QT Downloading File with QNetworkAccessManager - c++

I am trying to make the code in this question work.
qt - how to download and save image via http?
It creates the files, but no data is written to them.
My best guess is that the connect to the singals and slots is not working.
What am I doing wrong?
mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
QString getPageImage(QString url = "");
bool saveToDisk(const QString &filename, QIODevice *data);
~MainWindow();
private slots:
void on_btnDownload_clicked();
private:
Ui::MainWindow *ui;
};
#endif // MAINWINDOW_H
qdownload.h
#ifndef QDOWNLOADER_H
#define QDOWNLOADER_H
#include <QObject>
#include <QNetworkAccessManager>
#include <QNetworkRequest>
#include <QNetworkReply>
#include <QFile>
#include <QStringList>
#include <QDir>
#include <QDebug>
class QDownloader : public QObject
{
Q_OBJECT
public:
explicit QDownloader(QObject *parent = 0);
virtual ~QDownloader();
void setFile(QString fileURL, QString folderName, QString fileName);
private:
QNetworkAccessManager *manager;
QNetworkReply *reply;
QFile *file;
private slots:
void onDownloadProgress(qint64,qint64);
void onFinished(QNetworkReply*);
void onReadyRead();
void onReplyFinished();
};
#endif // QDOWNLOADER_H
mainwindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "QNetworkAccessManager"
#include "QNetworkReply"
#include "QFile"
#include "QDebug"
#include "QUrl"
#include "QStringList"
#include "qdownloader.h"
#include <QTimer>
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
ui->progressBar->setVisible(false);
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::on_btnDownload_clicked()
{
QString link = ui->txtURL->text();
int issue = ui->sbIssue->value();
ui->progressBar->setMaximum(issue);
ui->progressBar->setValue(0);
ui->progressBar->setVisible(true);
for(int j = 1; j <= issue; j++){
int i = 1;
while(getPageImage(link + "/" + QString::number(j) + "/" + QString::number(i) + "/").length() > 0){
QString filename = "http://" + getPageImage(link + "/" + QString::number(j) + "/" + QString::number(i) + "/");
qDebug() << filename;
QDownloader qDL;
qDL.setFile(filename,ui->txtTitle->text() + "_" + QString::number(j),ui->txtTitle->text() + "_" + QString::number(j) + "_" + QString::number(i));
//qDebug() << getPageImage(link + "/" + QString::number(j) + "/" + QString::number(i) + "/").length();
i++;
}
ui->progressBar->setValue(j);
}
ui->progressBar->setVisible(false);
}
QString MainWindow::getPageImage(QString url){
QString pic = "";
if(url.length() > 0){
QNetworkAccessManager manager;
QNetworkReply *response = manager.get(QNetworkRequest(QUrl(url)));
QEventLoop event;
connect(response,SIGNAL(finished()),&event,SLOT(quit()));
event.exec();
QString html = response->readAll();
if(html.length() > 0){
QStringList str;
str = html.split("\n");
//qDebug() << url;
for (int i = 0; i < str.size(); ++i){
if(str.at(i).contains("id=\"mainImg\"", Qt::CaseInsensitive)){
pic = str.at(i);
pic = pic.remove(QRegExp("<img[^>]*src=['|\"]", Qt::CaseInsensitive));
pic = pic.remove(QString::fromStdString("//"), Qt::CaseInsensitive);
pic = pic.remove('"');
pic = pic.remove("'");
pic = pic.remove('<');
pic = pic.remove('>');
pic = pic.remove(';');
pic = pic.left(pic.length()-1);
//qDebug() << str.at(i);
//qDebug() << pic;
}
}
}else{
pic = "";
}
//qDebug() << "Lines: " << str.size();
}else{
pic = "";
}
return pic;
}
qdownload.cpp
#include "qdownloader.h"
QDownloader::QDownloader(QObject *parent) :
QObject(parent)
{
manager = new QNetworkAccessManager;
}
QDownloader::~QDownloader()
{
manager->deleteLater();
}
void QDownloader::setFile(QString fileURL, QString folderName, QString fileName)
{
QDir dir;
if(dir.exists(folderName)){
//qDebug() << "Existis: " + folderName;
}else{
dir.mkdir(folderName);
//() << "Created: " + folderName;
}
QString filePath = fileURL;
QStringList filePathList = filePath.split('/');
QString fileExt = filePathList.at(filePathList.count() - 1);
fileExt = "jpg";
QString saveFilePath;
saveFilePath = QString(folderName + "/" + fileName + "." + fileExt );
QNetworkRequest request;
request.setUrl(QUrl(fileURL));
reply = manager->get(request);
file = new QFile;
file->setFileName(saveFilePath);
connect(reply,SIGNAL(downloadProgress(qint64,qint64)),this,SLOT(onDownloadProgress(qint64,qint64)));
connect(manager,SIGNAL(finished(QNetworkReply*)),this,SLOT(onFinished(QNetworkReply*)));
connect(reply,SIGNAL(readyRead()),this,SLOT(onReadyRead()));
connect(reply,SIGNAL(finished()),this,SLOT(onReplyFinished()));
}
void QDownloader::onDownloadProgress(qint64 bytesRead,qint64 bytesTotal)
{
qDebug(QString::number(bytesRead).toLatin1() +" - "+ QString::number(bytesTotal).toLatin1());
}
void QDownloader::onFinished(QNetworkReply * reply)
{
switch(reply->error())
{
case QNetworkReply::NoError:
{
qDebug("file is downloaded successfully.");
}break;
default:{
qDebug(reply->errorString().toLatin1());
};
}
if(file->isOpen())
{
file->close();
file->deleteLater();
}
}
void QDownloader::onReadyRead()
{
qDebug() << "Ready";
file->open(QIODevice::WriteOnly);
file->write(reply->readAll());
}
void QDownloader::onReplyFinished()
{
if(file->isOpen())
{
file->close();
file->deleteLater();
}
}

I prepared a very basic example you can use as reference.
