Presented at the first Django Meeting NL: Django Bingo!

Held a presentation yesterday at the first ever Dutch Django meeting held at the ABC Treehouse in Amsterdam. The meeting grew out of the Python Usergroup Netherlands. The turnout was surprisingly large.

More on the meeting here, or grab my slides+notes directly.

The presentation was the first time I openly discussed this Aperte-project: Dashboards for Django (and "Bingo" was his name, o!). It features a web-based query builder and allows you to easily set up dashboards for your Django applications.


I haven't released the project yet, hope to do so sometime next week. The interest in the project surprised me actually. It seems I'm not the only one who likes pretty graphs and tables, but hates all the work that surrounds building them...

EDIT: Photos of the meeting

Django admin, view-only permissions

The Django admin by default only has the add, change and delete permissions. These permissions allow you to section off your admin, allowing certain users to only modify certain objects (and with my sub-admin class you can limit permissions at an object-level!).

What the admin doesn't allow is giving read-only permissions. The reason for this, according to the Django developers, is that you must trust every user logging into the admin interface. Read-only or view permissions means you don't trust your users, thus they shouldn't have access anyway.

Of course, if we continue this reasoning, why would you have permissions at all? If you trust everyone who logs in you wouldn't need the ability to assign add, change and delete permissions. But the reason behind this is probably that the Django admin hasn't been thoroughly tested for security holes and that they'd rather not have anonymous viewing permissions, which makes sense.

I've written a quick add-view-permissions patch for Django 1.1. The results are unremarkable but effective, as the following screenshots show of a user with view-only permissions:

Feel free to use the patch, but be warned: if users logging in to your site really want to change something, they'll probably find a way through.

I've placed a couple of my Django patches together here.

N900: Just how good is mobile Free software?

Previous article, N900 hardware

The interface on the N900 has been completely revamped compared to the N810. Maemo 5 (fremantle) is much more suited to being used without the stylus, which makes the N900 much more usable as a phone.


There are 4 desktops, similar to the virtual desktops Unix has had for decades. You easily switch between them by swiping either to the left or right. Swiping seems to be a favorite guesture by the designers as it comes back everywhere: photo browsing, file and app lists, even the x terminal supports it for scrolling.

Each desktop can be arranged as you please with widgets, shortcuts and browser links as the above examples show. By default you get Twitter-shitter, Bookface widgets and the like, but who needs those?

The widgets make customizing your N900 for your own "workflow" very easy. I use my calendar a lot, so my main desktop prominently shows my latest todo's, but someone who mostly calls might put most of his contacts on a number of desktops: it's all up to you. I'll look into widget development in the next article.

From the desktop you only have one button in the top left. It either shows you your currently running applications or goes to the application menu screen:

My phone is Dutch (like you didn't notice) but the icons should show the idea. A lot of effort has gone into making multitasking as easy as possible, anyone that checks his email while reading the headlines and writing a blogpost will appreciate the ease of switching.


With the current generation of smartphones you're only as good as your applications are. The default apps on the N900 don't disappoint.

The browser is based on Gecko, the Mozilla rendering engine. One of the advantages is that it also supports add-ons: the web shouldn't be used without Adblock plus! Clicking on links can be a bit finniky, but the stylus makes that kind of browsing a lot more doable. Web sites render as well as with Firefox. Zooming works by either drawing a circle clockwise or counter-clockwise, easy with both finger and stylus.

The N900 has a fully-featured email application. It supports multiple IMAP folders which has already saved me once this week. Attaching multiple files works fine and emailing/texting is a breeze with the keyboard.

The contacts app is surprisingly useful. Instead of choosing to email, text, call or skype someone you first find the person you are looking for. This then gives you all the options you have to contact that person. Skype chat, google talk/jabber support out of the box, but msn, icq and other IM protocols can be installed.

The calendar application is probably my favorite. But that's probably because it's the one I use the most and without it I'd forget everything. Week-view rocks:

The built-in mediaplayer works as could be expected. The audio socket also supports video-out and the '9'-trailer looked great on my hdtv. Together with flash support and mplayer, you have plenty of options. 32GB of flash storage is built-in and a microSD socket is available for even more space: I finally gave my aging iPod away as I can't see myself using it anymore :)

I could go on about the other pre-installed apps, but what might be better to know is that you can install and run lots of maemo-applications. By default you only have access to the "verified" nokia applications repository but the application manager allows you to add new ones: simply add the maemo extras repository and you have access to hundreds of applications for free.

