httpget.cpp

QT4 gui programming的随书光盘

#include <QtCore>
#include <QtNetwork>
#include <iostream>

#include "httpget.h"

HttpGet::HttpGet(QObject *parent)
    : QObject(parent)
{
    connect(&http, SIGNAL(done(bool)), this, SLOT(httpDone(bool)));
}

bool HttpGet::getFile(const QUrl &url)
{
    if (!url.isValid()) {
        std::cerr << "Error: Invalid URL" << std::endl;
        return false;
    }

    if (url.scheme() != "http") {
        std::cerr << "Error: URL must start with 'http:'" << std::endl;
        return false;
    }

    if (url.path().isEmpty()) {
        std::cerr << "Error: URL has no path" << std::endl;
        return false;
    }

    QString localFileName = QFileInfo(url.path()).fileName();
    if (localFileName.isEmpty())
        localFileName = "httpget.out";

    file.setFileName(localFileName);
    if (!file.open(QIODevice::WriteOnly)) {
        std::cerr << "Error: Cannot write file "
                  << qPrintable(file.fileName()) << ": "
                  << qPrintable(file.errorString()) << std::endl;
        return false;
    }

    http.setHost(url.host(), url.port(80));
    http.get(url.path(), &file);
    http.close();
    return true;
}

void HttpGet::httpDone(bool error)
{
    if (error) {
        std::cerr << "Error: " << qPrintable(http.errorString())
                  << std::endl;
    } else {
        std::cerr << "File downloaded as "
                  << qPrintable(file.fileName()) << std::endl;
    }
    file.close();
    emit done();
}