![CamelOne 2013
CamelOne
MQTT Example
48
connection.connect(new Callback<Void>() {
public void onSuccess(Void aVoid) {
Topic[] topics = {
new Topic(utf8("test"), QoS.AT_LEAST_ONCE)
};
connection.subscribe(topics, null);
}
public void onFailure(Throwable value) {
connection.disconnect(null);
}
});](https://image.slidesharecdn.com/webmessaging-130612130810-phpapp02/75/Messaging-for-Web-and-Mobile-with-Apache-ActiveMQ-48-2048.jpg)
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Similar to Messaging for Web and Mobile with Apache ActiveMQ
Messaging for Web and Mobile with Apache ActiveMQ
- 1. CamelOne 2013 June 10-112013 Boston, MA Messaging for web and mobile with Apache ActiveMQ By Bosanac Dejan 1
- 2. CamelOne 2013 CamelOne 2 Bosanac Dejan? •Senior Sofware Engineer at RedHat • Apache ActiveMQ committer and PMC member • Co-author of ActiveMQ in Action • Blog – http://sensatic.net • Twitter – http://twitter.com/dejanb
- 3. CamelOne 2013 CamelOne Agenda • Challengesof web messaging • REST vs Stomp • In-browser messaging (Ajax vs Web Sockets) • Mobile messaging using MQTT • Striking the balance 3
- 4. CamelOne 2013 CamelOne Messaging forWeb • Connect from any web application backend (Ruby, PHP, Python, …) • Connect directly from the browser (AJAX, Web Sockets) • The main requirement is simplicity 4
- 5. CamelOne 2013 CamelOne What’s wrongwith Http? • Nothing at all! • Ideal for simple request-reply communication • Lacks semantics for publish-subscribe and point-to-point communication 5
- 6. CamelOne 2013 CamelOne Limitations • Pullbased protocol • Easy simple producing • There’s no concept of consumer or subscription • There’s no concept of transactions 6
- 7. CamelOne 2013 CamelOne Pull Consuming •HTTP techniques • Long polling • Comet • Maintain a state • Session • ClientID 7
- 8. CamelOne 2013 CamelOne Push Consuming •Web Hooks – http://webhooks.org • Provide a callback (HTTP URL) to be called on event • Trigger callback on every message 8
- 9. CamelOne 2013 CamelOne CamelHTTP component 9 <camelContext id="camel" xmlns="http://camel.apache.org/schema/spring”> <route> <from uri="activemq:topic:events"/> <to uri="http://mysite.com/events"/> </route> </camelContext> • HawtIO – http://hawt.io • Missing API for dynamically managing subscribers
- 10. CamelOne 2013 CamelOne Stomp –what it is? • http://stomp.github.com • Simple Text Orientated Messaging Protocol • HTTP for the messaging realm 10
- 11. CamelOne 2013 CamelOne Stomp –basics • Very simple, so it’s easy to write clients and servers in practically any language • A lot of client APIs in C, Java, Ruby, Pyhton, JS, PHP • Implemented by ActiveMQ, Apollo, HornetQ, RabbitMQ 11
- 12. CamelOne 2013 CamelOne Stomp -Protocol • Text based headers, similar to HTTP • Can transport binary bodies • Frame command for every messaging concept, like CONNECT, MESSAGE, SUBSCRIBE, ACK, etc. 12 MESSAGE subscription:0 message-id:007 destination:/queue/a content-type:text/plain hello queue a^@
- 13. CamelOne 2013 CamelOne Stomp +ActiveMQ • Available transports • NIO implementation for better scalability • SSL for secure communication 13 <transportConnectors> <transportConnector name=”stomp" uri=”stomp://0.0.0.0:61613"/> <transportConnector name=”stomp+nio" uri=”stomp+nio://0.0.0.0:61614"/> <transportConnector name=”stomp+ssl" uri=”stomp+ssl://0.0.0.0:61615"/> <transportConnector name=”stomp+nio+ssl" uri=”stomp+nio+ssl://0.0.0.0:61615"/> </transportConnectors>
