Tracking issue: HTTP_PROXY/HTTPS_PROXY/NO_PROXY support in Node.js

[joyeecheung]

• Support these environment variables in fetch() (behind NODE_USE_ENV_PROXY)
  • Initial support http: support HTTP[S]_PROXY environment variables in fetch #57165
  • align with curl: do not tunnel for http proxy ProxyAgent has different behavior from curl -x undici#4083
  • align with curl: support keep-alive Support proxy keep-alive undici#4086
• Support these environment variables in http(s) builtins (behind NODE_USE_ENV_PROXY)
  • Support for http(s).request: WIP
  • Support in http(s) Agent
• Enable support for NODE_USE_ENV_PROXY by default in fetch() (less risky since fetch is patched less in the wild)
• Enable support for NODE_USE_ENV_PROXY by default in http(s) builtins (might be too risky, need to investigate)
  • See if NODE_USE_ENV_PROXY interops well with existing ecosystem integration of these environment variables
• Share code between the fetch and the http(s) builtin implementation (e.g. env var parsing & matching)

[joyeecheung]

cc @nodejs/undici @nodejs/http

I have been looking into support for the http(s) builtins but it seems a bit too convoluted if this is hooked into the existing socket pooling of the agent and we need to perform tunnelling over the socket, as the lifecycle of the socket is exposed through the agent interface as well, So I am planning to take a different approach and just bypass the pooling when proxies are used for tunneling (that seems to be what most existing solutions on npm are already doing in their custom agents, anyway, just in a more convoluted way to combat with the Node.js internal invariants)