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Note on upgrading Postgres.app for Python developers (psycopg2)

Thu, 29 Oct 2015 14:46:43 +0100

The Postgres.app website has pretty detailed information on upgrading your installation, however it does not cover a situation I came across.

After upgrading a minor release (9.3.x -> 9.4.x) psycopg2 failed to run with the following error:

Library not loaded: /Applications/Postgres.app/Contents/Versions/9.3/lib/libssl.1.0.0.dylib

Fixing this issue required that I reinstall and rebuild psycopg2 without pip’s cache in all my environments.

$ pip uninstall psycopg2
$ pip install --no-cache-dir psycopg2

Though I experienced this issue as a user of Postgres.app, it is very likely that you might run into this issue using other installation methods on OSX and other environments.

Problem With Migrations Whilst Running Tests on a Django Project with PostGIS

Wed, 04 Dec 2013 16:27:23 +0100

So if you are using PostGIS 2.0 and get an error like this:

django.db.utils.ProgrammingError: type modifier is not allowed for type "geometry"

You probably still have your template_postgis template that Django checks for and you need to remove it.

Fix: Supervisord not reading configuration when setup from Debian Squeeze package

Thu, 27 Jun 2013 16:44:51 +0200

So I was setting up supervisord on a Debian server and figured the cleanest way to install and set it up would be to apt-get install supervisor however after a little bit of confusion I found this package is not properly set up to read the default config provided in /etc/supervisor/supervisord.conf.

So you need to open up /etc/defaults/supervisor and change the following line:

DAEMON_OPTS=""

to:

DAEMON_OPTS="-c /etc/supervisor/supervisord.conf"

Then:

/etc/init.d/supervisor stop
/etc/init.d/supervisor start

Then you should have a working setup of supervisord.

Serialize Mixin for Django Models

Wed, 01 May 2013 14:31:11 +0200

This is by no means finished and tested but I have been trying to find a simple way of serializing model instances data so I can just go ahead and json.dumps that data. I find the built in serializers in Django don’t quite fit what I want.

Here is what I got so far:

Django Tip: CSS classes on your form fields

Thu, 18 Apr 2013 14:29:57 +0200

I wanted to apply some Javascript to certain date fields (but not all) in an application I am working on. I wanted to keep it as simple as possible on the frontend. It is difficult to do this in a generic way when you are working with Django forms since a DateField is rendered as a plan old text input by default. At least that is what I thought…

After a very short time digging (surprised I missed it before) I found that you can pass an attrs argument to a widget that basically sets attributes on the rendered HTML element. So now my field looks like this:

date_from = forms.DateField(
    widget=forms.DateInput(attrs={'class': 'datepicker-pls'})
)

…and class="datepicker-pls" is on the rendered widget.

Django snippet: as_json decorator for simple views to return JSON

Tue, 16 Apr 2013 18:41:00 +0200

I find myself returning simple dict objects as JSON for the browser to use a lot so I find this little decorator handy in my views:

Geez! "error: no such option: --with-xunit" when running tests with django-nose

Wed, 10 Apr 2013 15:34:00 +0200

So I came across a problem where I was running tests with django-nose using the --with-xunit option and I was meeting the error:

error: no such option: --with-xunit

After much hair loss and confusion I found the following solution to work. The problem appears to be caused by south (although I do not know why) so moving ‘django_nose’ after 'south’ in the INSTALLED_APPS setting made the option available again.

"What you don’t know can hurt you, only you won’t know it."

Thu, 28 Mar 2013 10:59:23 +0100

“What you don’t know can hurt you, only you won’t know it.”

- found in fortunes-mod

Fix: Browser links not working in MonoDevelop

Wed, 27 Mar 2013 23:04:00 +0100

I came across this minor, but annoying problem after installing MonoDevelop where the clicking the browser links just caused an error.

Since I use a very simple lightweight setup of Xmonad it was sufficient to add the following to my ~/.xinitrc file:

export BROWSER=chromium

Or firefox, or opera or whatever you want I guess.

