import-google-fonts.php

<?php
$url  = 'https://fonts.googleapis.com/css2?family=Lato:wght@100;300;400;700&display=swap';

$opts = [
  'http' => [
    'method' => 'GET',
    'header' => 'User-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.121 Safari/537.36'
  ]
];

$context  = stream_context_create($opts);
$contents = file_get_contents($url, false, $context);

$rules = explode('}', $contents);
foreach ($rules as &$rule) {
    if (!empty(trim($rule))) {
        $open = explode('url(', $rule);
        if (count($open) == 2) {
            $close = explode(')', $open[1]);
            $link  = array_shift($close);
            $file  = str_replace('https://fonts.gstatic.com/', '/assets/fonts/', $link);
            
            $modx->cacheManager->writeFile(MODX_BASE_PATH . $file, file_get_contents($link));
            $rule  = $open[0] . 'url(' . $file . ')' . implode(')', $close);
        } else {
            $modx->log(modX::LOG_LEVEL_ERROR, 'Something wrong with rule:' . PHP_EOL . $rule);
        }
    }
}

$modx->cacheManager->writeFile(MODX_BASE_PATH . 'assets/fonts/fonts.css', implode('}', $rules));