wp_ajax_set_post_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_post_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

Constant

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

Instructions

30–63

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 78.

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 callbacksapply_filters()one call below wp_ajax_set_post_thumbnail()
• querycontent queryget_post()one call below wp_ajax_set_post_thumbnail()

Further down the call graph this can also reach option, serialize, cache 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 · 24 distinct outcomes

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

Uses · 7

• current_user_can()Returns whether the current user has the specified capability.
• wp_die()Kills WordPress execution and displays HTML page with an error message.
• check_ajax_referer()Verifies the Ajax request to prevent processing requests external of the blog.
• delete_post_thumbnail()Removes the thumbnail (featured image) from the given post.
• _wp_post_thumbnail_html()Returns HTML for the post thumbnail meta box.
• wp_send_json_success()Sends a JSON response back to an Ajax request, indicating success.
• set_post_thumbnail()Sets the post thumbnail (featured image) for the given post.

Source code

View on Trac ↗View on GitHub ↗

2736function wp_ajax_set_post_thumbnail() {2737	$json = ! empty( $_REQUEST['json'] ); // New-style request.2738 2739	$post_id = (int) $_POST['post_id'];2740	if ( ! current_user_can( 'edit_post', $post_id ) ) {2741		wp_die( -1 );2742	}2743 2744	$thumbnail_id = (int) $_POST['thumbnail_id'];2745 2746	if ( $json ) {2747		check_ajax_referer( "update-post_$post_id" );2748	} else {2749		check_ajax_referer( "set_post_thumbnail-$post_id" );2750	}2751 2752	if ( -1 === $thumbnail_id ) {2753		if ( delete_post_thumbnail( $post_id ) ) {2754			$return = _wp_post_thumbnail_html( null, $post_id );2755			$json ? wp_send_json_success( $return ) : wp_die( $return );2756		} else {2757			wp_die( 0 );2758		}2759	}2760 2761	if ( set_post_thumbnail( $post_id, $thumbnail_id ) ) {2762		$return = _wp_post_thumbnail_html( $thumbnail_id, $post_id );2763		$json ? wp_send_json_success( $return ) : wp_die( $return );2764	}2765 2766	wp_die( 0 );2767}

Changelog

Introduced in 3.1.0. 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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