Thoughts Electrique

I once had to install a custom PHP extension on a 1&1 managed server. In this case the company had already purchased a managed server which was running the corporate website. They wanted to install an extranet-like webapplication which needed the ImageMagick PHP extension. In the following post I will outlike how I compiled and installed this extension on the managed server without having administrative access.

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For a current hosting server I’m using the Plesk control panel 9.0.1 for Ubuntu 8.04. Since version 9 Plesk allows the usage of Postfix as an MTA and PHP via FastCGI. This is very nice and much more secure than the old model using mod_php.

The Problem

One problem with the current Plesk version (as with most Plesk versions :/) is that it has some nasty bugs. For example mod_rewrite doesn’t work with the FastCGI configuration. The problem is that the generated virtual host configuration has a small but important problem. The generated host looks something like this:

<VirtualHost 88.198.164.10:80>
  ServerName   playground.himberger.de:80
  ServerAlias  www.playground.himberger.de

  <IfModule mod_fcgid.c>
    <Files ~ (\.php)>
      SetHandler fcgid-script
      FCGIWrapper /usr/bin/php5-cgi .php
      Options ExecCGI
      allow from all
    </Files>
  </IfModule>
</VirtualHost>

The issue with this configuration is the line “Options ExecCGI“. This line enables the execution of CGI scripts for this particular directory but overrides all the Options set earlier. These are in parts needed for mod_rewrite. To fix this the line should be “Options +ExecCGI“. Sadly changing the configuration doesn’t help because at the next opportunity Plesk will regenerate the config file and your change is gone.

Luckily there is a way around this…

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I recently had to restart a Java webapplication because somehow the JDBC connection to the database server was hanging completely. This reminded me of a sentence a friend of mine told me during the OpenCms Days 2008.

“Enterprise software just means that it’s targeted at customers who can afford the guy who restarts the application server every few hours.”

I had to laugh because while the quote is clearly cynical it has a true core. Especially if you compare languages like Java and PHP it’s true that PHP doesn’t have these kind problems. This is mostly because of the throw-away-the-state nature of PHP. After every served request PHP forgets what it’s done before and has to completely rebuild the working environment at the next request. Java in contrast is able to remember things between requests. Which makes it more powerful but also harder to maintain (more state, more problems). I’m really not sure if I’m buying into this enterprise-thing anymore. Especially if you need scalability you definitely want to keep application state at a minimum and without state you don’t really need those big interconnected clusters of application servers any more.

Here is a nice talk about scalability and serious (speak enterprise) languages I found recently. It’s from Cal Henderson a software development guy at Flickr. It’s really worth watching. Even if you’re not into Python and Django.

(Watch it at: http://www.youtube.com/watch?v=i6Fr65PFqfk&feature=PlayList&p=D415FAF806EC47A1&index=10)

The forbidden fruit

I recently discovered runkit for PHP and thought it could be a solution for a few problems I ran into during my work on various projects.

At heart runkit allows you do to stuff with PHP you shouldn’t, but eventually want to, do. In my case this is basically Sandboxing and redefining (even PHP-internal) functions. It really adds some cool stuff to your PHP toolbox. Have a look at the function reference for the complete list.

Sadly enough the runkit PECL package does not work on Debian Etch (because Etch uses PHP 5.2.0+) so I had to build the package myself. Read on to find out how to build and install runkit on Debian etch and things to keep in mind when using runkit.

Important: If you are unsure of using runkit have a look at The sections The Caveat and Final Remarks before you walk through the hassle of installing it.

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