B4J Library MqttBroker

jMqttBroker library is based on the moquette open source project: https://github.com/andsel/moquette

It implements a MQTT broker. If you are not familiar with MQTT then start with this tutorial: https://www.b4x.com/android/forum/threads/59471/#content

The broker is like a "black box". It is responsible for managing the clients and routing the messages.

With this library you can embed the broker inside your app instead of using an external broker.

Note that this library can also be used with B4A. You can turn any Android or Linux board to a MQTT broker.
With B4A you need to add the INTERNET permission with the manifest editor:

AddPermission(android.permission.INTERNET)

Using this library is simple:

Sub Process_Globals
   Dim broker As MqttBroker
End Sub

Sub AppStart (Args() As String)
   broker.Initialize("", 51041) 'first parameter is the event name. It is currently not used.
   broker.DebugLog = True
   broker.Start
   StartMessageLoop 'Non-UI app
End Sub

jMQTTBroker V1: www.b4x.com/b4j/files/moqueutte.zip

jMQTTBroker v2 based on moquette v0.12 (December 2018) is available here: www.b4x.com/b4j/files/jMqttBroker2.zip
Unlike v1, the new version is not compatible with B4A.

Updates:

V2.02 - Fixes a compatibility issue with B4JPackager 11.
V2.01 - Changes an internal auto-flush timeout that caused delays.

 

[inakigarm]

I've an application prototype that uses B4J Mqtt Broker and I'd want to implement a Webapp server to catch all the messages events ,display them on a console window and save on a MYSQL DB.

Looking at Mqtt broker object, I can't access the events from code (don't expose the on connect, publish or disconnect events), so :

-Is there anyway to access this events from code ?? (I know I can save the log to a file -tslogger/jlogger-, but it should be simple if the events were accessible)

-Is there anyway to read the payload messages from mqtt broker to save to an external DB?

(Log of B4J MQTT Broker on UI app)

Received a message of type CONNECT
onEvent processing messaging event from input ringbuffer ProtocolEvent wrapping CONNECT
cleaning old saved subscriptions for client <User1>
Create persistent session for clientID <User1>
Connected client ID <User1> with clean session true
Received a message of type SUBSCRIBE
Received a message of type SUBSCRIBE
Received a message of type SUBSCRIBE
onEvent processing messaging event from input ringbuffer ProtocolEvent wrapping SUBSCRIBE
<User1> subscribed to topic <drawers/#> with QoS 0 - MOST_ONE
onEvent processing messaging event from input ringbuffer ProtocolEvent wrapping SUBSCRIBE
<User1> subscribed to topic <last> with QoS 1 - LEAST_ONE
onEvent processing messaging event from input ringbuffer ProtocolEvent wrapping SUBSCRIBE
<User1> subscribed to topic <user1> with QoS 1 - LEAST_ONE
Received a message of type PINGREQ
Received a message of type CONNECT
onEvent processing messaging event from input ringbuffer ProtocolEvent wrapping CONNECT
cleaning old saved subscriptions for client <User2>
Create persistent session for clientID <User2>
Connected client ID <User2> with clean session true
Received a message of type SUBSCRIBE
Received a message of type SUBSCRIBE
Received a message of type SUBSCRIBE
onEvent processing messaging event from input ringbuffer ProtocolEvent wrapping SUBSCRIBE
<User2> subscribed to topic <drawers/#> with QoS 0 - MOST_ONE
onEvent processing messaging event from input ringbuffer ProtocolEvent wrapping SUBSCRIBE
<User2> subscribed to topic <last> with QoS 1 - LEAST_ONE
onEvent processing messaging event from input ringbuffer ProtocolEvent wrapping SUBSCRIBE
<User2> subscribed to topic <user2> with QoS 1 - LEAST_ONE
Received a message of type PINGREQ

 

[Erel]

You should use a client that listens to all topics ("#").

 

[inakigarm]

Thanks for the reply, works fine reading all topics

 

[jayel]

Hey Erel,

Is there a way I can connect to the broker with pure javascript?
B4J apps I have no problem but I want to change my php site to have a page that can subscribe to my broker (B4J mqtt broker)

John

 

[Erel]

I don't think that JavaScript allows you to use raw sockets as required for a MQTT connection. You can use WebSockets instead.