Fix: Xmobar hidden by windows in Xmonad

Wed, 27 Mar 2013 10:30:00 +0100

I had this problem when I started up X this morning that Xmobar in my configuration was being hidden by windows, like they were displayed over it. My configuration had not changed in this regard for about 2 years and I had never come across this problem before, so I went to have a look on the Arch Forums. I came across this thread and whilst there is a number of solutions here what worked for me was the following:

$ vim ~/.xmonad/xmonad.hs  # Check config
$ xmonad --recompile

Then hit mod-q and it was back to normal.

Update

A day later, the same problem came up again when starting my work PC. I took another look at that same thread where the posters had suggested that it is a bug in Xmobar causing the problem. So I downgraded to 0.15-1 using the downgrade utility from AUR and this time my problem is resolved.

Update 2

This is seemingly fixed in 0.17-1.

Arch Linux: Clementine does not play some audio source after installing...

Tue, 26 Mar 2013 19:53:00 +0100

You need to install the following package:

$ sudo pacman -S gstreamer0.10-plugins

Now when you start Clementine, the audio source you are trying to play should play.

My son made a picture of me today, it’s interesting. The...

Tue, 16 Oct 2012 18:09:00 +0200

My son made a picture of me today, it’s interesting. The leaves are my facial hair.

Pricing - Net and Gross? Which is Which? (I didn't have a clue)

Tue, 25 Sep 2012 00:00:00 +0200

Just a quickie. It sounds ridiculous thinking about it now that I did not know this nor was I able to figure it out, but it’s showing more and more over time that I don’t have the aptitude for finance related concepts.

After searching on Google for an answer to “what number is net and what number is gross?” I found myself more confused by the answers I came across. Eventually I got a moderately straight answer so here it is described as I would have understood it.

Net - The price before tax (ie the amount your client is probably putting in to their online store admin)
Tax - A percentage of the net price (20% for example)
Gross - Net + Tax (the price the customer pays)

So if the most expensive can of Heinz Baked Beans is €120. That means it’s Net price will be €100 as there is €20 tax.

That’s all I needed to know. I hope there isn’t anyone else as bad at this stuff as me, but if there is, I hope they find this and it helps them.

Encoder for ids in the url for Django apps

Sat, 19 May 2012 14:50:00 +0200

Simple, fuzzy, timesince function for use in Javascript

Wed, 25 Jan 2012 11:23:00 +0100

Using The Old .deb Installer (gdebi) Instead of Software Centre in Ubuntu

Fri, 16 Sep 2011 06:55:00 +0200

The new Ubuntu Software Centre is really great, and I often explore it to find the awesome packages that are available to install. One thing that bugs the hell out of me, however, is that in recent versions of Ubuntu .deb files (ie when you download a deb package and manually install it) open in the Ubuntu Software Centre and the process is incredibly SLOW.

I have dealt with this and just accepted it, instead using the command line (dpkg) instead to avoid using the Ubuntu Software Centre, but I occasionaly forget and just double click the deb file to launch it. Today I decided to solve this problem for myself, so here is how I did it.

Tip: How to give the old deb installer it’s place back in newer versions of Ubuntu (instructions are assuming use of pcmanfm, if you are using nautilus, you should start using pcmanfm, it’s better - otherwise the process is much the same in nautilus)

First

sudo apt-get install gedbi

This will get gdebi installed. Next find a .deb file you wish to install with your file manager, right click it then select “Open with…”

In the “Custom Command Line” tab enter the following

gdebi-gtk %f

Click the checkbox next to “Set selected application as default…blah” and finally click “Ok”.

The deb should load up with gdebi and double-clicking .deb files in the future should fire up gdebi instead of Ubuntu Software Centre.

Again, Ubuntu Software Centre is great for discovering and installing software that is available in the Ubuntu repos but I just think it should be keep out of the loop if I found the software else where.

Stuff I learnt whilst not watching TV

Sat, 03 Sep 2011 11:00:00 +0200

So I noticed my partner’s younger brother (13) gets asked questions like, “Are you on the computer again?” and other naggy-like comments as he will spend a lot of time at the computer playing video games. I don’t think there is anything wrong with this, he is engaging his brain, socialising and having some fun at the same time.

