[Plugin: WPBook] Invite Friends under SSL

Trying to determine if the “chain issues: incomplete” rating ssl certs get is the problem, per Facebook:

If you enable SSL for your FBML app, please make sure that your SSL certificate includes all intermediate certificates in the chain of trust as our SSL validation is strict. You can use third-party SSL analysis tools (e.g., https://www.ssllabs.com/index.html) to check your certificate status and fix any errors (and warnings). If your SSL certificate has problems, you may see “Empty response received” error when you load your FBML canvas app.

See also https://developers.facebook.com/bugs/249561065079186 and https://developers.facebook.com/bugs/252437428134251

The only other longer term solution here would be to rewrite “invite friends” so that it runs in an iframe and doesn’t use FBML, but that will take some time.

@johneckman The SSL certificate gets an A (87) so how to find if its correct for FBML?

@christianebuddy does it report anything about the complete chain? That seems to be the issue here.

For some reason the verification is much stricter for FBML output than it is for iFrame

This weekend or next I might be able to rewrite invite friends in iframe mode, but it will take some time and testing

I get this in the report about the chain.

Chain length (size) 1 (1575 bytes)
Chain issues Incomplete

I do not know if this means something is not ok for FBML. And if this is the case, how to resolve this?

@christianebuddy I believe that’s what Facebook is referring to when they say:

If you enable SSL for your FBML app, please make sure that your SSL certificate includes all intermediate certificates in the chain of trust as our SSL validation is strict.

If the chain is incomplete Facebook won’t let your app load FBML. (Why the validation is stricter on FBML apps than on iFrame pages I don’t know).

As to how to fix it, I’ve no idea – does the ssl testing tool give any indication?

Well John, that’s the question, what do they mean exactly with ‘ includes all the certificates in the chain of trust’. The SSL certificate is an official SSL certificate. I do not know how to add something in the chain to it?? So I’ll have to wait on the iframe version of the plugin. The tool does not say anything else!

@johneckman I did some research and resolved the chain issue. You have to add the root certificate of the issuer to the ssl certificate on the webserver. For me I had to add the certificate of the Entrust Secure Server CA to the valid ssl certificate. https://www.tbs-certificats.com/FAQ/en/intermed_USERTrust_Legacy_2048.html (Every webserver (apache, nginx etc) has his own way of handling this. For nginx it’s simply concatenating the two certificates.

@christianebuddy And so now that the chain issue is resolved, does invite friends work again? It seemed to when I visited.

Seems that Facebook, per their roadmap, will be deprecating FBML in June/July.

Unfortunately there doesn’t seem to be any real path for how one is intended to do “invite friends to app” in an iFrame application, other than doing it yourself (fetching a list of all the user’s friends, outputting a table with checkboxes, sending the requests).

May be possible with the requests dialog https://developers.facebook.com/docs/reference/dialogs/requests/ but it looks like a lot of work.

Unfortunately I may have to just hide the invite friends feature once FBML stops working, or replace it with a simple “share” button unless I find time to code up the alternative.

@johneckman Invite Friends does actually work. Thanks for your work with this plugin John. Maybe FB themselves can help you with this part. Just ask them, they might have a good working solution or direction for you?