How to send a C2D Direct method from the Node.js SDK to a remote device?

Question

Hello folks

I am trying to connect my local Node.js API to Azure IOT Hub and send direct methods to a remote device.

When sending the direct method directly through the Azure portal, it works like a charm. However, when attempting to do the same through the API, I get a "Timed out waiting for the response from device" message.

Here is the code I tried so far:

"use strict";

exports.sendDirectMethod = async (req, res) => {    
	const connectionString = process.env.IOTHUB_CONNECTION_STRING;    
	const deviceId = "HW2";
	const serviceClient = iothub.Client.fromConnectionString(connectionString);
	const payload = {        
		methodName: "GetAllLockerStatus_method",
		responseTimeoutInSeconds: 30,
		payload: JSON.stringify({ MessageID: 1,}),
	};
	serviceClient.invokeDeviceMethod(deviceId, payload, (err, result) => {
		if (err) {
			console.error(err.message);
		} else {
			console.log(`Response status: ${result.status}`);
			console.log(`Response payload: ${result.payload}`);
		}
	});
};

Any ideas are welcome, as I am quite stuck at the moment. Thanks!

Answer 1

Hi @Florian Cartier Greetings! Welcome to Microsoft Q&A forum. Thank you for posting the question here.

Here is a code that I have tested and could successfully invoke the direct method on a device from Node.js code

'use strict';

const connectionString = '<Connection string>';
const serviceClient = iothub.Client.fromConnectionString(connectionString);
const methodName = 'reboot';
const payload = {    input1: 'someInput',    input2: 'anotherInput'};
serviceClient.invokeDeviceMethod('TestDevice4', { methodName, payload }, (err, result) => {    
   if (err) {        
       console.error('Failed to invoke method: ' + err.message);    
   } else {        
       console.log('Method response:');        
       console.log(JSON.stringify(result, null, 2));    
   }
});

I have used the Service policy connection string of IoT Hub in this code and here is the output I get from the code as I execute it.

Hope this helps. Please let us know if you have any additional questions or need further assistance.

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