Working cross domain too

oauth2client/client.go

@@ -15,11 +15,46 @@ func Authenticate(server string, w http.ResponseWriter, r *http.Request) error {
 	if err != nil {
 		return err
 	}
-	access, err := r.Cookie(oauth2.COOKIE)
-	if err == http.ErrNoCookie {
+	access, exists := findAccess(w, r)
+	if !exists {
 		return login(oauth2server, w, r)
 	}
-	return verify(access.Value, oauth2server, w, r)
+	return verify(access, oauth2server, w, r)
+}
+
+func findAccess(w http.ResponseWriter, r *http.Request) (string, bool) {
+	fresh, exists := findAccessFresh(w, r)
+	if exists {
+		return fresh, true
+	}
+	stable, exists := findAccessStable(w, r)
+	return stable, exists
+}
+
+func findAccessFresh(w http.ResponseWriter, r *http.Request) (string, bool) {
+	q := r.URL.Query()
+	access := q.Get(oauth2.COOKIE)
+	q.Del(oauth2.COOKIE)
+	r.URL.RawQuery = q.Encode()
+	if access == "" {
+		return "", false
+	}
+	cookie := &http.Cookie{
+		Name:     oauth2.COOKIE,
+		Value:    access,
+		SameSite: http.SameSiteLaxMode,
+		Path:     "/",
+	}
+	http.SetCookie(w, cookie)
+	return access, true
+}
+
+func findAccessStable(w http.ResponseWriter, r *http.Request) (string, bool) {
+	access, err := r.Cookie(oauth2.COOKIE)
+	if err == http.ErrNoCookie {
+		return "", false
+	}
+	return access.Value, true
 }
 
 func login(oauth2server *url.URL, w http.ResponseWriter, r *http.Request) error {
@@ -29,13 +64,9 @@ func login(oauth2server *url.URL, w http.ResponseWriter, r *http.Request) error
 	if url.Scheme == "" {
 		url.Scheme = "http"
 	}
-	cookie := &http.Cookie{
-		Name:     oauth2.REDIRECT,
-		Value:    url.String(),
-		SameSite: http.SameSiteLaxMode,
-		Path:     "/authorize",
-	}
-	http.SetCookie(w, cookie)
+	q := oauth2server.Query()
+	q.Set(oauth2.REDIRECT, url.String())
+	oauth2server.RawQuery = q.Encode()
 	http.Redirect(w, r, oauth2server.String(), http.StatusSeeOther)
 	return errors.New("logging in")
 }
@@ -63,3 +94,16 @@ func verify(access string, oauth2server *url.URL, w http.ResponseWriter, r *http
 	}
 	return nil
 }
+
+func setCookie(access string, w http.ResponseWriter) {
+	cookie := &http.Cookie{
+		Name:     oauth2.COOKIE,
+		Value:    access,
+		SameSite: http.SameSiteLaxMode,
+		Path:     "/",
+	}
+	if access == "" {
+		cookie.Expires = time.Now().Add(-1 * time.Hour)
+	}
+	http.SetCookie(w, cookie)
+}