This article contains an extensive (but not 100% comprehensive) list of the filter hooks available for use in plugin development in Version 2.1 and above of WordPress. For more information:<\/p>\n\n\n\n
Note: If you want to add to or clarify this documentation, please follow the style of the existing entries. Describe what data the filter is applied to, and if the filter function takes additional arguments, describe the argument list.<\/p>\n\n\n\n
See also #Category and Term Filters<\/a>, #Author and User Filters<\/a>, #Link Filters<\/a>, #Date and Time Filters<\/a>, and #Administrative Filters<\/a> below.<\/p>\n\n\n\n Filters in this section are applied to information read from the attachment_fields_to_edit<\/a> : applied to the form fields to be displayed when editing an attachment. Called in the attachment_icon<\/a> : applied to the icon for an attachment in the attachment_innerHTML<\/a> : applied to the title to be used for an attachment if there is no icon, in the author_edit_pre<\/a> : applied to post author prior to display for editing.<\/p>\n\n\n\n body_class<\/a> : applied to the classes for the HTML<\/p>\n\n\n\n content_edit_pre<\/a> : applied to post content prior to display for editing.<\/p>\n\n\n\n content_filtered_edit_pre<\/a> : applied to post content filtered prior to display for editing.<\/p>\n\n\n\n excerpt_edit_pre<\/a> : applied to post excerpt prior to display for editing.<\/p>\n\n\n\n date_edit_pre<\/a> : applied to post date prior to display for editing.<\/p>\n\n\n\n date_gmt_edit_pre<\/a> : applied to post date prior to display for editing.<\/p>\n\n\n\n get_attached_file<\/a> : applied to the attached file information retrieved by the get_enclosed<\/a> : applied to the enclosures list for a post by the get_pages<\/a> : applied to the list of pages returned by the get_pung<\/a> : applied to the list of pinged URLs for a post by the get_the_archive_title<\/a> : applied to the archive’s title in the get_the_excerpt<\/a> : applied to the post’s excerpt in the get_the_guid<\/a> : applied to the post’s GUID in the get_to_ping<\/a> : applied to the list of URLs to ping for a post by the icon_dir<\/a> : applied to the template’s image directory in several functions. Basically allows a plugin to specify that icons for MIME types should come from a different location.<\/p>\n\n\n\n icon_dir_uri<\/a> : applied to the template’s image directory URI in several functions. Basically allows a plugin to specify that icons for MIME types should come from a different location.<\/p>\n\n\n\n image_size_names_choose<\/a> : applied to the list of image sizes selectable in the Media Library. Commonly used to make custom image sizes<\/a> selectable.<\/p>\n\n\n\n mime_type_edit_pre<\/a> : applied to post mime type prior to display for editing.<\/p>\n\n\n\n modified_edit_pre<\/a> : applied to post modification date prior to display for editing.<\/p>\n\n\n\n modified_gmt_edit_pre<\/a> : applied to post modification gmt date prior to display for editing.<\/p>\n\n\n\n no_texturize_shortcodes<\/a> : applied to registered shortcodes. Can be used to exempt shortcodes from the automatic texturize function.<\/p>\n\n\n\n parent_edit_pre<\/a> : applied to post parent id prior to display for editing.<\/p>\n\n\n\n password_edit_pre<\/a> : applied to post password prior to display for editing.<\/p>\n\n\n\n post_class<\/a> : applied to the classes of the outermost HTML element for a post. Called in the pre_kses<\/a> : applied to various content prior to being processed\/sanitized by KSES. This hook allows developers to customize what types of scripts\/tags should either be allowed in content or stripped.<\/p>\n\n\n\n prepend_attachment<\/a> : applied to the HTML to be prepended by the protected_title_format<\/a> : Used to the change or manipulate the post title when the post is password protected.<\/p>\n\n\n\n private_title_format<\/a> : Used to the change or manipulate the post title when its status is private. single_post_title<\/a> : applied to the post title when used to create a blog page title by the status_edit_pre<\/a> : applied to post status prior to display for editing.<\/p>\n\n\n\n the_content<\/a> : applied to the post content retrieved from the database, prior to printing on the screen (also used in some other operations, such as trackbacks).<\/p>\n\n\n\n the_content_rss<\/a> : applied to the post content prior to including in an RSS feed. (Deprecated)<\/p>\n\n\n\n the_content_feed<\/a> : applied to the post content prior to including in an RSS feed.<\/p>\n\n\n\n the_editor_content<\/a> : applied to post content before putting it into a rich editor window.<\/p>\n\n\n\n the_excerpt<\/a> : applied to the post excerpt (or post content, if there is no excerpt) retrieved from the database, prior to printing on the screen (also used in some other operations, such as trackbacks).<\/p>\n\n\n\n the_excerpt_rss<\/a> : applied to the post excerpt prior to including in an RSS feed.