Prevent plugin from deleting important directories

Question

I want to allow users to upload custom files to specific plugin directory. The problem is, obviously, that WP removes everything upon plugin version update.

I think that the upgrader_pre_install and upgrader_post_install hooks may be useful, but unfortunately so far I wasn't able to find any info to help me.

In your opinion, can these hooks be used to retain a directory and if so, how? Should I simply copy the directory elsewhere, like the uploads folder, and copy it back with upgrader_post_install? What would be the best practice?

Thanks

Answer 1

To answer my own question here is what I've found for the sake of keeping questions answered. What this does is copying the important directory before upgrade and recovering it after upgrade:

function my_dir_copy($source, $dest)
{
    if (is_link($source)) {
        return symlink(readlink($source), $dest);
    }
    if (is_file($source)) {
        return copy($source, $dest);
    }
    if (!is_dir($dest)) {
        mkdir($dest);
    }
    $dir = dir($source);
    while (false !== $entry = $dir->read()) {
        if ($entry == '.' || $entry == '..') {
            continue;
        }
        my_dir_copy("$source/$entry", "$dest/$entry");
    }

    $dir->close();
    return true;
}


function my_dir_rmdirr($dirname)
{

    if (!file_exists($dirname)) {
        return false;
    }


    if (is_file($dirname)) {
        return unlink($dirname);
    }


    $dir = dir($dirname);
    while (false !== $entry = $dir->read()) {

        if ($entry == ‘.’ || $entry == ‘..’) {
        continue;
        }
        rmdirr(“$dirname/$entry”);
    }


    $dir->close();
    return rmdir($dirname);
}


function my_dir_backup()
{
        $to = dirname(__FILE__)."/../igr_backup/";
        $from = dirname(__FILE__)."/whatever_directory_you_preserve/";
        my_dir_copy($from, $to);
}
function my_dir_recover()
{
        $from = dirname(__FILE__)."/../igr_backup/";
        $to = dirname(__FILE__)."/whatever_directory_you_preserve/";
        my_dir_copy($from, $to);
        if (is_dir($from)) {
                my_dir_rmdirr($from);
        }
}
add_filter('upgrader_pre_install', 'my_dir_backup', 10, 2);
add_filter('upgrader_post_install', 'my_dir_recover', 10, 2);

Answer 2

The plugin directory cannot be used for uploads:

1. You might not have write access here.
2. It will be deleted on plugin updates as you just found out.
3. Required CDN settings will probably fail for this directory.

Use the uploads directory for uploads. It is the only safe place.
See also: How to prevent specific plugin files or subfolders from appearing under “plugin files” listing with related problem – and the same solution.