Uploads Handler for Wordpress to alter the directory based on Post type and/or Filetype (extension)

CustomUploadsHandler.php

<?php

/**
* Filters the uploads directory to use a custom structure for select post types
*/

class Custom_Uploads_Handler {

    public function __construct() {
        // initialize upload filters
        add_filter('wp_handle_upload_prefilter', [$this,'upload_prefilter'], 10, 1);
        add_filter('wp_handle_upload', [$this,'upload_postfilter'], 10, 1);
    }

    private function get_directory_by_posttype() {
        //Define the post types and their respective folders
        return array([
            'type' => '', // 'property'
            'folder' => '', // 'properties',
            'use_subdir' => false // false overrides year/month format
        ]);
    }

    private function get_directory_by_filetype() {
        //Define the post types and their respective folders
        return array([
            'type' => 'pdf', //the extension
            'folder' => 'documents', //the folder
            'use_subdir' => false // false overrides year/month format
        ]);
    }

    private function format_upload_by_type($upload, $type, $filter_array) {
        if (!is_array($filter_array) || empty($type) || empty($filter_array)) return $upload;

        // loop through each node in the array and check if it matches the type (posttype or extension)
        foreach ($filter_array as $node){
            // Check the post type of the current post (and parent)
            if( $node['type'] === $type ){
                // rewrite the subdirectory 
                $folder = isset($node['folder']) ? '/'. $node['folder'] : '';

                // rewrite the subdirectory if use_subdir is false, otherwise use default (year/month)
                $upload['subdir'] = ( isset($node['use_subdir']) && $node['use_subdir'] === false ) ? $folder : $folder . $upload['subdir'];

                // add the folder to the path
                $fullpath = $upload['basedir'] . $upload['subdir'];
                $upload['path'] = $fullpath; 
                $upload['url'] = $fullpath;
                
                // exit loop and return the upload path and filename
                return $upload;	  
            }	 
        }
        // return original upload if no match
        return $upload;
    }

    public function upload_prefilter($file){
        add_filter('upload_dir', [$this,'filter_uploads_dir'], 10, 1);
        return $file;
    }
    
    public function upload_postfilter($fileinfo){
        remove_filter('upload_dir', [$this,'filter_uploads_dir'], 10, 1);
        return $fileinfo;
    }
    
    public function filter_uploads_dir( $upload ) {
    
        // Exit early
        if (!empty($upload['error']) ) return $upload;

        // Define the filetypes and posttypes with their respective folders
        $file_types = $this->get_directory_by_filetype();
        $file_types = apply_filters('custom_upload_directories_by_filetype', $file_types);

        $post_types = $this->get_directory_by_posttype();
        $post_types = apply_filters('custom_upload_directories_by_posttype', $post_types);
    
        // Get the extension for 'pdf', change dir and exit
        if ( isset($_POST['name'])){
            //trim the 
            $extension = substr(strrchr($_POST['name'],'.'),1);
            
            // Check if this matches a filtered extension
            $upload = $this->format_upload_by_type($upload, $extension, $file_types);
        }
        
        global $post;
        // Get the ID and Posttype of the current post
        // NOTE: use $_REQUEST to catch both GET and POST requests    
        if ( !empty($post) ) {
            $id = $post->ID;
            $post_type = get_post_type( $post);
        } else {
            $id = isset($_REQUEST['post']) ? $_REQUEST['post'] : '';
            $id = isset($_REQUEST['post_id']) ? $_REQUEST['post_id'] : $id;
            $post_type = isset($_REQUEST['post_type']) ? $_REQUEST['post_type'] : get_post_type( $id );
        } 
        // Check if this matches a filtered posttype
        if (isset($post_type) && !empty($post_type)){
            $upload = $this->format_upload_by_type($upload, $post_type, $post_types);   
        }
    
        // output debug info to Query Monitory (if active)
        do_action( 'qm/debug', $upload );
        return $upload;
    }
}

add_action('init', function(){
    // Initialize the Class
    $customUploadsHandler = new Custom_Uploads_Handler();    
});

This defaults to putting PDFs in a "documents" folder.

Includes 2 hooks to modify these outside the class:

$file_types = apply_filters('custom_upload_directories_by_filetype', $file_types);
$post_types = apply_filters('custom_upload_directories_by_posttype', $post_types);

Both callbacks should return an array like this:

return array([
            'type' => 'property'
            'folder' => 'properties',
            'use_subdir' => false
        ]);