- 14. CamelOne 2013 CamelOne Stomp JavaClient • StompJMS - https://github.com/fusesource/stompjms • APIs: • JMS • Blocking • Future • Callback 14
- 15. CamelOne 2013 CamelOne 15 Stomp stomp= new Stomp("localhost", 61613); Future<FutureConnection> future = stomp.connectFuture(); FutureConnection connection = future.await(); CONNECT host:localhost accept-version:1.1 CONNECTED heart-beat:0,0 session:ID:vidra.local-56933-1369046267671-2:1 server:ActiveMQ/5.9-SNAPSHOT version:1.1
- 16. CamelOne 2013 CamelOne 16 StompFrame frame= new StompFrame(SEND); frame.addHeader(DESTINATION, StompFrame.encodeHeader("/queue/test")); frame.addHeader(MESSAGE_ID, StompFrame.encodeHeader("test")); frame.content(new Buffer("Important Message".getBytes("UTF-8"))); Future<Void> sendFuture = connection.send(frame); sendFuture.await(); SEND message-id:test destination:/queue/test content-length:17 Important Message
- 17. CamelOne 2013 CamelOne 17 StompFrame disconnect= new StompFrame(DISCONNECT); Future<Void> disconnectFuture = connection.send(disconnect); disconnectFuture.await(); DISCONNECT
- 18. CamelOne 2013 CamelOne 18 Stomp stomp= new Stomp("localhost", 61613); Future<FutureConnection> future = stomp.connectFuture(); FutureConnection connection = future.await(); CONNECT host:localhost accept-version:1.1 CONNECTED heart-beat:0,0 session:ID:vidra.local-56933-1369046267671-2:1 server:ActiveMQ/5.9-SNAPSHOT version:1.1
- 19. CamelOne 2013 CamelOne 19 Future<StompFrame> receiveFuture= connection.receive(); StompFrame frame = new StompFrame(SUBSCRIBE); frame.addHeader(DESTINATION, StompFrame.encodeHeader("/queue/test")); AsciiBuffer id = connection.nextId(); frame.addHeader(ID, id); Future<StompFrame> response = connection.request(frame); response.await(); SUBSCRIBE receipt:2 destination:/queue/test id:1 RECEIPT receipt-id:2
- 20. CamelOne 2013 CamelOne 20 StompFrame received= receiveFuture.await(); System.out.println(received.content()); MESSAGE message-id:ID:vidra.local-56933-1369046267671-2:1:-1:1:1 destination:/queue/test timestamp:1369046474700 expires:0 subscription:1 content-length:17 priority:4 Important Message
- 21. CamelOne 2013 CamelOne 21 StompFrame unsubscribe= new StompFrame(UNSUBSCRIBE); unsubscribe.addHeader(ID, id); Future<Void> unsubscribeFuture = connection.send(unsubscribe); unsubscribeFuture.await(); UNSUBSCRIBE id:1
- 22. CamelOne 2013 CamelOne 22 StompFrame disconnect= new StompFrame(DISCONNECT); Future<Void> disconnectFuture = connection.send(disconnect); disconnectFuture.await(); DISCONNECT
- 23. CamelOne 2013 CamelOne Advanced Stomp •Ack modes • Transactions • Reliable messaging • Protocol Negotiations • Heart-beating 23
- 24. CamelOne 2013 CamelOne Stomp andActiveMQ • Queues and Topics • Reliable Messaging • Temporary destinations • Durable topic subscribers • Destination wildcards • Message selectors 24
- 25. CamelOne 2013 CamelOne Stomp andActiveMQ • Message expiration • Composite destinations • Priority consumers • Exclusive consumers 25
- 26. CamelOne 2013 CamelOne In-browser Messaging •Use JavaScript to produce and consume messages directly from the browser • We need to leverage existing web technologies like Ajax and Web Sockets • We need a web server that’s able to communicate with the broker 26
- 27. CamelOne 2013 CamelOne Ajax • Old-schoolway • Comes bundled with ActiveMQ distribution 27
- 28. CamelOne 2013 CamelOne Ajax –explained • Requires additional servlet as an intermediary between broker and clients • POST to send messages • Jetty continuations to receive messages 28
- 29. CamelOne 2013 CamelOne Ajax –Example 29 <script type="text/javascript" src="js/jquery-1.4.2.min.js"></script> <script type="text/javascript" src="js/amq_jquery_adapter.js"></script> <script type="text/javascript" src="js/amq.js"></script> <script type="text/javascript"> var amq = org.activemq.Amq; amq.init({ uri: 'amq', logging: true, timeout: 20 }); </script>
- 30. CamelOne 2013 CamelOne Ajax –Example 30 amq.sendMessage(”queue://TEST”, “Important Message!”); var myHandler = { rcvMessage: function(message) { console.log(“Received message: ” + message); } }; amq.addListener(“myListener”, “queue://TEST”, myHandler.rcvMessage);
- 31. CamelOne 2013 CamelOne WebSocket • Evolutionover Ajax and Comet • Defines a “socket” – permanent duplex connection – between browser and server • Server and browser can exchange messages 31
- 32. CamelOne 2013 CamelOne WebSocket • Fullystandardized and part of HTML5 spec • Protocol – standardized by IETF • API – standardized by W3C • Supported by most modern web servers and browsers 32
- 33. CamelOne 2013 CamelOne WebSocket Example 33 varconnection = new WebSocket("ws://localhost:8161"); connection.onopen = function() { console.log("Connection opened!"); }; connection.onmessage = function(msg) { console.log("Received Message: " + msg.data); }; connection.onerror = function(error) { console.log("Error occured: " + error); } connection.onclose = function(evt) { console.log("Connection closed!"); }; connection.send("Important Message!"); connection.close();
- 34. CamelOne 2013 CamelOne WebSocket +ActiveMQ • WebSocket is a plain socket – like a raw TCP • We need a protocol on top of it to use all concepts of messaging and connect to broker • WebSocket+Stomp ideal combination! 34
- 35. CamelOne 2013 CamelOne WebSocket +ActiveMQ • New ws and wss transports • wss transport needs SSL context configuration 35 <transportConnectors> <transportConnector name="websocket" uri="ws://0.0.0.0:61613"/> <transportConnector name="secure_websocket" uri="wss://0.0.0.0:61614"/> </transportConnectors>
- 36. CamelOne 2013 CamelOne stomp-websocket • Clientside library stomp-websocket • http://github.com/jmesnil/stomp-websocket • Supports Stomp 1.1 • Not a “pure” Stomp as it requires WebSocket handshake 36
- 37. CamelOne 2013 CamelOne stomp-websocket Example 37 varclient = Stomp.client("ws://localhost:61614"); var connected = false; client.connect("admin", "admin", function() { connected = true; client.subscribe("/queue/test", function(message) { console.log("Received message " + message); } }); if (connected) { client.send("/queue/test", {priority: 9}, "Important Message!"); } if (connected) { client.disconnect(); }
- 38. CamelOne 2013 CamelOne Messaging forMobile • Different set of requirements • Low bandwidth network • Small footprint • Low power usage 38
- 39. CamelOne 2013 CamelOne MQTT • http://mqtt.org/- MQ Telemetry Transport • IoT (Internet of Things) protocol • Efficient binary protocol • Developed by IBM for embedded devices telemetry 39
- 40. CamelOne 2013 CamelOne MQTT Features •Low bandwidth • Smallest frame 2 bytes • Unreliable networks • Small footprint 40
- 41. CamelOne 2013 CamelOne MQTT formobile • Efficient battery usage - Power Profiliing: MQTT on Android - http://stephendnicholas.com/archives/219 • Ideal for native mobile applications • Usecase: Facebook messanger • Phone-to-phone delivery in milliseconds, rather than seconds • Without killing battery life 41
