Custom Data Connector with Custom Authentication

[atsats]

I need to develop a custom data connector for a proprietary data source that's protected via a login page.

Basically, the flow is like this:

1) The connector will go to the log on page

2) The end user will enter credentials

3) The authentication system will redirect the user (on successful login) to a page where JSON data will be downloaded.

All the example data connectors I've seen use OAuth for this authentication, but the system that protects the data source is not OAuth-based.

Does anyone have any concrete examples or references for custom connectors that use custom (non-OAuth) authentication methods?