I'm developing an application that connects to FreshBook's API. I can either integrate the account authentication process within my application, or I can develop an Online Account that could be used by other application developers.
I've looked at some of the code in the existing Online Accounts (with reference from How do I use OAuth from an Ubuntu Touch app?). However, FreshBooks is a bit more complicated. The way they work, each account has a dedicated sub-domain, each with its own separate OAuth URL. I can't just put a fixed endpoint in the code.
So my question is, how would I go about adding a field before the OAuth process that collects the sub-domain from the user, before opening the OAuth form page? I'm starting from zero knowledge of how Online Accounts are implemented, so I don't know where to start.
Edit: as a workaround, I put the OAuth process directly into my application, see this question: Get Qt WebKit HTML Content in QML