<\/p>\n\n\n\n the_password_form<\/a> : applied to the password form for protected posts.<\/p>\n\n\n\n the_tags<\/a> : applied to the tags retrieved from the database, prior to printing on the screen.<\/p>\n\n\n\n the_title<\/a> : applied to the post title retrieved from the database, prior to printing on the screen (also used in some other operations, such as trackbacks).<\/p>\n\n\n\n the_title_rss<\/a> : applied to the post title before including in an RSS feed (after first filtering with title_edit_pre<\/a> : applied to post title prior to display for editing.<\/p>\n\n\n\n type_edit_pre<\/a> : applied to post type prior to display for editing.<\/p>\n\n\n\n wp_dropdown_pages<\/a> : applied to the HTML dropdown list of WordPress pages generated by the wp_list_pages<\/a> : applied to the HTML list generated by the wp_list_pages_excludes<\/a> : applied to the list of excluded pages (an array of page IDs) in the wp_get_attachment_metadata<\/a> : applied to the attachment metadata retrieved by the wp_get_attachment_thumb_file<\/a> : applied to the attachment thumbnail file retrieved by the wp_get_attachment_thumb_url<\/a> : applied to the attachment thumbnail URL retrieved by the wp_get_attachment_url<\/a> : applied to the attachment URL retrieved by the wp_mime_type_icon<\/a> : applied to the MIME type icon for an attachment calculated by the wp_title<\/a> : applied to the blog page title before sending to the browser in the Filters in this section are applied to information prior to saving to add_ping<\/a> : applied to the new value of the pinged field on a post when a ping is added, prior to saving the new information in the database.<\/p>\n\n\n\n attachment_fields_to_save<\/a> : applied to fields associated with an attachment prior to saving them in the database. Called in the attachment_max_dims<\/a> : applied to the maximum image dimensions before reducing an image size. Filter function input (and return value) is either false (if no maximum dimensions have been specified) or a two-item list (width, height).<\/p>\n\n\n\n category_save_pre<\/a> : applied to post category comma-separated list prior to saving it in the database (also used for attachments).<\/p>\n\n\n\n comment_status_pre<\/a> : applied to post comment status prior to saving it in the database (also used for attachments).<\/p>\n\n\n\n content_filtered_save_pre<\/a> : applied to filtered post content prior to saving it in the database (also used for attachments).<\/p>\n\n\n\n content_save_pre<\/a> : applied to post content prior to saving it in the database (also used for attachments).<\/p>\n\n\n\n excerpt_save_pre<\/a> : applied to post excerpt prior to saving it in the database (also used for attachments).<\/p>\n\n\n\n image_save_pre<\/a> (deprecated) : use jpeg_quality<\/a> (deprecated) : use name_save_pre<\/a> (Deprecated): applied to post name prior to saving it in the database (also used for attachments).<\/p>\n\n\n\n phone_content<\/a> : applied to the content of a post submitted by email, before saving.<\/p>\n\n\n\n ping_status_pre<\/a> : applied to post ping status prior to saving it in the database (also used for attachments).<\/p>\n\n\n\n post_mime_type_pre<\/a> : applied to the MIME type for an attachment prior to saving it in the database.<\/p>\n\n\n\n status_save_pre<\/a> : applied to post status prior to saving it in the database.<\/p>\n\n\n\n thumbnail_filename<\/a> : applied to the file name for the thumbnail when uploading an image.<\/p>\n\n\n\n title_save_pre<\/a> : applied to post title prior to saving it in the database (also used for attachments).<\/p>\n\n\n\n update_attached_file<\/a> : applied to the attachment information prior to saving in post metadata in the wp_create_thumbnail<\/a> (deprecated)<\/p>\n\n\n\n wp_delete_file<\/a> : applied to an attachment file name just before deleting.<\/p>\n\n\n\n wp_generate_attachment_metadata<\/a> : applied to the attachment metadata array before saving in the database.<\/p>\n\n\n\n wp_save_image_file<\/a> (deprecated) : use wp_thumbnail_creation_size_limit<\/a> : applied to the size of the thumbnail when uploading an image. Filter function arguments: max file size, attachment ID, attachment file name.<\/p>\n\n\n\n wp_thumbnail_max_side_length<\/a> : applied to the size of the thumbnail when uploading an image. Filter function arguments: image side max size, attachment ID, attachment file name.<\/p>\n\n\n\n wp_update_attachment_metadata<\/a> : applied to the attachment metadata just before saving in the See also #Author and User Filters<\/a>, #Link Filters<\/a>, #Date and Time Filters<\/a>, and #Administrative Filters<\/a> below.<\/p>\n\n\n\n Filters in this section are applied to information read from the comment_excerpt<\/a> : applied to the comment excerpt by the comment_flood_filter<\/a> : applied when someone appears to be flooding your blog with comments. Filter function arguments: already blocked (true\/false, whether a previous filtering plugin has already blocked it; set to true and return true to block this comment in a plugin), time of previous comment, time of current comment.