my nest somewhere in GitHub's forest

Pinging Google With A Service Hook

Recently I added a sitemap to this site; Jekyll facilitated the creation act, so what was left to do? Pinging Google, just to say a name, automatically.

First of all, I thought about using something like the post-merge Git hook, but, assuming it worked, it would force a strict workflow (always work in a topic branch and merge on master only when you have a working connection). Another option could be to wrap everything in a micro-script to call manually after receiving Github’s notification of a successful rebuild. Then a “crazy” idea started to elbow its way toward my cortex… but first, a bit of background (for myself, actually, so that I can remember why I did things in a given way).

Let’s take Google’s instructions:

  • identify sitemap’s URL (say,;
  • escape it (;
  • use it to build the complete ping URL (;
  • then “ping” that last URL with wget or curl; if you get a 200 response, then you’re done.

N.B.: A simple use of wget or curl will generate a GET request.

Let’s turn to Github. In the administrative section of every repository there’s a long list of service hooks; the official Github’s guide is The Source of information about them, but let me note here that service hooks are POST requests with a given payload.

So, GET vs. POST? Can we POST to Google to report an updated sitemap? Maybe… if Google does not adhere to the REST credo.

As of today, in response to the preceding command Google returns a 200 response, i.e., it seems we can “ping” Google with a POST request and even extra data. Will it hold? Time will tell.

Back again to Github: the general post-receive service hook is the way to go because (at least at the moment) there’s no more specific hook. Let’s add the complete URL (that one with the escaped sitemap URL at the end) to the list and then test it: if it works we’re done.

If everything holds, when we push to the on-line repository Github will notify Google about the updated sitemap and rebuild the site. Maybe, occasionally, Github’s queue could be a bit clogged and Google could have some spare resources to re-read the sitemap before the refresh… in that case a manual (!) “ping” will fix the problem.