Android Question how create websocket server to B4A

[Roberto P.]

Hi all
You can give me the best way to create a websocket in an android app, which acts as a server, to another android application and b4j.

thank in advance

 

[DonManfred]

Isn´t wecksocket server a b4j library?

As far as i know you can not use Android to be a Websocketserver.

 

[Roberto P.]

yes it is a B4J library. Yes, you can use B4A as a server (see httpserverexample), but I need websockets to keep the connection active and to be able to exchange data between two apps.

Isn´t wecksocket server a b4j library?

As far as i know you can not use Android to be a Websocketserver.

 

[OliverA]

I need websockets to keep the connection active and to be able to exchange data between two apps.

Why not use AsyncStreams? See https://www.b4x.com/android/forum/threads/b4x-network-asyncstreams-b4xserializator.72149/

 

[Erel]

There is no server side implementation of WebSockets for B4A.

I recommend you to use MQTT instead.

 

[Roberto P.]

There is no server side implementation of WebSockets for B4A.

I recommend you to use MQTT instead.

ok. Can I use MQTT to for send image as CCTV camera?
thank you

 

[DonManfred]

What about informing about mqtt and its payload?

I don´t know mqtt much. Don´t know the limit of one message.
But if it is only text then you can create a base64 of an image and send this base64 string.

mqtt expects a bytearray as payload. So it should be possible to send images i guess. I would just use the available methods.
look at the chatexample project.

Public Sub SendMessage(Body As String)
    If connected Then
        client.Publish2("all", CreateMessage(Body), 0, False)
    End If
End Sub

Public Sub Disconnect
    BroadcastTimer.Enabled = False
    DiscoveredServer = ""
    CallSub(Main, "UpdateState")
    If connected Then
        client.Publish2("all/disconnect", serializator.ConvertObjectToBytes(Name), 0, False)
        client.Close
    End If
End Sub

Private Sub CreateMessage(Body As String) As Byte()
    Dim m As Message
    m.Initialize
    m.Body = Body
    m.From = Name
    Return serializator.ConvertObjectToBytes(m)
End Sub

As i never used mqtt in production and i just checked one of the available example codes i may be wrong.
But i´m positive that you can create your own Message customType which holds an Image (the bytes, not base64) in one of its properties and use Serializator to convert the customtype into a payload for mqtt. So my answer is YES.

 

[Erel]

ok. Can I use MQTT to for send image as CCTV camera?

Yes.

MQTT payloads are sent as raw bytes. No need to use base64 string.

 

[Roberto P.]

i'm trying the symple chat, but have this error:

*** Service (starter) Create ***
starter_service_create (java line: 457)
java.net.BindException: bind failed: EADDRINUSE (Address already in use)
at libcore.io.IoBridge.bind(IoBridge.java:104)
at java.net.PlainDatagramSocketImpl.bind0(PlainDatagramSocketImpl.java:103)
at java.net.AbstractPlainDatagramSocketImpl.bind(AbstractPlainDatagramSocketImpl.java:92)
at java.net.DatagramSocket.bind(DatagramSocket.java:411)
at java.net.DatagramSocket.<init>(DatagramSocket.java:261)
at java.net.DatagramSocket.<init>(DatagramSocket.java:318)
at java.net.DatagramSocket.<init>(DatagramSocket.java:290)
at anywheresoftware.b4a.objects.SocketWrapper$UDPSocket.Initialize(SocketWrapper.java:444)
at mqtt.chat.starter._service_create(starter.java:457)
at java.lang.reflect.Method.invoke(Native Method)
at anywheresoftware.b4a.BA.raiseEvent2(BA.java:196)
at anywheresoftware.b4a.BA.raiseEvent(BA.java:176)
at mqtt.chat.starter.onCreate(starter.java:56)
at android.app.ActivityThread.handleCreateService(ActivityThread.java:3558)
at android.app.ActivityThread.-wrap4(Unknown Source:0)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1812)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:7000)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:441)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1408)
Caused by: android.system.ErrnoException: bind failed: EADDRINUSE (Address already in use)
at libcore.io.Linux.bind(Native Method)
at libcore.io.ForwardingOs.bind(ForwardingOs.java:60)
at libcore.io.IoBridge.bind(IoBridge.java:100)
... 21 more

 

[Erel]

Please start a new thread for this.

 

[warwound]

ok. Can I use MQTT to for send image as CCTV camera?
thank you

If you want to send a stream of 'camera bytes' from one module to another you might be able to use my NamedPipe library...

 

[Roberto P.]

i'm trying the symple chat, but have this error:

created new thread