What to do with Locidesktop?

June 30th, 2010

So what to do with locidesktop.com? It's a desktop-like website bookmarking tool – if you haven't seen it, take a quick look at this example desktop.

I built Loci Desktop a few months ago and promoted it on a few geek sites. It's been running ever since, with no maintenance from myself, happily serving up start pages to a small number of regular users. There was a buzz when I promoted it, people were largely impressed, some were indifferent, but few ended up using it regularly. So now I'm left with a quandary.

I could try and promote it. But to what end? It's not like I need a certain number of visitors to cover the hosting. I'm using the same VPS as I am for my blog, and I designed Locidesktop to be ultra-low bandwidth anyway – so it effectively costs me nothing to run.

One option would be to sell the entire site outright, as the domain and technology rights. But there is currently no way of monetizing it and I doubt anyone would be interested as a commercial venture.

I could try and license it as a b2b service. A few people have commented that it would be a useful intranet service. I'm not sure about this, but it sounds plausible.

Alternatively, I could give back to the Django community and release it as open source, which I imagine would be the popular thing to do. Money isn't my primary motivator (a close second perhaps), so I wouldn't be averse to doing this. Thing is though, it would require work on my part to document it and maintain it, and I have other open source projects I would prefer to concentrate on. But I can't deny that it would be cool to see Locidesktop sites popping up over the interwebs.

Finally, I could just leave it as is. I'm pleased with how it turned out, and I have a few loyal users. Maybe I should just be satisfied.

Any options I haven't considered? Leave a comment…


PyFilesystem 0.3 released

June 20th, 2010

I am pleased to announce a new version of PyFilesystem (0.3), which is a Python module that provides a common interface to many kinds of filesystem. Basically it provides a way of working with files and directories that is exactly the same, regardless of how and where the file information is stored. Even if you don't plan on working with anything other than the files and directories on your hard-drive, PyFilesystem can simplify your code and reduce the potential of error.

PyFilesystem is a joint effort by myself and Ryan Kelly, who has created a number of new FS implementations such as Amazon S3 support and Secure FTP, and some pretty cool features such as FUSE support and Django storage integration.

As an example of how awesome this package is, take a look at the following 6 lines of code, which creates a ramdrive:

from fs.osfs import OSFS
from fs.memoryfs import MemoryFS
from fs.expose import fuse

home_fs = OSFS('~/')
home_fs.makedir('ramdrive', allow_recreate=True)
fuse.mount(MemoryFS(), home_fs.getsyspath('ramdrive'))

If you run this, a directory called ramdrive will appear in your home folder, the contents of which are stored purely in memory.

I prepared a screencast that gives a quick demonstration of some features – because if a picture is worth a thousand words, this video must be worth fifteen thousand words a second:

PyFilesystem screencast from Will McGugan on Vimeo.

See the project page on google code for more information, including API docs. There are also a couple of blog posts that will give a some more context.

This release has reached a good level of stability and maturity. I'd like to invite as many Pythonistas as possible to check out this module and possibly contribute to the project.


Review of Django 1.2 E-commerce

June 19th, 2010

I've worked with Django for more than two years now. The majority of the sites I have worked on have been social-networking or content based, but I have yet to do any serious work on a site where the main purpose is to advertise and sell products. So I when a copy of ‘Django 1.2 e-commerce’ landed on my desk I was intrigued by what it might cover that I hadn't been exposed to with other fields of Django development.

Django 1.2 e-commerce

Django 1.2 E-commerce

The book starts out with a brief run-down of Django. The first chapter is more of a explanation of the philosophy behind Django, and definitely not a tutorial. Which I think is fair enough; if you are building an e-commerce site, you are probably a professional Python developer and there are plenty of books to get you up to speed with Django. In the second chapter, the author runs through a simple web-shop application with an inventory and a ‘buy now’ button – which seemed more like a confidence building exercise than anything else, but it does do a good job of demonstrating how simple it can be to build this kind of application with Django.

The subsequent chapters go in to detail regarding managing users, shopping-carts and taking payments with Google Checkout and Amazon services. I've never used these payment services, so I found the information particularly interesting. I like the author's approach of making generic views in order to share functionality across payment services, but I would have liked some more detail in to the APIs involved.

Chapter 6 was a surprise, it covers a variety of modules that you can use to add powerful search capabilities to your application. Django's database querying will only get you so far with searching, if you need more sophisticated searching of the kind you would expect from Google then you will need to integrate one of a number of external modules and services, which chapter 6 covers pretty well. The following chapter covers exposing data via several APIs, and creating PDF reports with ReportLab, but not in any great detail.

