General purpose request signer and validator.

Sign an http request that can be authenticated with a shared secret.

Usage:

  $params = array('foo' => 'bar', 'Fid' => array('fig' => 'floo', 'soo' => 'tid'), 'nid' => 'nad');
  echo 'https:///SignedRequest.php/?' . $signer->generateValidQueryString($params) . "\n";

To validate the current request:

  echo $signer->validateCurrentRequest() ? "valid\n" : "invalid\n";