Patrick Valsecchi’s delirium

Today, I upgraded my two old rails applications to Rails 2.3.2. Those application were written originally for rails 2.0 and have been upgraded to each consecutive Rails versions. Each time I had some tweaking to do but they were usually documented. But this time nothing.

Here are the two problems I had to fix:

• uninitialized constant ApplicationController:
  For some reason, when I created my applications, the ApplicationController class was sitting in the app/controller/application.rb file. The new version doesn’t like that anymore. I renamed this file to application_controller.rb and voila.
• NoMethodError: undefined method `tmpdir’ for Dir:Class:
  Just had to add a require 'tmpdir' in the right place

Not too painful, but could have been documented in the release notes.

To continue the discussions around the methods introduced in my previous post, I’ve run some tests to compare the performance between:

• Direct MapServer
• TileCache in CGI mode
• TileCache in mod_python mode
• Apache caching

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In the web GIS world, it’s usual to have a base map that is a static layer. While MapServer and GeoServer are quite fast to serve raster maps, one can do better. Especially when serving tiles.

This post discusses my experiences with TileCache and pure apache caching.

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I worked or analyzed quite a few Java applications in my professional life. The majority of those applications where servlets and I hated to work on all of them.

Why? Because all of them where pure enterprise level scalable bloatware.

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Now a day, an average AJAX page uses around to 1MB of CSS and Javascript files. If the users or the servers have a poor bandwidth, it may take some time to download them.

In order to lessen the pain of those poor souls, you may consider displaying a progress bar while the page is loading.
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In this post I’ll try to explain why 10 megapixel are too much for the size of the lenses and sensors of a compact digital camera.
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If you want to use the Google Analytics service, you have to include some JavaScript code at the end of all your web pages.

When you are lazy like me, you don’t want to edit all your pages/scripts to do that. This post tells you how to do it in one minute. Read the rest of this entry »

I was trying to deploy one of my application in a Tomcat5.5 on Debian Edge the other day.

That application was running fine in unstable, but on Edge was failing to get a connection with my DB with this error:

java.lang.RuntimeException: org.apache.commons.dbcp.SQLNestedException:
Cannot create JDBC driver of class '' for connect URL 'null'

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OK, I’ll try to do like everybody and open my blog. It will be mostly technical and contain some tips and tricks in computer science.

So don’t expect funny stuff or pictures of nude girls in here. For geeks’ eyes only.