This got me thinking as I experienced the same sort of nagging when I was a child at home living with my parents. They would complain about the amount of time I spent at the computer and the amount of time I invested in video games - in fact they still do this. This is totally understandable, as hacking around on a PC and playing video games isn’t for everybody so I wouldn’t expect anything else. I feel the same way about TV; I do not understand the draw it has and wonder how people can sit and watch so much television.

So from whatever age I was when my parents first brought home a games console, and brought home a PC I was hooked on hacking, learning and gaming. As I grew older, I spent a larger portion of time at my PC learning new skills and leveling up - and this has continued right up until now. I don’t regret any of it, not one bit.

So here is a list of some of the stuff I learnt and did whilst not watching TV (in no particular order)

Learnt GFA Basic
Played Final Fantasy VII three times (possibly one of the best gaming experiences ever)
Learnt how to make visualisations for Winamp
Learnt Python (£££ this now pays my bills)
Learnt PHP (this does not pay my bills)
Learnt to write Javascript and later use awesome libraries like jQuery
Learnt about servers, how to build websites and services (£££)
Discovered loads of awesome music using last.fm
Played with and discovered many distributions of Linux including Fedora, SuSe, Debian, Ubuntu, Gentoo
Maintained and improved a private Bit-Torrent tracker website
Learnt to use CVS
Learnt to use Git :)
Learnt how to configure, maintain and modify various game server software
Played Chess with Chinese people
Learnt how to build a computer from a set of components
Learnt about disk partitioning - sounds boring but incredibly useful
Learnt to administer Linux and Windows systems
Leartn to compile from source (used to be very important a few years ago, almost never do it now)
Played Phantasy Star Online (maybe the first MMO on a console?)
Played Crazy Taxi (a lot)
Learnt how to sample, create waveforms, tempo match, and use a tracker to create music
Improved my questionable guitar skills by downloading tabs
…

There is loads more, but this is the stuff at the top of my head. Of course I have learnt a lot and done a lot of other stuff whilst away from the computer in this time but I am just writing to say I am sooo glad I didn’t watch TV and beer is good.

Things to do after downgrading to Ubuntu 10.10 (Maverick)

Tue, 03 May 2011 06:01:00 +0200

So after using Natty for a short while, I discovered that it isn’t quite ready for me to depend on full time. After a number of freezes and Wifi issues, I decided to return to Maverick Meerkat (10.10) by downgrading. Here is the script I ran after that. I commented out the lines that write to the home folder since this time I maintained the same home folder on a separate partition.

Things to do after installing Ubuntu 11.04 (Natty Narwhal)

Sat, 30 Apr 2011 05:19:00 +0200

Mouse vs Keyboard - What is happening with the modern desktop environment

Sun, 13 Feb 2011 15:41:00 +0100

I love and use Gnome but have been thinking a lot about how we use computers recently; with Unity coming to the desktop and other similar desktops already in use like iOS on ipad and Windows 7, this has raised thoughts about what desktops environments are.

Reducing it down to a very abstract idea, Gnome for me is a series of text boxes I write in. I’ll be writing here in my web browser to Posterous, then I’ll hit <Alt><Tab> and write to my friend in Empathy then I’ll hit F12 to open a terminal with Guake and manage code with Git then hit F12 to go back to my friend on Empathy then <Alt><Tab> twice and I’ll be editing code in gedit, then I’ll hit <Alt><Tab> twice again and I’ll return to writing to Posterous. I am more than aware that there is plenty to click about with in Gnome but ultimately, most the time I use it I am writing and Alt-Tabbing.

These newer ideas about what a desktop should be require a lot of clicking. Whilst I am very anxious to see Unity at it’s completion and running perfectly on the desktop, this new way of getting stuff done is making me feel old an scared. I know that Unity will still have such keyboard shortcuts but will people like me be able to make the most of these new desktops?

I know that it is going to be great for my girlfriend, but what about us folk who hate reaching for the mouse?