wppaste
WordPress

wp_attachment_is( string $type, int|WP_Post $post = null ): bool

Since
4.2.0
Source
wp-includes/post.php:7332
Verifies an attachment is of a given type.

Compatibility

WordPress
since 4.2.0
PHP
7.4–8.6-dev
  • 6.7.7
  • 6.8.8
  • 6.9.7
  • 7.0.4
  • 7.1.0

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Parameters

$typestring
Attachment type. Accepts image, audio, video, or a file extension.
$postint|WP_Postoptional
Attachment ID or object. Default is global $post.Default: null

Return value

bool
True if an accepted type or a matching file extension, false otherwise.

Performance profile

How much work a call to wp_attachment_is() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class
Heavy

Reaches the database via get_post().

Scaling
Constant

No loop in the body: the same number of instructions runs whatever you pass in.

Instructions
8–40

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 56.

Plugin surface
None

Nothing here hands control to plugin code.

Called by
13

13 places in core call this, so the cost is paid more often than your own code shows.

What it touches

  • querycontent queryget_post()called directly
  • hookthird-party callbacksapply_filters()one call below wp_attachment_is()

Further down the call graph this can also reach cache, serialize, option and transient. Those are the worst case, several calls deep and usually down an error path, not what a normal call pays.

What one call costs · 5 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost wp_attachment_is() can have, taken from its control-flow graph on PHP 8.5.

WhenInstructionsCalls it makes
always8get_post()
always15–19get_post(), get_attached_file()
always25–38get_post(), get_attached_file(), wp_check_filetype()
!empty($check)34–38get_post(), get_attached_file(), wp_check_filetype(), wp_get_audio_extensions()
!empty($check)34–40get_post(), get_attached_file(), wp_check_filetype(), wp_get_video_extensions()

Across PHP versions

PHPCompiledExecutedBranchesNotes
8.6-dev568–409
8.5568–409
8.4568–4099 fewer instructions than PHP 8.3
8.3658–469
8.2658–4691 more instruction than PHP 8.1
8.1648–4691 fewer instruction than PHP 7.4
7.4658–479

An instruction is not a fixed amount of time, so a matching count is not necessarily the same speed; what it rules out is a difference in the work itself.

Uses · 6

Used by · 13

Show all 13

Source code

function wp_attachment_is( $type, $post = null ) {	$post = get_post( $post ); 	if ( ! $post ) {		return false;	} 	$file = get_attached_file( $post->ID ); 	if ( ! $file ) {		return false;	} 	if ( str_starts_with( $post->post_mime_type, $type . '/' ) ) {		return true;	} 	$check = wp_check_filetype( $file ); 	if ( empty( $check['ext'] ) ) {		return false;	} 	$ext = $check['ext']; 	if ( 'import' !== $post->post_mime_type ) {		return $type === $ext;	} 	switch ( $type ) {		case 'image':			$image_exts = array( 'jpg', 'jpeg', 'jpe', 'gif', 'png', 'webp', 'avif', 'heic' );			return in_array( $ext, $image_exts, true ); 		case 'audio':			return in_array( $ext, wp_get_audio_extensions(), true ); 		case 'video':			return in_array( $ext, wp_get_video_extensions(), true ); 		default:			return $type === $ext;	}}

Changelog

Introduced in 4.2.0. Unchanged from 6.7.7 through 7.1.0.

  1. 6.7.7
  2. 6.8.8
  3. 6.9.7
  4. 7.0.4
  5. 7.1.0

Signature, return type and hooks compared across 5 parsed releases.

About this page

Parsed data
Generated from the wordpress-develop 7.1.0 tag, from src/wp-includes/post.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.
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