On 18 May 2005, at 1:03 am, David Powell wrote:
Can you explain some? I don't see atom:version would be more feasible. atom:version doesn't support some cases that atom:modified does, and it doesn't really seem easier to explain in the spec or implement.
The first problem is that not all systems track a modified date. If you're obtaining entries using an API on a closed system, and the system doesn't supply a modified date for whatever data you're syndicating, you're screwed.
The second problem is that "modification" is an incredibly hard thing to pin down, eg:
- I modify my atom-generating script to change which optional elements are included. Does the modification date change?
- I modify my atom-generating script to change the order elements appear in. Does the modification date change?
- I change the location of my entries, and therefore the atom:link element values. Does the modification date change?
- I change the location of my entries, and therefore the xml:base attribute on a parent element. Does the modification date change?
- I change the email address of an entry's author, but not the entry itself. Does the modification date change?
etc etc
Don't bother answering yes or no to any of these here. The point is that even if you do pin down exactly which count as modifications, you have to demonstrate it can easily be implemented and tracked exactly that way on the average CMS (Note adding new columns to the database may not be possible).
Graham
