GH Authentication Proxy

main.go

package main

import (
	"encoding/base64"
	"fmt"
	"net/http"
	"net/http/httputil"
	"net/url"
	"os"
)

const (
	localHost       = `127.0.0.1:8000`
	remoteHost      = `https://api.github.com`
	tokenEnvName    = `GH_TOKEN`
	usernameEnvName = `GH_USERNAME`
)

func main() {
	ghURL, err := url.Parse(remoteHost)
	if err != nil {
		panic(err)
	}

	proxy := httputil.NewSingleHostReverseProxy(ghURL)
	director, err := getDirector(proxy.Director)
	if err != nil {
		panic(err)
	}
	proxy.Director = director

	fmt.Printf("Proxying requests to %s to %s\n", localHost, remoteHost)
	if err := http.ListenAndServe(localHost, proxy); err != nil {
		panic(err)
	}
}

func getDirector(defaultDirector func(*http.Request)) (func(*http.Request), error) {

	accessToken := os.Getenv(tokenEnvName)
	username := os.Getenv(usernameEnvName)
	if accessToken == "" || username == "" {
		fmt.Fprintf(os.Stderr, "Could not detect %s value; Requests will be unauthenticated.\n", tokenEnvName)
	}

	return func(req *http.Request) {
		defaultDirector(req)
		req.Host = "api.github.com"

		fmt.Printf("Proxying request: %s\n", req.URL)
		if accessToken != "" && username != "" {
			token := base64.StdEncoding.EncodeToString([]byte(username + ":" + accessToken))
			req.Header.Set("Authorization", "Basic "+token)
		}
	}, nil
}