【Qt编程】基于Qt的词典开发系列--用户登录及API调用的实现

在上一篇文章《调用网络API》中，我只讲述了如何直观的使用API接口以及调用API后返回的结果，本文则从程序实现的角度来实现API的调用，当然本程序的实现也是借助于扇贝网的API接口文档http://www.shanbay.com/help/developer/api/。

由API文档可知，要想调用其API，必须先注册。因此，我就注册了，账户名为nineheadedbird， 密码为123456。显然，我们要查词，首先必须得登录该账户。如果用浏览器，那就很简单，只需单纯的输入用户名和密码就可以了。可实际上，这一操作并不简单，只是浏览器为我们做了这一切。如果我们要通过程序来实现上述功能的话，就需要用到Qt中的get()函数了，而发送请求的内容格式就至关重要了。

查看请求格式

我们可以通过浏览器来查看请求格式：首先用谷歌浏览器(其他浏览器也可以，不过你要百度一下怎么来查看这些格式)打开扇贝网的登录界面http://www.shanbay.com/accounts/login/ ，在谷歌浏览器的设置中单击开发者选项，然后刷新一下页眉，就会出现如下的界面： 

然后点击右边的第一个文件login，就会出现下面的内容： 

从上图可以看出，内容分为三类：General、Response Headers、Request Headers 
在General中可以看到Request Method为GET(一般还有另一种方式POST，这在Qt中都有对应的函数),Status Code为200表示正常。在Response Headers 中我们关注的是Set-Cookie中的csrftoken的值，因为这在我们登录时需要这个值。我们最关心的是Request Headers的内容，这部分就是我们请求函数中内容格式！参考上述的具体内容如下： 

我们的程序可以写成如下的方式：

QNetworkRequest request;
        request.setUrl(QUrl("http://www.shanbay.com/accounts/login/"));
        request.setRawHeader("Accept","text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8");
        request.setRawHeader("Accept-Language","zh-CN,zh;q=0.8");
        request.setRawHeader("Cache-Control","max-age=0");
        request.setRawHeader("Connection","keep-alive");
        request.setRawHeader("Host","www.shanbay.com");
        request.setRawHeader("User-Agent","Mozilla/5.0 (Windows NT 6.1) AppleWebKit/535.7 (KHTML, like Gecko) Chrome/16.0.912.63 Safari/535.7");
        http->get(request);

当我们执行上述的请求之后，服务器就会作答，作答的内容就是上面的Response Headers，而我们需要的是Set-Cookie中的csrftoken的值。在Qt中，我们将程序中finished信号与我们定义的槽关联，即每当网络应答结束时，都会发射这个信号，从而触发该槽函数的执行，来处理服务器的应答内容。在程序中，getCookie函数就是来获取csrftoken的值。

用户登录

获得csrftoken的值后，我们就需要实现登录操作了。除了上述的请求格式之外，我们还需要加入csrftoken的值、用户名以及密码。具体格式可见下述代码：

QNetworkRequest request;  request.setUrl(QUrl("http://www.shanbay.com/accounts/login/"));
       request.setRawHeader("Accept","text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8");
       request.setRawHeader("Accept-Language","zh-CN,zh;q=0.8");
       request.setRawHeader("Cache-Control","max-age=0");
       request.setRawHeader("Connection","keep-alive");
       request.setRawHeader("Host","www.shanbay.com");
       request.setRawHeader("User-Agent","Mozilla/5.0 (Windows NT 6.1) AppleWebKit/535.7 (KHTML, like Gecko) Chrome/16.0.912.63 Safari/535.7");
       request.setRawHeader("Origin","http//www.shanbay.com");
       request.setRawHeader("Referer","http://www.shanbay.com/accounts/login/");
       request.setRawHeader("Host","www.shanbay.com");
       request.setRawHeader("Content-Type","application/x-www-form-urlencoded");
       QByteArray postData;
       postData.append(QString("csrfmiddlewaretoken=%1&").arg(sessionid));//csrftoken的值
       postData.append(QString("username=%1&password=%2&").arg(QUrl::toPercentEncoding(username).constData()).arg(password));//用户名及密码
       postData.append("login=登录&continue=home&u=1&next=");
       request.setHeader(QNetworkRequest::ContentLengthHeader,postData.size());
       httpAction=LoginAction;
       http->post(request,postData);

