Talk about dynamically re-skinning a legacy .NET portal with python. The look and feel wasn’t compelling. The usability wasn’t that good in certain spots. The content management was poor (as they bought the portal product of the commercial vendor and not, for lots of money, the content management product). And vendor lock-in: even small changes were very expensive.
The customer wanted a much more flexible and maintainable system. And as the current system was monolithic, they wanted to be able to choose the best programs for the various parts. Moodle, plone and some of the existing system. But they couldn’t actually touch the existing system for contractual reasons.
A cunning plan: put a new skin in front of the current website by using a transformation proxy. The core element: Deliverance as the proxy. Deliverance removes the need of skinning an application inside the application itself. Deliverance is basically “xslt for dummies” that transforms an incoming html page according to some rules.
Another component: WSGI (“web service gateway interface”) for chaining small modules together in a pipeline. There are a lot of existing components out there that you can reuse. And it is easy to make your own components to plug into the pipeline. The pipeline they’re using now, to give an example:
/news/1234. From 205 characters to just 41 in their case. lxml has a method that returns all links in a document; you can also pass it a method that rewrites all those links.
(Comment for myself: experiment more with WSGI, there’s a whole lot of things I want to experiment with). The performance is good. They do all this on-the-fly. It sure helps that the old system was dog-slow, so every improvement is noticeable.
They’ve got several pipelines (one for the old site, one for plone and one for moodle with more to come). And several pipeline plugins are shared between several pipelines: reuse!
Of course there were complications:
The complications were solvable and the site is about to go live.
My name is Reinout van Rees and I work a lot with Python (programming language) and Django (website framework). I live in The Netherlands and I'm happily married to Annie van Rees-Kooiman.
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