google.go

package auth

import (
	"github.com/dgrijalva/jwt-go"
)

type (
	Google struct {
	}
)

type GoogleTokenInfo struct {
	Sub       string `json:"sub"`
	Name      string `json:"name"`
	FirstName string `json:"given_name"`
	LastName  string `json:"family_name"`
	Email     string `json:"email"`
	Picture   string `json:"picture"`
	jwt.StandardClaims
}

func (c *GoogleTokenInfo) Valid() error {
	// leeway in seconds
	expiresLeeway := Leeway
	issuedLeeway := Leeway

	c.StandardClaims.ExpiresAt += expiresLeeway
	c.StandardClaims.IssuedAt -= issuedLeeway
	
	err := c.StandardClaims.Valid()
	
	c.StandardClaims.ExpiresAt -= expiresLeeway
	c.StandardClaims.IssuedAt += issuedLeeway
	
	return err
 }

const googleKeysEndpoint = "https://www.googleapis.com/oauth2/v2/certs"

func (s *Google) auth(token string) (ud *UserDetails, err error) {
	return s.authWithCheckAUD(token, "")
}

func (s *Google) authWithCheckAUD(token, aud string) (ud *UserDetails, err error) {
	t, err := new(jwt.Parser).ParseWithClaims(token, &GoogleTokenInfo{}, getTokenValidateFunc(googleKeysEndpoint))
	if err != nil {
		return nil, err
	}
	info, _ := t.Claims.(*GoogleTokenInfo)

	if aud != "" {
		if ok := info.VerifyAudience(aud, true); !ok {
			return nil, ErrNotValidAudience
		}
	}

	if info != nil {
		ud = &UserDetails{
			ID:        info.Sub,
			UserName:  info.Name,
			FirstName: info.FirstName,
			LastName:  info.LastName,
			Email:     info.Email,
			Picture:   info.Picture,
		}
	}
	return
}