 

[jayel]

What do you mean? I use websockets for my connection from my php page with javascript to my B4J broker?
I tried with this (https://eclipse.org/paho/clients/js/), but it gives an error :
WebSocket connection to 'ws://192.168.xxx.xxx:51041/mqtt' failed: Connection closed before receiving a handshake response

<script type="text/javascript">

// Create a client instance
var client = new Paho.MQTT.Client("192.168.xxx.xxx", 51041, "clientId_" + parseInt(Math.random() * 100, 10));

console.log(client);
// set callback handlers
client.onConnectionLost = onConnectionLost;
client.onMessageArrived = onMessageArrived;

// connect the client
client.connect({onSuccess:onConnect});


// called when the client connects
function onConnect() {
  // Once a connection has been made, make a subscription and send a message.
  console.log("onConnect");
  client.subscribe("all/#");
  message = new Paho.MQTT.Message("Hello");
  message.destinationName = "all/connect";
  client.send(message);
}

// called when the client loses its connection
function onConnectionLost(responseObject) {
  if (responseObject.errorCode !== 0) {
    console.log("onConnectionLost:"+responseObject.errorMessage);
  }
}

// called when a message arrives
function onMessageArrived(message) {
  console.log("onMessageArrived:"+message.payloadString);
}
</script>

Any ideas?

 

[Erel]

This JavaScript will only work with a MQTT broker that implements MQTT over WebSockets.

What I meant is that you should run a B4J server together with the broker. For example: https://www.b4x.com/android/forum/threads/iot-welcome-to-the-internet-of-things.60663/

 

[jayel]

So, B4J webserver with my B4J broker and than websockets that connects my php page with the data received fom the broker aka my B4J webserver?

 

[Erel]

Yes. More or less.

 

[jinyistudio]

Hi

Does mqttbroker has Event ? What are they ?

 

[Erel]

No. There are no events.

 

[janderkan]

Hi

I created an Android app using jMqttBroker (version: 1.03).

Dim broker As MqttBroker

broker.Initialize("", 51041)
broker.Start

It works FINE in debug mode,

LOG debug mode:
** Service (starter) Create **
** Service (starter) Start **
** Activity (main) Create, isFirst = true **
Persistent store file: //moquette_store.mapdb
Starting without ACL definition
Server binded host: 0.0.0.0, port: 51041
Server binded host: 0.0.0.0, port: 8080
** Activity (main) Resume **

but when I try to run in release mode I get a lot of errors,

LOG release mode:
** Service (starter) Create **
** Service (starter) Start **
** Activity (main) Create, isFirst = true **
Persistent store file: //moquette_store.mapdb
Starting without ACL definition
main_activity_create (java line: 327)
io.netty.channel.ChannelException: Unable to create Channel from class class io.netty.channel.socket.nio.NioServerSocketChannel
at io.netty.bootstrap.AbstractBootstrap$BootstrapChannelFactory.newChannel(AbstractBootstrap.java:457)
at io.netty.bootstrap.AbstractBootstrap.initAndRegister(AbstractBootstrap.java:308)
at io.netty.bootstrap.AbstractBootstrap.doBind(AbstractBootstrap.java:273)
at io.netty.bootstrap.AbstractBootstrap.bind(AbstractBootstrap.java:269)
at io.netty.bootstrap.AbstractBootstrap.bind(AbstractBootstrap.java:251)
at org.eclipse.moquette.server.netty.NettyAcceptor.initFactory(NettyAcceptor.java:142)
at org.eclipse.moquette.server.netty.NettyAcceptor.initializePlainTCPTransport(NettyAcceptor.java:155)
at org.eclipse.moquette.server.netty.NettyAcceptor.initialize(NettyAcceptor.java:105)
at org.eclipse.moquette.server.Server.startServer(Server.java:96)
at anywheresoftware.b4j.objects.MqttBroker.Start(MqttBroker.java:72)
at b4a.example.main._activity_create(main.java:327)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at anywheresoftware.b4a.BA.raiseEvent2(BA.java:169)
at b4a.example.main.afterFirstLayout(main.java:102)
at b4a.example.main.access$000(main.java:17)
at b4a.example.main$WaitForLayout.run(main.java:80)
at android.os.Handler.handleCallback(Handler.java:615)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4745)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:794)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:561)
at dalvik.system.NativeStart.main(Native Method)
Caused by: io.netty.channel.ChannelException: Failed to open a server socket.


I tried the Android SimpleChat app, it Works fine.
I have included the same libraries.

 

[Erel]

Add this line to the manifest editor:

AddPermission(android.permission.INTERNET)

 

[Hypnos]

Just tried this mqtt borker, when the service start, I can see the server also binded to port 8080, what is the usage for this port? When I use my browser go to this port 8080, I got the following message:

"not a WebSocket handshake request: missing upgrade"

What's this mean ?

Thanks!

 

[Erel]

The broker can also work with WebSockets. This is the WebSockets port.

 

[narek adonts]

is there a way to get the logs of mqttbroker in an event?

 

[Erel]

You can add a client that listens to all messages (#). It can be in the same process as the broker. The broker itself doesn't raise any events.

 

[narek adonts]

any updated of when Mqtt over ssl will be available?

 

[Erel]

jMQTT does support SSL connections. The broker doesn't support SSL but you can use any other broker you like.

 

[uniplan]

So, B4J webserver with my B4J broker and than websockets that connects my php page with the data received fom the broker aka my B4J webserver?

Also I would like to achieve something similar. You've made a few examples that can be of help?
Thank you.