调用API

完成登录之后，就可以进行查词和添词操作了。除了上述提到的请求头格式之外，只需要遵守API规范（《调用网络API》中提到请求格式）即可。查词及添词的程序实现分别如下：

void netWork::queryWord(const QString &word)//查词操作
{
      QNetworkRequest request;
      request.setUrl(QUrl("http://www.shanbay.com/api/word/"+word));
      request.setRawHeader("Accept","text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8");
      request.setRawHeader("Accept-Charset","GBK,utf-8;q=0.7,*;q=0.3");
      request.setRawHeader("Accept-Language","zh-CN,zh;q=0.8");
      request.setRawHeader("Cache-Control","max-age=0");
      request.setRawHeader("Connection","keep-alive");
      request.setRawHeader("Host","www.shanbay.com");
      request.setRawHeader("User-Agent","Mozilla/5.0 (Windows NT 6.1) AppleWebKit/535.7 (KHTML, like Gecko) Chrome/16.0.912.63 Safari/535.7");
      httpAction=QueryWordAction;
      http->get(request);
}

void netWork::addWord(const QString &word)//添词操作
{
    if(word.isEmpty())
        qDebug()<<"你的输入有误";
    else
    {
        QNetworkRequest request;
        request.setUrl(QUrl("http://www.shanbay.com/api/learning/add/"+word));
        request.setRawHeader("Accept","text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8");
        request.setRawHeader("Accept-Charset","GBK,utf-8;q=0.7,*;q=0.3");
        request.setRawHeader("Accept-Language","zh-CN,zh;q=0.8");
        request.setRawHeader("Cache-Control","max-age=0");
        request.setRawHeader("Connection","keep-alive");
        request.setRawHeader("Host","www.shanbay.com");
        request.setRawHeader("User-Agent","Mozilla/5.0 (Windows NT 6.1) AppleWebKit/535.7 (KHTML, like Gecko) Chrome/16.0.912.63 Safari/535.7");
        httpAction=AddWordAction;
        http->get(request);
    }
}

完整流程

至此，API调用的各个功能已经实现，下面给出程序的整体思路：首先获取csrftoken的值（每次都不同）；然后利用用户名、密码及csrftoken的值来登录；接着就可以调用API了。在程序中，每当进行请求，都会在replyfinished函数中用case语句来分别处理这些请求对应的应答。注意，不要连续的进行请求，否则可能发生冲突。在程序中，为了防止冲突，我在connectNet请求后，在其应答处理函数中再进行loginShanbay的登录，然后在其应答函数中进行queryWord查词请求，然后在其对应的应答处理函数中进行addWord添词请求。其结果显示如下：

程序实现

下面我们给出具体的程序实现(qt 5版本，使用到网络类，需要加上QT += network)：首先建立一个空的qt子项目，然后添加一个名为netWork的类，继承自QObject，然后再添加一个名为main的源文件，这三个文件的内容分别如下： 
1、network.h文件

#ifndef NETWORK_H
#define NETWORK_H

#include <QObject>
#include <QtNetwork/QNetworkAccessManager>
#include<QtNetwork/QNetworkReply>
#include<QtNetwork/QNetworkRequest>
#include<QtNetwork/QNetworkCookie>
#include<QtNetwork/QNetworkCookieJar>
#include <QJsonDocument>
#include <QJsonObject>
#include <QJsonArray>
#include <QJsonValue>
#include<QString>
#include<QDebug>
#include<QList>
#include<QUrl>
#include<QByteArray>

class netWork : public QObject //由于程序文件直接摘自整个项目文件，所以程序中有关的定义或函数没有使用，但是这个程序可以单独运行
{
    Q_OBJECT
public:
    explicit netWork(QObject *parent = 0);
 //   ~netWork();

    enum HttpAction{NoAction,NetStudy,GetSessionidAction,LoginAction,QueryWordAction,AddWordAction,AddExampleAction,QueryWordExamplesAction};
    HttpAction httpAction;
    QNetworkAccessManager * http;
    QString sessionid;
    QString queryword;//要查询的单词
    QString nickname;
    QString username;
    QString password;
    bool isBusy;

