I’ve been cleaning up my personal blog a bit, and I noticed that my tagging system recently broke. I’ve investigated the cause, and it appears to be because I removed some apps but the contenttypes remained. This meant that whenever I tried calling a tag with a TaggedItem that had been deleted, I was getting this error: 'NoneType' object has no attribute '_meta' The solution is to first list all app_labels for contenttypes, and then delete any not in use.

I recently had the desire to send small updates to my so called lifestream page via XMPP/GTalk. I played around with Twisted Words and several other Python XMPP clients, but I didn’t really want to keep a daemon running if unnecessary. It turns out imified took a lot of the pain out of it. The steps for me were as follows: Create an account with imified, and create a URL, e.g. /app/api/ We then configure the urls.conf

I was having some issues with my personal mail server (Postfix) and my phone (Android). The logs depicted the below issue: Jan 9 09:19:53 ip-11-222-23-223 postfix/smtpd[12345]: NOQUEUE: reject: RCPT from 12-13-14-15.abc.com.au[12.13.14.15]: 504 5.5.2 <localhost>: Helo command rejected: need fully-qualified hostname; from=<emailaddr kelvinism.com="kelvinism.com"> to=<emailaddr gmail.com="gmail.com"> proto=ESMTP helo=<localhost> </localhost></emailaddr></emailaddr></localhost> We can see here that the stock Android email client is doing a ‘helo localhost’. One part of my main.cf file specifies this:

I’ve recently returned from a short trip home, and I had a wonderful time. I had the opportunity to visit family and friends, eat plenty of delicious food, and generally relax. I reduced the amount of old belongings stored under the house by 80% and gave away all my old books, which are archived on Goodreads.

A few weeks ago I saw an opening to give a 5-10 minute lightening talk at SyPy (Sydney Python), and with two nights to prepare, decided it would be interesting to explore Splunk’s usage of Python. You can see the presentation video

I like using Ubuntu’s UFW command, but today I needed to allow outgoing ICMP. I received results as so: $ ping 4.2.2.2 PING 4.2.2.2 (4.2.2.2) 56(84) bytes of data. ping: sendmsg: Operation not permitted ping: sendmsg: Operation not permitted ping: sendmsg: Operation not permitted To allow outbound icmp I edited ‘before.rules’ and added the following lines. $ sudo vi /etc/ufw/before.rules # allow outbound icmp -A ufw-before-output -p icmp -m state --state NEW,ESTABLISHED,RELATED -j ACCEPT -A ufw-before-output -p icmp -m state --state ESTABLISHED,RELATED -j ACCEPT

I recently had the need to add some HTML to the label for a form field using Django. The solution is pretty easy, except I didn’t see it written explicitly anywhere, and I missed the memo of the function I should be using. My form first just had the HTML in the form label as so: from django import forms class AccountForm(forms.Form): name = forms.CharField(widget=forms.TextInput(), max_length=15, label='Your Name (why?') However, when I displayed it, the form was autoescaped.

I’ve started to get into Google’s App Engine again, and have started developing a simple product that I had a use for. The initial first draft was a quick 200 lines in webapp, and it worked great. However, I’m starting to find certain things quite cumbersome. I’m a huge fan of Django, and but also about keeping things as simple as possible, which is why I picked webapp to begin with. I’m now considering making a swap to Django, but there are some development issues; namely, I’m using Ubuntu 10.04, Python 2.6, and Django 1.2. This setup presents several setbacks, as GAE has the requirement of Django 1.1 and Python 2.5. There are two solutions that I found: a) use virtualenv, …

All my Django sites are running 1.2, which poses a conflict with writing apps for Google’s App Engine, as use_library currently only supports < Django 1.1. There are two solutions that I found: a) use virtualenv, or b) chroot, which I’ve already detailed. This document will hopefully show you how to create a virtual environment to use a secondary django version, especially for GAE. Of the two options, I think this one is a bit quicker, but there will likely be tradeoffs that a chroot environment can deal with better, e.g. python imaging (I don’t use it for GAE). First, install PIP and virtualenv:

One thing I love about open source stuff is that the developers usually take great care to allow awesome debug messages. There’s a catch-22, however: how much logging to enable? Today I was creating a Postfix/Dovecot/Postgresql install and I kept getting an error message in mail.log, but it wasn’t very helpful. Luckily you can turn up the verbosity in Postfix for error messages. You’ll need to find out what component is in error, e.g. “postfix/virtual[4467]: warning:”, and then open master.cf. Add a -v to the end of the daemon that’s faulting, and you’ll get more logging than you know what to do with.