BASIC CODE for MQTT connection

HiveMQ Cloud
1

Hello,

I have a Ewon Flexy205 and I sending MQTT data. It needs BASIC (or java) code for do it.

I have problems with the code in the MQTT connection with my HIVEMQ cloud.

I wanna put a code thats is working actually for connection with IoTHub Azure. I need to know what I have to addpat for HIVEMQ cloud.

THE CODE IS:

CONNECTMQTT:
MQTT “OPEN”, SerNum$ , MQTTBrokerURL$
MQTT “SETPARAM”, “PORT”, MQTTPort$
MQTT “SETPARAM”, “LOG”, “1”
MQTT “SETPARAM”, “KEEPALIVE”, “20”
MQTT “SETPARAM”, “TLSVERSION”, “tlsv1.2”
MQTT “SETPARAM”, “PROTOCOLVERSION”, “3.1.1”
MQTT “SETPARAM”, “cafile”,"/usr/BaltimoreCyberTrustRoot.pem"
MQTT “SETPARAM”, “CertFile”,"/usr/"+DeviceId$+".crt"
MQTT “SETPARAM”, “KeyFile”,"/usr/"+DeviceId$+".key"

//AZURE//
MQTT “SETPARAM”,“Username”,IotHubName$+ “.azure-devices.net/”+DeviceId$+"/api-version=2016-11-14"
MQTT “SETPARAM”,“Password”,“HostName=”+IotHubName$+";DeviceID="+DeviceId$+";x509=true"

MQTT “SETPARAM”, “WILLTOPIC”, “/willtopic”
MQTT “SETPARAM”, “WILLPAYLOAD”, “Flexy " + SerNum$ + " is disconnected”

MQTT “SUBSCRIBE”,TopicToSubscribe$,1

//Launch the MQTT process in the background

SETSYS PRG,“RESUMENEXT”,1 //Continue in case of error at MQTT “CONNECT”
MQTT “CONNECT”

END CODE

Can anyone help me to adapt this code to HIVE connetion

Thanks so much
Jose

2

Hello Jose,

Thanks for your interest in MQTT and HiveMQ MQTT Broker!

Looking at your code, it seems that the issue is the “cafile”:

MQTT “SETPARAM”, “cafile”,"/usr/BaltimoreCyberTrustRoot.pem"

You would need to use HiveMQ Broker “server.pem”.
You can create the Server Certificate file using the openssl s_client towards your HiveMQ Cloud broker cluster:

openssl s_client -connect XXXXXXXXXXXXXXXXXXXXX.s2.eu.hivemq.cloud:8883 -showcerts < /dev/null 2> /dev/null | sed -n '/BEGIN/,/END/p' > server.pem

This will create a file called “server.pem”, which you can use as “Server Certiciate”.

Please let me know if this helps.

Kind regards,
Dasha from HiveMQ Team

3

Hi Dasha,

Yes you rigth. It was just and example with the *.pem. I will generate the server.pem and upload that file into the Flexy.

But I have doubts with the next lines:

LINE1

MQTT “SETPARAM”,“Username”,IotHubName$+ “.azure-devices.net/”+DeviceId$+"/api-version=2016-11-14"

I understund that IotHubName don’t need it. I have to eliminate it and put just “broker address”…

And what about: /api-version=2016-11-14" ??? thats for Azure… but in HIVE how is that??

LINE 2

MQTT “SETPARAM”,“Password”,“HostName=”+IotHubName$+";DeviceID="+DeviceId$+";x509=true"

I understund I have to eliminate IotHubName again… but the other is OK… in’s it?

Thanks so much
Jose

4

Hi Jose,

What happens if you use Username and Password credentials that you set in HiveMQ Cloud → Cluster → Access Management → MQTT Credentials?

Thanks,
Dasha from HiveMQ Team