Setting up MQTT connection

To set up MQTT adapters in InterSystems IRIS, follow these steps:

1. Setting Up MQTT Inbound Adapter:

• Create a Business Service Class:
  Define a new class extending Ens.BusinessService and set its ADAPTER parameter to EnsLib.MQTT.Adapter.Inbound. Implement the OnProcessInput method to handle received messages. Example:
  ```objectscript
  Class EMQTT.NewService1 Extends Ens.BusinessService {
  Parameter ADAPTER = "EnsLib.MQTT.Adapter.Inbound";

   Method OnProcessInput(pInput As EnsLib.MQTT.Message, pOutput As %RegisteredObject) As %Status {
       set tsc=$$$OK
       // Process incoming message (pInput)
       Quit tsc
   }
  

  }
  ```

  • Available configuration settings for this adapter include Client ID, Credentials Name, Keep Alive, URL, and Topic, among others [1][2].

• Compile, Add to Production, and Configure:
  After creating and compiling the class, add it to your production and configure the settings such as broker URL, topic name, and credentials. You can find details about these settings under the "Settings for the MQTT Adapter" section [2].

2. Setting Up MQTT Outbound Adapter:

• Create a Business Operation Class:
  Define a new class extending Ens.BusinessOperation and set its ADAPTER parameter to EnsLib.MQTT.Adapter.Outbound. Implement the method that constructs a message and sends it using the adapter. Example:
  ```objectscript
  Class EMQTT.NewOperation1 Extends Ens.BusinessOperation {
  Parameter ADAPTER = "EnsLib.MQTT.Adapter.Outbound";

   Method OnMessage(pRequest As packagename.Request, Output pResponse As packagename.Response) As %Status {
       set tSC=$$$OK
       try {
           set message = ##class(EnsLib.MQTT.Message).%New()
           set message.Topic = ..Adapter.Topic
           set message.StringValue = "Sample Message Data"
           set tSC=..Adapter.Send(message.Topic, message.StringValue)
       } catch e {
           set tSC = e.AsStatus()
       }
       Quit tSC
   }
  

  }
  ```

  • Similar settings for outbound adapters include Client ID, Topic, QOS Quality Level, and SSL Configurations [1][2].

3. Use Passthrough Services:

If you need basic consumption and production of MQTT messages without complex logic, you can use the built-in passthrough services EnsLib.MQTT.Service.Passthrough and EnsLib.MQTT.Operation.Passthrough. These simplify setup by using the lower-level MQTT functionalities [3][4].

4. Additional Context on MQTT in IRIS:

InterSystems IRIS supports the MQTT protocol, with version 3.1.1 built as an OASIS standard. Its interoperability module enables seamless integrations with IoT devices leveraging MQTT brokers [3][4].

Refer to these examples and settings documentation to develop and manage inbound and outbound MQTT adapters effectively [2][3][4].

Sources: