翻出历史项目，先上传，未测试（MQTT3.1.1已经支持）

packet/pingreq.go

@@ -0,0 +1,71 @@
+package packet
+
+import (
+	"fmt"
+)
+
+type PingReq struct {
+	Header
+}
+
+func (msg *PingReq) Decode(buf []byte) (int, error) {
+	msg.dirty = false
+
+	//Tips. remain length is fixed 0 & total is fixed 2
+	total := len(buf)
+	if total < 2 {
+		return 0, fmt.Errorf("Ping expect fixed 2 bytes, got %d", total)
+	}
+
+	offset := 0
+
+	//Header
+	msg.header = buf[0]
+	offset++
+
+	//Remain Length
+	if l, n, err := ReadRemainLength(buf[offset:]); err != nil {
+		return offset, err
+	} else if l != 0 {
+		return 0, fmt.Errorf("Remain length must be 0, got %d", l)
+	} else {
+		msg.remainLength = l
+		offset += n
+	}
+
+	// FixHead & VarHead
+	msg.head = buf[0:offset]
+
+	return offset, nil
+}
+
+func (msg *PingReq) Encode() ([]byte, []byte, error) {
+	if !msg.dirty {
+		return msg.head, nil, nil
+	}
+
+	//Tips. remain length is fixed 0 & total is fixed 2
+	//Remain Length
+	msg.remainLength = 0
+
+	//FixHead & VarHead
+	hl := msg.remainLength
+
+	hl += 1 + LenLen(msg.remainLength)
+	//Alloc buffer
+	msg.head = make([]byte, hl)
+
+	//Header
+	ho := 0
+	msg.head[ho] = msg.header
+	ho++
+
+	//Remain Length
+	if n, err := WriteRemainLength(msg.head[ho:], msg.remainLength); err != nil {
+		return nil, nil, err
+	} else {
+		ho += n
+	}
+
+	return msg.head, nil, nil
+}