Support digest authentication for HTTP proxies.

[lovelydinosaur]

Escalating discussion #2028 into an issue.

HTTP proxies are sometimes configured to use digest authentication.
Right now we only support basic authentication with HTTP proxies.
It'd be worthwhile to also support digest - which requires following up the initial CONNECT request to the proxy with a subsequent authentication request before the proxy tunnel is established.

Here's the original discussion...

^{Originally posted by raffaem January 13, 2022}
Does httpx support DigestAuthentication for proxies, and if so, can you connect to HTTPS websites through a proxy that requires DigestAuthentication?

requests-toolbet has a HTTPProxyDigestAuth class, but it does not allow you to connect to HTTPS through the proxy.

Apparently that feature won't be implemented in the foreseeable future in requests.

The only working implementation that I have found, and which allows you to connect to HTTPS websites through the proxy, is this one, which was provided in this StackOverflow post.

Does httpx support this feature, or will it support it?

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[lovelydinosaur]

Still valid thx, @Stale bot.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[lovelydinosaur]

I think we should consider closing this since we've only had one person ever request this.

There's enough documentation and pointers around httpcore for someone who's interested to be able to start tackling it. If someone ends up interested and invested in resolving that, then I think that'd be a good indicator that it'd be worth re-opening.

Seem valid @encode/maintainers?

[lovelydinosaur]

I'm going to close this ticket off for now - if someone bumps into this as a requirement please let us know.
Otherwise / until then, we'll be treating this as out of scope.