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wp_ajax_media_create_image_subsizes()

Ajax handler for creating missing image sub-sizes for just uploaded images.

Source

File: wp-admin/includes/ajax-actions.php 

function wp_ajax_media_create_image_subsizes() {
	check_ajax_referer( 'media-form' );

	if ( ! current_user_can( 'upload_files' ) ) {
		wp_send_json_error( array( 'message' => __( 'Sorry, you are not allowed to upload files.' ) ) );
	}

	if ( empty( $_POST['attachment_id'] ) ) {
		wp_send_json_error( array( 'message' => __( 'Upload failed. Please reload and try again.' ) ) );
	}

	$attachment_id = (int) $_POST['attachment_id'];

	if ( ! empty( $_POST['_wp_upload_failed_cleanup'] ) ) {
		// Upload failed. Cleanup.
		if ( wp_attachment_is_image( $attachment_id ) && current_user_can( 'delete_post', $attachment_id ) ) {
			$attachment = get_post( $attachment_id );

			// Created at most 10 min ago.
			if ( $attachment && ( time() - strtotime( $attachment->post_date_gmt ) < 600 ) ) {
				wp_delete_attachment( $attachment_id, true );
				wp_send_json_success();
			}
		}
	}

	// Set a custom header with the attachment_id.
	// Used by the browser/client to resume creating image sub-sizes after a PHP fatal error.
	if ( ! headers_sent() ) {
		header( 'X-WP-Upload-Attachment-ID: ' . $attachment_id );
	}

	// This can still be pretty slow and cause timeout or out of memory errors.
	// The js that handles the response would need to also handle HTTP 500 errors.
	wp_update_image_subsizes( $attachment_id );

	if ( ! empty( $_POST['_legacy_support'] ) ) {
		// The old (inline) uploader. Only needs the attachment_id.
		$response = array( 'id' => $attachment_id );
	} else {
		// Media modal and Media Library grid view.
		$response = wp_prepare_attachment_for_js( $attachment_id );

		if ( ! $response ) {
			wp_send_json_error( array( 'message' => __( 'Upload failed.' ) ) );
		}
	}

	// At this point the image has been uploaded successfully.
	wp_send_json_success( $response );
}

Uses

Uses Description
wp-admin/includes/image.php: wp_update_image_subsizes()

If any of the currently registered image sub-sizes are missing, create them and update the image meta data.
wp-includes/capabilities.php: current_user_can()

Returns whether the current user has the specified capability.
wp-includes/l10n.php: __()

Retrieve the translation of $text.
wp-includes/pluggable.php: check_ajax_referer()

Verifies the Ajax request to prevent processing requests external of the blog.
wp-includes/functions.php: wp_send_json_error()

Send a JSON response back to an Ajax request, indicating failure.
wp-includes/functions.php: wp_send_json_success()

Send a JSON response back to an Ajax request, indicating success.
wp-includes/media.php: 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.
wp-includes/post.php: wp_attachment_is_image()

Determines whether an attachment is an image.
wp-includes/post.php: wp_delete_attachment()

Trash or delete an attachment.
wp-includes/post.php: get_post()

Retrieves post data given a post ID or post object.

Changelog

Version Description
5.3.0 Introduced.

© 2003–2019 WordPress Foundation
Licensed under the GNU GPLv2+ License.
https://developer.wordpress.org/reference/functions/wp_ajax_media_create_image_subsizes