In some place in "my" downloader I launch the request:
QNetworkRequest request;
request.setUrl(org);
_reply = _manager->get(request); // Manager is my QNetworkAccessManager
connect(_reply, SIGNAL(error(QNetworkReply::NetworkError)),
this, SLOT(error(QNetworkReply::NetworkError)));
connect(_reply, SIGNAL(downloadProgress(qint64, qint64)),
this, SLOT(updateProgress(qint64, qint64)));
connect(_reply, SIGNAL(finished()),
this, SLOT(finished()));
As you can see all you need to do is to get() and properly use the signals of the QNetworkReply.
Following "my" slots:
void MyDownloader::error(QNetworkReply::NetworkError err)
{
// Manage error here.
_reply->deleteLater();
}
void MyDownloader::updateProgress(qint64 read, qint64 total)
{
// This is where you can use the progress info for, lets say, update a progress bar:
// progressBar->setMaximum(total);
// progressBar->setValue(read);
}
void MyDownloader::finished()
{
// Save the image here
QByteArray b = _reply->readAll();
QFile file(des); // "des" is the file path to the destination file
file.open(QIODevice::WriteOnly);
QDataStream out(&file);
out << b;
_reply->deleteLater();
// done
}
Notice that you can write to the file in updateProgress() instead of writing the whole file at once when the reply is finished.
For writing on updateProgress(), open and/or create the QFile at get time. Then use reply's readAll on every update and write the read data to the file then close the file when finished.
// ...
_file = new QFile(des);
_reply = _manager->get(request);
/// ...
void MyDownloader::updateProgress(qint64 read, qint64 total)
{
QByteArray b = _reply->readAll();
QDataStream out(_file);
out << b;
}
void MyDownloader::finished()
{
// Done
_reply->deleteLater();
_file->close();
// probably delete the file object too
}

Related

Qt, C++, XML reader crashes/freezes when I try parsing deeper data values

In an earlier Question I asked about why my program/QTcpServer was crashing all the time, and I really appreciate the help I got from everyone.
However, I have decided to try and rebuild the Program from scratch in order to see why it crashes, and I may have found something.
Allow me to post the new Code below:
//mainwindow.h
#include <QMainWindow>
#include <QPushButton>
#include <QTextEdit>
#include <QStandardItemModel>
#include <QTcpServer>
#include <QTcpSocket>
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
MainWindow(QWidget *parent = nullptr);
~MainWindow();
void startServer();
void handleConnection();
void readMessage();
void ReadXML(QString XMLString);
private:
QPushButton *SServer;
QTextEdit * ContainerView; //not changing to QTableView just yet
int Pallet_Number;
QTcpServer *tcpServer;
QTcpSocket *tcpSocket;
};
//mainwindow.cpp
#include "mainwindow.h"
#include <QLabel>
#include <QLayout>
#include <QDebug>
#include <QDomDocument>
#include <QRegularExpression>
static QRegularExpression Box_Code("B");
static QRegularExpression Cylinder_Code("C");
MainWindow::MainWindow(QWidget *parent)
: QMainWindow(parent),
SServer(new QPushButton("Start Listening")),
ContainerView(new /*QTableView*/QTextEdit),
tcpServer(new QTcpServer),
tcpSocket(new QTcpSocket)
{
QStringList HeaderRow;
HeaderRow.append("Pallet");
HeaderRow.append("Container");
HeaderRow.append("Code");
HeaderRow.append("Height");
HeaderRow.append("Breadth/Diameter");
HeaderRow.append("Length");
HeaderRow.append("Weight");
resize(800,300);
connect(SServer, &QPushButton::clicked, this, &MainWindow::startServer);
connect(tcpServer, &QTcpServer::newConnection, this, &MainWindow::handleConnection);
connect(tcpSocket, &QTcpSocket::readyRead, this, &MainWindow::handleConnection);
QLabel *Lab1(new QLabel("Listening on Port 6164"));
QHBoxLayout *HB(new QHBoxLayout);
QVBoxLayout *VB(new QVBoxLayout);
HB->addWidget(SServer);
HB->addWidget(Lab1);
VB->addItem(HB);
VB->addWidget(ContainerView);
