Load a url and check headers for rough 'is it ok' use

header_check.php

<?php

$headers = get_headers($_GET['url']);

$resp = explode(' ', $headers[0])[1];

$OK_CODES = array('200', '301', '302', '303', '307');

if(in_array($resp, $OK_CODES)) {
  echo "<h1>URL IS OK</h1>";
} else {
  echo "<h1>URL IS BAAAAAD</h1>";
}


?>

<form>
  <input type="text" name="url" value="<?=$_GET['url'] ?>" />
  <input type="submit">
</form>

<?php

echo "<pre>";
var_dump($headers);
echo "</pre>";

?>