Android Question MQTT Chat with Auto Discovery - Sending a message to a specific one client

Lakhtin_V · Mar 27, 2023

In the chat example, messages from one client are shown to all clients. How can you send a message to only one specific client if you know his name.

Num3 · Mar 27, 2023

You can make the client subscribe to a specific topic.

For example:

B4X:

mqtt.Subscribe("msgQ/secret_hash_for_private_msgs/#", 0)

Then make the private messages go into that topic

Lakhtin_V · Mar 27, 2023

Num3 said:
You can make the client subscribe to a specific topic.

For example:

B4X:

mqtt.Subscribe("msgQ/secret_hash_for_private_msgs/#", 0)

Then make the private messages go into that topic

Is this method only suitable for the chat example? Or can this line be used anyway? This is permission for private messages, but it is not clear how to aim at the right client. How to publish a message to a specific client?
Example:
client.Publish2("NickCleent", CreateMesage, 0, False)

josejad · Mar 27, 2023

Lakhtin_V said:
How to publish a message to a specific client?

You can do it the way Num3 told, in your example:

mqtt.Subscribe("NickCleent", 0)

Make sure the nickname is unique, and then it will act as the secret hash Num3 said.

teddybear · Mar 27, 2023

Lakhtin_V said:
In the chat example, messages from one client are shown to all clients. How can you send a message to only one specific client if you know his name.

Mqtt it just is a messaging protocol, how to send message to a specific client it depends on how you design your chat room，if everyone has an unique ID, you can publish message using id as topic and the client subscirble it by id

Android Question MQTT Chat with Auto Discovery - Sending a message to a specific one client

Lakhtin_V

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Num3

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Lakhtin_V

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josejad

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teddybear

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Android Question MQTT Chat with Auto Discovery - Sending a message to a specific one client

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