auth.go

package main

import (
	"encoding/json"
	log "github.com/sirupsen/logrus"
	"golang.org/x/oauth2"
	"golang.org/x/oauth2/google"
	"io/ioutil"
)


// User is a retrieved and authenticated user.
type GoogleUser struct {
	Sub string `json:"sub"`
	Name string `json:"name"`
	GivenName string `json:"given_name"`
	FamilyName string `json:"family_name"`
	Profile string `json:"profile"`
	Picture string `json:"picture"`
	Email string `json:"email"`
	EmailVerified bool `json:"email_verified"`
	Gender string `json:"gender"`
}


func authInit (ClientID, ClientSecret, RedirectUrl string) {
	oauthConf = &oauth2.Config{
		ClientID:     ClientID,
		ClientSecret: ClientSecret,
		RedirectURL:  RedirectUrl,
		Scopes: []string{
			"https://www.googleapis.com/auth/userinfo.email",
			"https://www.googleapis.com/auth/userinfo.profile",
		},
		Endpoint: google.Endpoint,
	}
}


func userInfoFromToken (token *oauth2.Token) (err error, user *GoogleUser) {
	if !token.Valid() {
		log.Error(err)
		return
	}

	client := oauthConf.Client(oauth2.NoContext, token)
	response, err := client.Get("https://www.googleapis.com/oauth2/v3/userinfo")
	if err != nil {
		log.Error("Error getting user from token ", err)
		return
	}

	defer response.Body.Close()
	contents, err := ioutil.ReadAll(response.Body)

	err = json.Unmarshal(contents, &user)
	if err != nil {
		log.Error("Error unmarshaling Google user", err)
		return
	}

	return
}