attribute of the header logo above login form.
@since 2.1.0
apply_filters( 'login_body_class', $classes, $action )
Filters the login page body classes.
@since 3.5.0
do_action( 'login_header' )
Fires in the login page header after the body tag is opened.
@since 4.6.0
apply_filters( 'login_message', $message )
Filters the message to display above the login form.
@since 2.1.0
do_action( 'login_form' )
Fires following the ‘Password’ field in the login form.
@since 2.1.0

login_footer()

do_action( 'login_footer' )
Fires in the login page footer.
@since 3.1.0

wp-admin/admin-ajax.php

DOING_AJAX, WP_ADMIN

wp-load.php

wp-admin/includes/admin.php

wp-admin/includes/ajax-actions.php

do_action( 'admin_init' )

if ( is_user_logged_in() )

do_action( "wp_ajax_{$action}" )
Fires authenticated Ajax actions for logged-in users.
The dynamic portion of the hook name, `$action`, refers to the name of the Ajax action callback being fired.
@since 2.1.0

コアで用意されている wp_ajax_{$action}

$action = 'query-attachments'

wp_ajax_query_attachments

apply_filters( 'ajax_query_attachments_args', $query )
Filters the arguments passed to WP_Query during an Ajax call for querying attachments.
@since 3.7.0
メディアに表示させる添付ファイルを取得するためのクエリを変更することができます。例えばユーザー自身がアップロードしたファイルだけをメディアに表示させる場合はこのフィルターにフックさせます。

else

do_action( "wp_ajax_nopriv_{$action}" )
Fires non-authenticated Ajax actions for logged-out users.
The dynamic portion of the hook name, `$action`, refers to the name of the Ajax action callback being fired.
@since 2.8.0