ETags are a feature of V2 of the Google Data APIs. Picasa Web Albums does not yet support V2. The "album_version_number" in your example functions in a similar manner as the ETag might, except it is a part of the URL rather than a separate entity.
It would help to see a packet capture of the full request/response. Cheers, -Jeff On Thu, Apr 2, 2009 at 11:10 PM, aaronluo <aaron...@gmail.com> wrote: > > hi all > I am trying to update some properties of a speicifc album. I sent a > PUT request to URI 'http://picasaweb.google.com/data/entry/api/user/ > <myid>/albumid/<albumid>/<album_version_number>. > > The header of the request seems like following: > Authorization:GoogleLogin auth=<my_auth_token> > Content-type: application/atom+xml > > The body of the reqeust is the new album data like following: > <entry xmlns='http://www.w3.org/2005/Atom' > xmlns:media='http://search.yahoo.com/mrss/' > xmlns:gphoto='http://schemas.google.com/photos/2007'> > <title type='text'>newTitle</title> > <summary type='text'>newTitle</summary> > <gphoto:access>public</gphoto:access> > <gphoto:commentingEnabled>true</gphoto:commentingEnabled> > <media:group> > <media:keywords>newTitle</media:keywords> > </media:group> > <category scheme='http://schemas.google.com/g/2005#kind' > term='http://schemas.google.com/photos/2007#album'></category> > </entry> > But unfortunately, I got a HTTP 500 error. I check the reference of > the API, and I read some information about ETags which will be used > when a user wants to update a entry. So I add a new key-value pair to > the header according to the reference. > If-Match: <album_version_number> > > But this time I got an HTTPPreconditionFailed. It seems that the > album_version_number doesn't equal ETag of this entry. > So there are tow questions. One is why I can't update the properites > of a album via API. Another is how can I get the ETag of a album? > > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Google Picasa Web Albums API" group. To post to this group, send email to Google-Picasa-Data-API@googlegroups.com To unsubscribe from this group, send email to google-picasa-data-api+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/Google-Picasa-Data-API?hl=en -~----------~----~----~----~------~----~------~--~---