QWidget *window(new QWidget);
window->setLayout(VB);
setCentralWidget(window);
}
MainWindow::~MainWindow()
{
}
void MainWindow::startServer()
{
if(!tcpServer->listen(QHostAddress::LocalHost, 6164)){
qDebug() << "Error connecting to Server";
tcpServer->close();
return;
} else {
qDebug() << "Started Successfully";
}
}
void MainWindow::handleConnection()
{
tcpSocket = tcpServer->nextPendingConnection();
qDebug() << "New Connection!";
connect(tcpSocket, &QTcpSocket::readyRead, this, &MainWindow::readMessage);
}
void MainWindow::readMessage()
{
ContainerView->clear(); //clear table to prepare for new XMLString
QByteArray buffer = tcpSocket->readAll();
QString FromContainer = QString::fromUtf8(buffer);
ReadXML(FromContainer);
}
void MainWindow::ReadXML(QString XMLString)
{
ContainerView->append(XMLString);
QDomDocument Xml_String;
Xml_String.setContent(XMLString);
QDomElement Xml_Root = Xml_String.documentElement();
if(Xml_Root.tagName() == "Pallets")
{
QDomElement Xml_Pallet = Xml_Root.firstChildElement();
while(!Xml_Pallet.isNull())
{
if(Xml_Pallet.tagName() == "Pallet")
{
int PN = Xml_Pallet.attribute("Number").toInt(nullptr,10);
QDomElement Box_Cyl = Xml_Pallet.firstChildElement();
while(!Box_Cyl.isNull())
{
if(Box_Cyl.tagName() == "Box")
{
QString BC = Box_Cyl.tagName();
ContainerView->append("Pallet No. " + QString::number(PN) + "\nContainer: " + BC);
// QDomElement Box_Info = Box_Cyl.firstChildElement();
// while(!Box_Info.isNull())
// {
// ...more code
// Box_Info = Box_Info.nextSiblingElement();
// }
} else if(Box_Cyl.tagName() == "Cylinder")
{
QString BC = Box_Cyl.tagName();
ContainerView->append("Pallet No. " + QString::number(PN) + "\nContainer: " + BC);
}
Box_Cyl = Box_Cyl.nextSiblingElement();
}
}
Xml_Pallet = Xml_Pallet.nextSiblingElement();
}
}
}
The XML String I am trying to read is shown below:
When I include the commented code to read the Elements within 'Box' or 'Cylinder' (I altered the code to check both sides), the program freezes.
This hasn't happened to me before, so I have no idea what to do.

How to make an MQTT connection from a large number of objects? QT C++

I have a "cell" class that describes some kind of smart device. I've got plenty of them. Each of these devices must implement a connection to the server. I have written methods in the "cell" class.
cell.cpp
#include "cell.h"
#include <QDateTime>
#include <QMessageBox>
cell::cell(QObject *parent) : QObject(parent)
{
}
void cell::Connect(){
m_client = new QMqttClient(this);
m_client->setHostname("192.111.11.111");
m_client->setPort(1883);
m_client->connectToHost();
QObject::connect(m_client, &QMqttClient::stateChanged, this, &cell::updateLogStateChange);
QObject::connect(m_client, &QMqttClient::disconnected, this, &cell::brokerDisconnected);
}
void cell::MsgReceive(){
connect(m_client, &QMqttClient::messageReceived, this, [this](const QByteArray &message, const QMqttTopicName &topic) {
const QString content =
QLatin1String(" Received Topic: ")
+ topic.name()
+ QLatin1String(" Message: ")
+ message
+ QLatin1Char('\n');
setMsg(content);
});
}
void cell::Publish()
{
QString topic = "topic/";
QString msg = "HELLO";
m_client->publish(topic, msg.toUtf8());
}
void cell::Subscribe()
{
QString topic = "topic/";
auto subscription = m_client->subscribe(topic);
if (!subscription) {
return;
}
}
void cell::updateLogStateChange()
{
const QString content = QDateTime::currentDateTime().toString()
+ QLatin1String(": State Change")
+ QString::number(m_client->state())
+ QLatin1Char('\n');
setLogState(content);
}
void cell::brokerDisconnected()
{
}
In the main window, I create objects through a loop and call the connection methods as an example, just to get a message in the ListWidget.
But it doesn't show up, what's the problem? I would be very grateful if you help me. I just started learning c++.
MainWindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QDateTime>
#include <QMessageBox>
#include <modelcell.h>
#include <cell.h>
#include <QThread>
MainWindow::MainWindow(QWidget *parent)
: QMainWindow(parent)
, ui(new Ui::MainWindow)
{
ui->setupUi(this);
QVector <cell *> listcell;
QString val;
QFile file;
file.setFileName("C:\\Users\\User\\Desktop\\cell.json");
file.open(QIODevice::ReadOnly | QIODevice::Text);
val = file.readAll();
file.close();
QJsonParseError error;
QJsonDocument doc = QJsonDocument::fromJson(val.toUtf8(), &error);
if (doc.isObject())
{
QJsonObject json = doc.object();
QJsonArray jsonArray = json["cell"].toArray();
foreach (const QJsonValue & value, jsonArray)
{
if (value.isObject())
{
QJsonObject obj = value.toObject();
QString id = obj["ID"].toString();
QString name = obj["Name"].toString();
QString IP = obj["IP"].toString();
QString status = obj["status"].toString();
cell * cell_obj = new cell;
cell_obj->setName(name);
cell_obj->setID(id);
cell_obj->setIP(IP);
cell_obj->setStatus(status);
cell_obj->Connect();
cell_obj->MsgReceive();
cell_obj->Subscribe();
cell_obj->Publish();
listcell.append(cell_obj);
}
}
}
for(int i = 0; i < listcell.size(); i++){
ui->listWidget->addItem(listcell[i]->getName() + " | " + listcell[i]->getID() + " | " + listcell[i]->getIP()+ " | " + listcell[i]->getStatus());
ui->listWidget->addItem(listcell[i]->getMsg());
}
}
MainWindow::~MainWindow()
{
delete ui;
}
I want the listWidget to display a "hello" message from each created object. But it doesn't happen. Where is the mistake?

Data Appending while sending Data through Qt NamedPipe

Data Appending Problem While sending the data through Namedpipe using QT
localserver.h
#ifndef LOCALSERVER_H
#define LOCALSERVER_H
#include "QLocalSocket"
#include "QLocalServer"
class QLocalSocket;
class LocalServer : public QLocalServer
{
Q_OBJECT
public:
explicit LocalServer(QObject *parent = 0);
void send(QString &msj);
QLocalSocket *mSocket;
private slots:
void receive();
private:
};
#endif // LOCALSERVER_H
localserver.cpp
#include "localserver.h"
#include "QLocalSocket"
#include "QTextStream"
#include "QMessageBox"
LocalServer::LocalServer(QObject *parent) : QLocalServer(parent)
{
mSocket = nullptr;
connect(this,&LocalServer::newConnection,[&](){
mSocket = nextPendingConnection();
});
qDebug()<<"Hello World";
}
void LocalServer::send(QString &msj)
{
qDebug()<<"Sending Data";
if(mSocket)
{
QTextStream T(mSocket);
T<<msj.toStdString().c_str();
mSocket->flush();
}
}
void LocalServer::receive()
{
qDebug()<<"Im here";
QDataStream in(mSocket);
in.setVersion(QDataStream::Qt_5_2);
mSocket->readAll();
qDebug()<<"Data Received";
}
widget.h
#ifndef WIDGET_H
#define WIDGET_H
#include <QWidget>
#include "QProcess"
#include "QTimer"
#include "QLocalSocket"
#include "localserver.h"
namespace Ui {
class Widget;
}
class Widget : public QWidget
{
Q_OBJECT
public:
explicit Widget(QWidget *parent = 0);
~Widget();
void Connection();
private slots:
void on_start_clicked();
void on_send_clicked();
void on_quit_clicked();
void detect_connection();
void connect_terminate();
void connected();
void send_data();
void receive_data();
QString RandomData();
void on_pbtn_Stop_clicked();
private:
Ui::Widget *ui;
LocalServer *mLocalServer;
QTimer *timer;
QLocalSocket *mSocket;
bool first;
QString data_received;
};
#endif // WIDGET_H
widget.cpp
#include "widget.h"
#include "ui_widget.h"
#include "QProcess"
#include "QDebug"
#include "localserver.h"
#include "QMessageBox"
#include <iostream>
#include <cstdlib>
#include <ctime>
using namespace std;
Widget::Widget(QWidget *parent) :
QWidget(parent),
ui(new Ui::Widget)
{
ui->setupUi(this);
Connection();
first = true;
}
void Widget::Connection()
{
mLocalServer = new LocalServer(this);
mLocalServer->listen("Server1");
connect(mLocalServer,SIGNAL(newConnection()),this,SLOT(detect_connection()));
first = true;
timer = new QTimer(this);
timer->setInterval(8);
connect(timer,SIGNAL(timeout()),this,SLOT(send_data()));
}
Widget::~Widget()
{
delete ui;
}
void Widget::on_start_clicked()
{
timer->start();
}
void Widget::on_send_clicked()
{
timer->stop();
}
void Widget::on_quit_clicked()
{
timer->stop();
this->close();
}
void Widget::detect_connection()
{
qDebug()<<"Write Pipe Established";
mSocket = new QLocalSocket(this);
mSocket->connectToServer("Server2");
connect(mSocket,SIGNAL(disconnected()),this,SLOT(connect_terminate()));
connect(mSocket,SIGNAL(connected()),this,SLOT(connected()));
qDebug()<<"Connection Established, Ready to Read";
connect(mSocket,&QLocalSocket::readyRead, [&]() {
QTextStream T(mSocket);
ui->receivedText->addItem(T.readAll());
});
}
void Widget::connect_terminate()
{
qDebug()<<"Read Server Connection Terminated";
QString string = "Stop_Session";
mLocalServer->send(string);
ui->sentText->addItem(string);
}
void Widget::connected()
{
qDebug()<<"Socket Connected to Server";
QString s=" Connection Done ";
mLocalServer->send(s);
}
void Widget::send_data()
{
QString string = RandomData();
mLocalServer->send(string);
ui->sentText->addItem(string);
}
QString Widget::RandomData()
{
srand(time(NULL));
int random_number = rand()%(1920-0 + 1) + 0; // rand() return a number between ​0​ and RAND_MAX
int random_number1 = rand()%(1080-0 + 1) + 0;
int random_number2 = rand()%(10-0 + 1) + 0;
QString s="Contour,"+QString::number(random_number)+","+QString::number(random_number1)+","+QString::number(random_number2);
// Basically this data in "s" gives the actual contours detected data but am using a random generator to test the Local Server and Socket .
