QT调用WebService的尝试和最终实现

最近接触的QT项目与平台对接时需要用到WebService。博主从毕业起大部分工作都是在做桌面开发，所以对WebService只能说是一知半解。唯一的接触就是在.NET平台下编写，发布和调用WebService。这其中大部分工作微软都帮我们做好了，我们只需添加web引用，就像引用本地的库一样。不得不说VS确实强大且易用性好。但是很多事情都是两面性的。就像现在习惯了vs的方便，当面临linux C++的WebService调用时，博主直接就懵逼了。闲话少说，进入正题。

最初的尝试 qtsoap

由于是QT项目，一向懒惰的博主首先想到的是去找QT下的开源方案。几番查找，找到了这个4、5年前的开源项目qtsoap。

通过官方示例和各种查阅文档。最终博主终于完成一个调用类，结构如下：


#ifndef WEBSERVICE_H
#define WEBSERVICE_H
#include <qtsoap.h>
class WebService:public QObject
{
        Q_OBJECT
public:
    /**********************************************
     * description: Constructor
     * parameter:   serviceUrl  webservice url
     *              opration    request method
     * ********************************************/
    WebService(QString serviceUrl,QString operation);
    ~WebService();
    /*************************************
     * description: Submit Request
     * parameter:   argument for operation
     * ***********************************/
    void SubmitRequest(QString argument);

private slots:
    /***********************************************
     * description: Response after operation
     * parameter:   responseMessage
     * *********************************************/
    void getResponse(const QtSoapMessage &response);

private:
    //服务地址
    QString serviceUrl;
    //执行的操作名称
    QString operation;
    QtSoapHttpTransport http;
};

只有两个函数：提交请求和获得响应，博主高高兴兴的编译运行，

又是一脸懵，无论怎么检查，响应永远是Network transport error。没办法开始翻源码。当我看到要翻3000+行C++代码时，我的内心是拒绝的。

无奈之下改翻头文件，XMLschema和namespace深深的吸引了我

这地址1998和1999，主观上以我对自己的了解，我是不会再改这货了。最后还是去QT开源社区的群咨询了一下下。许久只得到了以下回复其余都是乱扯：

1	qtsoap,我已经放弃了。

最后还是默默的关掉了项目，寻求其他方案。

进一步了解WebService和QNetworkAccessManager

无奈之下只能进一步开始了解WebService。什么是WebService呢？简单的说就是一种可以接受和相应网络上其他系统传递的请求，轻量的通讯技术，通过soap协议在web上提供服务。这里就不做详细解释了，想了解的同学可以自行搜索或参阅文末链接。基于对WebService的进一步了解，也就是说我们只需要通过网络向WebService发送soap消息请求就可以了。于是下一步就是解决QT下的网络通信了。于是主角QNetworkAccessManager登场。在了解了如何使用QNetworkAccessManager发送post和get请求后懒癌晚期的还是选择了寻找现成的方法。最后找到了这个：QNetworkAccessManager调用WebService
因为目标WebService需要客户端传递xml格式的字符串，博主在以上方案上修改了部分代码又加了两个函数。源码奉上：

头文件


/** *****************************************************
 *                      QWebService
 *
 * 通过http post或get请求调用WebService
 *
 * ******************************************************/
#ifndef QWEBSERVICE_H
#define QWEBSERVICE_H

