WP_REST_Attachments_Controller::update_item() WordPress Method

	public function update_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 )
			);
		}

		$attachment_before = get_post( $request['id'] );
		$response          = parent::update_item( $request );

		if ( is_wp_error( $response ) ) {
			return $response;
		}

		$response = rest_ensure_response( $response );
		$data     = $response->get_data();

		if ( isset( $request['alt_text'] ) ) {
			update_post_meta( $data['id'], '_wp_attachment_image_alt', $request['alt_text'] );
		}

		$attachment = get_post( $request['id'] );

		$fields_update = $this->update_additional_fields_for_object( $attachment, $request );

		if ( is_wp_error( $fields_update ) ) {
			return $fields_update;
		}

		$request->set_param( 'context', 'edit' );

		/** This action is documented in wp-includes/rest-api/endpoints/class-wp-rest-attachments-controller.php */
		do_action( 'rest_after_insert_attachment', $attachment, $request, false );

		wp_after_insert_post( $attachment, true, $attachment_before );

		$response = $this->prepare_item_for_response( $attachment, $request );
		$response = rest_ensure_response( $response );

		return $response;
	}