mnot’s blog

Design depends largely on constraints.” — Charles Eames

Monday, 5 September 2005

Python Syndication Web XML

Feed History -04

Feed History draft -04 is out, with the only major change being the replacement of fh:stateful with fh:incremental, with corresponding changes throughout the document, to make the concepts a bit clearer.

This revision also makes cardinality, relative URIs and white space handling more explicit, and adds an acknowledgements section as promised.

On the implementation front, here’s a quick-n-dirty Python script that demonstrates reconstruction of an incremental feed (RSS or Atom); while it’s more prototype code than something you’d want to deploy, it should give an idea of the effort involved for implementation on the client-side, and I’m more than happy to take patches.

You use it by first calling it with the name of the local store (just a Python pickle) you want to use, along with the feed URI;

~> ./ store

and then, to update the feed subsequently, you just call it with the store name;

~> ./ store

Each time you call it, it’ll walk back archives as necessary and then spit out the complete list of titles in the feed.

I’ve also updated the Putting History in Your Feed entry; there wasn’t any change necessary for -04, but there was a bug in the instructions regarding fh:prev in the subscription feed.

BTW, Feed History is also referenced in the latest Media RSS specification as a Best Practice. Cool!

One Comment

Robert Sayre said:

How about ‘fh:sliding’ instead of ‘fh:incremental’? Mmmmm… field names.

Monday, October 3 2005 at 9:15 AM