Tracking the aggregation chain is an interesting problem that I played with in the past. One comment in this note grabbed my attention: "In general you need to be very careful about making *any* changes to an entry when you're republishing someone else's content verbatim in an aggregated feed." One issue in particular is handling *signed* entries. Any modification to the entry breaks the signature. One thought I had is to use foreign markup to indicate the aggregation chain, but to exclude the foreign markup in computing the signature. This way the original signature authenticates. Of course, this then begs the issue of authenticating the aggregation information...
Brett Lindsley, Motorola Applied Research & Technology Center -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of James Holderness Sent: Tuesday, February 17, 2009 2:53 PM To: [email protected] Subject: Re: feedsets and atom:source Erik Wilde wrote: > thanks for pointing that out. i was (almost) proposing to leave > atom:source unchanged, with the exception of the foreign markup of the > via:via attribute. Sorry, I misunderstood you. I thought you had intended to add multiple source elements to each entry. The foreign markup doesn't bother me that much. > or would the via:via element no simply be a repetition of <link> and it > should be like this: > > <feed xmlns="http://www.w3.org/2005/Atom"; xml:via="..."> > <link xml:id="id1" rel="via" href="http://example.com/feed-C"; /> > <link xml:id="id2" rel="via" href="http://example.com/feed-D"; /> > ... > <entry> > <link rel="via" href="http://example.com/feed-C"/> > <source> > <link rel="self" href="http://example.com/feed-A"; /> The spec is a bit vague in its description, but the intended purpose of the via link, as I understood it, was so that the entry author could credit the source of their "story". For example, if you read about a new iPhone release on Engadget and decided to blog about it, your blog entry could include a via link back to Engadget. Since you're not the author of these entries, you have no right to makes claims about the source of the story. In general you need to be very careful about making *any* changes to an entry when you're republishing someone else's content verbatim in an aggregated feed. As for the use of xml:id, I think that's unwise considering you can't guarantee uniqueness across the whole feed (which could make the document invalid). You have no way of knowing what other extensions might be using xml:id attributes which could conflict with yours (they would also be unwise to do so, but if you're considering it, you have to assume that someone else is too). It wouldn't be so bad if you were using something more universally unique in your ids, like a URI of some sort. But in that case, you might just as well reference the link href and avoid the xml:id altogether. Regards James
