OS X: Using scutils to discover whether/what a web proxy is in use

When looking for ways to discover whether a proxy is being used by OS X, you will be typically pointed to

networksetup -getwebproxy

However that does not always work - for example when using "Auto Proxy Discovery" and/or "Automatic Proxy Configuration" with a proxy.pac file. scutils --proxy seems to detect all these cases (though it cannot give you the proxy when using auto config, I suppose):

# With "Automatic Proxy Configuration"
$ scutil --proxy
<dictionary> {
  ExceptionsList : <array> {
    0 : *.local
    1 : 169.254/16
  }
  FTPPassive : 1
  ProxyAutoConfigEnable : 1
  ProxyAutoConfigURLString : http://proxconf.example.com/proxy.pac
}

# With "Auto Proxy Discovery"
$ scutil --proxy
<dictionary> {
  ExceptionsList : <array> {
    0 : *.local
    1 : 169.254/16
  }
  FTPPassive : 1
  ProxyAutoConfigEnable : 1
  ProxyAutoConfigURLString : http://112.43.172.105/proxy.pac
  ProxyAutoDiscoveryEnable : 1
}

# With manual HTTP proxy configuration
$ scutil --proxy
<dictionary> {
  ExceptionsList : <array> {
    0 : *.local
    1 : 169.254/16
  }
  FTPPassive : 1
  HTTPEnable : 1
  HTTPPort : 8888
  HTTPProxy : http://example.com
}

# No proxy
$ scutil --proxy
<dictionary> {
  ExceptionsList : <array> {
    0 : *.local
    1 : 169.254/16
  }
  FTPPassive : 1
}

See Alex Argo's proxysetup.sh Gist for proxy detection and proxy env variable configuration.

Tags: productivity tool