There is quite a large overhead when using separate requests to get each individual contact compared to issuing one request for all contacts in an address book and as such i can see the use of putting the "last updated" in the contact information instead of in the response headers.
Is this something that is or will be supported?
Andreas:
The Last-Modified header is a standard http header that applies by defiinition to all the entity on the response body. You can add the If-Modified-Since header with a date you define to your GET http request, but that will return:
So, unfortunately, at least as far as I know, there is no way to get a list of only the contacts that have changed since a certain Date and Time. However, you can use the If-Modified-Since header to retrieve the list of contacts only if there is any change.
I can see the use for this feature if Windows Live indeed wants to become the central address book for many different systems as updating a contact directly against Windows Live is much slower than updating a local database. For the later synchronisation of these two databases you would then really need two timestamps to compare the last updated fields or possibly a complete index over the last known state of a certain contact, and i would definitely prefer the timestamp variant.
If there is no current plans for this "last updated" timestamp on a per contact basis, may i please suggest an addition to a "future features" list if there is such a thing (and the beta isnt too far gone to make any further changes).
Thank you for any insights into this matter.
Andreas
Andreas,
Yes, we are seeking solution for providing server data state per contact level (as contact field). "last update" is one of the solutions. It is meaningful to client, however it is lack of granularity. As you pointed out "last update" at contact level is more desirable than at address book level. we are also considering complex index over server state (per contact level as well), which is blob to client. Ultimately, the goal will be providing full functional synchronization support in the near future.
They are tradeoffs. You feedback is definitely important to us.
Thanks,
- Dawei
