Ideas for evolution of RSS

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Ideas for evolution of RSS

Author:		Dave Winer
Posted:		5/19/2002; 7:58:38 AM
Topic:		Ideas for evolution of RSS
Msg #:		140 (top msg in thread)
Prev/Next:		139/141
Reads:		24825

Here's a list of ideas for new features for RSS

1. <pubDate> sub-element of <item>

pubDate stands for "publication date."

Its value is a date, indicating when the item was published. If it's a date in the future, aggregators may choose to not display the item until that date.

Example: <pubDate>Sun, 19 May 2002 15:21:36 GMT</pubDate>

2. <guid> sub-element of <guid>

guid stands for "globally unique identifier."

It's a string that uniquely identifies the item. When present, an aggregator may choose to use this string to determine if an item is new.

Example: <guid>http://some.server.com/weblogItem3207</guid>

Note: There are no rules for the syntax of a guid. Aggregators must view them as a string. It's up to the source of the feed to establish the uniqueness of the string.

See comments below.

3. <ttl> sub-element of <channel>

ttl stands for "time to live."

It's a number of minutes that indicates how long a channel can be cached before refreshing from the source. This makes it possible for RSS sources to be managed by a file-sharing network such as Gnutella.

Example: <ttl>60</ttl>

Version number, compatibility

All new elements are optional.

For the sake of discussion, assume the version number is X.

Upward compatible with RSS 0.92, 0.91. That is, every 0.91 and 0.92 source is also a X source

Should IDs be global?

At first I specified a globally unique ID, then "realized" that they don't need to be global, and then flipped back, in less than 24 hours.

Flip: At first I spec'd this as a "guid" or globally unique id, but then realized there was no need for global uniqueness. It must only be unique to the RSS source. The goal is to have aggregators not have to guess whether an item is new or not. In today's world of aggregation if you change a single character in the title or description, or change the link, it counts as new, even though the reader may have already seen it.

Flop: Sjoerd Visscher and Rahul Dave both offered the same convincing argument for global IDs instead of local ones, so I flipped it back. It's not uncommon for an item to appear in more than one feed. If the IDs were globally unique, the user could set a pref that kept repeats from showing up. A good feature, perhaps (but what if the forwarder added a comment). No matter, guid's are almost as easy as non-guid's. Thanks for the feedback.

Last update: Monday, May 20, 2002 at 9:20:29 AM Pacific.