Generating activity stream feeds using foaflib and feedformatter
Yesterday I threw together a really quick and simple little script that combines the ActivityStream utility from foaflib with feedformatter to produce RSS1, RSS2 and Atom feeds containing events from the various webpages and accounts that are listed
in my FOAF profile. These feeds should include all of my posts to this blog, all of my identi.ca notices and all of my delicio.us bookmarks. The functionality is a little like that provided by FriendFeed, except it’s powered by FOAF files, which means that as long as you know where to get someone’s FOAF file you don’t have to manually add all their various presences yourself — especially handy for when a friend creates a new account somewhere.
The code to generate the feeds is delightfully simple. It took about 5 minutes to get something working just fine. This was the first time I’d used either of these libraries in a long time (just because I wrote them doesn’t mean I remember the syntax a few months down the track!), but the examples on the respective project wikis made it really easy to figure out how to do this:
from foaflib.classes.person import Person
from foaflib.utils.activitystream import ActivityStream
from feedformatter import Feed
# Fetch the FOAF profile of the friend to watch
p = Person("http://www.luke.maurits.id.au/foaf.rdf")
# Create an ActivityStream object for that friend
stream = ActivityStream(p)
# Create the feed
feed = Feed()
# Set the feed/channel level properties
feed.feed["title"] = "Luke Maurits' Activity Stream Feed"
feed.feed["link"] = "http://www.luke.maurits.id.au"
feed.feed["author"] = "Luke Maurits"
feed.feed["description"] = "A feed of my activity at various places, built hourly using my FOAF profile."
# Iterate over the latest things they've done:
for event in stream.get_latest_events():
# Create an item
item = {}
item["title"] = event.type + ": " + event.detail
item["link"] = event.link
item["pubDate"] = event.timestamp
item["guid"] = event.link
feed.items.append(item)
# Save the feed to a file in various formats
feed.format_rss1_file("/output/path/goes/here/activity_rss1.xml")
feed.format_rss2_file("/output/path/goes/here/activity_rss2.xml")
feed.format_atom_file("/output/path/goes/here/activity_atom.xml")
Just 21 lines of code, excluding comments and blanks! I’m quite pleased with how parsimonious both libraries have turned out to be in a model usage case. I run the above as an hourly cron job and that’s all there is to it.
Currently the ActivityStream object in foaflib only supports pulling in events from: Twitter feeds, Identi.ca feeds, Delicio.us bookmarks and blog entries if (i) the blog is identified using foaf:weblog and (ii) has an RSS or Atom feed specified in a <link rel="alternate" type="application/rss+xml/> tag in the page pointed to. But this is only because those are the kinds of events that I wanted support for at the time. Any social service that either provides data in RSS or Atom form, or which has a Python API for extracting data, is a perfectly viable candidate for inclusion in future releases. Photo sharing sites like Flickr would be an obvious addition.
It’s very easy to see how projects like these could easily replace Facebook, MySpace, etc., making the social web a much more decentralised and accessible place, where nobody has to have an account at any special place to see what other people are doing. A lot would need to happen to make this model user-friendly enough for the average Facebook user, and I’m not even going to pretend I have what it takes to do work in that direction, but with some luck somebody will, one day.
The biggest missing piece of the puzzle in my little application here is any kind of privacy/security. Places like Facebook let you designate people as friends (and divide your friends into groups), and set who can see what aspects of your activity based on those credentials. Some equivalent process to this would absolutely have to be present in any FOAF-based Facebook-killer. Fortunately, the absolutely ingenious idea that is FOAF+SSL makes this possible. There’s no support for it in foaflib yet, which is the library’s greatest current shortcoming. Hopefully I’ll have the time to implement it one day. Of course, getting that technology made easier enough for the average netizen is an even bigger hurdle again. This combined with the fact that the average person probably doesn’t understand the appeal of decentralisation makes me wonder if we ever will see a trend in the direction of this sort of thing.
Here’s hoping.
