import "github.com/RangelReale/osincli"

config := &osincli.ClientConfig{
	ClientId:                 "xxxxxxxxxxxx.apps.googleusercontent.com",
	ClientSecret:             "secret",
	AuthorizeUrl:             "https://accounts.google.com/o/oauth2/auth",
	TokenUrl:                 "https://accounts.google.com/o/oauth2/token",
	RedirectUrl:              "http://localhost:14001/appauth",
	ErrorsInStatusCode:       true,
	SendClientSecretInParams: true,
	Scope: "https://www.googleapis.com/auth/plus.login",
}
client, err := osincli.NewClient(config)
if err != nil {
	panic(err)
}

// create a new request to generate the url
areq := client.NewAuthorizeRequest(osincli.CODE)
areq.CustomParameters["access_type"] = "online"
areq.CustomParameters["approval_prompt"] = "auto"

// Home
http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
	u := areq.GetAuthorizeUrl()
	w.Write([]byte(fmt.Sprintf("<a href=\"%s\">Login</a>", u.String())))
})

// Auth endpoint
http.HandleFunc("/appauth", func(w http.ResponseWriter, r *http.Request) {
	// parse a token request
	if areqdata, err := areq.HandleRequest(r); err == nil {
		treq := client.NewAccessRequest(osincli.AUTHORIZATION_CODE, areqdata)

		// exchange the authorize token for the access token
		ad, err := treq.GetToken()
		if err == nil {
			w.Write([]byte(fmt.Sprintf("Access token: %+v\n\n", ad)))
			
			// use the token in ad.AccessToken
		} else {
			w.Write([]byte(fmt.Sprintf("ERROR: %s\n", err)))
		}
	} else {
		w.Write([]byte(fmt.Sprintf("ERROR: %s\n", err)))
	}
})

http.ListenAndServe(":14001", nil)

http://localhost:14001