title: PHP check if file contains a string
body: <p>I'm trying to see if a file contains a string that is sent to the page.  I'm not sure what is wrong with this code:</p>
  
  <pre><code>?php
      $valid = FALSE;
      $id = $_GET['id'];
      $file = './uuids.txt';
  
      $handle = fopen($file, "r");
  
  if ($handle) {
      // Read file line-by-line
      while (($buffer = fgets($handle)) !== false) {
          if (strpos($buffer, $id) === false)
              $valid = TRUE;
      }
  }
  fclose($handle);
  
      if($valid) {
  do stufff
  }
  </code></pre>