proxy

netrc

Go library to load and prepare proxy authentication by parsing the netrc file as defined in ftp(1). Its purpose is now mainly to have a standard way of specifying the credentials for proxy authentication.

Requirements

• Go >= 1.10

Installation

This is a pure library, there is no associated command (like I do in some of my other packages such as RIPE Atlas or Cryptcheck).

Installation is like many Go libraries with a simple

go get github.com/keltia/proxy

Proxy also has vgo support & metadata (see the articles on vgo). It respects the Semantic Versioning principle with tagged releases.

API Usage

The API is very simple in net/http. You have to create a custom transport and look for credentials.

The main work is done by SetupAuthProxy() which looks at the standard file .netrc file. This file was defined a long time by the ftp(1) command to store FTP sites' credentials. We (ab)use it with a special site called "proxy".

The goal is to avoid polluting (and leaking) your credentials in the environment variable.

import "github.com/keltia/proxy"

authstr, err := proxy.SetupProxyAuth()

This looks for proxy credentials and store that internally. If you need the credentials later, you can still call GetAuth():

authstr := proxy.GetAuth()

autstr is suitable for inclusing in a Proxy-Authorization standard HTTP header like this (this only support Basic Authentication):

req.Header.Add("Proxy-Authorization", authstr)

To create the tailored HTTP Transport, you can use SetupTransport().

req, transport := proxy.SetupTransport(URL)

URL is there to trigger the search for the various proxy definitions (through the environment variables like HTTP_PROXY or other means that are supported by net/http.

There are also two functions dealing with logging, log levels and stuff:

proxy.SetLevel(N)         // 0 (default), 1 (verbose), 2 (debug)

proxy.SetLog(logger)      // logger is a *log.Logger object

By default, nothing is logged but if you set to 1 or more, the default is to log to Stderr in a fairly classic way.

netrc file

On UNIX systems like FreeBSD, macOS or Linux, the .netrcfile is located in the user's home directory (aka $HOME). On Windows, I have decided to emulate this by looking for a netrc file (no ".") located in the AFAIK traditional location, designed by the %LOCALAPPDATA% variable.

Format:

machine HOST username USER password PASS

in our case, HOST must be proxy or default.

If there is no netrc file or no proxy entry with credentials, the HTTP proxy can still be used but without authentication.

License

This is under the 2-Clause BSD license, see LICENSE.md.

History

I originally wrote this code for the erc-cimbl project and have re-used it enough time to think about putting it into its own module.

Contributing

Please see CONTRIBUTING.md for some simple rules.