Simon Willison’s Weblog

Footnotes that work in RSS readers. Chris Coyier explained the mechanism used by Feedbin to render custom footnotes back in 2019.

I stumbled upon this after I spotted an inline footnote rendered in NetNewsWire the other day (from this post by Drew Breunig):

Since feed readers generally strip JavaScript and CSS and only allow a subset of HTML tags I was intrigued to figure out how that worked.

I found this code in the NetNewsWire source (it's MIT licensed) which runs against elements matching this CSS selector:

sup > a[href*='#fn'], sup > div > a[href*='#fn']

So any link with an href attribute containing #fn that is a child of a <sup> (superscript) element.

In Drew's post the HTML looks like this:

<!-- Footnote link: -->
<sup id="fnref:precision" role="doc-noteref">
  <a href="#fn:precision" class="footnote" rel="footnote">1</a>
</sup>
<!-- Then at the bottom: -->
<div class="footnotes" role="doc-endnotes">
  <ol>
    <li id="fn:precision" role="doc-endnote">
      <p>This is the footnote.
        <a href="#fnref:precision" class="reversefootnote" role="doc-backlink">&#8617;</a>
      </p>
    </li>
  </ol>
</div>

Where did this convention come from? It doesn't seem to be part of any specific standard. Chris linked to www.bigfootjs.com (no longer resolving) which was the site for the bigfoot.js jQuery plugin, so my best guess is the convention came from that.

# 1st August 2024, 9:57 pm / atom, jquery, rss, netnewswire

ooh.directory: A page for every blog. I hadn’t checked in on Phil Gyford’s ooh.directory blog directory since it first launched in November 2022. I’m delighted to see that it’s thriving—2,117 blogs have now been carefully curated, and the latest feature is a page for each blog showing its categories, description, an activity graph and the most recent posts syndicated via RSS/Atom.

# 9th January 2024, 10:15 pm / atom, blogs, syndication, phil-gyford, rss

Subscribe to my blog on Telegram (via) I created a Telegram bot that’s subscribed to my Atom feed, so if you want to get notifications when I post to my blog you can do that using Telegram now.

# 20th January 2019, 4:11 am / blog, atom

pubsubhubbub. From Brad Fitzpatrick, a simple but clever way of using web hooks (HTTP callbacks) to inform subscribers that an Atom feed has updated in almost real-time—solving the constant polling problem and making it easier for small sites to offer publish-subscribe APIs. Any Atom feed can delegate subscriber updates to a “hub” server. An example hub server implementation is provided running on App Engine.

# 20th April 2009, 6:49 pm / brad-fitzpatrick, pubsub, realtime, atom, pubsubhubbub, appengine, python, webhooks

Magnificent Seven—the value of Atom. The seven core things that Atom solves so that you don’t have to.

# 19th October 2008, 10:24 pm / atom, xml, rest, bill-de-hora

FriendFeed Blog: Simple Update Protocol. FriendFeed infamously poll RSS feeds on the 43 services they support millions of times an hour in an effort to keep their content as real-time as possible. SUP is a new proposal by FriendFeed for a sort of “master feed” of changes to a site—instead of hitting the Flickr feed for each of their users they would just poll Flickr’s SUP feed every minute or so to find out who had uploaded a new photo, and only retrieve the RSS feed for those users.

# 28th August 2008, 12:16 pm / friendfeed, sup, feeds, atom, rss, flickr, polling

Flickr Developer Blog: API Responses as Feeds (via) Flickr API calls that return a “standard photos response” (e.g. flickr.photos.search and flickr.favorites.getList) can now output eight different feed formats as well, including Atom, RSS flavours, geoatom, geordf and KML. Error codes are returned as X-FlickrErrCode HTTP headers.

# 25th August 2008, 10:20 pm / flickr, apis, feeds, kml, atom, geordf, rss, geoatom, http

RSS Duplicate Detection. “Detecting duplicate items in an RSS feed is something of a black art”. I hadn’t realised quite how involved such a basic function of an aggregator could be.

# 22nd January 2008, 8:11 pm / rss, syndication, atom, duplicates, aggregator, blackart, james-holderness

HTTP Cache Channels (via) Interesting extension to the HTTP caching model by Mark Nottingham: caches can be told to subscribe to an Atom feed which alerts them to cached data that has gone stale. Group invalidation is also supported.

# 4th January 2008, 12:48 pm / mark-nottingham, caching, http, cachechannels, atom, squid

Updates to template_utils. James Bennett’s Django template_utils library now provides tags for consuming external RSS and Atom feeds. Combine with template fragment caching for an instant mashup written just using templates.

# 10th December 2007, 3:25 pm / james-bennett, django, templateutils, rss, atom, feeds, universalfeedparser, python

RFC 5023: The Atom Publishing Protocol. It’s done!

# 9th October 2007, 10:17 am / atom, atompub, rfc

Atom Models. Building Python classes that act as utility wrappers around data stored in an lxml DOM object.

# 7th August 2007, 4:02 pm / lxml, dom, xml, python, ian-bicking, atom

Google AJAX Feed API (via) Simple cross-domain proxy to allow JavaScript to access any publically addressable syndication feed, with the same logic as Google Reader providing normalisation.

# 18th April 2007, 5:29 pm / google-reader, ajax, javascript, crossdomain, google, rss, feed, atom, syndication

Triplr. Ultra simple GET-based web service for converting RSS / Atom / RDF / Microformats+GRDDL to HTML / ntriples / RDF / RSS / JSON / Turtle. Small pieces, loosely joined.

# 30th March 2007, 3:30 pm / triplr, rss, atom, rdf, microformats, grddl, html, ntriples, json, turtle, semanticweb

Pipes. New Yahoo! service for combining and remixing Atom/RSS feeds using a really sophisticated drag-and-drop UI.

# 8th February 2007, 7:52 am / draganddrop, pipes, atom, rss, syndication

Gmail Atom feeds. Could be useful as a pipe for creating an e-mail interface to an existing Atom-consuming application.

# 16th January 2007, 2:50 pm / gmail, atom

Atom API for AOL Journals. AOL are doing some really cool things with the Atom Publishing Protocol.

# 10th January 2007, 11:06 pm / atom, aol, app

DeWitt Clinton: On RSS and Atom. Atom is lossless.

# 5th July 2006, 8:06 am / atom, dewitt-clinton, rss