return s;
}
void Widget::receive_data()
{
QString string;
QTextStream T(mSocket);
T.readLine();
if(T.readAll()=="Stop")
{
qDebug()<<"Socket About to Close";
QString string = "Stop";
mLocalServer->send(string);
}
else
{
qDebug()<<"Program can continue"<<T.readAll();
}
}
void Widget::on_pbtn_Stop_clicked()
{
timer->stop();
}
At Receiver SIde Program
Receiver.cpp
void Receiver ::Declaration_Of_Server2()
{
// Declaration Of LocalServer i.e Server2
ServerIS = new LocalServer(this);
ServerIS->listen("Server2");
// Connect To a LocalSocket TO The Above LocalServer i.e Server_IS with Server_VS
connect(ServerIS,SIGNAL(newConnection()),this,SLOT(DetectConnection_WithServer1()));
}
void CoFire_MainPage::DetectConnection_WithServer1()
{
// Declaration of LocalSocket i.e Server_VS
SocketIS = new QLocalSocket(this);
SocketIS->connectToServer("Server1");
connect(SocketIS,SIGNAL(readyRead()),this,SLOT(Receiving_VS_Data()));
}
void CoFire_MainPage::Receiving_VS_Data()
{
// Receiving Vs Data From Socket "Socket_IS"
QTextStream msg(SocketIS);
QString str = msg.readLine();
qDebug()<<" VS DATA : "<<str;
}
By this am trying to send data ( example : Contour,1000,800,1 ) from one program to other program
with a speed of 1 data / 8msec but in real scenario it might even go to 1msec data transfer.
but by this at receving end every now and then incomming data is been appended
(example: Contour,1000,800,1Contour,200,400,1Contour,500,650,1 etc... ).
But actually expentected data is
1st
Contour,1000,800,1
next
Contour,200,400,1
next
Contour,500,650,1
etc....
This way the data is getting appeneded before i capture and process the data at receiver .
By this am loosing the precious information .
how do i solve this issue .
readLine() waits for an end-of-line ("\n" or "\r\n"), but in your case you do not send it, you must change to the following:
QString Widget::RandomData(){
srand(time(NULL));
int random_number = rand()%(1920-0 + 1) + 0; // rand() return a number between ​0​ and RAND_MAX
int random_number1 = rand()%(1080-0 + 1) + 0;
int random_number2 = rand()%(10-0 + 1) + 0;
return QString("Contour,%1,%2,%3\n")
.arg(random_number)
.arg(random_number1)
.arg(random_number2);
}
On the other hand it is not necessary to use the reference of the QString, and also it is unnecessary to use toStdString().c_str().
void LocalServer::send(const QString &msj)
{
qDebug()<<"Sending Data";
if(mSocket)
{
QTextStream T(mSocket);
T << msj;
mSocket->flush();
}
}

Qt QJsonModel isn't working at end of network request

So, after I make my QJsonModel, load the data, and set the treeView model, it will load the data normally into the treeView. Although, when I do this after a network request has been finished (serviceRequestFinished(QNetworkReply* reply)), it just doesn't woek. I can qDebug the Json data that is passed, but when it comes down to the Json loading and the model setting. It just fails to finish. Also, for some reason it won't set the Json from the network request, but if I just set it to set the json from a separate button, the json get added successfully. So that means that the Json is formatted correctly. The QJsonModel & QJsonItem are external classes not provided with Qt, that located here.
