Pubgate: unsupported protocol scheme

Describe the bug

Confirming the fix in #111, we discovered a different issue with followers using pubgate.

All POST requests against the Pubgate user return an error:

..Post : unsupported protocol scheme ""

It looks like we store an empty string as their inbox.

Steps to reproduce (if necessary)

Steps to reproduce the behavior:

1. Follow a writefreely (running the fix for support pubgate #111) blog from pubgate
2. Post or delete a post on the writefreely blog
3. Check logs

Expected behavior

POSTs should go out to an actual URL and succeed.

Application configuration

• Single mode
• Database? mysql?
• Open registration? no
• Federation enabled? yes

Version or last commit:
WF commit 95215aa on branch gh100

[thebaer]

Good catch. To be sure, this is the error returned on our end? If so, what's the full log around that error look like?

Jun 03 15:32:53 mangrove rob[8586]: 2019/06/03 15:32:53 POST
Jun 03 15:32:53 mangrove rob[8586]: ERROR: 2019/06/03 15:32:53 log.go:26: Couldn't delete post! Post : unsupported protocol scheme ""

This is among a bunch of successful POSTs for the same action

[thebaer]

I see. So looking into the code... actually we're not storing the user's shared inbox (I assume it doesn't have one). Looking at the database, we do have an inbox for that pubgate user.

So to fix this issue, we need to fix the logic in various activitypub.go funcs that compile an inboxes map to fall back to a RemoteUsers Inbox if their SharedInbox is empty. E.g. in places like this: https://github.com/writeas/writefreely/blob/95215aa39db51f9510ded34480a62fb61242c4dd/activitypub.go#L550-L557 we need to check if f.SharedInbox == "" and if so, use f.Inbox instead.

perfect, thanks @thebaer

[thebaer]

No problemo! If you want to tackle this fix, please feel free to assign yourself.

just testing now