proxy-watch

The operating system's proxy settings for Python, layered with http_proxy, https_proxy, all_proxy and no_proxy, and the route each URL takes under them. Windows, macOS and Linux (GNOME, KDE) settings are read directly; nothing is spawned.

pip install proxy-watch

import proxy_watch

snapshot = proxy_watch.read()
route = snapshot.route("https://example.com/")
if route.kind == "steps":
    print(route.steps)  # ["direct"] or proxy URLs, credentials included
else:
    print(route.kind)   # "pac", "pac-inline" or "wpad": the caller runs the script

PAC

route(url, pac=...) chooses who runs a PAC configuration:

script= runs a PAC body you fetched yourself, and wpad=True lets the OS discover one (Windows, macOS). route.engine says which engine answered. QuickJS's default policy answers as if off every network (myIpAddress() is 127.0.0.1 and dnsResolve answers None), so a script that picks a proxy by network needs a PacPolicy that says where the machine is.

Watching

with proxy_watch.watch(lambda err, snapshot: print(err or snapshot.route("https://example.com/").kind)) as watcher:
    ...

on_change runs on the watch's own thread after each change.

Wheels

One abi3 wheel per platform serves CPython 3.10 and later: Linux x86-64 and AArch64 (manylinux2014 and musllinux 1.2), macOS x86-64 and arm64, Windows x86-64 and ARM64. QuickJS is built into each of them.

License

MIT OR Apache-2.0. Each wheel carries THIRD-PARTY-LICENSES.txt for the Rust crates, the C sources and the Rust standard library linked into it.