#include <QTimer>
#include <QThread>
#include <QNetworkAccessManager>
#include <QNetworkRequest>
#include <QNetworkReply>
/**
 * xml字符串，转义符替换。
 **/
void Xml2Esc(QString &xmlString);
void Esc2Xml(QString &escString);
class NetDataListenerThread:public QThread
{
    Q_OBJECT
public:
    NetDataListenerThread(QNetworkAccessManager *manager,QNetworkReply * reply,int timeoutms,QObject *parent = 0);
    ~NetDataListenerThread();
    QByteArray getBa() const;
    bool getIsWaitTimeOut() const;
protected:
    virtual void run();
private:
    bool waitForConnect();
protected slots:
    void slot_waitTimeout();
signals:
    void sig_waitTimeout();
private:
    QNetworkAccessManager *mManager;
    int m_TimeOutms;
    bool m_waitTimeOut;
    bool m_isWaitTimeOut;
    QNetworkReply * m_reply;
};
/**
 * @brief The WebServiceHelp class webservice调用帮助类
 * @author zp
 */
class   WebServiceHelp:public QObject
{
    Q_OBJECT
private:
    QString   postXml = "<?xml version=\"1.0\" encoding=\"utf-8\"?><soap:Envelope xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xmlns:xsd=\"http://www.w3.org/2001/XMLSchema\" xmlns:soap=\"http://schemas.xmlsoap.org/soap/envelope/\"><soap:Body><toTraditionalChinese xmlns=\"http://webxml.com.cn/\"><sText>ARGUMENT</sText></toTraditionalChinese></soap:Body></soap:Envelope>";
    class Dispose
    {
    public:
        ~Dispose();
    };
public:
    static WebServiceHelp * getInstance();
public:
    /**
     * @brief sendGetRequest 发送Get请求
     * @param urlStr  url
     * @param ba      返回数据
     * @param timeOutms 超时时间
     * @return  返回错误代码
     */
    QNetworkReply::NetworkError sendGetRequest(QString urlStr, QByteArray & ba, int timeOutms=3000);
    /**
     * @brief sendPostRequest 发送post请求
     * @param website  网址
     * @param methodName 方法名称
     * @param param 参数
     * @param postBa    post数据
     * @param code      返回代码
     * @param message   返回信息
     * @param data      返回数据
     * @param timeOutms 超时时间
     * @return 返回错误代码
     */
    QNetworkReply::NetworkError sendPostRequest(QString website,const QString argument, QByteArray& retBa, int timeOutms=3000);
protected slots:
    void slot_error(QNetworkReply::NetworkError code);
private:
    static WebServiceHelp * serverHelp;
    static WebServiceHelp::Dispose disp;
    QNetworkAccessManager *manager;
    QNetworkReply::NetworkError m_errCode;
private:
    WebServiceHelp(QObject *parent=0);
    ~WebServiceHelp();
};

