How do you notify Google through code that there is a updated sitemap?

Question

On this page of Google help:

https://www.google.com/webmasters/tools/docs/en/sitemap-generator.html#submitting

Google mentions that there is a way to notify them of an updated sitemap using an HTTP request.

When you click the link, it takes you to this page:

http://www.google.com/support/webmasters/bin/answer.py?answer=34592&topic=8482&hl=en#ping

But there is no information on where to ping with what request.

Does anyone know what this address is and what parameters are required?

Answer 1

http://www.google.com/webmasters/sitemaps/ping?sitemap=URL-encoded URL to your sitemap

Answer 2

Simplest solution: file_get_contents("https://www.google.com/webmasters/tools/ping?sitemap={$sitemap}");

That will work on every major hosting provider. If you want optional error reporting, here's a start:

$data = file_get_contents("https://www.google.com/webmasters/tools/ping?sitemap={$sitemap}");
$status = ( strpos($data,"Sitemap Notification Received") !== false ) ? "OK" : "ERROR";
echo "Submitting Google Sitemap: {$status}\n";

As for how often you should do it, as long as your site can handle the extra traffic from Google's bots without slowing down, you should do this every time a change has been made.