添加文件群发和消息撤回功能

message.go

@@ -472,6 +472,16 @@ func (s *SentMessage) Revoke() error {
 	return s.Self.RevokeMessage(s)
 }
 
+// 转发该消息给好友
+func (s *SentMessage) ForwardToFriends(friends ...*Friend) error {
+	return s.Self.ForwardMessageToFriends(s, friends...)
+}
+
+// 转发该消息给群组
+func (s *SentMessage) ForwardToGroups(groups ...*Group) error {
+	return s.Self.ForwardMessageToGroups(s, groups...)
+}
+
 type appmsg struct {
 	Type      int    `xml:"type"`
 	AppId     string `xml:"appid,attr"` // wxeb7ec651dd0aefa9

relations.go

@@ -172,6 +172,28 @@ func (f Friends) SendImage(file *os.File, delay ...time.Duration) error {
 	return nil
 }
 
+// 群发文件
+func (f Friends)SendFile(file *os.File, delay ...time.Duration) error {
+	total := getTotalDuration(delay...)
+	var (
+		sentMessage *SentMessage
+		err         error
+		self        *Self
+	)
+	for _, friend := range f {
+		self = friend.Self
+		time.Sleep(total)
+		if sentMessage != nil {
+			err = self.ForwardMessageToFriends(sentMessage, f...)
+			return err
+		}
+		if sentMessage, err = friend.SendFile(file); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 type Group struct{ *User }
 
 // implement fmt.Stringer