folder.php

CMS editable default folder

<?php


private static $has_one = array(
    'ImagePath' => 'Folder'
);

// in settings
$fields->insertBefore(
    new TreeDropdownField(
      "ImagePathID",
      'Folder',
      "Folder"
    ),'Content');

// in getcmsfields
if($this->ImagePath()->exists()) {
    $file->setFolderName(str_replace('assets', '', $this->ImagePath()->RelativeLink()));
} else {
    $file->setFolderName('Uploads/Splash-Images');
}


// silverstripe 4 setting folder name is a bit more complicated 

    public function setFolder($upload) {
        $name = $this->getFolderPath($this->ImagePath());
        $upload->setFolderName($name);
        return $upload;
    }

    /**
     * Generate the folder path of the folder
     * @param $parent
     * @return string
     */
    public function getFolderPath($folder)
    {
        $name = [];
        array_push($name, $folder->Name);

        while (($folder = $folder->Parent()) && $folder->exists()) {
            array_push($name, $folder->Name);
        }

        $name = array_reverse($name);
        return implode('/', $name);
    }