A simple wrapper around socat to use as a git proxy command

gitproxy-socat

#!/bin/sh
# Use socat to proxy git through an HTTP CONNECT firewall.
# Useful if you are trying to clone git:// from inside a company.
# Requires that the proxy allows CONNECT to port 9418.
#
# Save this file as gitproxy somewhere in your path (e.g., ~/bin) and then run
# chmod +x gitproxy
# git config --global core.gitproxy gitproxy
#
# More details at http://tinyurl.com/8xvpny
# Configuration. Common proxy ports are 3128, 8123, 8000.

# As mentioned by James Hanley in the comments

# Gratuisly taken from bsdstats - http://ftp.netbsd.org/pub/NetB...
# Dynamically Handle HTTP proxy services
#
# HTTP_PROXY/http_proxy can take the following form:
# [http://][username:password@]proxy[:port][/]
# Authentication details may also be provided via HTTP_PROXY_AUTH:
# HTTP_PROXY_AUTH="basic:*:username:password"

if [ -z "${HTTP_PROXY}" -a -n "${http_proxy}" ]; then
  HTTP_PROXY=${http_proxy}
fi
if [ -n "${HTTP_PROXY}" ]; then
  # Attempt to resolve any HTTP authentication
  if [ -n "${HTTP_PROXY_AUTH}" ]; then
    PROXY_AUTH_USER=`echo ${HTTP_PROXY_AUTH} | sed -E 's/^.+:\*:(.+):.+$/\1/g'`
    PROXY_AUTH_PASS=`echo ${HTTP_PROXY_AUTH} | sed -E 's/^.+:\*:.+:(.+)$/\1/g'`
  else
    # Check for authentication within HTTP_PROXY
    HAS_HTTP_AUTH=`echo ${HTTP_PROXY} | sed -E 's/^(http:\/\/)?(.+:.+)?@.+/\2/'`
    if [ -n "$HAS_HTTP_AUTH" ]; then
      # Found HTTP authentication details
      PROXY_AUTH_USER=`echo $HAS_HTTP_AUTH | cut -d: -f1`
      PROXY_AUTH_PASS=`echo $HAS_HTTP_AUTH | cut -d: -f2`
    fi
  fi

  # Determine the proxy components
  PROXY_HOST=`echo ${HTTP_PROXY} | sed -E 's/^(http:\/\/)?(.+:.+@)?([^@:]+)(:.+)?/\3/'`
  PROXY_PORT=`echo ${HTTP_PROXY} | sed -E 's/^(http:\/\/)?(.+:.+@)?(.+):([0-9]+)/\4/' | sed -e 's/[^0-9]//g'`
  if [ -z "${PROXY_PORT}" ]; then
    # Use default proxy port
    PROXY_PORT=80
  fi
fi

if [ -z "${PROXY_HOST}" ]; then
  # Direct connect
  exec socat STDIO TCP:${1}:${2}
elif [ -z "${PROXY_AUTH_USER}" ]; then
  # No-Auth
  exec socat STDIO PROXY:${PROXY_HOST}:${1}:${2},proxyport=${PROXY_PORT}
else
  # Auth Proxy
  exec socat STDIO PROXY:${PROXY_HOST}:${1}:${2},proxyport=${PROXY_PORT},proxyauth=${PROXY_AUTH_USER}:${PROXY_AUTH_PASS}
fi