wp_ajax_media_create_image_subsizes()

Compatibility

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

Performance profile

How much work a call to wp_ajax_media_create_image_subsizes() 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

31–88

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 90.

Plugin surface

None

Nothing here hands control to plugin code.

Called by

0

Nothing in core calls this; the cost is only what you spend yourself.

What it touches

• querycontent queryget_post()called directly
• hookthird-party callbacksdo_action()one call below wp_ajax_media_create_image_subsizes()

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

What one call costs · 108 distinct outcomes

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

Uses · 10

• check_ajax_referer()Verifies the Ajax request to prevent processing requests external of the blog.
• current_user_can()Returns whether the current user has the specified capability.
• wp_send_json_error()Sends a JSON response back to an Ajax request, indicating failure.
• __()Retrieves the translation of $text.
• wp_attachment_is_image()Determines whether an attachment is an image.
• get_post()Retrieves post data given a post ID or post object.
• wp_delete_attachment()Trashes or deletes an attachment.
• wp_send_json_success()Sends a JSON response back to an Ajax request, indicating success.
• wp_update_image_subsizes()If any of the currently registered image sub-sizes are missing, create them and update the image meta data.
• wp_prepare_attachment_for_js()Prepares an attachment post object for JS, where it is expected to be JSON-encoded and fit into an Attachment model.

Source code

View on Trac ↗View on GitHub ↗

2504function wp_ajax_media_create_image_subsizes() {2505	check_ajax_referer( 'media-form' );2506 2507	if ( ! current_user_can( 'upload_files' ) ) {2508		wp_send_json_error( array( 'message' => __( 'Sorry, you are not allowed to upload files.' ) ) );2509	}2510 2511	if ( empty( $_POST['attachment_id'] ) ) {2512		wp_send_json_error( array( 'message' => __( 'Upload failed. Please reload and try again.' ) ) );2513	}2514 2515	$attachment_id = (int) $_POST['attachment_id'];2516 2517	if ( ! empty( $_POST['_wp_upload_failed_cleanup'] ) ) {2518		// Upload failed. Cleanup.2519		if ( wp_attachment_is_image( $attachment_id ) && current_user_can( 'delete_post', $attachment_id ) ) {2520			$attachment = get_post( $attachment_id );2521 2522			// Created at most 10 min ago.2523			if ( $attachment && ( time() - strtotime( $attachment->post_date_gmt ) < 600 ) ) {2524				wp_delete_attachment( $attachment_id, true );2525				wp_send_json_success();2526			}2527		}2528	}2529 2530	/*2531	 * Set a custom header with the attachment_id.2532	 * Used by the browser/client to resume creating image sub-sizes after a PHP fatal error.2533	 */2534	if ( ! headers_sent() ) {2535		header( 'X-WP-Upload-Attachment-ID: ' . $attachment_id );2536	}2537 2538	/*2539	 * This can still be pretty slow and cause timeout or out of memory errors.2540	 * The js that handles the response would need to also handle HTTP 500 errors.2541	 */2542	wp_update_image_subsizes( $attachment_id );2543 2544	if ( ! empty( $_POST['_legacy_support'] ) ) {2545		// The old (inline) uploader. Only needs the attachment_id.2546		$response = array( 'id' => $attachment_id );2547	} else {2548		// Media modal and Media Library grid view.2549		$response = wp_prepare_attachment_for_js( $attachment_id );2550 2551		if ( ! $response ) {2552			wp_send_json_error( array( 'message' => __( 'Upload failed.' ) ) );2553		}2554	}2555 2556	// At this point the image has been uploaded successfully.2557	wp_send_json_success( $response );2558}

Changelog

Introduced in 5.3.0. 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-admin/includes/ajax-actions.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

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