WordPress at a glance
filter is not described

(action)_prefilter filter-hook . WP 2.9.0

Filters the data for a file before it is uploaded to WordPress.

The dynamic portion of the hook name, $action, refers to the post action.

Usage

add_filter( '(action)_prefilter', 'filter_function_name_278' );
function filter_function_name_278( $file ){
	// filter...

	return $file;
}
$file(string[])
An array of data for a single file.

Changelog

Since 2.9.0 Introduced.
Since 2.9.0 as 'wp_handle_upload_prefilter'.
Since 4.0.0 Converted to a dynamic hook with $action.

Where the hook is called

_wp_handle_upload()
(action)_prefilter
wp-admin/includes/file.php 723
$file = apply_filters( "{$action}_prefilter", $file );

Where the hook is used (in WP core)

wp-admin/includes/ms-admin-filters.php 11
add_filter( 'wp_handle_upload_prefilter', 'check_upload_size' );
wp-includes/default-filters.php 111
add_filter( 'add_term_metadata', 'wp_check_term_meta_support_prefilter' );
wp-includes/default-filters.php 112
add_filter( 'update_term_metadata', 'wp_check_term_meta_support_prefilter' );
wp-includes/default-filters.php 113
add_filter( 'delete_term_metadata', 'wp_check_term_meta_support_prefilter' );
wp-includes/default-filters.php 114
add_filter( 'get_term_metadata_by_mid', 'wp_check_term_meta_support_prefilter' );
wp-includes/default-filters.php 115
add_filter( 'update_term_metadata_by_mid', 'wp_check_term_meta_support_prefilter' );
wp-includes/default-filters.php 116
add_filter( 'delete_term_metadata_by_mid', 'wp_check_term_meta_support_prefilter' );
wp-includes/default-filters.php 117
add_filter( 'update_term_metadata_cache', 'wp_check_term_meta_support_prefilter' );
wp-includes/default-filters.php 110
add_filter( 'get_term_metadata', 'wp_check_term_meta_support_prefilter' );
wp-includes/ms-default-filters.php 65
add_filter( 'update_blog_metadata_by_mid', 'wp_check_site_meta_support_prefilter' );
wp-includes/ms-default-filters.php 67
add_filter( 'update_blog_metadata_cache', 'wp_check_site_meta_support_prefilter' );
wp-includes/ms-default-filters.php 66
add_filter( 'delete_blog_metadata_by_mid', 'wp_check_site_meta_support_prefilter' );
wp-includes/ms-default-filters.php 60
add_filter( 'get_blog_metadata', 'wp_check_site_meta_support_prefilter' );
wp-includes/ms-default-filters.php 64
add_filter( 'get_blog_metadata_by_mid', 'wp_check_site_meta_support_prefilter' );
wp-includes/ms-default-filters.php 63
add_filter( 'delete_blog_metadata', 'wp_check_site_meta_support_prefilter' );
wp-includes/ms-default-filters.php 62
add_filter( 'update_blog_metadata', 'wp_check_site_meta_support_prefilter' );
wp-includes/ms-default-filters.php 61
add_filter( 'add_blog_metadata', 'wp_check_site_meta_support_prefilter' );
wp-includes/ms-site.php 393
add_filter( 'update_blog_metadata_cache', 'wp_check_site_meta_support_prefilter' );