B4J Question Data transfert

[fishwolf]

i need create a server for receive and send data from clients (raspberry) with a permanent connection.

client send data to server and write into database
server read data into database and send to client

what is the best component in b4j for many connections?

Thanks

 

[Erel]

You have two options:
1. MQTT
2. WebSockets

MQTT is simpler to use.

 

[fishwolf]

i'm tring to use mqtt protocol

the broken manager the connection from client and server as chat example
the devices are the clients

but the process that write and read into database is a broken implementation?
or i a client that subscribe all flows?

 

[Erel]

There is no implementation in the broker side. You should add a client that subscribes to whichever topics you like and write the data into the database.

 

[fishwolf]

1) if i understand well, if i have 1.000 client, i have a "hub" client that subscribe 1.000 channels
right?

2) the broken don't receive events, but i have notice the Inizializate method have the event name, can i check if all clients are connected? or manage other events?

 

[Erel]

1) More or less. You can subscribe to all topics by subscribing to #.

2) Note that it is broker. Not broken
As the documentation says there are currently no events.
However you can monitor the connected clients. It requires using Last Will. See the chat example: https://www.b4x.com/android/forum/threads/b4x-mqtt-chat-room.61568/#content