MQTT with Java - a protocol for IoT and M2M communication
!Christian Götz, dc-square
IoT?
M2MIoT
IoEWoT
Web of Things
Internet of Things
Internet of Everything
Machine to Machine communication
UbicompUbiquitous computing
CPSCyper Physical Systems Pervasive
Computing
Technology that connects Devices
over wired or wireless communication
GPSGPS
GPSGPS
GPS
GPSGPS
Detected: Traffic Jam!
Hi, I’m Christian Götz
author & speakerbuilding solutions
CEO & co-founder
developer@goetzchr
IoT is happening now
WHY?
6,5 per person
DEVICES outnumber people
0,0
15,0
30,0
45,0
60,0
2003 2010 2015 2020
50,0
25,0
12,5
0,5
6,0
19,5
33,0
46,5
60,0
2003 2010 2015 2020
7,67,36,86,3
250 new every sec
http://blogs.cisco.com/news/cisco-connections-counter/
http://www.cisco.com/web/about/ac79/docs/innov/IoT_IBSG_0411FINAL.pdf
2020in billions
people
devices
Open Hardware is everywhere
Raspberry Pi is a trademark of the Raspberry Pi Foundation
Screenshot from JavaOne 2013
Java back to the roots
Screenshot from JavaOne 2013
Java back to the roots
HTTP is not suitable
WHY?
Request/Response Point-2-Point widely known
HTTP is too verbose
Challenges
Constrained devices
Bi-directional
Scalability
Unreliable Networks
Push Messaging
Security
… there are more ;)
IoTHTTP
IoT challenges
MQTT is a good fit
WHY?
Subscribe
Publish
Temperaturfühler MQTT-Broker
Laptop
Mobiles Endgerät
publish: “21°C“publish: “21°C“
publish: “21°C“
subscribe
subscribe
munichschwabing
isarvorstadt
people
temp
people
temp
/ /
MQTT topics 101
munichschwabing
isarvorstadt
people
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people
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/ /
munich/schwabing/temp
MQTT topics 101
munichschwabing
isarvorstadt
people
temp
people
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/ /
munich/+/temp
MQTT topics 101
munichschwabing
isarvorstadt
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people
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munich/schwabing/#
MQTT topics 101
munichschwabing
isarvorstadt
people
temp
people
temp
/ /
#
MQTT topics 101
On top of TCP
Simple
Publish/Subscribe Architecture
BinaryMinimal Overhead
Designed for unreliable networks
Data agnostic
MQTT facts
- Establishing 1st Connection(compensated after 5,5 min)
+ Reconnect
+ Maintaining Connection
+ Receiving Messages
+ Sending Messages
less battery better throughput
MQTT (with SSL) vs HTTPS
+ Less Overhead
+ Persistent Sessions
+ Pub/Sub Architecture
Source: http://stephendnicholas.com/archives/1217
1999 2010 2013 2014
Arlen Nipper & Andy Stanford-Clark
invent MQTTroyalty free OASIS TC
formedMQTT becomes Standard
MQTT history
Push instead of Poll
Minimal Bandwidth is important Mobile meets Enterprise
Unreliable networks Constrained devices
Low Latency
MQTT use cases
MQTT real world usage
https://www.facebook.com/notes/facebook-engineering/building-facebook-messenger/
10150259350998920
Quality of Service
Retained Messages Last Will and Testament
Persistent Sessions Heartbeats
Topic Wildcards
MQTT features
MQTT features Quality of Services
QoS 1
QoS 2
QoS 0B
B
B
MQTT features Last Will and Testament
BConnect
LWT
device123/status: „offline“
Bdropped
device123/status: „offline“
MQTT features w/o Retained Messages
Bdevice1/temp: „23,0“
device1
every 5 min
device2
device1/temp: „23,0“
Delay <= 5min
MQTT features Retained Messages
Bdevice1/temp: „23,0“ R
device1
every 5 min
device2
device1/temp: „23,0“ R
No Delay!
