gistfile1.go

package main

import (
	"code.google.com/p/goauth2/oauth"
	urlshortener "code.google.com/p/google-api-go-client/urlshortener/v1"
	"flag"
	"fmt"
	"log"
)

var (
	clientId     = flag.String("id", "", "Client ID")
	clientSecret = flag.String("secret", "", "Client Secret")
	redirectURL  = flag.String("redirect_url", "oob", "Redirect URL")
	authURL      = flag.String("auth_url", "https://accounts.google.com/o/oauth2/auth", "Authentication URL")
	tokenURL     = flag.String("token_url", "https://accounts.google.com/o/oauth2/token", "Token URL")
	code         = flag.String("code", "", "Authorization Code")
	cachefile    = flag.String("cache", "cache.json", "Token cache file")
	url          = flag.String("url", "http://www.vende.pe", "URL to shorten")
)

const usageMsg = `
To obtain a request token you must specify both -id and -secret.

To obtain Client ID and Secret, see the "OAuth 2 Credentials" section under
the "API Access" tab on this page: https://code.google.com/apis/console/

Once you have completed the OAuth flow, the credentials should be stored inside
the file specified by -cache and you may run without the -id and -secret flags.
`

func main() {
	flag.Parse()
	config := &oauth.Config{
		ClientId:     *clientId,
		ClientSecret: *clientSecret,
		RedirectURL:  *redirectURL,
		Scope:        urlshortener.UrlshortenerScope,
		AuthURL:      *authURL,
		TokenURL:     *tokenURL,
		TokenCache:   oauth.CacheFile(*cachefile),
	}
	transport := &oauth.Transport{Config: config}
	token, err := config.TokenCache.Token()

	if err != nil {

		if *code == "" {
			// Get an authorization code from the data provider.
			// ("Please ask the user if I can access this resource.")
			url := config.AuthCodeURL("")
			fmt.Println("Visit this URL to get a code, then run again with -code=YOUR_CODE\n")
			fmt.Println(url)
			return
		}
		// Exchange the authorization code for an access token.
		// ("Here's the code you gave the user, now give me a token!")
		token, err = transport.Exchange(*code)
		if err != nil {
			log.Fatal("Exchange:", err)
		}
		// (The Exchange method will automatically cache the token.)
		fmt.Printf("Token is cached in %v\n", config.TokenCache)
	}

	transport.Token = token

	httpClient := transport.Client()
	svc, err := urlshortener.New(httpClient)

	shortUrl, err := svc.Url.Insert(&urlshortener.Url{
		Kind:    "urlshortener#url", // Not really needed
		LongUrl: *url,
	}).Do()

	fmt.Printf("The URL %s goes to %s\n", shortUrl.Id, *url)
}