WordPress Plugin: Auto Rename Uploads to Match Post Slug

auto-rename-uploads-to-match-post-slug.php

<?php
/**
 * Plugin Name: Auto Rename Uploads to Match Post Slug
 * Plugin URI: https://gist.github.com/chrisdavidmiles/770ffbfe428b440fd007bcb6b08e94d7
 * Description: Uploads will be automatically renamed to match the post slug
 * Author: Chris David Miles
 * Version: 0.1
 */

function auto_rename_uploads_to_post_slug( $filename ) {
    $info = pathinfo( $filename );
    $ext  = empty( $info['extension'] ) ? '' : '.' . $info['extension'];
    $name = basename( $filename, $ext );

    if ( isset( $_REQUEST['post_id'] ) && is_numeric( $_REQUEST['post_id'] ) ) {
        $postObj  = get_post( $_REQUEST['post_id'] );
        $postSlug = sanitize_title( $postObj->post_title );
    }

    if ( isset( $postSlug ) && ! empty( $postSlug ) && $postSlug != 'auto-draft' ) {
        $finalFileName = $postSlug;
    } // File name will be the same as the post slug.
    else {
        $finalFileName = sanitize_title( $name );
    } // File name will be the same as the image file name, but sanitized.

    return $finalFileName . $ext;
}

add_filter( 'sanitize_file_name', 'auto_rename_uploads_to_post_slug', 100 );