Do I Need to Worry About This?
The following may be useful if making the pipes work is your job, and:
- You need to produce RSS or Atom feeds.
- You consume feed data.
- You cache, proxy, or transform feed data.
- You present feed data to an end user.
- You need to create feed extensions.
- You want to provide open, standard APIs for your data.
Where Are You?
- Producer?
- Consumer?
- Intermediary Syndicator?
- Server?
- Client?
(diagram source: Patrick Chanezon)
General Guidelines for Producing Feeds
- Prefer Atom 1.0 format (second choice: RSS 2.0).
- Use the Feed Validator early and often.
- Ensure unique IDs for articles.
- Support autodiscovery; don't use text/xml content type.
- Use atom:summary for summary data, atom:content for full content.
- Embed well formed XHTML; escape anything not guaranteed to be well formed.
- Consider an XSLT style sheet.
- Consider using the standard feed subscription widget.
Producing Public Feeds
- Consider using Feedburner.
- Consider embedding license metadata (details).
- Support caching through Conditional GETs.
- Consider using a proxy cache for high traffic feeds (e.g., Akamai Feeds Platform)
- Use a 301 permanent redirect to send clients to the new source when a feed URL changes.
- Consider using ping services (Technorati, Blogpulse, Feedster, Moreover, Pingomatic, Buddy Feeds, Yahoo!, etc.) to notify 3rd parties about feed updates.
Producing Private Feeds
- For reasonable interoperability+reasonable security: Use HTTP Basic Auth over SSL.
- For high interoperability+low security: Use 'obscure' feed URLs.
Consuming Feeds
- Accept at least Atom 1.0 and RSS 2.0. Consider supporting other variants.
- Use a library or proxy to normalize all feed formats for you (RSS 0.9x, RSS 1.0, RSS 2.0, Atom 1.0).
- Consider using the Feeds Platform to proxy, normalize, and cache (and for storing subscription data)
- Support autodiscovery.
- Honor license metadata (details).
- Support caching, conditional GETs, and 301 permanent redirects.
- Honor RSS TTL directives; do not over-poll.
Intermediary Syndicators
- Follow all guidelines for producing and consuming.
- Pass through all content whenever possible (especially unknown extensions)
- Strongly consider following the User-Agent subscriber reporting de facto standard.
- Support private feeds if relevant.
- If mashing up multiple feeds into a single synthetic feed:
- Use Atom 1.0's atom:source element to preserve source feed information.
- Honor and maintain all source feed licenses.
Adding Extensions
- Re-use or borrow from existing extensions. (Atom elements can be used as extensions in RSS if necessary.)
- Document your extensions publicly.
- Consider using a microformat instead.
