HPR3082: RFC 5005 Part 1 – Paged and archived feeds? Who cares?

This conversation took almost an hour, so I split it into two shows:

• Part 1 talks mostly about the RFC itself, what it means and why.
• Part 2 goes into personal experiences with the RFC and with syndication in general, in particular in the context of web comics. This is part 1.

The why

When serving most RSS/Atom feed readers today, you have to choose: Do you make a complete feed with all the things you ever published, or do you make a shorter feed with just the latest entries?

This is a trade-off with pros and cons, and it seems like a trade-off you have to make, but a solution to let your Atom feed have the cake and eat it too existed already 13 years ago, if only any of our feed readers would adhere to it: RFC 5005, Feed Paging and Archiving

The what

https://tools.ietf.org/html/rfc5005 was published in September 2007

• The XML namespace for RFC 5005 elements is https://purl.org/syndication/history/1.0, aliased as fh below.
• Section 2 defines the complete feed: It is one document (Atom file) that contains the entire set the feed describes. The document is marked with an fh:complete element.
• Section 3 defines the paged feed: It is a series of documents connected with Atom link elements with rel set to the link relations first, last, previous or next.
• Section 4 defines the archived feed: It has a subscription document that may change at any time, and a series of archive documents that are expected to have stable contents and URIs. The link relations defined are current, prev-archive and next-archive. The semantics are clearer: prev-archive refers to previously published entries, and because the contents are stable you can stop when you see a URI to a document you already have. Archive documents are marked with the fh:archive element.

The who

In this show I’m talking to:

fluffy

• Federated social web:
  https://queer.party/@fluffy
• Writes and makes things in several creative fields:
  https://beesbuzz.biz/
• Publ is like a static site generator, but dynamic. It produces RFC 5005 archive feeds, of course:
  https://publ.beesbuzz.biz/
• Thoughts on ephemeral content vs content worth archiving and how they relate to protocols:
  https://beesbuzz.biz/blog/5709-Keeping-it-personal

Jamey

• Federated social web:
  https://toot.cat/@jamey
• Blog:
  https://minilop.net/
• Made a prototype full-history reader that follows RFC 5005 links:
  https://reader.minilop.net/
• Made a webcomic reader mostly mentioned in Part 2:
  https://www.comic-rocket.com/
• Made a WordPress plugin implementing RFC 5005:
  https://github.com/jameysharp/wp-fullhistory
• Made an RFC 5005 archive feed synthesizer for sites with a predictable post frequency and URL structure:
  https://github.com/jameysharp/predictable/
  Hosted at https://fh.minilop.net/
• Was on HPR 9 years ago, talking about Xorg!
  https://hackerpublicradio.org/eps.php?id=0825

Conversation notes

• Google Reader was terminated 2013-07-01, all subscription data permanently gone on 2013-07-15:
  https://www.google.com/reader/about/
• Mastodon had Atom feeds with paging, but the feeds went away when OStatus went away:
  https://github.com/tootsuite/mastodon/pull/11247
• HTML4 does indeed define the HTML link relations:
  https://www.w3.org/TR/html4/types.html#h-6.12
  It has prev rather than the previous of RFC 5005, but mentions that some browsers support previous as an alias.
• HTML5 also defines the HTML link relations:
  https://html.spec.whatwg.org/multipage/links.html
  Here previous is a lower-case must for historical reasons.
• IANA manages the Registry of Link Relations:
  https://www.iana.org/assignments/link-relations/link-relations.xhtml
  It references RFC 5005 for the Section 4 relations, but not the Section 3 ones.
• RFC 5005 singles out its own Section 3 (Paged Feeds) as the best-effort, loose, discouraged model.
  • Section 3:

    Therefore, clients SHOULD NOT present paged feeds as coherent or complete, or make assumptions to that effect.

  • Section 4:

    Unlike paged feeds, archived feeds enable clients to do this without losing entries.

• I’m confused about it in the show, but the RFC is clear that an archived feed has one dynamic subscription document, which points to a chain of immutable archive documents.
• Back in 2002, Aaron Swartz published his joke MIME-header-based RSS 3:
  https://www.aaronsw.com/weblog/000574
  The cultural context at the time and the rivalry between RSS 0.91+, RSS 1.0, RSS 2.0 and Atom deserves a show of its own.

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