    QString getCookie(const QString &name);

    void loginShanbay();
    void queryWord(const QString &word);
    void queryExamples(QString learningid);
    void connectNet(QString username="nineheadedbird", QString password="123456");
    void addWord(const QString &word);

signals://这里的信号都没有用到

    void connectSuccess(); 
    void connectFail();
    void verifySuccess();
    void verifyFail();
    void NetState(bool);
public slots:
    void replyfinished(QNetworkReply*);

};

#endif // NETWORK_H

2、network.cpp文件

#include "network.h"
#include<QList>
#include<QDesktopServices>
netWork::netWork(QObject *parent) :
    QObject(parent)
{
        http=new QNetworkAccessManager(this);
        http->setCookieJar(new QNetworkCookieJar(this));
        connect(http,SIGNAL(finished(QNetworkReply*)),this,SLOT(replyfinished(QNetworkReply*)));//将finished信号与我们定义的槽关联，每当网络应答结束时，都会发射这个信号
        isBusy=true;

}

QString netWork::getCookie(const QString &name)//用于获得SessionId
{
    foreach(QNetworkCookie cookie , http->cookieJar()->cookiesForUrl(QUrl("http://www.shanbay.com/")))
    {
            if(cookie.name()==name)
            {
                qDebug()<<"csrftoken:"<<cookie.value();
                return cookie.value();
            }
    }
        return "";
}
void netWork::connectNet(QString username, QString password)//连接网络,使用默认的用户名和密码
{
        this->username=username;
        this->password=password;
        QNetworkRequest request;
        request.setUrl(QUrl("http://www.shanbay.com/accounts/login/"));
        request.setRawHeader("Accept","text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8");
        request.setRawHeader("Accept-Language","zh-CN,zh;q=0.8");
        request.setRawHeader("Cache-Control","max-age=0");
        request.setRawHeader("Connection","keep-alive");
        request.setRawHeader("Host","www.shanbay.com");
        request.setRawHeader("User-Agent","Mozilla/5.0 (Windows NT 6.1) AppleWebKit/535.7 (KHTML, like Gecko) Chrome/16.0.912.63 Safari/535.7");
        httpAction=GetSessionidAction;
        http->get(request);
}

void netWork::replyfinished(QNetworkReply *reply)//每当执行网站应答结束后，就会执行该槽函数
{
    QVariant status_code=reply->attribute(QNetworkRequest::HttpStatusCodeAttribute);
    qDebug()<<"code_state="<<status_code;//网络状态,200代表正常，302代表重定向，404：not found等等
    if(status_code==QVariant::Invalid)//判断是否连接到网站,即当前设备能否上网
        emit NetState(false);
    else
        emit NetState(true);

    switch(httpAction)//根据我们都进行了什么网络请求
    {
    case NoAction:
        break;
    case GetSessionidAction://获取SessionId
        sessionid=getCookie("csrftoken");
        if(!sessionid.isEmpty())
        {
            emit connectSuccess();
            qDebug()<<("已经连接扇贝网，正在验证用户名密码...");
            loginShanbay();
        }else
        {
            emit connectFail();

             qDebug()<<("Cannot connect to the website!");
        }

        break;
    case LoginAction: //进行登录操作
        httpAction=NoAction;
        if(0==reply->readAll().size())
        {
            QString nickname=QUrl::fromPercentEncoding(getCookie("username").toLatin1());
            emit verifySuccess();

