/
google.go
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/
google.go
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// Townsourced
// Copyright 2015 Tim Shannon. All rights reserved.
package app
import (
"encoding/base64"
"encoding/json"
"fmt"
"io/ioutil"
"net/http"
"net/url"
"strings"
"time"
"github.com/timshannon/townsourced/data/private"
"github.com/timshannon/townsourced/fail"
)
const (
googleClientID = private.GoogleClientID
googleClientSecret = private.GoogleClientSecret
googleDiscoveryDocumentURL = "https://accounts.google.com/.well-known/openid-configuration"
)
type googleDiscoveryDocument struct {
AuthorizationEndpoint string `json:"authorization_endpoint"`
TokenEndpoint string `json:"token_endpoint"`
JWKSURI string `json:"jwks_uri"`
}
type googleOauthSession struct {
AccessToken string `json:"access_token"`
IDToken string `json:"id_token"`
Error string `json:"error"`
ErrorDescription string `json:"error_description"`
jwt *googleJWT
}
type googleJWT struct {
ISS string `json:"iss"`
UserID string `json:"sub"`
Email string `json:"email"`
AppID string `json:"aud"`
Expires int64 `json:"exp"`
}
type googlePeople struct {
DisplayName string `json:"displayName"`
Error *googleAPIError `json:"error"`
session *googleOauthSession
}
type googleAPIError struct {
Code int `json:"code"`
Message string `json:"message"`
}
func (ge *googleAPIError) Error() string {
return fmt.Sprintf("%s Code: %d", ge.Message, ge.Code)
}
// GoogleOpenIDConfig retrieves the open ID connection information
func GoogleOpenIDConfig() (clientID, authURL string, err error) {
dDoc, err := googleGetDiscoveryDoc()
if err != nil {
return
}
authURL = dDoc.AuthorizationEndpoint
clientID = googleClientID
return
}
func googleGetDiscoveryDoc() (dDoc *googleDiscoveryDocument, err error) {
//TODO: respect cache / wrap in mutex w/ timer?
res, err := httpClient.Get(googleDiscoveryDocumentURL)
if err != nil {
return nil, err
}
val, err := ioutil.ReadAll(res.Body)
defer func() {
if cerr := res.Body.Close(); cerr != nil && err == nil {
err = cerr
}
}()
if err != nil {
return nil, err
}
dDoc = &googleDiscoveryDocument{}
err = json.Unmarshal(val, dDoc)
if err != nil {
return nil, err
}
return dDoc, nil
}
func googleGetOauthSession(code, redirectURI string) (gSes *googleOauthSession, err error) {
dDoc, err := googleGetDiscoveryDoc()
if err != nil {
return nil, err
}
values := url.Values{}
values.Add("code", code)
values.Add("client_id", googleClientID)
values.Add("client_secret", googleClientSecret)
values.Add("redirect_uri", redirectURI)
values.Add("grant_type", "authorization_code")
res, err := httpClient.Post(dDoc.TokenEndpoint, "application/x-www-form-urlencoded", strings.NewReader(values.Encode()))
if err != nil {
return nil, err
}
val, err := ioutil.ReadAll(res.Body)
defer func() {
if cerr := res.Body.Close(); cerr != nil && err == nil {
err = cerr
}
}()
if err != nil {
return nil, err
}
gSes = &googleOauthSession{}
err = json.Unmarshal(val, gSes)
if err != nil {
return nil, err
}
if gSes.Error != "" {
return nil, fail.New(fmt.Sprintf("Error getting google session - %s : %s", gSes.Error, gSes.ErrorDescription))
}
return gSes, nil
}
func (gs *googleOauthSession) userData() (people *googlePeople, err error) {
req, err := http.NewRequest("GET", "https://www.googleapis.com/plus/v1/people/me", nil)
if err != nil {
return nil, err
}
req.Header.Add("Authorization", "Bearer "+gs.AccessToken)
res, err := httpClient.Do(req)
if err != nil {
return nil, err
}
val, err := ioutil.ReadAll(res.Body)
defer func() {
if cerr := res.Body.Close(); cerr != nil && err == nil {
err = cerr
}
}()
if err != nil {
return nil, err
}
people = &googlePeople{}
err = json.Unmarshal(val, people)
if err != nil {
return nil, err
}
if people.Error != nil {
return nil, people.Error
}
people.session = gs
return people, nil
}
func (gs *googleOauthSession) getJWT() (*googleJWT, error) {
if gs.jwt != nil {
return gs.jwt, nil
}
if gs.IDToken == "" {
return nil, fmt.Errorf("Invalid Google JWT")
}
parts := strings.Split(gs.IDToken, ".")
if len(parts) < 2 {
return nil, fmt.Errorf("Malformed Google JWT: %s", gs.IDToken)
}
idToken := parts[1]
jwt := &googleJWT{}
// Decode the ID token
switch len(idToken) % 4 {
case 2:
idToken += "=="
case 3:
idToken += "="
}
b, err := base64.URLEncoding.DecodeString(idToken)
if err != nil {
return nil, fmt.Errorf("Malformed Google JWT: %v", err)
}
err = json.Unmarshal(b, jwt)
if err != nil {
return nil, fmt.Errorf("Malformed Google JWT: %v", err)
}
gs.jwt = jwt
return jwt, nil
}
func (j *googleJWT) validate() error {
if j.AppID != googleClientID {
return fmt.Errorf("Invalid Google JWT, AppID mismatch")
}
if j.ISS != "accounts.google.com" && j.ISS != "https://accounts.google.com" {
return fmt.Errorf("Invalid Google JWT, invalid ISS")
}
if time.Unix(j.Expires, 0).Before(time.Now()) {
return fmt.Errorf("Invalid Google JWT, expired")
}
//TODO: Check googles cryptographic keys
return nil
}
// GoogleUser gets a user (if possible)
// from the passed in google code
func GoogleUser(code, redirectURI string) (*User, error) {
gSes, err := googleGetOauthSession(code, redirectURI)
if err != nil {
return nil, err
}
jwt, err := gSes.getJWT()
if err != nil {
return nil, err
}
//Lookup user
usr, err := userGetGoogle(jwt.UserID)
if err == ErrUserNotFound {
data, err := gSes.userData()
if err != nil {
return nil, err
}
usrFail := fail.NewFromErr(ErrUserNeedUsername, map[string]string{
"username": urlify(data.DisplayName).make(),
"email": jwt.Email,
"idToken": gSes.IDToken,
"accessToken": gSes.AccessToken,
})
return nil, usrFail
}
if err != nil {
return nil, err
}
return usr, nil
}
// GoogleNewUser creates a new google user with the passed in username and email,
// using the passed in temporary token
func GoogleNewUser(username, email, googleID, idToken, accessToken string) (*User, error) {
gSes := &googleOauthSession{
AccessToken: accessToken,
IDToken: idToken,
}
jwt, err := gSes.getJWT()
if err != nil {
return nil, err
}
err = jwt.validate()
if err != nil {
return nil, err
}
u, err := googleNewUser(username, email, gSes)
if err != nil {
return nil, err
}
return u, nil
}
func googleNewUser(username, email string, gSes *googleOauthSession) (*User, error) {
//Get email address and name
data, err := gSes.userData()
if err != nil {
return nil, err
}
jwt, err := gSes.getJWT()
if err != nil {
return nil, err
}
if email == "" {
email = jwt.Email
}
u, err := userNewGoogle(username, email, data.DisplayName, jwt.UserID)
if err != nil {
return nil, err
}
return u, nil
}