wp-includes/rest-api/endpoints/class-wp-rest-attachments-controller.php:187Creates a single attachment.
$requestWP_REST_RequestWP_REST_Response|WP_ErrorOne hook fires while WP_REST_Attachments_Controller::create_item() runs, in this order:
Fires after a single attachment is completely created or updated via the REST API.
public function create_item( $request ) { if ( ! empty( $request['post'] ) && in_array( get_post_type( $request['post'] ), array( 'revision', 'attachment' ), true ) ) { return new WP_Error( 'rest_invalid_param', __( 'Invalid parent type.' ), array( 'status' => 400 ) ); } $insert = $this->insert_attachment( $request ); if ( is_wp_error( $insert ) ) { return $insert; } $schema = $this->get_item_schema(); // Extract by name. $attachment_id = $insert['attachment_id']; $file = $insert['file']; if ( isset( $request['alt_text'] ) ) { update_post_meta( $attachment_id, '_wp_attachment_image_alt', sanitize_text_field( $request['alt_text'] ) ); } if ( ! empty( $schema['properties']['featured_media'] ) && isset( $request['featured_media'] ) ) { $thumbnail_update = $this->handle_featured_media( $request['featured_media'], $attachment_id ); if ( is_wp_error( $thumbnail_update ) ) { return $thumbnail_update; } } if ( ! empty( $schema['properties']['meta'] ) && isset( $request['meta'] ) ) { $meta_update = $this->meta->update_value( $request['meta'], $attachment_id ); if ( is_wp_error( $meta_update ) ) { return $meta_update; } } $attachment = get_post( $attachment_id ); $fields_update = $this->update_additional_fields_for_object( $attachment, $request ); if ( is_wp_error( $fields_update ) ) { return $fields_update; } $terms_update = $this->handle_terms( $attachment_id, $request ); if ( is_wp_error( $terms_update ) ) { return $terms_update; } $request->set_param( 'context', 'edit' ); /** * Fires after a single attachment is completely created or updated via the REST API. * * @since 5.0.0 * * @param WP_Post $attachment Inserted or updated attachment object. * @param WP_REST_Request $request Request object. * @param bool $creating True when creating an attachment, false when updating. */ do_action( 'rest_after_insert_attachment', $attachment, $request, true ); wp_after_insert_post( $attachment, false, null ); if ( wp_is_serving_rest_request() ) { /* * Set a custom header with the attachment_id. * Used by the browser/client to resume creating image sub-sizes after a PHP fatal error. */ header( 'X-WP-Upload-Attachment-ID: ' . $attachment_id ); } // Include media and image functions to get access to wp_generate_attachment_metadata(). require_once ABSPATH . 'wp-admin/includes/media.php'; require_once ABSPATH . 'wp-admin/includes/image.php';Introduced in 4.7.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/rest-api/endpoints/class-wp-rest-attachments-controller.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.