The Ovi-store has a new N900 section that opened last week. The idea is of course to provide a channel for developers to sell their Maemo-applications, but it should also provide a means to easily get high-quality free software.

Teething issues: battery-life and a limited root filesystem

I mentioned some issues I was having in the previous article I wrote on the N900. The N900 being a new direction for Nokia, it's not strange that not everything is perfect.

My main issue is currently battery-life. With such a lot of features and widgets it's not strange to go overboard and install eveything you could possibly want. This eats up power though, and I felt lucky if I didn't have to hook the N900 up multiple times a day. There seems to be a major issue with wifi that rapidly drains the battery, so I'm sticking with 3G for the time being. The N900 has an option to automatically switch to wifi if a known accesspoint is detected, but this drained the battery in a matter of hours. For now I am cutting down on widgets and background-apps (long live 'top'!) which seems to be doing the trick. Improvements and fixes in this area should go a long way.

A more long-term issue is the limited root filesystem size. 'df' shows that the main filesystem only has 228MB, total, of which I have used 163MB. New applications are stored in this filesystem, instead of the 32GB storage available for 'documents' so I can see this becoming a major pita soon. PyMaemo (more on that next time) already uses mount-binding to limit the amount of space wasted on root.

Once the battery-life improves I'll be able to recommend the N900 to the average user. For now it is wise to take the usb cable or adapter with you, just in case.

Next time I'll look at N900 development. Eating my own dog food, this article has been written on the N900.

N900: Is that Debian in your pocket, or are you just happy to see me?

By popular request, a review of the N900, after being submitted to a week of testing!

What is the N900, and why would you want one?

The N900 is a smartphone, but done differently. Where the typical smartphone is locked to a large degree by telco's and manufacturers, the N900 is completely open to use and abuse. It stems from the Nokia internet tablet series (N700->N810) with the Debian / Maemo operating system but this time they finally were able to make a tablet with which you can call.

The N900 is a remarkable tablet and a decent smartphone, however it is a work-in-progress. It is probably most suited to geeks that want Linux on their phone but want a more freer environment than the Android handsets. Normal users probably should wait a couple of months until all the teething issues have been sorted out, but even with those issues it is a full-featured phone for anyone who needs to be online everywhere.

The hardware

Its tablet-origins are clear when compared to the N810:

On your right you have the N95, on the top the N810 and on the bottom the N900.

The N900 has a qwerty keyboard similar to the N810, however the 4-way directional pad was removed. Instead we have arrow keys like a proper keyboard :) The N900 is rather large compared to a regular phone but comparable in size to a iPhone. It also is quite a bit thicker due to the keyboard. The keyboard itself feels decent and lets you type texts and email in a flash.

The screen is smaller than the N810 and like the N810 is resistive (instead of capacitive like the iPhone). On the downside this means that you actually have to press the screen which needs getting used to if you are used to an iPhone, on the upside you can use the integrated stylus for tasks that are too delicate for your fingers (browsing, copy/paste etc).

The phone sports a 5MP camera with two flash-LEDs which to my non-photographer eyes look quite decent. The GPS works properly and quickly (unlike my old N95). The only port is the same as the N810 (micro-usb?), unfortunately without a separate Nokia charger socket but the N900 comes with an adapter for that purpose. Audio socket, speaker and a standard on the back that keeps the phone in a handy 45-degree angle.

Next N900 article: just how good is mobile Free software?

Happy new decade!

And before you know it 2 months have passed and you're in the Tennies. Best wishes to all!

Last night we returned from France after a week of 'boarding and relaxing:

New years resolutions: How about at least one blogpost each month? That, and a lot more snowboarding!

Resume Layout

After reading through a mildly interesting article via slashdot on resume styles and layout, I decided to ignore most of the tips and update my own.

My old resume had 3 pages, which were 2 pages too many (that I do agree with the article). Recently I came across a 3-column resume layout and I really liked it: all the information on one page while, if you do it carefully, it doesn't have to feel cramped. Like all resume's my new one is a work in progress, but by scrapping and reorganizing I've finally fit it all on one page.

In other areas I've been working along similar lines: data visualization on a single screen (dashboards). Many of my company projects are screaming for such an application, so I'm slowly developing my own flexible solution for this problem. Watch this space...

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