Abstract
For Draft -09
Status
Proposed
Rationale
Having a way of indicating the date the entry was last modified is a good optimization to avoid having to HEAD each individual member URI to get the Last-Modified header. The element is also useful for detecting minor changes that do not impact the value of atom:updated.
Having a way of associating a unique revision token with an entry is also useful.
Proposal
8.# The "app:modified" Element
The "app:modified" element is a Date construct as defined by [RFC4287] whose
value indicates the most recent instant in time when an entry was modified in
any way. Atom entry elements MAY contain one "app:modified" element.
appModified = element app:modified ( atomDateConstruct )
Publishers MUST change the value of this element every time a collection member
resource has been updated and SHOULD change the value of this element
whenever an associated Media Resource has been modified.
8.# The "app:revision" Element
The "app:revision" element provides an opaque token that can be used to identify
the state of an atom:entry. Atom entry elements MAY contain one "app:revision"
element.
appRevision = element app:revision { text }
Publishers MUST change the value of this element every time a collection member
resource has been updated and SHOULD change the value of this element
whenever an associated Media Resource has been modified.
Instances of app:revision elements can be compared to determine whether
entries sharing the same atom:id value are equivalent representations.
Processors MUST compare app:revision elements on a character-by-character
basis (in a case-sensitive fashion).
Impacts
Very little. Use of the elements are optional.
Notes
Example:
<entry xmlns="http://www.w3.org/2005/Atom" xmlns:app="...">
<id>urn:lsid:example.org:entries:1</id>
<updated>2006-07-11T12:12:12Z</updated>
<app:revision>urn:lsid:example.org:entries:1:2</app:revision>
<app:modified>2006-07-11T12:13:13Z</app:modified>
...
</entry>
(Note that app:revision and app:modified play a similar role as atom:id and atom:updated)
