Go oauth client for Reddit

reddit_oauth.go

package main

import (
	"fmt"
	"github.com/codegangsta/martini"
	"github.com/porjo/goauth2/oauth"
	"io/ioutil"
	"log"
	"net/http"
)

var config = &oauth.Config{
	ClientId:     "xxxxxxxx",
	ClientSecret: "yyyyyyyyy",
	Scope:        "identity",
	AuthURL:      "https://ssl.reddit.com/api/v1/authorize?duration=permanent",
	TokenURL:     "https://ssl.reddit.com/api/v1/access_token",
	RedirectURL:  "http://myhost/reddit_oauth_callback",
	TokenCache:   oauth.CacheFile("oauth_cache.json"),
}

func main() {
	m := martini.Classic()
	m.Get("/reddit_oauth", redditHandler)
	m.Get("/reddit_oauth_callback", callbackHandler) //Reddit redirects to this URL after authorize request
	m.Run()
}

// URL to request once the oauth dance is complete
var requestURL = "https://oauth.reddit.com/api/v1/me"

func redditHandler(w http.ResponseWriter, r *http.Request) {

	t := &oauth.Transport{Config: config}

	// Does token exist?
	// Try to pull the token from the cache; if this fails, we need to get one.
	token, err := config.TokenCache.Token()

	if err != nil || token.AccessToken == "" {

		// No token. We need to get a new token
		// Get an authorization code from the data provider.
		// ("Please ask the user if I can access this resource.")
		url := config.AuthCodeURL("state_string")
		fmt.Printf("Redirecting to %s\n", url)
		http.Redirect(w, r, url, http.StatusFound)

	} else {
		// Yes. Re-use token
		t.Token = token
	}

	fmt.Printf("Token %s\n", token)

	log.Printf("Requesting URL %s\n", requestURL)
	// Make the request.
	cres, err := t.Client().Get(requestURL)
	if err != nil {
		log.Fatal("Get:", err)
	}
	defer cres.Body.Close()

	// Write the response to client
	body, err := ioutil.ReadAll(cres.Body)
	w.Write([]byte(body))
	log.Printf("Got response %s\n", body)
}

func callbackHandler(w http.ResponseWriter, r *http.Request) {

	t := &oauth.Transport{Config: config}

	//Get the code from the response
	code := r.FormValue("code")
	println(code)

	if code == "" {
		w.WriteHeader(401)
		w.Write([]byte("Auth Error in Reddit callback"))
		return
	}

	// Exchange the received code for a token
	token, err := t.Exchange(code)
	if err != nil {
		w.WriteHeader(401)
		w.Write([]byte(err.Error()))
		return
	}

	fmt.Printf("Token %s\n", token)

	// Make the actual request using the cached token to authenticate.
	// ("Here's the token, let me in!")
	t.Token = token

	w.Write([]byte("Congratulations, you've authenticated to Reddit!"))
}