wp_ajax_set_attachment_thumbnail()

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_set_attachment_thumbnail() 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

Scales with input

The body loops, so the work grows with how much data it finds.

Instructions

34–47

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 70.

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

• hookthird-party callbacksdo_action()one call below wp_ajax_set_attachment_thumbnail()
• querycontent queryget_post()one call below wp_ajax_set_attachment_thumbnail()

Further down the call graph this can also reach option, cache, serialize 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 · 18 distinct outcomes

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

Uses · 6

• wp_send_json_error()Sends a JSON response back to an Ajax request, indicating failure.
• check_ajax_referer()Verifies the Ajax request to prevent processing requests external of the blog.
• attachment_url_to_postid()Tries to convert an attachment URL into a post ID.
• current_user_can()Returns whether the current user has the specified capability.
• set_post_thumbnail()Sets the post thumbnail (featured image) for the given post.
• wp_send_json_success()Sends a JSON response back to an Ajax request, indicating success.

Source code

View on Trac ↗View on GitHub ↗

2801function wp_ajax_set_attachment_thumbnail() {2802	if ( empty( $_POST['urls'] ) || ! is_array( $_POST['urls'] ) ) {2803		wp_send_json_error();2804	}2805 2806	$thumbnail_id = (int) $_POST['thumbnail_id'];2807	if ( empty( $thumbnail_id ) ) {2808		wp_send_json_error();2809	}2810 2811	if ( false === check_ajax_referer( 'set-attachment-thumbnail', '_ajax_nonce', false ) ) {2812		wp_send_json_error();2813	}2814 2815	$post_ids = array();2816	// For each URL, try to find its corresponding post ID.2817	foreach ( $_POST['urls'] as $url ) {2818		$post_id = attachment_url_to_postid( $url );2819		if ( ! empty( $post_id ) ) {2820			$post_ids[] = $post_id;2821		}2822	}2823 2824	if ( empty( $post_ids ) ) {2825		wp_send_json_error();2826	}2827 2828	$success = 0;2829	// For each found attachment, set its thumbnail.2830	foreach ( $post_ids as $post_id ) {2831		if ( ! current_user_can( 'edit_post', $post_id ) ) {2832			continue;2833		}2834 2835		if ( set_post_thumbnail( $post_id, $thumbnail_id ) ) {2836			++$success;2837		}2838	}2839 2840	if ( 0 === $success ) {2841		wp_send_json_error();2842	} else {2843		wp_send_json_success();2844	}2845 2846	wp_send_json_error();2847}

Changelog

Introduced in 4.0.0. 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 6.9.7 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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