AlexHopmann.com

From the biking trails at Whistler.

I’ve been playing with building apps for Facebook the last few days. Mostly it is going pretty well, but there are a couple of little issues I’ve been struggling with. I’ve noticed via email and comments that some of my posts about technical problems I’ve faced and solutions have been the most popular, so I’m going to try to keep up a good flow of these.

Their documentation doesn’t really have step-by-step explanations of what happens over the wire yet. I think all the details are there somewhere, but it took reading the PHP sources to fix some issue with the app I was building in .NET. The big issue is that the example sources showed doing a redirect when a user is first connecting to your app and hasn’t authenticated yet. However if the user is accessing you in the “canvas” (IE- inside Facebook), a normal HTTP redirect is NOT the right thing to do. Instead you need to return the FBML for a redirect-

Response.Write(”<fb:redirect url=’http://www.facebook.com/login.php?api_key=” + AppAPIKey + @”&v=1.0′/>”);

Another issue I hit is that it feels like I really need two accounts to test my application and its interaction with other users. I have not gotten notifications to work yet. The catch with this is there is a checkbox that hides your application from people other than yourself while you are developing it (’developer mode’). But while that checkbox is checked, my second account can’t access the app. So this is a bit of a catch-22.

The other thing I’ve noticed is that Facebook won’t let me be signed in from more than one computer at a time. I typically am using 2-4 computers at once and really appreciate that most of the Google sites, GTalk, and others let me be signed in all over and they just work. Its a real pain when testing stuff that whenever I use a different computer to access Facebook it makes me sign in again.

Probably my favorite moment of the year in Seattle. That first unmistakable roar of F-18s crossing overhead, fast and low.