wp_maybe_generate_attachment_metadata( WP_Post $attachment )

Compatibility

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

Parameters

$attachmentWP_Post

Attachment object.

Performance profile

How much work a call to wp_maybe_generate_attachment_metadata() 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

Reads or writes the filesystem via file_exists().

Scaling

Constant

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

Instructions

4–48

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 49.

Plugin surface

None

Nothing here hands control to plugin code.

Called by

1

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

What it touches

• transienttransientget_transient()called directly
• filesystemfilesystem accessfile_exists()called directly
• hookthird-party callbacksapply_filters()one call below wp_maybe_generate_attachment_metadata()
• querycontent queryget_post()one call below wp_maybe_generate_attachment_metadata()
• cacheobject cachewp_cache_get()one call below wp_maybe_generate_attachment_metadata()
• optionoption read or writeget_option()one call below wp_maybe_generate_attachment_metadata()

Further down the call graph this can also reach serialize. That is the worst case, several calls deep and usually down an error path, not what a normal call pays.

What one call costs · 6 distinct outcomes

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

Uses · 8

• get_attached_file()Retrieves attached file path based on attachment ID.
• wp_get_attachment_metadata()Retrieves attachment metadata for attachment ID.
• get_post_meta()Retrieves a post meta field for the given post ID.
• get_transient()Retrieves the value of a transient.
• set_transient()Sets/updates the value of a transient.
• wp_update_attachment_metadata()Updates metadata for an attachment.
• wp_generate_attachment_metadata()Generates attachment meta data and create image sub-sizes for images.
• delete_transient()Deletes a transient.

Used by · 1

• edit_form_image_editor()Displays the image and editor in the post editor

Source code

View on Trac ↗View on GitHub ↗

5458function wp_maybe_generate_attachment_metadata( $attachment ) {5459	if ( empty( $attachment ) || empty( $attachment->ID ) ) {5460		return;5461	}5462 5463	$attachment_id = (int) $attachment->ID;5464	$file          = get_attached_file( $attachment_id );5465	$meta          = wp_get_attachment_metadata( $attachment_id );5466 5467	if ( empty( $meta ) && file_exists( $file ) ) {5468		$_meta = get_post_meta( $attachment_id );5469		$_lock = 'wp_generating_att_' . $attachment_id;5470 5471		if ( ! array_key_exists( '_wp_attachment_metadata', $_meta ) && ! get_transient( $_lock ) ) {5472			set_transient( $_lock, $file );5473			wp_update_attachment_metadata( $attachment_id, wp_generate_attachment_metadata( $attachment_id, $file ) );5474			delete_transient( $_lock );5475		}5476	}5477}

Changelog

Introduced in 3.9.0. 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 6.8.8 tag, from src/wp-includes/media.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

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