Add scope to token refresh request. Closes #447

Author: lancerushing

oauth2.go

@@ -267,10 +267,16 @@ func (tf *tokenRefresher) Token() (*Token, error) {
 		return nil, errors.New("oauth2: token expired and refresh token is not set")
 	}
 
-	tk, err := retrieveToken(tf.ctx, tf.conf, url.Values{
+
+	v := url.Values{
 		"grant_type":    {"refresh_token"},
 		"refresh_token": {tf.refreshToken},
-	})
+	}
+	if len(tf.conf.Scopes) > 0 {
+		v.Set("scope", strings.Join(tf.conf.Scopes, " "))
+	}
+
+	tk, err := retrieveToken(tf.ctx, tf.conf, v)
 
 	if err != nil {
 		return nil, err

oauth2_test.go

@@ -440,7 +440,7 @@ func TestTokenRefreshRequest(t *testing.T) {
 			t.Errorf("Unexpected Content-Type header %q", headerContentType)
 		}
 		body, _ := ioutil.ReadAll(r.Body)
-		if string(body) != "grant_type=refresh_token&refresh_token=REFRESH_TOKEN" {
+		if string(body) != "grant_type=refresh_token&refresh_token=REFRESH_TOKEN&scope=scope1+scope2" {
 			t.Errorf("Unexpected refresh token payload %q", body)
 		}
 		w.Header().Set("Content-Type", "application/json")