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Planet Engines: Plagger and Planet

Posted in , , Mon, 31 Jul 2006 04:16:00 GMT

Planet engines are applications that aggregate RSS/Atom feeds and generate composite feeds as well as a website. The generated feeds typically include RSS, Atom, FOAF and OPML. Two popular open source planet engines are Planet and Plagger. I've used both to create planet-style websites and here are my observations:

  • Planet: This is a Python-based planet engine originally created for Planet Gnome and Planet Debian. It is super easy to to install as there's not even really an install to speak of, you just untar it into place. The issue with Planet is that it has limited functionality and uses a monolithic architecture that makes adding features difficult. For example, the code to generate the HTML and XML files is in a 953-line file called I hacked a feature on to Planet a while back and had to modify some methods and add a new one to It worked but didn't seem clean or very maintainable so I'm reluctant to add even more features at this point. Here are my notes on Installing Planet.
  • Plagger: This is a Perl-based planet engine written by Tatsuhiko Miyagawa who currently works for SixApart, the makers of MovableType, LiveJournal, TypePad and Vox. Although Plagger is a planet engine it does a lot more and is really a pluggable RSS/Atom feed aggregation framework/platform that supports building planet-style websites via one of its many plugins. Its plugin architecture supports the following types of plugins: Aggregator, Bundle, CustomFeed, Filter, Notify, Publish, Search, SmartFeed, Subscription and Widget. Planet sites are generated by Plagger::Plugin::Bundle::Planet. Plagger will also send aggregated feeds to your email account using Plagger::Plugin::Publish::Gmail. This is similiar to what Newspipe (Python-based) does but Newspipe only does RSS to email. Configuring Plagger is simple once you've installed it, but installation can be tricky since it has many CPAN dependencies. However, it's not too difficult and I've done it on a dedicated CentOS server as well as on a shared hosting account at Dreamhost using these Installing Plagger instructions.

If you are interested in running a planet-style feed aggregation site, I highly recommend Plagger since it's just as easy to configure but has many more capabilities and a better architecture for extensibility. Installation takes a bit longer but give it a shot, it's worth it. Engines: Plagger and Planet digg:Planet Engines: Plagger and Planet reddit:Planet Engines: Plagger and Planet spurl:Planet Engines: Plagger and Planet wists:Planet Engines: Plagger and Planet simpy:Planet Engines: Plagger and Planet newsvine:Planet Engines: Plagger and Planet blinklist:Planet Engines: Plagger and Planet furl:Planet Engines: Plagger and Planet fark:Planet Engines: Plagger and Planet blogmarks:Planet Engines: Plagger and Planet Y!:Planet Engines: Plagger and Planet smarking:Planet Engines: Plagger and Planet magnolia:Planet Engines: Plagger and Planet segnalo:Planet Engines: Plagger and Planet



  1. Aristotle Pagaltzis said 4 days later:

    Unfortunately, Plagger currently emits invalid Atom 1.0. I’m afraid that’s a knockout argument against it.

  2. John Wang said 8 days later:

    Planet Catalyst has been updated to Plagger rev1238 and the Atom feed is now valid according to the W3C feed validator. There are some warnings but it’s a valid Atom 1.0 feed. If there are still issues, mention them here, on the catalyst mailing list or on the #plagger IRC channel. Miyagawa’s been good about updates. I’m going to look into getting rid of the warnings in a bit.

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