申し訳ありませんが、コメントを投稿するのに十分な評判がありませんが、EdwardOcampo-Goodingの回答からのデッドリンクの内容は次のとおりです。
SimpleXMLを使用したPHPの例（PHP 5以降）
以下のスクリプトは、ShopifyからスクリプトにXMLデータを取り込み、ファイルをアーカイブし、適切なヘッダーを送信する方法を示しています...
Webhookの管理者での新しい注文サブスクリプションの設定は次のとおりです。http：//example.com/some-script.php？key = 123456789
http://example.com/のsome-script.phpの内容：
<?
// Protect URL from rogue attacks/exploits/spiders
// Grab from GET variable as given in Shopify admin URL
// for the webhook
//
// NOTE: This is not necessary, just a simple verification
//
// A digital signature is also passed along from Shopify,
// as is the shop's domain name, so you can use one or both of those
// to ensure a random person isn't jacking with your script (or some
// spider just randomly hitting it to see what's there).
//
// If $key doesn't matched what should be passed in from the
// webhook url, the script simply exits
$key = $_GET['key'];
if ($key != '123456789') {
header('HTTP/1.0 403 Forbidden');
exit();
}
// Variables used for processing/saving
$xmlString = ; // Used to get data from Shopify into script
$name = ; // Saves the billing address name to be used for later ...
$email = ; // Save the email address of the user to be used for later ...
$productTitles = array(); // Saves all titles of products purchased to be used for later ...
// Get XML data and read it into a string for use with SimpleXML
// Thanks to David Oxley (http://www.numeriq.co.uk) for help with this
$xmlData = fopen('php://input' , 'rb');
while (!feof($xmlData)) { $xmlString .= fread($xmlData, 4096); }
fclose($xmlData);
// Save order XML in file in orders directory
// This creates a file, write the xml for archival purposes, and closes the file ...
// If the file already exists, it appends the data ... this should create a separate
// file for every order but if two orders are processed the same second, they'll both
// be in the same file
file_put_contents('orders/order' . date('m-d-y') . '-' . time() . '.xml', $xmlString, FILE_APPEND);
// Use SimpleXML to get name, email, and product titles
// SimpleXML allows you to use the $xml object to easily
// retrieve the data ...
// Please note, if hyphens are used in the xml node, you must
// surround the call to that member with {'member-name'} as is
// shown below when getting the billing-address name & the
// line items
$xml = new SimpleXMLElement($xmlString);
$name = trim($xml->{'billing-address'}->name);
$email = trim($xml->email);
// Create productTitles array with titles from products
foreach ($xml->{'line-items'}->{'line-item'} as $lineItem) {
array_push($productTitles, trim($lineItem->title));
}
// You would then go on using $name, $email, $productTitles in your script
// to do whatever the heck you please ...
// Once you are done doing what you need to do, let Shopify know you have
// the data and all is well!
header('HTTP/1.0 200 OK');
exit();
// If you want to tell Shopify to try sending the data again, i.e. something
// failed with your processing and you want to try again later
header('HTTP/1.0 400 Bad request');
exit();
?>