Verifying windows 8 purchases (receipts) using PHP

Question

I need to verify in-app purchases made in Windows 8 applications server-side using PHP. MSDN\'s documentation page has an example only in C#. Right now I\'ve spent a whole d

Answer 1

I managed to verify WP8 IAP receipt using xmlseclibs library.

Also, you need php curl enabled.

do {
    $doc = new DOMDocument();

    $xml = $_POST['receipt_data']; // your receipt xml here!

    // strip unwanted chars - IMPORTANT!!!
    $xml = str_replace(array("\n","\t", "\r"), "", $xml);
    //some (probably mostly WP8) receipts have unnecessary spaces instead of tabs
    $xml = preg_replace('/\s+/', " ", $xml);
    $xml = str_replace("> <", "><", $xml);

    $doc->loadXML($xml);
    $receipt = $doc->getElementsByTagName('Receipt')->item(0);
    $certificateId = $receipt->getAttribute('CertificateId');

    $ch = curl_init("https://lic.apps.microsoft.com/licensing/certificateserver/?cid=$certificateId");
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0);
    curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);

    $publicKey = curl_exec($ch);
    $errno = curl_errno($ch);
    $errmsg = curl_error($ch);
    curl_close($ch);

    if ($errno != 0) {
        $verifyFailed = true;
        break;
    }

    // Verify xml signature
    require('./xmlseclibs.php');
    $objXMLSecDSig = new XMLSecurityDSig();
    $objDSig = $objXMLSecDSig->locateSignature($doc);
    if (!$objDSig) {
        $verifyFailed = true;
        break;
    }
    try {
        $objXMLSecDSig->canonicalizeSignedInfo();
        $retVal = $objXMLSecDSig->validateReference();
        if (!$retVal) {
            throw new Exception("Error Processing Request", 1);
        }
        $objKey = $objXMLSecDSig->locateKey();
        if (!$objKey) {
            throw new Exception("Error Processing Request", 1);
        }
        $key = NULL;
        $objKeyInfo = XMLSecEnc::staticLocateKeyInfo($objKey, $objDSig);
        if (! $objKeyInfo->key && empty($key)) {
            $objKey->loadKey($publicKey);
        }
        if (!$objXMLSecDSig->verify($objKey)) {
            throw new Exception("Error Processing Request", 1);
        }
    } catch (Exception $e) {
        $verifyFailed = true;
        break;
    }

    $productReceipt = $doc->getElementsByTagName('ProductReceipt')->item(0);
    $prodictId = $productReceipt->getAttribute('ProductId');
    $purchaseDate = $productReceipt->getAttribute('PurchaseDate');
} while(0);

if ($verifyFailed) {
    // invalid receipt
} else {
    // valid receipt
}