Deprecate BasicAuth in favor of middleware based auth

[bdraco]

We can replace BasicAuth and proxy auth with a middleware helper instead so we don't have to maintain two methods. This will be a long deprecation cycle.

[Dreamsorcerer]

Or even just ask users to set the header, which is going to more efficient. A middleware to set a header on every request to a fixed value is probably overkill (as is the existing BasicAuth implementation).

[bdraco]

Or even just ask users to set the header, which is going to more efficient

While more efficient, I expect it to be beyond the skill level of many first time users

[bdraco]

We also need to think about the case or the username and password is embedded in the URL

[Dreamsorcerer]

Or even just ask users to set the header, which is going to more efficient

While more efficient, I expect it to be beyond the skill level of many first time users

Maybe the encoding, but we can keep a helper for that. So, already today, you could probably just do:
headers={"Authorization": BasicAuth(user, password).encode()}

[Dreamsorcerer]

We also need to think about the case or the username and password is embedded in the URL

I think that's a separate thing from the auth parameter, so probably little to do there. There are tests for it anyway, so it won't be forgotten.