06 Feb 09 Member Map Part 1

I started working on the Member Map application last weekend. This will be a port of the PHP-Nuke module I wrote, which you can find here. In a nutshell, this application displays a Google Map on your site, and allows site members to place markers representing their location on the map. If you click on a marker, a balloon pops up which displays the user’s avatar, a link to their profile, and a short message that they have typed previously. The Nuke version of this application is a big hit on the current site, and last time I checked, we had over 220 members on the map.

The existing application consists of the PHP-Nuke code, written in PHP, on the server side, and a fair amount of Javascript on the client side. All interaction with Google Maps is done through the Javascript code.

For the port to Django, I want to do a couple of things different.

1. Leverage jQuery in the client-side Javascript. The existing version was written before I was aware of Javascript libraries, and it is all “vanilla” Javascript. By using jQuery, the amount of code I have to write will be much smaller. And by taking advantage of jQuery, it should be more portable and browser robust.
2. On the server side, the existing application did not use any JSON encoder library. I simply constructed the JSON by hand. I can’t remember why I did this. I think it was partly because I didn’t know any better, and partly because the PHP version I had on the original hosting server may not have had it. I will explore what Python and/or Django options exist.
3. I’ll leverage the markItUp! editor that I’ve been using for comments to let the users enter Markdown comments. I’ve used this in the last couple of apps I’ve written and it will be easy to implement. The only concern with doing this is the user may be tempted to write a lot more than in the older app, and it may make for large “balloons”. We’ll see.
4. I want to make the new application less database and computationally intense than the older version. I don’t have any problems running the current version with 200 users, but I think I could do it a bit smarter this time around. This means I am going to try to save marked up and JSON encoded strings in the database rather than compute them on every page load. I am also wary of instantiating 200+ map entry model objects with the Django ORM (albeit in a loop) just to generate the JSON. Luckily Django lets you use raw SQL when needed. But in this case I think a simple use of the values() method will really be useful here.

So, those are my going in goals. I’ve already started working on this, and I’ve learned a lot so far. In the next post or two I will detail the progress and what problems I ran into.

Tags: django, jquery, json, markitup, membermap