Trouble connecting to aws iot using QMqtt and QSsl stack.

eluppai

Brief Description: I am using QMqtt and QSsl stack to connect to perform a secure Mqtt connection and then publish some data on the aws server. But the Client state always stays on connecting never changes to connected

Expected behavior: First I tried connecting to test.mosquitto.org, I was able to connect and publish the data. So the expected behavior was to see some similar results.

Send_MqTT::Send_MqTT(QObject *parent) : QObject(parent)
{
    m_socket=new QSslSocket();
    m_client=new QMqttClient();
    m_topicname = new QMqttTopicName();
    m_topicname->setName("Pubtopic/test");

    connect(m_client,&QMqttClient::stateChanged,[](QMqttClient::ClientState state){
        if(state == QMqttClient::Disconnected)
        {
            qDebug()<<"State is Disconnected: "<<state;
        }
        else if(state == QMqttClient::Connecting)
        {
            qDebug()<<"State is Connecting: "<<state;
        }
        else if(state == QMqttClient::Connected)
        {
            qDebug()<<"State is Connected: "<<state;
        }

    });
    connect(m_client,&QMqttClient::errorChanged,[](QMqttClient::ClientError error_state){
        qDebug()<<"Error State is: "<<error_state;
    });
}
void Send_MqTT::connect_toserver()
{
    if(QSslSocket::supportsSsl())
      {
        qDebug()<<"SSL SUPORTED";
        m_socket->setLocalCertificate("<certificatelocation>",QSsl::Pem);
        m_socket->setPrivateKey("<private Key Location>",QSsl::Rsa,QSsl::Pem);
        m_client->setHostname("host-name");
        m_client->setPort(8883);
        m_client->setTransport(m_socket,QMqttClient::SecureSocket);
        m_client->connectToHostEncrypted();
    }
}

Am I missing something. Do I have to set Mqtt connection properties before I begin the connection?

SGaist

Hi,

Can you explain what result you are getting ?
What errors are you getting ?
What version of Qt are you using ?

eluppai

@sgaist The clientState stays on connecting and never goes to connected. Because of which I am unable to publish any data. The ClientState has to transition to connected for me to publish or subscribe

enum QMqttClient::ClientState
Constant	                             Value	
QMqttClient::Disconnected	              0	
QMqttClient::Connecting	                      1	      
QMqttClient::Connected	                      2

So the state always stays on connecting. I do not get any errors.
Qt version is 5.12.3
and system is an Ubuntu 18.04

SGaist

From the looks of it, you didn't connect any of the QOpenSSLSocket error signals. You should add them.

eluppai

@SGaist okay I will add that. But Don't you think if there was any error. Mqtt should also throw an error. Because if I remove a certificate or a private key from the file or add any wrong information, I do get an error stating that the transport properties are not set properly and the ClientState goes to disconnected it does not stays on connecting for a long period of time.