<\/p>\n\n\n\n comment_post_redirect<\/a> : applied to the redirect location after someone adds a comment. Filter function arguments: redirect location, comment info array.<\/p>\n\n\n\n comment_text<\/a> : applied to the comment text before displaying on the screen by the comment_text_rss<\/a> : applied to the comment text prior to including in an RSS feed.<\/p>\n\n\n\n comments_array<\/a> : applied to the array of comments for a post in the comments_number<\/a> : applied to the formatted text giving the number of comments generated by the get_comment_excerpt<\/a> : applied to the comment excerpt read from the database by the get_comment_ID<\/a> : applied to the comment ID read from the global get_comment_text<\/a> : applied to the comment text of the current comment in the get_comment_type<\/a> : applied to the comment type (“comment”, “trackback”, or “pingback”) by the Database Reads<\/h3>\n\n\n\n
database, prior to displaying on a page or editing screen.<\/p>\n\n\n\nget_attachment_fields_to_edit<\/code> function. Filter function arguments: an array of form fields, the post object.<\/p>\n\n\n\nget_attachment_icon<\/code> function. Filter function arguments: icon file as an HTML IMG tag, attachment ID.<\/p>\n\n\n\nget_attachment_innerHTML<\/code> function. Filter function arguments: inner HTML (defaults to the title), attachment ID.<\/p>\n\n\n\nget_attached_file<\/code> function. Filter function arguments: file information, attachment ID.<\/p>\n\n\n\nget_enclosed<\/code> function.<\/p>\n\n\n\nget_pages<\/code> function<\/a>. Filter function arguments: list of pages (each item of which contains a page data array), get_pages<\/code> function argument list (telling which pages were requested).<\/p>\n\n\n\nget_pung<\/code> function.<\/p>\n\n\n\nget_the_archive_title<\/code> function.<\/p>\n\n\n\nget_the_excerpt<\/code> function.<\/p>\n\n\n\nget_the_guid<\/code> function.<\/p>\n\n\n\nget_to_ping<\/code> function.<\/p>\n\n\n\nget_post_class<\/code><\/a> function. Filter function arguments: an array of class names, an array of additional class names that were added to the first array, and the post ID.<\/p>\n\n\n\nprepend_attachment<\/code> function.<\/p>\n\n\n\n
sanitize_title<\/a> : applied to a post title by the sanitize_title<\/code> function, after stripping out HTML tags.<\/p>\n\n\n\nwp_title<\/code> and single_post_title<\/code> functions.<\/p>\n\n\n\nthe_title<\/code>.<\/p>\n\n\n\nwp_dropdown_pages<\/code> function.<\/p>\n\n\n\nwp_list_pages<\/code> function.<\/p>\n\n\n\nwp_list_pages<\/code> function.<\/p>\n\n\n\nwp_get_attachment_metadata<\/code> function. Filter function arguments: meta data, attachment ID.<\/p>\n\n\n\nwp_get_attachment_thumb_file<\/code> function. Filter function arguments: thumbnail file, attachment ID.<\/p>\n\n\n\nwp_get_attachment_thumb_URL<\/code> function. Filter function arguments: thumbnail URL, attachment ID.<\/p>\n\n\n\nwp_get_attachment_url<\/code> function. Filter function arguments: URL, attachment ID.<\/p>\n\n\n\nwp_mime_type_icon<\/code> function. Filter function arguments: icon URI calculated, MIME type, post ID.<\/p>\n\n\n\nwp_title<\/code> function.<\/p>\n\n\n\nDatabase Writes<\/h3>\n\n\n\n
the database.<\/p>\n\n\n\nmedia_upload_form_handler<\/code> function. Filter function arguments: an array of post attributes, an array of attachment fields including the changes submitted from the form.<\/p>\n\n\n\nimage_editor_save_pre<\/code><\/a> instead.<\/p>\n\n\n\nwp_editor_set_quality<\/code><\/a> or WP_Image_Editor::set_quality()<\/code> instead.<\/p>\n\n\n\nupdate_attached_file<\/code> function. Filter function arguments: attachment information, attachment ID.<\/p>\n\n\n\nwp_save_image_editor_file<\/code><\/a> instead.<\/p>\n\n\n\nwp_update_attachment_metadata<\/code> function. Filter function arguments: meta data, attachment ID.<\/p>\n\n\n\nComment, Trackback, and Ping Filters<\/h2>\n\n\n\n
Database Reads<\/h3>\n\n\n\n
database, prior to displaying on a page or editing screen.<\/p>\n\n\n\ncomment_excerpt<\/code> function. See also get_comment_excerpt<\/code>.<\/p>\n\n\n\ncomment_text<\/code> function, and in the admin menus.<\/p>\n\n\n\ncomments_template<\/code> function. Filter function arguments: array of comment information structures, post ID.<\/p>\n\n\n\ncomments_number<\/code> function. See also get_comments_number<\/code>.<\/p>\n\n\n\nget_comment_excerpt<\/code> function (which is also called by comment_excerpt<\/code>. See also comment_excerpt<\/code>.<\/p>\n\n\n\n$comments<\/code> variable by the get_comment_ID<\/code> function.<\/p>\n\n\n\nget_comment_text<\/code> function, which is also called by the comment_text<\/code> function.<\/p>\n\n\n\nget_comment_type<\/code> function (which is also called by comment_type<\/code>).<\/p>\n\n\n\n