Monthly Archives: February 2009

A Simple PHP Google Sitemap Generator

I just hacked together a very simple class and CLI script to help me generate Google sitemap XML on a daily basis using PHP. If you have not yet heard of it: Google sitemaps help you promote your content if you have certain deep links that only show up if a visitor for example performs a search and clicks a result.

Check the documentation of the Google Sitemap Format

Here is the code: Google Sitemap Generator

It works like this:

$ php generate_gsitemaps.php; #will generate your standard sitemap
$
php generate_gsitemaps.php -e > my_sitemap.xml; #echo sitemap xml to another file

Example: generated_example_sitemap.xml

Have fun being found!

Upgrade PHP5 with an alternative sources.list on Debian etch

I was having trouble with a server running Debian 4.0 (etch). Using the standard sources in the /etc/apt/sources.list the supported PHP5 version was 5.2.0-8+etch13 which contained a very annoying bug for my application.

A daily running script – let’s call it the Importer – regularly exited randomly with a “Fatal error: Out of memory (allocated 12320768) (tried to allocate 2851436 bytes) in …” and I had to restart it manually nearly every morning. I had…

  • …checked my application for memory wasting operations and loops and fixed them,
  • …used ini_set(‘memory_limit’, ’64M’); at runtime, and
  • …finally increased memory_limit = 64M in my php.ini.

But all this did not change the bahaviour of the Importer!

So I took a look at the PHP5 Changelog to find potentially fixed bugs in newer releases. Bug #39438 described exactly my problem. So a simple upgrade would help me. But it did not work with ‘apt-get upgrade’ or ‘apt-get install php5=5.2.8′ since the highest version in the apt source I used was the one that I already had: 5.2.0-8+etch13, issued in November 2006… (pretty ancient)

Finally it was this page that had the information we needed: an alternative apt source

deb http://packages.dotdeb.org etch all
deb-src http://packages.dotdeb.org etch all

After getting an impression whether dotdeb was a trustworthy source, we first tried it on our dev-system with ‘apt-get update; apt-get upgrade;’. At this point I was once more glad to have written so many UnitTests. They all passed and everything looked good.

Thanks Kim for your help!

Etherpad

EtherPad is a free webbsased editor which lets people remotely and simultaneously edit the same text document. Just click ‘Create new Pad‘ and you see the URL which you can send to your remote friend(s).

etherpad_screen

Use it for group development on code snippets, catch realtime meeting minutes, brainstorming ideas and many things more…

Thanks AppJet for this nice tool!

Clickjacking

Today I learned a new term from the web security section – Clickjacking – which I would like to make you aware of.

To see it in action, please visit the blog post of Flash developer Guy Aharonovsky, where he demonstrates in a video how a user unintentionally changes his browser’s security settings while playing a JavaScript game. As a result the user ‘allows’ activation of his webcam and microphone without knowing about it.

The above mentioned exploit in the video has already been fixed by Adobe. But there are more ways to hijack your clicks. The clickjacking exploit opens a wide playingfield for the bad guys out there. Get more background info (in German) here.