App not running as a canvas

[zugaldia]

It runs well as a standalone app, but when I try to run it as a canvas app (following the instructions here: http://devcenter.heroku.com/articles/configuring-your-facebook-app-as-a-canvas-page) I always get an "Invalid Credentials" error message and then I get redirected to the app domain in heroku, where it seems to work.

I have tried disabling the latest patch (enforcing HTTPS in production) but it doesn't seem to help.

Please let me know if there're any diagnostics you want me to run on the app.

[ewjordan]

AFAICT, the getHome() function in AppInfo.php just needs to return the Facebook app address if this is running inside the iFrame, rather than the Heroku URL; it also should probably be urlencoded in FBUtils before being added to the string. That "Invalid Credentials" message should probably not be displayed at all when this is running as a canvas app, because we're just waiting to be redirected to the authorization page.

[pamo]

Thanks ewjordan!

I set up a new heroku environment variable, FACEBOOK_APP_URL, and set it as my canvas page url (apps.facebook.com/appname/).

Then replaced
return ($_SERVER['HTTP_X_FORWARDED_PROTO'] ?: "http") . "://" . $_SERVER['HTTP_HOST'] . "/";
in AppInfo::getHome() with
return ($_SERVER['HTTP_X_FORWARDED_PROTO'] ?: "http") . "://". getenv('FACEBOOK_APP_URL');

Cheers!

P.S. This fix did nothing to prevent the display of the Invalid Credentials message, decided to comment that out for now.It did prevent the app from breaking out of the frame.

[catahoulaleopard]

Hi, I'm having the same problem and I did everything that pamo did -- now my app goes into a loop, I guess getHome() now sends it back to the apps.facebook.com/my_app page, which starts my app, which triggers getHome() again and starts the whole process over. Anyone had this, or am I missing a step in the solution?
THANKS in advance.

Addendum:
I figured my problem out, thanks to a post here:

      http://stackoverflow.com/questions/7208642/canvas-authorization-error-191/7208845#7208845

basically, a line in FBUtils.php referring to
top.location.href= ...
when it should be
window.location.href= ....