- 42. CamelOne 2013 CamelOne MQTT • Publish/subscribeprotocol – topics only • 3 QoS Options: • At Most Once – message loss might occur • At Least Once – duplicates might occur • Exactly Once – guaranteed delivery 42
- 43. CamelOne 2013 CamelOne MQTT +ActiveMQ • Available transports • NIO implementation for better scalability • SSL for secure communication 43 <transportConnectors> <transportConnector name=”mqtt" uri=”mqtt://0.0.0.0:1883"/> <transportConnector name=”mqtt+nio" uri=”mqtt+nio://0.0.0.0:1884"/> <transportConnector name=”mqtt+ssl" uri=”mqtt+ssl://0.0.0.0:1885"/> <transportConnector name=”mqtt+nio+ssl" uri=”mqtt+nio+ssl://0.0.0.0:1886"/> </transportConnectors>
- 44. CamelOne 2013 CamelOne MQTT client •mqtt-client https://github.com/fusesource/mqtt- client • APIs: • Blocking • Callback • Future 44
- 45. CamelOne 2013 CamelOne MQTT Example 45 MQTTmqtt = new MQTT(); mqtt.setHost("localhost", 1883); final CallbackConnection connection = mqtt.callbackConnection();
- 46. CamelOne 2013 CamelOne MQTT Example 46 connection.connect(newCallback<Void>() { public void onSuccess(Void value) { connection.publish("test", "Important Message!".getBytes(), QoS.AT_LEAST_ONCE, false, null ); } public void onFailure(Throwable value) { connection.disconnect(null); } });
- 47. CamelOne 2013 CamelOne MQTT Example 47 finalPromise<Buffer> result = new Promise<Buffer>(); connection.listener(new Listener() { public void onConnected() {} public void onDisconnected() {} public void onPublish(UTF8Buffer topic, Buffer body, Runnable ack) { result.onSuccess(body); ack.run(); } public void onFailure(Throwable value) { result.onFailure(value); connection.disconnect(null); } }); LOG.info("Received: " + result.await(5, TimeUnit.MINUTES));
- 48. CamelOne 2013 CamelOne MQTT Example 48 connection.connect(newCallback<Void>() { public void onSuccess(Void aVoid) { Topic[] topics = { new Topic(utf8("test"), QoS.AT_LEAST_ONCE) }; connection.subscribe(topics, null); } public void onFailure(Throwable value) { connection.disconnect(null); } });
- 49. CamelOne 2013 CamelOne MQTT AndroidExample • https://github.com/jsherman1/android-mqtt- demo/ 49
- 50. CamelOne 2013 CamelOne Striking theBalance • Lots of possibilities, how to choose right? • Native mobile apps should consider MQTT • Do you need live updates in your browser? • WebSockets ideal for HTML5 apps with limited number of users that needs instant update • For everyone else, there's backend messaging 50
- 51. CamelOne 2013 CamelOne Stomp pitfall •Short-lived connections • Every page view, open a new connection to the broker • Puts heavy load on the broker • Eliminates all advance messaging mechanisms – message prefetches, producer flow control, etc. 51
- 52. CamelOne 2013 CamelOne Stomp configuration 52 <destinationPolicy> <policyMap> <policyEntries> <policyEntryqueue=">" producerFlowControl="false"> </policyEntry> </policyEntries> </policyMap> </destinationPolicy> <transportConnectors> <transportConnector name="stomp+nio" uri="stomp+nio://0.0.0.0:61613?transport.closeAsync=false"/> </transportConnectors>
- 53. CamelOne 2013 CamelOne Conclusion • Messagingis not the thing of the enterprise anymore • Things want to get integrated • We have technology to do that TODAY! 53
- 54. CamelOne 2013 CamelOne AMA • Links •Stomp - http://stomp.github.com • https://github.com/fusesource/stompjms • MQTT – http://mqtt.org • https://github.com/fusesource/mqtt-client • Blog: http://sensatic.net • Twitter: http://twitter.com/dejanb 54