Qt--Http请求封装(Get Post)

川长思鸟来 2022-09-26 03:15 578阅读 0赞

之前使用c++开发的程序都是使用curl库进行各种http操作。

qt为我们继承了一些网络操作的类，因此不需要第三方库的支持了。今天就跟大家分享一下qt中对http请求的封装。

其中用到了：  
**QNetworkRequest**  
The QNetworkRequest class holds a request to be sent with QNetworkAccessManager.  
[http://doc.qt.io/qt-4.8/qnetworkrequest.html\#details][http_doc.qt.io_qt-4.8_qnetworkrequest.html_details]

**QNetworkAccessManager**  
The QNetworkAccessManager class allows the application to send network requests and receive replies.  
[http://doc.qt.io/qt-5/qnetworkaccessmanager.html\#details][http_doc.qt.io_qt-5_qnetworkaccessmanager.html_details]

**QNetworkReply**  
The QNetworkReply class contains the data and headers for a request sent with QNetworkAccessManager.  
[http://doc.qt.io/qt-5/qnetworkreply.html\#details][http_doc.qt.io_qt-5_qnetworkreply.html_details]

这里不再过多的介绍上面三个类，因为qt的文档描述的非常非常的清楚。

开始写我们自己的http api：

写一个基类，命名为**BaseAPI**:  
baseapi.h

#ifndef BASEAPI_H
    #define BASEAPI_H
    
    #include <QSettings>
    #include <QNetworkRequest>
    #include <QNetworkReply>
    #include <QNetworkAccessManager>
    
    #include "base/constants.h"
    
    class BaseAPI : public QObject
    {
        Q_OBJECT
    
    public:
        BaseAPI();
        ~BaseAPI();
        void get(const QString url);
        void post(const QString url, const QByteArray &data);
    
    protected:
        virtual void requestFinished(QNetworkReply *reply, const QByteArray data, const int statusCode) = 0;
    
    public slots:
        void serviceRequestFinished(QNetworkReply *reply);
    
    private:
        QNetworkRequest httpRequest;
        QNetworkAccessManager networkAccessManager;
        QSettings *settings;
    };
    
    #endif // BASEAPI_H

baseapi.cc

#include "baseapi.h"
    
    BaseAPI::BaseAPI()
    {
        httpRequest.setRawHeader("Accept", API_ACCEPT);
        httpRequest.setRawHeader("User-Agent", API_USER_AGENT);
        httpRequest.setRawHeader("X-XXX-API-Key", API_KEY);
        httpRequest.setRawHeader("X-XXX-API-Secret", API_SECRET);
        httpRequest.setRawHeader("Accept-Encoding", "gzip, deflate");
        httpRequest.setRawHeader("Content-Type", "application/json");
    
        settings = new QSettings("XXX");
        QString id = settings->value(SETTING_ACCOUNT_ID, "").toString();
        QString token = settings->value(SETTING_ACCOUNT_TOKEN, "").toString();
    
        if(!id.isEmpty()) {
            httpRequest.setRawHeader("X-XXX-User-ID", id.toStdString().c_str());
        }
    
        if (!token.isEmpty()) {
            httpRequest.setRawHeader("X-XXX-User-Token", token.toStdString().c_str());
        }
    
        qDebug() << "BaseAPI...id:" << id << " token:" + token;
    
        QObject::connect(&networkAccessManager, SIGNAL(finished(QNetworkReply*)), this, SLOT(serviceRequestFinished(QNetworkReply*)));
    }
    
