How to apply the user's HTML environment in a Python programme?

[BobAalsma]

I'd like to write a programme that will be offered as a web service (Django), in which the user will point to a specific URL and the programme will be used to read the text of that URL.

This text can be behind a username/password, but for several reasons, I don't want to know those. 

So I would like to set up a situation where the user logs in (if/when appropriate), points out the URL to my programme and my programme would then be able to read that particular text.

I'm aware this may sound fishy. It should not be: I want the user to be fully aware and in control of this process.

Any thoughts on how to approach this?

Best regards,
Bob