It looks like I'm now writing a Windows Live gadget every week. My latest gadget is a port of the Flickr badge to a Windows Live gadget. It's in the approval pipeline and should show up under the list of gadgets I've written in the next day or so. To get the gadget working, I had to use the Flickr API. Specifically, I used the flickr.people.findByUsername method to convert a username to an internal Flickr ID. Ironically Coincidentally, I had recently read something by Alex Bosworth criticizing this very aspect of the Flickr API in his post How To Provide A Web API where he wrote

Simple also means don’t be too abstract. Flickr for example chooses in its API to require the use of its internal ids for all API calls. This means for example that every call to find information about a user requires a call first to find the internal id of the user. Del.icio.us on the other hand just requires visible names, in fact internal ids are hidden everywhere.

Actually, it's much worse than this. It seems that Flickr is inconsistent in how it maps user names back to internal IDs. For example, take Mike Torres who has 'mtorres' as his Flickr ID. I can access his Flickr photos by going to http://flickr.com/photos/mtorres. When I use the Flickr API explorer for flickr.people.findByUsername and pass in 'mtorres' as the username I get back the following ID; 25553748@N00. When I go to http://flickr.com/photos/25553748@N00 I end up going to some other person's page who seems to be named 'mtorres' as well.

However when I plug "Mike Torres" into the flickr.people.findByUsername method instead of 'mtorres' I get '37996581086@N01' which turns out to be the right ID since going to http://www.flickr.com/photos/37996581086@N01 takes me to the same page as http://flickr.com/photos/mtorres. Weird.

Perhaps this is a naming collision caused by the merging of Flickr & Yahoo! IDs?