I was impressed with chapter 8, which covers writing JavaScript to create rich AJAX interfaces – something which is pretty much expected in a modern web-site. I would have preferred a more detail here, but only because I have a particular interest in front-end technologies. The next chapter explains how to integrate a Django application with Amazon payment services and S3 storage to sell digital goods, and goes it to more detail than other chapters.

The final chapter covers a number of options you will have for deploying your application. If your application is moderately sophisticated and has many components, deployment can be a tricky affair. This chapter explains how Python technologies such as Fabric, Buildout and Virtualenv can ease deployment headaches. It also covers serving the site with Apache and ‘mod_wsgi’.

The code snippets in this book are pretty good at demonstrating the subjects covered, but I did notice some quite glaring syntax errors in several of the code examples. The errors weren't subtle either; they would result in the code not even running. I suspect that many of them were likely to be the result of a non-technical editor re-formating the code and not a mistake on the part of the author, but there were also a number of programming errors and bad practices which were a little disapointing to see in a book aimed at professionals. For instance, the author consistently used the ‘is’ operator in place of the equality operator (they are not interchangable even though they may appear to be).

Overall, my impression of this book was favourable. It's definitely not a tutorial book in that its not going to teach you any new skills – since it covers so many technologies and doesn't go in to great detail about any of them. What it will do is give you a grounding of the components in an e-commerce system. If you are looking to build some kind of web-shop in Django then I would recommend this book. It's less of an essential purchase if you aren't working with e-commerce, but since many of the topics discussed in Django 1.2 e-commerce are applicable to other web-sites you may still want to check this book out.


Creationists in Oxford

June 18th, 2010

I often read about creationism in the US, and its followers. I tend to find it amusing, and just a little worrying as their numbers are not insignificant. We have plenty of street preachers here in the UK, but until today I have never seen those US-style anti-science evolution deniers on the streets.

Creationists in Oxford


I watched for 10 minutes as I ate my sausage roll, and listened to the standard creationist spiel of how everything must have a beginning and an end, and how everything created must have a creator and how there are no transitional fossils. It was quite entertaining!

Amazing to have that right here in Oxford, a place of learning. There's a natural history museum just around the corner. I wonder if they had ever been?


Announcing Sore Thumb, a thumbnail and image processing module for Django

June 14th, 2010

I recently worked on the re-design of 2 Degrees, which required a lot of image processing on thumbnails. The thumbnails where to be in a variety of different sizes, all with rounded corners and keylines on a selection of virtually identical off-white backgrounds and gradients. And they all had to work on IE6 *spit* without the transparency hack.

Sorethumb examples

A variety of thumbnails generated by Sore Thumb

A lesser engineer may have told the front-end developer where to stick his rounded corners, but I didn't want see a grown man cry, so I built Sore Thumb, an on-the-fly thumbnail and image processing system for Django.

Sore Thumb uses a declarative method of defining thumbnails, similar to Django's model and form definitions. Here's an example of how to declare a thumbnail processor that produces a 120x100 pixel thumbnail with 10 pixel rounded corners and a dark grey keyline:

from sorethumb.djangothumbnail import DjangoThumbnail
from sorethumb.filters.defaultfilters import ThumbnailFilter
from sorethumb.filters.drawfilters import RoundedCornerFilter

class RoundedCornersEdged(DjangoThumbnail):
    format = 'png'
    filters = [ThumbnailFilter(120, 100),
               RoundedCornerFilter(10, border='#333')]

Once this class has been imported, the thumbnail processor will be available in templates via the sorethumb filter which takes a Django FileField and returns the url to the thumbnail.

For example:

{% load sorethumb %}

<img src="{{ profile.photo|sorethumb:"rounded_corners_edged" }} />

You will also need to add sorethumb to your INSTALLED_APPS for this to work.

That's pretty much all there is to working with Sore Thumb, see these examples for inspiration and the documentation for the details.

You can install sorethumb with easy_install, PIP, or directly from source:

easy_install -U sorethumb

Please let me know what you think of Sore Thumb. I'd rather not spend too much time maintaining it, but since most of the code has been in production for a number of months already, there shouldn't be many changes required. If you have any feature requests or bug-reports, now would be a good time to raise them while I have the time to do the work!

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