Twilio message forwarder

twilio.php

<?php
require 'twilio-php/Services/Twilio.php';
include 'marg/marg.php';

class Messenger {
    private $AccountSid   = "guff";
    private $AuthToken    = "junk";
    private $ourNumber    = "+440987654321";
    private $validSenders = array(
        "+441234567890"   => "Joe Eaves"
    );
    private $Members  = array(
        "+441234567890"   => "Joe Eaves"
    );

    private function debugPrint($data) {
        $fp=fopen('/tmp/debug.txt','w');
        fwrite($fp, $data . "\n");
        fclose($fp);
    }

    private function receiveMessage($request) {
        $client = new Services_Twilio($this->AccountSid, $this->AuthToken);
        $reqBody = $request->request_body;


        $this->debugPrint("Function called");
        if ($request->verb == 'POST') {
            if(!isset($reqBody["Body"]) || !isset($reqBody["To"]) ||
                !isset($reqBody["From"]) || !isset($reqBody["MessageSid"]) ||
                !isset($reqBody["AccountSid"]))
                return response("There was an error processing your message.");

            $body = $reqBody['Body'];
            $from = $reqBody['From'];

            $this->debugPrint($reqBody['From'] . " " . $reqBody['Body']);
            if (array_key_exists($from, $this->validSenders)) {
                $failedNumbers = array();
                $returnMessage = "Thank you for your message!";
                foreach ($this->Members as $number => $name) {
                    try {
                        $message = $client->account->messages->create(array(
                            "From" => $this->ourNumber,
                            "To" => $number,
                            "Body" => "Message System\nSender: " .
                                $this->validSenders[$from] . "\n" . $body
                        ));
                    } catch (Services_Twilio_RestException $e) {
                        $failedNumbers[] = $number;
                    }
                }
                if (count($failedNumbers) > 0) {
                    $returnMessage = $returnMessage . "\nThe following numbers failed:";
                    foreach ($failedNumbers as $f_number) {
                        $returnMessage = $returnMessage . "\n" .
                            $this->Members[$f_number] . ": " . $f_number;
                    }
                }
                $this->response($returnMessage);
            }
        }
    }

    private function response($message) {
        header("content-type: text/xml");
        echo "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n";
        echo "<Response><Message>" . $message . "</Message></Response>";
        return true;
    }

    public function post() {
        global $request;
        $this->receiveMessage($request);
    }
}

$margRoutes    = array(
    "/message" => "Messenger",
);
Marg::run($margRoutes);

?>

Depends upon https://github.com/Joeasaurus/marg