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PaceXmlBaseId


Abstract

The [WWW]Atom Syndication Format 0.3 pre-draft calls out exactly two places where xml:base processing is required: the [WWW]"href" attribute of the [WWW]link construct and the [WWW]atom:url element of the [WWW]person construct.

The purpose of this proposal is to add this requirement to the [WWW]atom:id element.

Status

Accepted

Rationale

While the [WWW]atom:id element is specified to be a [WWW]URI, it does not specify what the URI is to be evaluated relative to.

For an example of the problem that this creates, take a look at the use of GUIDs in the [WWW]Blogdex RSS 2.0 feed. Each item is associated with a seven digit monotonically increasing integer. It is hard to make the case that such numbers are guaranteed "globally unique".

From the [WWW]RSS 2.0 spec:

So, in this case, the problem is the combination of "no rules for the syntax of a guid" and the fact that the server did not sufficiently "establish the uniqueness of the string".

The fact that [WWW]atom:id is a URI only partially addresses this problem. Unless there is agreement on how to resolve relative URIs, there may still be inadvertent collisions.

Making atom:id relative to xml:base allows a feed to control what such values are relative to, with the default being that such ids are relative to the feed itself.

Proposal

Update [WWW]4.8 "atom:id" Element to read (additions in bold):

Impacts

None

Notes


CategoryProposals