            qDebug()<<"Successfully Login"<<nickname;
            queryWord("hello");
        }else
        {
            emit verifyFail();
            qDebug()<<"Failed to login!";
        }
        break;

    case QueryWordAction://查词操作
        qDebug()<<"----query word----";
        qDebug()<<reply->readAll();//读取查词结果

        addWord("hello");//添加单词到单词本
        break;
    case AddWordAction://添词操作
        qDebug()<<"---add word----";
        qDebug()<<reply->readAll();//返回添加词语的learning_id
        break;
    default:break;
    }
}

void netWork::loginShanbay()//账户密码的登录操作
{
       QNetworkRequest request;
       request.setUrl(QUrl("http://www.shanbay.com/accounts/login/"));
       request.setRawHeader("Accept","text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8");
       request.setRawHeader("Accept-Language","zh-CN,zh;q=0.8");
       request.setRawHeader("Cache-Control","max-age=0");
       request.setRawHeader("Connection","keep-alive");
       request.setRawHeader("Host","www.shanbay.com");
       request.setRawHeader("User-Agent","Mozilla/5.0 (Windows NT 6.1) AppleWebKit/535.7 (KHTML, like Gecko) Chrome/16.0.912.63 Safari/535.7");
       request.setRawHeader("Origin","http//www.shanbay.com");
       request.setRawHeader("Referer","http://www.shanbay.com/accounts/login/");
       request.setRawHeader("Host","www.shanbay.com");
       request.setRawHeader("Content-Type","application/x-www-form-urlencoded");
       QByteArray postData;
       postData.append(QString("csrfmiddlewaretoken=%1&").arg(sessionid));
       postData.append(QString("username=%1&password=%2&").arg(QUrl::toPercentEncoding(username).constData()).arg(password));
       postData.append("login=登录&continue=home&u=1&next=");
       request.setHeader(QNetworkRequest::ContentLengthHeader,postData.size());
       httpAction=LoginAction;
       http->post(request,postData);

}

void netWork::queryWord(const QString &word)//查词操作
{
      QNetworkRequest request;
      request.setUrl(QUrl("http://www.shanbay.com/api/word/"+word));
      request.setRawHeader("Accept","text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8");
      request.setRawHeader("Accept-Charset","GBK,utf-8;q=0.7,*;q=0.3");
      request.setRawHeader("Accept-Language","zh-CN,zh;q=0.8");
      request.setRawHeader("Cache-Control","max-age=0");
      request.setRawHeader("Connection","keep-alive");
      request.setRawHeader("Host","www.shanbay.com");
      request.setRawHeader("User-Agent","Mozilla/5.0 (Windows NT 6.1) AppleWebKit/535.7 (KHTML, like Gecko) Chrome/16.0.912.63 Safari/535.7");
      httpAction=QueryWordAction;
      http->get(request);
}

void netWork::addWord(const QString &word)//添词操作
{
    if(word.isEmpty())
        qDebug()<<"你的输入有误";
    else
    {
        QNetworkRequest request;
        request.setUrl(QUrl("http://www.shanbay.com/api/learning/add/"+word));
        request.setRawHeader("Accept","text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8");
        request.setRawHeader("Accept-Charset","GBK,utf-8;q=0.7,*;q=0.3");
        request.setRawHeader("Accept-Language","zh-CN,zh;q=0.8");
        request.setRawHeader("Cache-Control","max-age=0");
        request.setRawHeader("Connection","keep-alive");
        request.setRawHeader("Host","www.shanbay.com");
        request.setRawHeader("User-Agent","Mozilla/5.0 (Windows NT 6.1) AppleWebKit/535.7 (KHTML, like Gecko) Chrome/16.0.912.63 Safari/535.7");
        httpAction=AddWordAction;
        http->get(request);
    }
}

3、main.cpp文件

#include <QApplication>
#include "network.h"

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    netWork *nW = new netWork();
   //
    nW->connectNet();
  //  nW->loginShanbay();
  //  nW->queryWord("hello");
    return a.exec();
}