Here is my code:
Mainwindow.h:
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <QModelIndex>
#include <QItemSelection>
#include <QFile>
#include <QFileInfo>
#include <QList>
#include <QtNetwork/QNetworkAccessManager>
#include <QtNetwork/QNetworkRequest>
#include <QtNetwork/QNetworkReply>
#include <QStringList>
#include <QTimer>
#include <QUrl>
#include <QTreeWidgetItem>
#include <QJsonDocument>
#include <QJsonObject>
#include "qjsonmodel.h"
#include <QClipboard>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
void setJson(QString json);
void getPlaylistList(QString accessToken);
QString disableStreams();
void appendEditValues(int currentRow);
void addVectorItems();
void streamCheck();
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
private slots:
void on_radioButtonNoStream_clicked()
{
streamCheck();
}
void on_radioButtonTwitchStream_clicked()
{
streamCheck();
}
void on_radioButtonYTStream_clicked()
{
streamCheck();
}
void on_pushButtonAddVid_clicked();
void on_pushButtonApplyAddVid_clicked();
void on_pushButtonDeleteSelection_clicked();
void on_pushButtonApplyAll_clicked();
public slots:
void serviceRequestFinished(QNetworkReply* reply);
void connectAPI(QString code);
signals:
void authenticate(QString accessCode);
private:
Ui::MainWindow *ui;
};
#endif // MAINWINDOW_H
Mainwindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "authdialog.h"
#include <qDebug>
#include <QVector>
#include <QMessageBox>
#include <QStandardItemModel>
#include <QFile>
#include <QUrlQuery>
int val = 0;
int selected;
QVector<QString> vidTitles;
QVector<QString> vidUrls;
QVector<int> vidNumber;
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
streamCheck();
ui->groupBoxEditVideo->setEnabled(false);
connect(this, SIGNAL(authenticate(QString)), SLOT(connectAPI(QString)));
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::streamCheck()
{
if (ui->radioButtonNoStream->isChecked())
{
ui->groupBoxStreamSetup->setEnabled(false);
ui->groupBoxStreamSetup->setTitle("No Stream Selected!");
}
else if (ui->radioButtonTwitchStream->isChecked())
{
ui->groupBoxStreamSetup->setEnabled(true);
ui->groupBoxStreamSetup->setTitle("Twitch Setup");
}
else if (ui->radioButtonYTStream->isChecked())
{
ui->groupBoxStreamSetup->setEnabled(true);
ui->groupBoxStreamSetup->setTitle("YouTube Stream Setup");
}
}
void MainWindow::on_pushButtonAddVid_clicked()
{
AuthDialog *auth = new AuthDialog(this);
auth->setModal(true);
auth->exec();
delete auth;
}
void MainWindow::setJson(QString json)
{
qDebug() << json;
QJsonModel * model = new QJsonModel;
model->loadJson(json.toUtf8());
ui->treeView->setModel(model);
delete model;
}
void MainWindow::getPlaylistList(QString accessToken)
{
QNetworkAccessManager *networkManager = new QNetworkAccessManager(this);
connect(networkManager, SIGNAL(finished(QNetworkReply*)), this, SLOT(serviceRequestFinished(QNetworkReply*)));
//
QNetworkRequest request(QUrl("https://www.googleapis.com/youtube/v3/search?part=snippet&forMine=true&order=viewCount&type=video&access_token=" + accessToken));
networkManager->get(request);
}
QString MainWindow::disableStreams()
{
QString line = "";
QString test = "";
QFile file;
file.setFileName("C:/WampStack/apache2/htdocs/index.html");
file.open(QIODevice::ReadWrite);
QTextStream in(&file);
while(!in.atEnd())
{
line += in.readAll();
}
if (line.contains("<!--t-->") && !line.contains("<!--y-->"))
{
//Twitch Stream is on, must turn it off
test = line.replace("<!--t-->", "<!--t");
test = test.replace("><!--tt-->", ">tt-->");
return test;
}
else if (line.contains("<!--y-->") && !line.contains("<!--t-->"))
{
//YouTube Stream is on, must turn it off
test = line.replace("<!--y-->", "<!--y");
test = test.replace("><!--yy-->", ">yy-->");
return test;
}
else if (line.contains("<!--y-->") && line.contains("<!--t-->"))
{
test = line.replace("<!--y-->", "<!--y");
test = test.replace("><!--yy-->", ">yy-->");
test = test.replace("<!--t-->", "<!--t");
test = test.replace("><!--tt-->", ">tt-->");
return test;
}
else
{
return line;
}
file.close();
return line;
}
void MainWindow::connectAPI(QString code)
{
QNetworkAccessManager *networkManager = new QNetworkAccessManager(this);
connect(networkManager, SIGNAL(finished(QNetworkReply*)), this, SLOT(serviceRequestFinished(QNetworkReply*)));
QUrlQuery postData;
postData.addQueryItem("code", code);
postData.addQueryItem("client_id", "CLIENT-ID");
postData.addQueryItem("client_secret", "CLIENT-SECRET");
postData.addQueryItem("redirect_uri", "REDIRECT-URI");
postData.addQueryItem("grant_type", "authorization_code");
QNetworkRequest request(QUrl("https://accounts.google.com/o/oauth2/token"));
request.setHeader(QNetworkRequest::ContentTypeHeader, "application/x-www-form-urlencoded");
networkManager->post(request, postData.toString(QUrl::FullyEncoded).toUtf8());
}
void MainWindow::appendEditValues(int currentRow)
{
}
void MainWindow::addVectorItems()
{
}
void MainWindow::on_pushButtonApplyAddVid_clicked()
{
}
void MainWindow::on_pushButtonDeleteSelection_clicked()
{
QMessageBox::StandardButton reply;
reply = QMessageBox::question(this, "Are you sure?", "Do you want to permanently delete this entry?", QMessageBox::Yes|QMessageBox::No);
if (reply == QMessageBox::Yes)
{
}
addVectorItems();
}
void MainWindow::on_pushButtonApplyAll_clicked()
{
QString line = disableStreams();
QFile::remove("C:/WampStack/apache2/htdocs/index.html");
QFile file;
file.setFileName("C:/WampStack/apache2/htdocs/index.html");
file.open(QIODevice::ReadWrite);
//Start code for streaming
if (ui->radioButtonTwitchStream->isChecked() && line.contains("<!--t") && line.contains(">tt-->") && !line.contains("<!--t-->") && !line.contains("<!--tt-->"))
{
QString test = line.replace("<!--t", "<!--t-->");
test = line.replace(">tt-->", "><!--tt-->");
QTextStream stream( &file );
stream << test;
}
else if (ui->radioButtonYTStream->isChecked() && line.contains("<!--y") && line.contains(">yy-->") && !line.contains("<!--y-->") && !line.contains("<!--yy-->"))
{
QString test = line.replace("<!--y", "<!--y-->");
test = test.replace(">yy-->", "><!--yy-->");
QTextStream stream( &file );
stream << test;
}
else if (ui->radioButtonNoStream->isChecked())
{
QTextStream stream(&file);
stream << line;
}
//End code for streaming
file.close();
}
void MainWindow::serviceRequestFinished(QNetworkReply* reply)
{
QByteArray json = reply->readAll();
QString output = QString::fromUtf8(json);
QJsonDocument settdoc = QJsonDocument::fromJson(output.toUtf8());
QJsonObject sett2 = settdoc.object();
if (val == 0)
{
val++;
getPlaylistList(sett2.value(QString("access_token")).toString());
}
else if (val == 1)
{
setJson(output.toUtf8());
}
}
Main.cpp:
#include "mainwindow.h"
#include <QApplication>
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MainWindow w;
w.show();
return a.exec();
}
QJsonModel only works if the the JSON's root element is an object (see the bug report on github.com). I guess your JSON's root is an array.