MQTT features Persistent Sessions
BConnect
Subscribedevice/+/status
device/12/status: „1“
1st
BRe-Connect
device/12/status: „1“2nd
MQTT-SN Overview
Gateway MQTT-Broker
MQTT-SN MQTT / -SN
• UDP instead of TCP • Topic is just an ID (Preregister/Register) • Sleeping Clients • Different types of Gateways • Discovery Mechanisms
Devices
B
MQTT over Websockets
MQTT Security
Protocol
Username/Password
Transport
TLS, client certificate authentification
Broker
fine-grained authentication, 3rd party integration
Broker implementationsWhat ?
MQTT Broker Mosquitto
Open Source
Ideal for constraint devices Supports Bridging
Written in C
MQTT Broker HiveMQ
High performance broker
Open Plugin System for Java Clustering
Bridging Scalable to > 100.000 connections
Native Websocket support
MQTT Broker
+ othershttp://mqtt.org/wiki/doku.php/brokers
Getting StartedHow ?
MQTT Implementation
Open Source
“Reference Implementation”
Many languages: Java, Javascript, Lua, C, C++, Go, Python
Active Community
JS Library uses MQTT over Websockets
Paho facts
MqttClient client = new MqttClient( "tcp://localhost:1883", //URI "publisher", //Client ID new MemoryPersistence()); //Persistence
Paho Init Connection
MqttClient client = new MqttClient(...); !MqttConnectOptions connOptions = new MqttConnectOptions(); !connOptions.setKeepAliveInterval(120); connOptions.setWill("my/status", "offline".getBytes(), 2, true); connOptions.setCleanSession(false); connOptions.setUserName("user"); connOptions.setPassword(„pass".toCharArray()); !client.connect(connOptions);
Paho Init Connection
!!client.publish("my/topic/123",//topic "Hello!".getBytes(), //message
1, //QoS false); //retained !!
client.disconnect();
Paho Synchronous API
final MqttClient client = new MqttClient(...); client.setCallback(new MqttCallback() { @Override public void connectionLost(Throwable cause) {} !@Override public void messageArrived(String topic, MqttMessage message)throws Exception { System.out.println(new String(message.getPayload())); } !@Override public void deliveryComplete(IMqttDeliveryToken token) {} }); !client.connect(); client.subscribe("#");
Paho Synchronous API
MqttAsyncClient client = new MqttAsyncClient(...); client.connect(null, new IMqttActionListener() { @Override public void onSuccess(IMqttToken asyncActionToken) { try { client.publish(...); } catch (MqttException e) {}
} @Override public void onFailure(IMqttToken asyncActionToken, Throwable exception) {} }); !client.disconnect();
Paho Asynchronous API
MQTT Implementation
FuseSource MQTT Client
Open Source
3 API Styles
Automatic Reconnect
Maven Central
Less active Community
FuseSource facts
MQTT mqtt = new MQTT(); mqtt.setHost("localhost", 1883); mqtt.setClientId("publisher"); mqtt.setCleanSession(true); mqtt.setWillTopic("publisher/status"); mqtt.setWillMessage("offline"); mqtt.setKeepAlive((short) 60); mqtt.setUserName("mqtt-client"); mqtt.setPassword("mqtt");
FuseSource Init Connection
BlockingConnection connection = mqtt.blockingConnection(); !connection.connect(); !connection.publish( "publisher/status", // topic "online".getBytes(StandardCharsets.UTF_8), QoS.AT_MOST_ONCE, false);
FuseSource Blocking API
FutureConnection connection = mqtt.futureConnection(); !Future<Void> f1 = connection.connect(); f1.await(); !Future<Void> f2 = connection.publish( "publisher/status", "online".getBytes(), QoS.AT_LEAST_ONCE, true); !f2.await(); !Future<Void> f3 = connection.disconnect(); f3.await();
FuseSource Future API
CallbackConnection connection = mqtt.callbackConnection(); connection.connect(new Callback<Void>() { public void onSuccess(Void v) { connection.publish( "publisher/status", "online".getBytes(), QoS.AT_LEAST_ONCE, false, new Callback<Void>() { public void onSuccess(Void v) {} public void onFailure(Throwable value){} }); } ! public void onFailure(Throwable value) {} });
FuseSource Callback API
It’s ShowtimeDemo
Demo from device to the web with MQTT
https://github.com/dc-square/mqtt-with-paho-eclipsecon2013
available on
Demo Under the hood
Danke! Thanks!
@goetzchr
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