Fix pass_through with HTTP proxy

[tboerstad]

This PR addresses an issue where pass_through in a proxy environment causes requests to fail:

$ https_proxy=http://proxy:8080 python
>>> with respx.mock:
...     respx.route().pass_through()
...     httpx.get("https://example.com")
httpx.InvalidURL: Invalid port: '8080example.com:443'

When a proxy is configured, httpcore sends a CONNECT request to establish a tunnel. This request uses authority-form URLs (e.g. example.com:443) with no scheme. When respx intercepts this and tries to parse it into an httpx.URL, the parser crashes.

This PR fixes the URL construction in to_httpx_request so that CONNECT requests flow through the normal route matching system. This means CONNECT tunnels can be mocked just like any other request:

with respx.mock:
    respx.route(method="CONNECT").pass_through()
    respx.get("https://foo.bar/").pass_through()
    httpx.Client(proxy="https://proxy:8080").get("https://foo.bar/")

Or mock proxy errors:

with respx.mock:
    respx.route(method="CONNECT").mock(return_value=httpx.Response(407))
    ...

[tboerstad]

First, thank you for making respx, very neat!

This PR is a compromise, a small implementation which I think could solve a real issue for users, namely using this library behind a proxy. I ran into this myself when using Anthropic web based Claude Code offering, which is behind a proxy.

However this also means mocking the proxy CONNECT request will not work properly, which is not great.
I leave it up to the maintainer to make a decision here, full understanding if this PR is closed instead

[lundberg]

Thanks for raising the issue @tboerstad, and sorry for the late reply 😅 ..

.. It feels like there should be a better place to address the issue, e.g. where the URL parsing error happens, and let the connect request successfully flow through the respx router and properly be passed through 🤔

i.e. ending up with this being possible ..

respx.route(method="CONNECT").pass_through()

[tboerstad]

Thank you @lundberg. I agree, that's a better solution.
I've updated this PR with a new approach better matching your suggestion

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (4dd0eec) to head (12590d1).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

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##            master      #303   +/-   ##
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  Coverage   100.00%   100.00%           
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  Files           22        22           
  Lines         2941      2996   +55     
  Branches       200       204    +4     
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+ Hits          2941      2996   +55     

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[lundberg]

Looks good, fix failing workflow jobs and we're good to go!

Btw, you can locally run lint fix, test matrix etc with task command (no args)

[tboerstad]

Looks good, fix failing workflow jobs and we're good to go!

Btw, you can locally run lint fix, test matrix etc with task command (no args)

Oops, sorry for the back and forth. It's working locally now, except for a formatter issue with CHANGELOG.md (which this PR didn't touch).

[lundberg]

.. formatter issue with CHANGELOG.md (which this PR didn't touch).

My bad 😉 .. I've pushed a fix to master, please rebase.

[tboerstad]

My bad 😉 .. I've pushed a fix to master, please rebase.

Thanks, have rebased, everything is passing locally now.