How to interact with a child QProcess?

In my program I have a child process that interacts with a serial port specified to it when the parent process demands it. For example the parent process commands the child process to read a number of bytes with a certain time out from the opened port by sending this command: read 100 1000. The child process launches and opens the port successfully and I can see the message port openned successfully! but from there onwards it won't read the parent commands.
Here's the child source code:
SerialPortHandler.h
#ifndef SERIALPORTHANDLER_H
#define SERIALPORTHANDLER_H
#include <QObject>
#include <QSocketNotifier>
#include <QTextStream>
#include <QSerialPort>
#include <QFile>
#include <QTimer>
#include <QDebug>
#include <QtCore>
enum CommandType { READ, WRITE, BAD, UNKNOWN };
class SerialPortHandler : public QObject
{
Q_OBJECT
public:
explicit SerialPortHandler(QString portname, QString baudrate, QObject *parent = 0);
signals:
public slots:
void execmd();
bool open(const QString& portname, const QString& baudrate);
qint64 read(char * buff, const qint64 size, const qint32 timeout);
QString convertToCaseInsensitiveRegExp(QString str);
CommandType analyze(const QString& line);
qint64 getNum(const QString &line, int index);
void reply(char *buff);
private:
QSocketNotifier *innotif;
QSerialPort *sp;
QTimer *timer;
};
#endif // SERIALPORTHANDLER_H
SerialPortHandler.cpp
#include "SerialPortHandler.h"
#include <unistd.h>
#include <limits>
SerialPortHandler::SerialPortHandler(QString portname, QString baudrate, QObject *parent) :
QObject(parent)
{
timer = new QTimer(this);
sp = new QSerialPort(this);
if(!open(portname, baudrate)) {
qDebug() << sp->error() << sp->errorString();
exit(sp->error());
}
innotif = new QSocketNotifier(STDIN_FILENO, QSocketNotifier::Read, this);
connect(innotif, SIGNAL(activated(int)), this, SLOT(execmd()));
}
void SerialPortHandler::execmd()
{
qDebug() << "command received. analyzing...";
// qint64 nbr = -1, size = -1;
// qint32 timeout = -1;
// char * buff = 0;
// QTextStream in(stdin);
// QString ln = in.readAll();
// switch (analyze(ln)) {
// case READ:
// size = getNum(ln, 1);
// timeout = getNum(ln, 2);
// if(size > -1 && timeout > -1)
// nbr = read(buff, size, timeout);
// if(nbr > -1)
// reply(buff);
// break;
// default:
// break;
// }
}
bool SerialPortHandler::open(const QString &portname, const QString &baudrate)
{
sp->setPortName(portname);
if (!sp->open(QIODevice::ReadWrite) ||
!sp->setBaudRate(baudrate.toInt()) ||
!sp->setDataBits(QSerialPort::Data8) ||
!sp->setParity(QSerialPort::NoParity) ||
!sp->setStopBits(QSerialPort::OneStop) ||
!sp->setFlowControl(QSerialPort::NoFlowControl)) {
return false;
}
sp->clear();
qDebug() << "port openned successfully!";
return true;
}
//day light wont affect this timer so the system wont freeze
qint64 SerialPortHandler::read(char *buff, const qint64 size, const qint32 timeout)
{
qint64 numbytesread = -1;
timer->start(timeout);
while (true) {
if(timer->remainingTime() > 0) {
return -1;
}
if((sp->isReadable() && sp->bytesAvailable() > 0) ||
(sp->isReadable() && sp->waitForReadyRead(10))) {
numbytesread += sp->read(buff, size);
}
if(numbytesread < 0) {
return -1;
}
if(numbytesread == size) {
break;
}
}
return numbytesread;
}
void SerialPortHandler::notify()
{
}
QString SerialPortHandler::convertToCaseInsensitiveRegExp(QString str)
{
QString result;
for(int i = 0 ; i < str.size() ; ++i) {
result.append("[");
result.append(str.at(i).toLower());
result.append(str.at(i).toUpper());
result.append("]");
}
return result;
}
CommandType SerialPortHandler::analyze(const QString &line)
{
QString read, write;
read = convertToCaseInsensitiveRegExp("read");
write = convertToCaseInsensitiveRegExp("write");
if(line.contains(QRegExp(QString("^.*%1\\s+[1-9]\\d*\\s+[1-9]\\d*.*").arg(read)))) {
return READ;
}
return UNKNOWN;
