Use Alpaca to Evaluate PAC for Command-Line Tools

Use Alpaca's local HTTP endpoint so a CLI can follow PAC routing without parsing the script itself.

A PAC-aware local proxy gives command-line tools a fixed endpoint while evaluating the network's routing policy for each destination. Alpaca provides this adapter role: the tool talks HTTP proxy locally, and Alpaca chooses an upstream proxy or a direct connection.

With an existing installation, start its loopback listener using the documented flags:

ALPACA_PROXY_AUTH_ALLOWLIST=.corp.example.net \
alpaca -l 127.0.0.1 -p 3128 \
  -C https://config.corp.example.net/proxy.pac

The PAC URL, proxy-authentication allowlist and port are deployment examples. Supply the upstream authentication inputs supported by the installed version and platform when the selected proxies require them. The allowlist identifies proxy hosts allowed to receive those credentials.

Configure the command-line tool to use the local endpoint:

export http_proxy=http://127.0.0.1:3128
export https_proxy=http://127.0.0.1:3128

The tool can keep those values while the PAC sends an intranet destination direct and a public destination through the corporate proxy. It does not need to evaluate PAC JavaScript itself.

The project also documents temporary direct bypass when selected parents become unreachable. Include that fallback in the deployment policy when deciding whether the adapter provides the required route.

Check the adapter's supported PAC result types. The documented Alpaca CLI makes SOCKS5 PAC routes an explicit opt-in through -enable-socks; the local HTTP interface and the selected upstream protocol are different parts of the route.

Erthyglow kevrennek