<八>–用户登录及API调用的实现
最后更新于：2022-04-01 07:11:25
# 【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](http://blog.csdn.net/tengweitw/article/details/45484803)》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/](http://www.shanbay.com/help/developer/api/)。
由[API文档](http://www.shanbay.com/help/developer/api/)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/](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](http://blog.csdn.net/tengweitw/article/details/45484803)》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();
}
~~~