Merge pull request #578 from shivamkm07/master

Support for AutoAckOff - Enables users to disable automatic ACK for incoming messages. Users MUST call `m.Ack()` themselves if this is set yo `true`. Please remember that the MQTT standard does not require the broker to sesend messages except when the connection is re-established.

Author: MattBrittan

options.go

@@ -104,6 +104,7 @@ type ClientOptions struct {
 	MaxResumePubInFlight    int // // 0 = no limit; otherwise this is the maximum simultaneous messages sent while resuming
 	Dialer                  *net.Dialer
 	CustomOpenConnectionFn  OpenConnectionFunc
+	AutoAckDisabled         bool
 }
 
 // NewClientOptions will create a new ClientClientOptions type with some
@@ -147,6 +148,7 @@ func NewClientOptions() *ClientOptions {
 		WebsocketOptions:        &WebsocketOptions{},
 		Dialer:                  &net.Dialer{Timeout: 30 * time.Second},
 		CustomOpenConnectionFn:  nil,
+		AutoAckDisabled:         false,
 	}
 	return o
 }
@@ -446,3 +448,10 @@ func (o *ClientOptions) SetCustomOpenConnectionFn(customOpenConnectionFn OpenCon
 	}
 	return o
 }
+
+// SetAutoAckDisabled enables or disables the Automated Acking of Messages received by the handler.
+//	By default it is set to false. Setting it to true will disable the auto-ack globally.
+func (o *ClientOptions) SetAutoAckDisabled(autoAckDisabled bool) *ClientOptions {
+	o.AutoAckDisabled = autoAckDisabled
+	return o
+}

router.go

@@ -186,7 +186,9 @@ func (r *router) matchAndDispatch(messages <-chan *packets.PublishPacket, order
 						wg.Add(1)
 						go func() {
 							hd(client, m)
-							m.Ack()
+							if !client.options.AutoAckDisabled {
+								m.Ack()
+							}
 							wg.Done()
 						}()
 					}
@@ -201,7 +203,9 @@ func (r *router) matchAndDispatch(messages <-chan *packets.PublishPacket, order
 						wg.Add(1)
 						go func() {
 							r.defaultHandler(client, m)
-							m.Ack()
+							if !client.options.AutoAckDisabled {
+								m.Ack()
+							}
 							wg.Done()
 						}()
 					}
@@ -212,7 +216,9 @@ func (r *router) matchAndDispatch(messages <-chan *packets.PublishPacket, order
 			r.RUnlock()
 			for _, handler := range handlers {
 				handler(client, m)
-				m.Ack()
+				if !client.options.AutoAckDisabled {
+					m.Ack()
+				}
 			}
 			// DEBUG.Println(ROU, "matchAndDispatch handled message")
 		}