Support for multiple domains does not work as advertised

Question

In October, Facebook announced support for multiple domains for a single app. This is great news for developers whose apps have multiple domain aliases - no more iframe hacks to get the JavaScript SDK working regardless of which of your domains the user is viewing the page from!

Unfortunately, it does not seem to work as advertised.

In the blog post, they say:

Your App’s URL (Website and/or Mobile Web URL) must be derived from one of the domains listed in the App Domain field.

Which is reasonable enough, but the form in the developer app seems to be enforcing the converse policy. I have a pair of domains (say, abc.com and xyz.com) and the site URL set to (http://abc.com), and when I save I get the error message:

xyz.com must be derived from your Site URL or your Mobile Web URL.

Does anyone know a workaround for this problem? Or is this what they intended and the content of the blog post is wrong? If so it seems pretty silly, since it's hard to have multiple domains be derived from a single site URL.

I commented on the blog entry hoping that a Facebook engineer will see it... but in the mean time...

Variation

The workaround I used was to specify my other domain in the mobile url field. I don't know if there are any negative consequences to this, but it seems to be working for us. We have two domains that are the same website and we didn't want to have to create more than one application. This would only work for 2 domains though. I think they are definitely misleading in saying they support multiple domains. I think this is what they actually mean by multiple domains: something.mysite.com and somethingelse.mysite.com NOT mysite.com and yoursite.com – Kantar

Answer 1

This is a known issue and is filed under

https://developers.facebook.com/bugs/288905901157023

You can help raise awareness and get it fixed by visiting the bug link on facebook and subscribing to it; facebook prioritizes defects by number of subscribers, so raising this number will also raise priority.

Please click the link above and subscribe!

Thanks! A.

Stockman

Answer 2

Yeah it's true enough that

Your App’s URL (Website and/or Mobile Web URL) must be derived from one of the domains listed in the App Domain field.

But their documentation should spell out that it's more like the other way around: the Site URL (and Mobile if present) dictates what domains are permitted in App Domain field, and they all have to be derived from the Site/Mobile URL. So you got it right, a.bc.com and d.bc.com would be allowed but not x.yz.com

Ambert