"keyPath" : "/node_app_slot/certs/thunder10-private.pem.key",}
"certPath" : "/node_app_slot/certs/thunder10-certificate.pem.crt",
"caPath" : "/node_app_slot/certs/root-ca.crt",
"region" : "eu-west-1",
"clientId" : "thunder10",
"sleepTime" : 2000
Since one of the communication protocol supported is MQTT, the obvious question is: can I use directly a MQTT client (in addition to the AWS SDK that we have used in the last post)?
Yes, you can.
For example, if you have some familiarity with MQTT, you probably have installed and worked with Mosquitto.
With Mosquitto you get installed two utilities that can be used to test publish and subscribe:
To test the transmission of a MQTT messages to your IoT gateway in AWS you need, as always, the certificate and the private key generated when you have registered your thing (the abstract representation in AWS of your device).
To publish a message:
/usr/local/bin/mosquitto_pub --cafile ./rootCA.pem --cert ./thunder10-certificate.pem.crt --key ./thunder10-private.pem.key -p 8883 -q 1 -d -t thunder10/test -m "Hello" -h A1NQFCHBXLAAH3.iot.eu-west-1.amazonaws.com
Client mosqpub/29492-MacBook-P sending CONNECT
Client mosqpub/29492-MacBook-P received CONNACK
Client mosqpub/29492-MacBook-P sending PUBLISH (d0, q1, r0, m1, 'thunder10/test', ... (5 bytes))
Client mosqpub/29492-MacBook-P received PUBACK (Mid: 1)
Client mosqpub/29492-MacBook-P sending DISCONNECT
The value you pass in the parameter -h is the hostname you have to refer to. You find it in your AWS IoT console.
-m: the value of the message (any sequence of bytes).
-p is the port
-q for the QoS; 1 means “at least once”. AWS doesn’t support “only once”.
You can easily run also a subscriber (mosquito_sub) on the same topic (in the example thunder10/test) and receive on your board (or laptop) the msg sent.
/usr/local/bin/mosquitto_sub --cafile ./rootCA.pem --cert ./thunder10-certificate.pem.crt --key ./thunder10-private.pem.key -p 8883 -d -t thunder10/test -h A1NQFCHBXLAAH3.iot.eu-west-1.amazonaws.com
Client mosqsub/29874-MacBook-P sending CONNECT
Client mosqsub/29874-MacBook-P received CONNACK
Client mosqsub/29874-MacBook-P sending SUBSCRIBE (Mid: 1, Topic: thunder10/test, QoS: 0)
Client mosqsub/29874-MacBook-P received SUBACK
Subscribed (mid: 1): 0
Client mosqsub/29874-MacBook-P received PUBLISH (d0, q0, r0, m0, 'thunder10/test', ... (5 bytes))
Hello
Client mosqsub/29874-MacBook-P received PUBLISH (d0, q0, r0, m0, 'thunder10/test', ... (5 bytes))
Hello
npm install aws-iot-device-sdkAfter having installed the SDK and having uploaded keys and certificate to the directory chosen, you can quickly test a connection and send a ms with the following NodeJS code
var awsIot = require('aws-iot-device-sdk');take care that the program will stay on and connected waiting for… a CTRL-C.
console.log('Started Test with AWS !!!');
var device = awsIot.device({
keyPath: "/node_app_slot/certs/thunder10-private.pem.key",
certPath: "/node_app_slot/certs/thunder10-certificate.pem.crt",
caPath: "/node_app_slot/certs/root-ca.crt",
clientId: "thunder10",
region: "eu-west-1"
});
device
.on('connect', function() {
console.log('connect');
});
device.publish('thunder10/test', JSON.stringify({ test_data: 1}));
var awsIot = require('aws-iot-device-sdk');It is easy. In more or less 1.5 hours.
var connected = false;
console.log('Started Test with AWS !!!');
var device = awsIot.device({
keyPath: "/node_app_slot/certs/thunder10-private.pem.key",
certPath: "/node_app_slot/certs/thunder10-certificate.pem.crt",
caPath: "/node_app_slot/certs/root-ca.crt",
clientId: "thunder10",
region: "eu-west-1"
});
device
.on('connect', function() {
console.log('connect');
connected = true;
});
function doSomething()
{
if (connected)
{
device.publish('thunder10/test', JSON.stringify({ temp: 25}));
console.log('Sent...');
}
// re-schedule executionn of publish
setTimeout(doSomething, 5000);
}
doSomething();