    BaseAPI::~BaseAPI()
    {
        networkAccessManager.disconnect();
        if (settings){
            delete settings;
            settings = nullptr;
        }
    }
    
    void BaseAPI::get(const QString url)
    {
        httpRequest.setUrl(QUrl(url));
        networkAccessManager.get(httpRequest);
    }
    
    void BaseAPI::post(const QString url, const QByteArray &data)
    {
        httpRequest.setUrl(QUrl(url));
        networkAccessManager.post(httpRequest, data);
    }
    
    void BaseAPI::serviceRequestFinished(QNetworkReply *reply)
    {
        int statusCode = reply->attribute(QNetworkRequest::HttpStatusCodeAttribute).toInt();
    
        qDebug() << "BaseAPI...serviceRequestFinished...statusCode:" << statusCode;
    
        if(reply->error() == QNetworkReply::NoError) {
            requestFinished(reply, reply->readAll(), statusCode);
        } else {
            requestFinished(reply, "", statusCode);
        }
    
        // At the end of that slot, we won't need it anymore
        reply->deleteLater();
    }

解释：  
1 使用了qt中的QSettings，就是一个存储功能  
The QSettings class provides persistent platform-independent application settings  
[http://doc.qt.io/qt-4.8/qsettings.html][http_doc.qt.io_qt-4.8_qsettings.html]

2 声明了一个纯虚函数，使得子类根据自己的情况进行重写

基类就这样写完了，下面写一个应用，比如从服务器请求游戏列表：  
写一个子类**GameAPI**继承自BaseAPI：  
gameapi.h

#ifndef GAMEAPI
    #define GAMEAPI
    
    #include <functional>
    #include <QList>
    #include <QPair>
    #include "baseapi.h"
    
    class GameAPI: public BaseAPI
    {
    public:
        GameAPI();
        ~GameAPI();
        void getGameList(std::function<void(bool, QList<QPair<QString,QString>>)> callback);
    
    protected:
        void requestFinished(QNetworkReply* reply, const QByteArray data, const int statusCode);
    
    private:
        std::function<void(bool, QList<QPair<QString,QString>>)> checkCallback;
    };
    
    #endif // GAMEAPI

gameapi.cc

#include "gameapi.h"
    
    #include "qdebug.h"
    
    #include <QJsonArray>
    #include <QJsonObject>
    #include <QJsonDocument>
    
    const QString GET_GAME = QString("https://www.xxx.com").append("/apps");
    
    GameAPI::GameAPI()
    {
    
    }
    
    GameAPI::~GameAPI()
    {
    
    }
    
    void GameAPI::requestFinished(QNetworkReply* reply, const QByteArray data, const int statusCode)
    {
        if (statusCode == 200) {
            QJsonParseError jsonError;
            QJsonArray json_array = QJsonDocument::fromJson(data, &jsonError).array();
            if(jsonError.error == QJsonParseError::NoError) {
                QList<QPair<QString,QString>> games;
                for(int i = 0; i < json_array.size(); ++i) {
                       QJsonObject json = json_array.at(i).toObject();
                       games.append(qMakePair(json.value("key1").toString(), json.value("key2").toString()));
                }
                this->checkCallback(true, games);
                return;
            }
        }
        QList<QPair<QString,QString>> games;
        this->checkCallback(false, games);
    }
    
    void GameAPI::getGameList(std::function<void(bool, QList<QPair<QString,QString>>)> callback)
    {
        this->checkCallback = callback;
        get(GET_GAME);
    }

使用接口：

GameAPI game_api = new GameAPI();
        game_api->getGameList([&](bool success, QList<QPair<QString,QString>> games){
            if (success)
            {
               //do something
            }
        });

[http_doc.qt.io_qt-4.8_qnetworkrequest.html_details]: http://doc.qt.io/qt-4.8/qnetworkrequest.html#details
[http_doc.qt.io_qt-5_qnetworkaccessmanager.html_details]: http://doc.qt.io/qt-5/qnetworkaccessmanager.html#details
[http_doc.qt.io_qt-5_qnetworkreply.html_details]: http://doc.qt.io/qt-5/qnetworkreply.html#details
[http_doc.qt.io_qt-4.8_qsettings.html]: http://doc.qt.io/qt-4.8/qsettings.html