When I set up Pylons today in a virtual isolated Python environment on my Windows machine, I had a little fight with psycopg2 (which usually allows me to connect to my PostgreSQL database). At first, everytime I tried to “easy_install psycopg2″, I ended up with the error message “unable to find vcvarsall.bat”.

Luckily I found a solution to get the  “unable to find vcvarsall.bat” problem fixed.

But unfortunately there was another error when I wanted paster to serve:

File “C:\Python26\lib\site-packages\psycopg2\__init__.py”,
line 60, in <module>
from _psycopg import BINARY, NUMBER, STRING, DATETIME, ROWID
ImportError: DLL load failed: This application has failed to start because the application configuration is incorrect. Reinstalling the application may fix this problem.

Of course, reinstallation did not fix the problem. I thought the whole challenge might be caused by my virtual environment, because Jason Erickson (who publishes the psycopg Windows binaries) mentioned problems that would occur when using psycopg with virtual environments in his blog. But nothing I tried improved my situation.

Solution: Use an older version (2.0.10) of psycopg2!

Later on I found a post in Google Groups, where someone had a similar problem with psycopg2 under Windows. He figured out that there was something wrong with the build of psycopg2 (version 2.0.12) and that simply using an older version (for example 2.0.10) worked fine… That made my day!

Im Rahmen meines Studium an der University of Western Sydney führe ich bis zum 17. September eine Online-Umfrage zum Thema “Web Analytics für Blogs” durch. Konkret soll anhand der Umfrage festgestellt werden, ob und wie Blogger Web Analytics betreiben, sowie herauszuarbeiten, wodurch die Entscheidung Web Analytics im Zusammenhang mit Blogs zu verwenden beeinflusst wird.

Aufruf!

Hiermit rufe ich alle Blogger auf an der Online-Umfrage teilzunehmen und auf die Umfrage hinzuweisen.

Die Teilnahme dauert weniger als fünf Minuten und unter allen Teilnehmern wird eine Ausgabe von April Hodge Silver’s und Hasin Hayder’s WordPress 2.7 Complete (eBook) verlost!

» Zur Online-Umfrage!

Die Ergebnisse der auf der Umfrage aufbauenden Studie werden voraussichtlich im November auf der Website wopsta.org veröffentlicht, auf der es um Web Analytics für Blogs im Allgemeinen und die Entwicklung eines WordPress real-time Visitor Statistics Plug-in im Speziellen geht.

During the last few hours I was playing around with Ext JS charts. I got stuck for a while because the height of my y-axis was limited to one; no matter what I tried and how high the numbers of my records were – the y-scale was fixed to 1.

After some time I figured out that there’s a problem with PHP’s json_encode(). Due to that problem I formatted the data for my chart as strings (with quotation marks) instead of integers (without quotation marks).

There are two solutions to fix this problem: First, you can make sure that the PHP variables that contain integers are really numeric types (and not strings). The second, much easier solution, is to properly define the Ext JS fields for the charts:

fields = [
  {name: 'interval'},
  {name: 'field1', type: 'int'},
  {name: 'field2', type: 'int'}
];

And that’s it!

Although it is quite easy to reload the data that underlies an Ext JS GridPanel, I spent some time figuring out how to do it, especially because the first result on my search on Google leaded me into a wrong direction…

Ext.getCmp('<GridPanel-ID>').getStore().reload();

That’s all you need! Get your GridPanel by its ID and reload its DataStore. The data will be fetched from the ressource specified and the GUI will be refereshed immediately.