Qt--Http请求封装(Get Post)

发布时间：2020-12-13 21:15:00 所属栏目：PHP教程来源：网络整理

导读：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1些网络操作的类，因此不需要第3方库的支持了。今天就跟大家分享1下qt中对http要求的封装。其中用到了： QNetworkRequest The QNetworkRequest class holds a request to be sent wit

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1些网络操作的类，因此不需要第3方库的支持了。今天就跟大家分享1下qt中对http要求的封装。

其中用到了：
QNetworkRequest
The QNetworkRequest class holds a request to be sent with QNetworkAccessManager.
http://doc.qt.io/qt⑷.8/qnetworkrequest.html#details

QNetworkAccessManager
The QNetworkAccessManager class allows the application to send network requests and receive replies.
http://doc.qt.io/qt⑸/qnetworkaccessmanager.html#details

QNetworkReply
The QNetworkReply class contains the data and headers for a request sent with QNetworkAccessManager.
http://doc.qt.io/qt⑸/qnetworkreply.html#details

这里不再过量的介绍上面3个类，由于qt的文档描写的非常非常的清楚。

开始写我们自己的http api：

写1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1个存储功能
The QSettings class provides persistent platform-independent application settings
http://doc.qt.io/qt⑷.8/qsettings.html

2 声明了1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1个利用，比如从服务器要求游戏列表：
写1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 int statusCode);

private:
    std::function<void(bool,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 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,QString>>)> callback)
{
    this->checkCallback = callback;
    get(GET_GAME);
}

使用接口：

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

（编辑：李大同）

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