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PaceAppModified


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)


CategoryProposals