imgh_upload.php

<?php
/**
 * A little php script to accept images and make folders based on the hash,
 * with a bonus _ folder at the end to detect if collisions occur.
 *
 * For example, using a form on this page would convert the following image
 * https://dev.nektro.net/assets/nektro.png
 * http://localhost/imgh/cdn/89/9e/84/39/49/12/16/7a/06/c7/b1/ae/c5/18/e5/3b/d7/8e/b6/a5/eb/7d/29/9e/cf/fa/ec/63/51/d8/19/1b/_0/c.png
 */
$home_dir = '/imgh/';

function getDup($h,$i) {
  $d = $h . '/_' . $i . '/';
  return !is_dir($d) ? $d : getDup($h, $i+1);
}

// there's a utf face at the end
header("Content-type: text/html; charset=UTF-8");

// make sure the form was sent
if (isset($_FILES['img'])) {
  $file = $_FILES['img'];
  var_dump($file['name']);

  switch ($file['type']) {
    case 'image/png':
    case 'image/jpeg':
    case 'image/gif':
      $fgc = file_get_contents($file['tmp_name']);
      $hash = hash('sha256', $fgc);
      // cdn/ is the content folder, not part of hash
      $dir = "cdn/" . implode('/', str_split($hash, 2));
      $dirf = getDup($dir, 0);
      $name = 'c.' . array( 'image/png'=>'png', 'image/jpeg'=>'jpg', 'image/gif'=>'gif' )[$file['type']];
      $path = $dirf . $name;
      $d = intval(substr(array_reverse(explode('/', $dirf))[1], 1));
      // if _x > 0, check for duplicate images and return link
      // ie, has this exact image been uploaded before?
      if ($d > 0) {
        for ($i = 0; $i < $d; $i++) {
          $tf = $dir.'/_'.$i.'/'.scandir($dir.'/_'.$i)[2];
          if (file_get_contents($tf) == $fgc) {
            var_dump($i);
            // copy found, show them the link
            echo "<a href='" . $tf . "' target='_blank'>Get your image here.</a><br>";
            echo "<a href='$home_dir'>Return</a>";
            die();
          }
        }
        
        // you found a collision in sha-2
      }
      var_dump($d);
      mkdir($dirf, 0777, true);
      file_put_contents($path, $fgc);
      // new file, give them a link
      echo "<a href='" . $path . "' target='_blank'>Upload successful.</a><br>";
      echo "<a href='$home_dir'>Return</a>";
      break;
    default:
    echo "<span style='color:red'>Unavailable file type (╯︵╰,)</span><br><a href='$home_dir'>Return</a>";
  }
}
else {
  echo "<span style='color:red'>Unknown error, cannot find image (╯︵╰,)</span><br><a href='$home_dir'>Return</a>";
}