#endif // QWEBSERVICE_H

类文件

   #include "qwebservice.h"
#include <QEventLoop>

NetDataListenerThread::NetDataListenerThread(QNetworkAccessManager *manager, QNetworkReply *reply, int timeoutms, QObject *parent)
    :QThread(parent),mManager(manager),m_TimeOutms(timeoutms),m_reply(reply)
{
    m_waitTimeOut = false;
    m_isWaitTimeOut = false;
}
NetDataListenerThread::~NetDataListenerThread()
{
}
void NetDataListenerThread::run()
{
    m_isWaitTimeOut = waitForConnect();
}
bool NetDataListenerThread::waitForConnect()
{
    QEventLoop eventLoop;
    QTimer * timer = NULL;
    m_waitTimeOut = false;
    bool bWaitTimeOut = false;
    if (m_TimeOutms > 0)
    {
        timer = new QTimer;
        connect(timer, SIGNAL(timeout()), this, SLOT(slot_waitTimeout()));
        timer->setSingleShot(true);
        timer->start(m_TimeOutms);
        connect(this, SIGNAL(sig_waitTimeout()), &eventLoop, SLOT(quit()));
    }
    connect(mManager, SIGNAL(finished(QNetworkReply *)), &eventLoop, SLOT(quit()));
    if (m_reply != NULL)
    {
        connect(m_reply, SIGNAL(readyRead()), &eventLoop, SLOT(quit()));
    }
    eventLoop.exec();
    if (timer != NULL)
    {
        timer->stop();
        delete timer;
        timer = NULL;
    }
    bWaitTimeOut = m_waitTimeOut;
    m_waitTimeOut = false;
    return !bWaitTimeOut;
}
void NetDataListenerThread::slot_waitTimeout()
{
    m_waitTimeOut = true;
    emit sig_waitTimeout();
}
bool NetDataListenerThread::getIsWaitTimeOut() const
{
    return m_isWaitTimeOut;
}
WebServiceHelp * WebServiceHelp::serverHelp = NULL;
WebServiceHelp::Dispose WebServiceHelp::disp;
WebServiceHelp::WebServiceHelp(QObject *parent):QObject(parent)
{
    manager = new QNetworkAccessManager();
    m_errCode= QNetworkReply::NoError;
}
WebServiceHelp::~WebServiceHelp()
{
    manager->deleteLater();
}
WebServiceHelp *WebServiceHelp::getInstance()
{
    if(serverHelp==NULL)
    {
        serverHelp = new WebServiceHelp();
    }
    return serverHelp;
}
QNetworkReply::NetworkError WebServiceHelp::sendGetRequest(QString urlStr, QByteArray & ba,int timeOutms)
{
    QNetworkReply::NetworkError retError = QNetworkReply::NoError;
    m_errCode= QNetworkReply::NoError;
    QNetworkRequest request;
    QUrl url(urlStr);
    request.setUrl(url);
    QNetworkReply *reply = manager->get(request);
    connect(reply,static_cast<void (QNetworkReply::*)(QNetworkReply::NetworkError)>(&QNetworkReply::error),this,&WebServiceHelp::slot_error);
    QEventLoop eventLoop;
    NetDataListenerThread * thread = new NetDataListenerThread(manager,reply,timeOutms);
    connect(thread, &NetDataListenerThread::finished,&eventLoop,&QEventLoop::quit);
    thread->start();
    eventLoop.exec();
    if(thread->getIsWaitTimeOut())
    {
        ba = reply->readAll();
    }
    else
    {
        m_errCode=QNetworkReply::TimeoutError;
    }
    thread->deleteLater();
    delete reply;
    delete thread;
    thread = NULL;
    retError = m_errCode;
    m_errCode= QNetworkReply::NoError;
    return retError;
}
QNetworkReply::NetworkError WebServiceHelp:: sendPostRequest(QString website, const QString argument, QByteArray &retBa, int timeOutms)
{
    QString urlStr =website;
    QByteArray postBa=postXml.replace("ARGUMENT",argument).toUtf8();
    qDebug()<<postBa;
    QNetworkReply::NetworkError retError = QNetworkReply::NoError;
    m_errCode= QNetworkReply::NoError;
    QNetworkRequest request;
    QSslConfiguration config;
    config.setPeerVerifyMode(QSslSocket::VerifyNone);
    config.setProtocol(QSsl::TlsV1SslV3);
    request.setSslConfiguration(config);
    QUrl url(urlStr);
    request.setUrl(url);
    request.setHeader(QNetworkRequest::ContentTypeHeader,"text/xml; charset=utf-8");
    request.setHeader(QNetworkRequest::ContentLengthHeader,postBa.length());
    QNetworkReply *reply = manager->post(request,postBa);
    connect(reply,static_cast<void (QNetworkReply::*)(QNetworkReply::NetworkError)>(&QNetworkReply::error),this,&WebServiceHelp::slot_error);
    QEventLoop eventLoop;
    NetDataListenerThread * thread = new NetDataListenerThread(manager,reply,timeOutms);
    connect(thread, &NetDataListenerThread::finished,&eventLoop,&QEventLoop::quit);
    thread->start();
    eventLoop.exec();
    if(thread->getIsWaitTimeOut())
    {
        retBa = reply->readAll();
    }
    else
    {
        m_errCode=QNetworkReply::TimeoutError;
    }
    thread->deleteLater();
    delete reply;
    delete thread;
    thread = NULL;
    retError = m_errCode;
    m_errCode= QNetworkReply::NoError;
    return retError;
}
void WebServiceHelp::slot_error(QNetworkReply::NetworkError code)
{
    m_errCode = code;
}
WebServiceHelp::Dispose::~Dispose()
{
    if(WebServiceHelp::serverHelp!=NULL)
    {
        delete WebServiceHelp::serverHelp;
        WebServiceHelp::serverHelp=NULL;
    }
}

void Xml2Esc(QString &xmlString)
{
    xmlString.replace("<","&lt;");
    xmlString.replace(">","&gt;");
    xmlString.replace("&","&amp;");
    xmlString.replace("'","&apos;");
    xmlString.replace("\"","&quot;");
}
void Esc2Xml(QString &escString)
{
    escString.replace("&lt;","<");
    escString.replace("&gt;",">");
    escString.replace("&amp;","&");
    escString.replace("&apos;","'");
    escString.replace("&quot;","\"");
}

这样我们只需在项目加入以上代码，直接调用函数发送请求就ok了

1	QNetworkReply::NetworkError ret=WebServiceHelp::getInstance()->sendPostRequest(url,argement,retba);

最终的选择 gsoap

虽然博主已经通过发送post请求实现了WebService的调用，但开会时平台方还是建议用gsoap实现WebService服务或调用WebService。最终博主还是默默的将gsoap下载下来。默默的查了查C++的调用方法。然后默默的将项目替换成使用gsoap调用WebService。
关于gsoap的C++使用方法博主会有单独的文章介绍。今天就先写到这里，出差在宾馆写这些已经很佩服我自己了。继续加油吧。。。