Does the Paho Java client has any callback function called when a new client connection is established? Within that function I want to validate user and if failed refuse connection.
When a new client connect from javascript or any client I should be able to allow or refuse new client.
This is not possible to do from a client, the MQTT protocol has no support for anything other than passing authentication information from a single client to the broker, not the other way round.
You have to do it from within the broker. Different brokers all implement authentication differently so it will depend entirely on which broker you are using.
Mosquitto has an API to write authentication plugins. e.g. https://github.com/jpmens/mosquitto-auth-plug
HiveMQ Also has an API http://www.hivemq.com/blog/mqtt-security-fundamentals-advanced-authentication-mechanisms
Mosca - https://github.com/mcollina/mosca/wiki/Authentication-&-Authorization
Related
I have multiple devices sending messages to a mosquito broker. I would like to manage a kind of device revocation so that when a device is revoked, I want the mosquito broker to automatically close the connection for this specific device.
Is there any command or way to ask the broker to explicitly close a connection to a specific client?
Thanks in advance,
hak
I do not think you can kick an already connected client.
But what you can do if using the Authentication Plugin (either a 3rd party or the included dynamic security plugin) to change the ACL that the user can publish/subscribe to which should effectively stop the client sending or receiving any messages and when it next tries to connect it will not be allowed.
How can an Application Server send a downlink message to a LoRaWAN end device connected to Actility ThingPark Community platform?
ThingPark Community Platform offers a REST API to allow Application Servers sending a downlink message to an end-device. Every http request sent to that API need to be validated by a one-time token so that ThingPark can verify the integrity of the request.
The interface between ThingPark Enterprise Network Server and an external Application Server is described in the TPE LRC AS tunnel interface development guide.
For a quick test please check our simple javascript example.
Don't forget to update the constants at the beginning of the script.
The AS_KEY is the Tunnel Interface Authentication Key that you set on the
CREATE HTTP APPLICATION form.
The AS_ID is the Application ID that you can see once you have creeted the application.
If you prefer testing with curl see our curl test shell script.
Please note that this script does not calculate the one-time token. You need to calculate it yourself according to the Tunnel interface development guide or by studying the former javascript code.
I wanted to make use of Shared Subscription feature of MQTT v5. But currently I am using AKKA MQTT client which doesn't support MQTT v5 client. Can I still use v3 MQTT paho client and use Shared Subscription feature?
That should not be a problem as from the viewpoint of an MQTT v3 client a shared subscription is just like any subscription.
The broker has to do all the work regarding shared subscription logic.
The only hindrances I can see are:
that an MQTT broker might support v5 but not v3/v3.1.1
the broker doesn't support shared subscriptions in general (yes they exist)
the broker supports all MQTT versions but handles them as two different protocols (not sure if this is a thing)
Using paho client write an app(ensure that this will use MQTT v5) that will have two clients.
Client_v3 will subscribe to the topics from the source i.e. from the app that sends MQTT v3
Client_v5 will publish the received topics as it is received in the above step.
In your application where you want to use shared subscription(again ensure it uses MQTT v5) alter the topics $share/<topic> and make it to get the topics from the client_v5 publish
In simple word: make you paho client code to act as a broker between v3 and v5 apps.
MQTT Broker can disconnect the existing client if the following condition is came up.
http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718090
If the ClientId represents a Client already connected to the Server then the Server MUST disconnect the existing Client
[MQTT-3.1.4-2].
At this time, can broker send any specific message excluding "DISCONNECT" to client before server disconnect the existing client ?
Most brokers are going to follow the spec, if you want one to do something different then you will have to either write your own or modify one of the open source versions.
We have used Erlang/Cowboy to develop a simple chatting service based on WebSockets. Right now, We are using localhost:8080 to connect server.
I want to do user authentication, that will be done based on the URL parameter, and it will return user id or none for the connection.
How to do that?
Before the websocket exchange, you can ask a token to your application and use it with your websocket client.