I recently had to find out if a PNG has transparency using PHP. All the code I found didn't seemed to work correctly for the various kind of PNG I had to deal with. Here is the function I used.
I recently had to find a way to cache a webservice anwsers. Here is the Varnish configuration fitting my needs.
I recently had to deal with CIDR blocks to tighten some webservice security. Here is how I designed it to fulfill my needs.