[Qt] Qt实现HTTP请求 [2013-12-18更新]

- 通过QTcpSocket实现

实现原理：通过tcp socket向Web服务器的80端口发送HTTP请求字符串

/*********************************************************

    mainwindow.h

 *********************************************************/

#include <QMainWindow>

#include <QTcpSocket>

#include <QDebug>

namespace Ui {

class MainWindow;

}

class MainWindow : public QMainWindow

{

    Q_OBJECT

public:

    explicit MainWindow(QWidget *parent = 0);

    ~MainWindow();

private:

    Ui::MainWindow *ui;

    QTcpSocket *tcpSocket;

private slots:

    void slotConnected();

    void slotReadyRead();

    void slotDisconnected();

};

/*********************************************************

    mainwindow.cpp

 *********************************************************/

#include "mainwindow.h"

#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent) :

    QMainWindow(parent),

    ui(new Ui::MainWindow)

{

    ui->setupUi(this);

    tcpSocket = new QTcpSocket(this);

    connect(tcpSocket, SIGNAL(connected()), this, SLOT(slotConnected()));

    connect(tcpSocket, SIGNAL(readyRead()), this, SLOT(slotReadyRead()));

    connect(tcpSocket, SIGNAL(disconnected()), this, SLOT(slotDisconnected()));

    // 假设Web服务器的IP地址为192.168.1.239

    tcpSocket->connectToHost("192.168.1.239", 80);

}

MainWindow::~MainWindow()

{

    delete ui;

}

void MainWindow::slotConnected()

{

    qDebug() << "connected";

    tcpSocket->write("GET / HTTP/1.1\r\n"   // “/”表示访问默认主页，可修改为“/cgi-bin/test.cgi”等等

                     "Connection: Keep-Alive\r\n"

                     "Accept-Encoding: gzip\r\n"

                     "Accept-Language: zh-CN,en,*\r\n"

                     "User-Agent: Mozilla/5.0\r\n"

                     "Host: 192.168.1.239\r\n\r\n");  // Host必须与目标Web服务器一致

}

void MainWindow::slotReadyRead()

{

    qDebug() << "readyread";

    qDebug() << QString(tcpSocket->readAll());

}

void MainWindow::slotDisconnected()

{

    qDebug() << "disconnected";

}

---

- 通过QNetworkAccessManager实现

/*********************************************************

    mainwindow.h

 *********************************************************/

#include <QMainWindow>

#include <QNetworkAccessManager>

#include <QNetworkRequest>

#include <QNetworkReply>

#include <QDebug>

namespace Ui {

class MainWindow;

}

class MainWindow : public QMainWindow

{

    Q_OBJECT

public:

    explicit MainWindow(QWidget *parent = 0);

    ~MainWindow();

private:

    Ui::MainWindow *ui;

    QNetworkAccessManager *manager;

    QNetworkRequest *request;

    QNetworkReply *reply;

private slots:

    void slot_ReadyRead();

    void slot_ReplyFinished(QNetworkReply*);

};

/*********************************************************

    mainwindow.cpp

 *********************************************************/

#include "mainwindow.h"

#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent) :

    QMainWindow(parent),

    ui(new Ui::MainWindow)

{

    ui->setupUi(this);

    manager = new QNetworkAccessManager(this);

    request = new QNetworkRequest(QUrl("http://192.168.1.239/cgi-bin/out.cgi?name=name&ok=ok"));

    reply = manager->get(*request);

    connect(manager, SIGNAL(finished(QNetworkReply*)), this, SLOT(slot_ReplyFinished(QNetworkReply*)));

    connect(reply, SIGNAL(readyRead()), this, SLOT(slot_ReadyRead()));

}

MainWindow::~MainWindow()

{

    delete ui;

}

void MainWindow::slot_ReplyFinished(QNetworkReply *reply)

{

    qDebug() << "slot_ReplyFinished";

    qDebug() << QString(reply->readAll()).simplified();

}

void MainWindow::slot_ReadyRead()

{

    qDebug() << "slot_ReadyRead";

}

---

- 两种实现方式的比较

1. 通过QTcpSocket实现有助于理解Web服务器的工作方式和HTTP协议，但是返回的结果需要自己去掉HTTP协议头。

2. 通过QNetworkAccessManager实现屏蔽了内部细节，返回的结果会自动去掉HTTP协议头。