根据另一个数组过滤$ _REQUEST数组？

Array $ALLOWED_CALLS contains a function name and required parameters. I'd like to filter $_REQUEST array obtaining a $params array with only required paramets in it. How to?

$call = 'translate';

$ALLOWED_CALLS = array(
    'getLanguages' => array(),
    'detect' => array('text'),
    'translateFrom' => array('text', 'from', 'to'),
    'translate' => array('text', 'to'),
);

$params = array(); // Should contain $_REQUEST['text'] and $_REQUEST['to']

I'd use array_intersect_key() like so:

$params = array_intersect_key($_REQUEST, array_flip($ALLOWED_CALLS[$call]));

Thus, the whole thing:

$call = 'translate';

$ALLOWED_CALLS = array(
    'getLanguages' => array(),
    'detect' => array('text'),
    'translateFrom' => array('text', 'from', 'to'),
    'translate' => array('text', 'to'),
);

$params = array_intersect_key($_REQUEST, array_flip($ALLOWED_CALLS[$call]));

Have a look at array_intersect()

Something like:

$contains_required = true;
foreach( $ALLOWED_CALLS[$call] as $key => $value )
{
    if(!in_array($value, $_REQUEST))
    {
        $contains_required = false;
    }
}

function getParams ($call, $allowedCalls) {
  // Return FALSE if the call was invalid
  if (!isset($allowedCalls[$call])) return FALSE;
  // Get allowed params from $_REQUEST into result array
  $result = array();
  foreach ($allowedCalls[$call] as $param) {
    if (isset($_REQUEST[$param])) {
      $result[$param] = $_REQUEST[$param];
    }
  }
  // Return the result
  return $result;
}

Returns the $params array, or FALSE on failure.