Clear image cache for Github markdown images with PHP cron script

Github markdown image cache clear with PHP cron.md

Clear image cache for Github markdown images with PHP cron script

🤔 What?

As per this post dated back from 2015, there is an issue with Github caching images you've embedded in markdown, eg README.md files.

This script is a PHP cron that accepts an array of images & clears their cache.

It should be run at a fairly sensible interval that clears the cache of the image(s) you've specified.

🔥 How to run

Upload this to a PHP server, then just hit the URL of the file you've created.

To automate this, most hosting providers offer a cron solution. Simply curl to this file on your server, eg curl "https://YOUR_SERVER.com/PATH/TO/THIS_FILE.php". Example cron interval 0 4 * * * (04:00 every day).

🤓 The PHP cron script

// Show all PHP errors.
ini_set('display_errors', 1);
ini_set('display_startup_errors', 1);
error_reporting(E_ALL);

// Array of images.
$images = [
  'https://camo.githubusercontent.com/...', // Update this to your image(s).
];

// Loop over each image.
foreach ($images as $image) {
  echo clearCache($image);
  echo "\n\n";
}

// Output done.
echo "\n\n== All done ==";

/**
 * Function to clear the cache for a given image URL.
 * @param $image
 * @return response from curl request
 */
function clearCache($image) {
  $curl = curl_init();

  curl_setopt_array($curl, [
    CURLOPT_URL => $image,
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_ENCODING => '',
    CURLOPT_MAXREDIRS => 10,
    CURLOPT_TIMEOUT => 0,
    CURLOPT_FOLLOWLOCATION => true,
    CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
    CURLOPT_CUSTOMREQUEST => 'PURGE',
  ]);

  $response = curl_exec($curl);
  curl_close($curl);

  return $response;
}