}
qint64 SerialPortHandler::getNum(const QString& line, int index) {
QStringList args(line.split(QRegExp("\\s+")));
bool done;
qint64 size = args.at(index).toInt(&done, 10);
if(done) {
return size;
}
return -1;
}
void SerialPortHandler::reply(char * buff) {
QDataStream out(stdout);
out << buff;
}
main.cpp
#include <QCoreApplication>
#include <QDebug>
#include "SerialPortHandler.h"
int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);
if(argc != 3) {
qDebug() << "usage:" << argv[0] << "port" << "baudrate";
} else {
SerialPortHandler *sph = new SerialPortHandler(argv[1], argv[2]);
}
return a.exec();
}
My parent process consists of the following:
ParentProcess.h
#ifndef PARENTPROCESS_H
#define PARENTPROCESS_H
#include <QObject>
#include <QtCore>
class ParentProcess : public QObject
{
Q_OBJECT
public:
explicit ParentProcess(QObject *parent = 0);
signals:
public slots:
private slots:
void sendRead();
void writeSomething();
void handleError(QProcess::ProcessError error);
private:
QProcess *p;
};
#endif // PARENTPROCESS_H
ParentProcess.cpp
#include "ParentProcess.h"
#include <QDebug>
ParentProcess::ParentProcess(QObject *parent) :
QObject(parent)
{
p = new QProcess(this);
connect(p, SIGNAL(readyReadStandardOutput()), this, SLOT(sendRead()));
connect(p, SIGNAL(readyReadStandardError()), this, SLOT(sendRead()));
connect(p, SIGNAL(started()), this, SLOT(writeSomething()));
connect(p, SIGNAL(error(QProcess::ProcessError)), this, SLOT(handleError(QProcess::ProcessError)));
QStringList args;
args << "/dev/ttyUSB0" << "115200";
p->start("/home/moki/Work/Programs/build-serialio-Desktop_Qt_5_3_0_GCC_64bit-Debug/serialio", args, QProcess::ReadWrite);
}
void ParentProcess::sendRead() {
qDebug() << "data:" << p->readAllStandardError() << p->readAllStandardOutput();
}
void ParentProcess::writeSomething() {
qDebug() << "writing";
QString cmd = "read 10 10000\n";
qint64 a = p->write(cmd.toStdString().c_str());
qDebug() << "wrote:" << a;
}
void ParentProcess::handleError(QProcess::ProcessError error)
{
switch (error) {
case QProcess::FailedToStart:
qDebug() << "failed to start";
break;
case QProcess::Crashed:
qDebug() << "crashed.";
break;
default:
break;
}
}
main.cpp
#include <QCoreApplication>
#include "ParentProcess.h"
int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);
ParentProcess p;
return a.exec();
}
I have seen a couple of other answers in SO but none of them address my issue. As you can see my child process is not supposed to complete and exit. It will remain launched as long as the parent process wishes. Is it correct to use QProcess-launched processes this way?
I changed my code to the following and now it's working. But I haven't understood why this code works and my original one doesn't.
in the parent process source i changed the constructor as follows:
ParentProcess::ParentProcess(QObject *parent) :
QObject(parent)
{
p = new QProcess(this);
connect(p, SIGNAL(error(QProcess::ProcessError)), this, SLOT(handleError(QProcess::ProcessError)));
connect(p, SIGNAL(readyRead()), this, SLOT(sendRead()));
connect(p, SIGNAL(started()), this, SLOT(writeSomething()));
QStringList args;
args << "/dev/ttyUSB0" << "115200";
p->setProcessChannelMode(QProcess::MergedChannels);
p->start("/home/moki/Work/Programs/build-serialio-Desktop_Qt_5_3_0_GCC_64bit-Debug/serialio", args, QProcess::ReadWrite);
}
and the sendRead() function to this:
void ParentProcess::sendRead() {
int bytes = p->bytesAvailable();
qDebug() << "data:" << p->read(bytes);
}
finally, the writeSomething() to:
void ParentProcess::writeSomething() {
qDebug() << "gonna write.";
if(p->state() == QProcess::Running) {
qDebug() << "writing";
QString cmd = "read 10 10000\n";
qint64 a = p->write(cmd.toStdString().c_str());
qDebug() << "wrote:" << a << "bytes.";
}
}
and now it works. If anyone could please explain this to me, I would be really grateful.