SimpleSerial/main.cpp

#include <QCoreApplication>
#include <QSerialPort>
#include <QFile>
#include <QDebug>
#include <QFileSystemWatcher>
#include <QDir>
#include <QScopedPointer>
#include <QTimer>
#include <iostream>

int main(int argc, char *argv[])
{
    QString comPortPath;
    QString commandFile;

    QCoreApplication a(argc, argv);

    if(a.arguments().count() != 3) {
        qCritical() << "Usage SimpleSerial <COM Port> <File name>";
        return 1;
    }

    commandFile = QDir(".").absoluteFilePath(a.arguments().at(2));
    comPortPath = a.arguments().at(1);

    QSerialPort* port(new QSerialPort(comPortPath));
    port->setFlowControl(QSerialPort::SoftwareControl);
    port->setBaudRate(QSerialPort::Baud115200);
    port->setStopBits(QSerialPort::OneStop);
    port->setDataBits(QSerialPort::Data8);
    port->setParity(QSerialPort::NoParity);
    port->setReadBufferSize(100000);
    QObject::connect(port, &QSerialPort::readyRead, [&](){
        std::cout << port->readAll().data();
    });

    QObject::connect(port, &QSerialPort::errorOccurred, [&](QSerialPort::SerialPortError serialPortError){
        qCritical() << serialPortError;
    });

    if(!port->open(QIODevice::ReadWrite)) {
        qCritical() << "Unable to open" << port->portName();
        delete port;
        return 1;
    }

    QFileSystemWatcher* watcher(new QFileSystemWatcher(QStringList() << commandFile));
    QObject::connect(watcher, &QFileSystemWatcher::fileChanged, [&](const QString &path){
        qDebug() << "watcher alarm";
        if(path == commandFile) {
            QFile file(commandFile);
            if(!file.open(QFile::ReadOnly)) {
                qCritical() << "Unable to open command file: " << commandFile;
                a.exit(1);
            }
            while(!file.atEnd()) {
                QByteArray command = file.readLine();
                port->write(command);
            }
            file.close();
            watcher->addPath(commandFile);
        }
    });

    QTimer testTimer;
    testTimer.setInterval(1000);
    testTimer.setSingleShot(true);
    QObject::connect(&testTimer, &QTimer::timeout, [&]() {
        QFile file(commandFile);
        if(!file.open(QFile::ReadOnly)) {
            qCritical() << "Unable to open command file: " << commandFile;
            a.exit(1);
        }

        while(!file.atEnd()) {
            QByteArray command = file.readLine();
            port->write(command);
        }
        file.close();
    });
    testTimer.start();
    int retVal =  a.exec();
    port->close();
    delete port;
    return retVal;
}