Qt中简单使用Firebase

小灰灰 2022-09-26 02:18 196阅读 0赞

上一篇对Firebase进行了简要的介绍。

今天对Firebase进行简单的应用。在qt中，因为我不会Android和ios开发。

代码出自github:  
[https://github.com/clkasd/qt-firebaseapi][https_github.com_clkasd_qt-firebaseapi]

最主要的就是写一个类，Firebase.

直接代码：  
firebase.h

#ifndef FIREBASE_H
    #define FIREBASE_H
    
    #include <QObject>
    #include <QtNetwork/QNetworkAccessManager>
    #include <QtNetwork/QNetworkReply>
    #include <QtNetwork/QNetworkRequest>
    #include <QUrl>
    #include <QUrlQuery>
    #include <QDebug>
    #include <QtGlobal>
    #include <datasnapshot.h>
    class Firebase : public QObject { 
        Q_OBJECT
    public:
        explicit Firebase(QObject *parent = 0);
        Firebase(QString hostName,QString child);
        Firebase(QString hostName);
        void init();
        void setValue(QString str);
        void getValue();
        void deleteValue();
        void setToken(QString);
        void listenEvents();
        Firebase* child(QString childName);
    
    signals:
        void eventResponseReady(QString);
        void eventDataChanged(DataSnapshot*);
    public slots:
        void replyFinished(QNetworkReply*);
        void onReadyRead(QNetworkReply*);
        void eventFinished();
        void eventReadyRead();
    private:
        QString host;
        QString firebaseToken="";
        QNetworkAccessManager *manager;
        QString currentNode;
        QString latestNode;
        QString buildPath(int);
        QString createJson(QString);
        void open(const QUrl &url);
        QByteArray trimValue(const QByteArray &line) const;
    };
    
    #endif // FIREBASE_H

firebase.cc

#include "firebase.h"
    #include <string.h>
    #include <QIODevice>
    #include <QBuffer>
    #include <QJsonDocument>
    #include <datasnapshot.h>
    Firebase::Firebase(QObject *parent) :
        QObject(parent)
    {
    
    }
    void Firebase::init()
    {
        manager=new QNetworkAccessManager(this);
        connect(manager,SIGNAL(finished(QNetworkReply*)),this,SLOT(replyFinished(QNetworkReply*)));
    }
    Firebase::Firebase(QString hostName)
    {
        host=hostName;
        currentNode="";
        init();
    }
    void Firebase::setToken(QString token)
    {
        firebaseToken=token;
    }
    Firebase::Firebase(QString hostName,QString child)
    {
        host=hostName
                .append(child).append("/");
        latestNode=child;
        init();
    }
    Firebase* Firebase::child(QString childName)
    {
        Firebase *childNode=new Firebase(host,childName);
        childNode->setToken(firebaseToken);
        return childNode;
    }
    void Firebase::open(const QUrl &url)
    {
        QNetworkRequest request(url);
        request.setRawHeader("Accept",
                             "text/event-stream");
        QNetworkReply *_reply = manager->get(request);
        connect(_reply, &QNetworkReply::readyRead, this, &Firebase::eventReadyRead);
        connect(_reply, &QNetworkReply::finished, this, &Firebase::eventFinished);
    }
    void Firebase::eventFinished()
    {
        QNetworkReply *reply = qobject_cast<QNetworkReply*>(sender());
        if (reply)
        {
            QUrl redirectUrl = reply->attribute(QNetworkRequest::RedirectionTargetAttribute).toUrl();
            if (!redirectUrl.isEmpty())
            {
                reply->deleteLater();
                open(redirectUrl);
                return;
            }
            reply->deleteLater();
        }
    }
    void Firebase::eventReadyRead()
    {
        QNetworkReply *reply = qobject_cast<QNetworkReply*>(sender());
        if(reply)
        {
            QByteArray line=reply->readLine();
            if(!line.isEmpty())
            {
                QByteArray eventName=trimValue(line);
                line=reply->readAll();
                if(eventName=="put")
                {
                    DataSnapshot *dataSnapshot=new DataSnapshot(line);
                    emit eventDataChanged(dataSnapshot);
                }
            }
        }
        reply->readAll();
    }
    void Firebase::onReadyRead(QNetworkReply *reply)
    {
        /*qDebug()<<"incoming data"; qDebug()<<reply->readAll();*/
    }
    void Firebase::replyFinished(QNetworkReply *reply)
    {
        //qDebug()<<reply->readAll();
        QString data=QString(reply->readAll());
        emit eventResponseReady(data);
    }
    void Firebase::setValue(QString strVal)
    {
        //Json data creation
        QNetworkRequest request(buildPath(1));
        request.setHeader(QNetworkRequest::ContentTypeHeader,
                          "application/x-www-form-urlencoded");
        QBuffer *buffer=new QBuffer();
        buffer->open((QBuffer::ReadWrite));
        buffer->write(createJson(strVal).toUtf8());
        buffer->seek(0);
        /* * To be able to send "PATCH" request sendCustomRequest method is used. * sendCustomRequest requires a QIOdevice so QBuffer is used. * I had to seek 0 because it starts reading where it paused. */
        manager->sendCustomRequest(request,"PATCH",buffer);
        buffer->close();
    }
    void Firebase::getValue()
    {
        QNetworkRequest request(buildPath(0));
        manager->get(request);
    }
    void Firebase::listenEvents()
    {
        open(buildPath(0));
    }
    void Firebase::deleteValue()
    {
        QNetworkRequest request(buildPath(0));
        manager->deleteResource(request);
    }
    QString Firebase::createJson(QString str)
    {
        QString data=QString(QString("{").append("\"").append(latestNode).append("\"").append(":").append("\"").append(str).append("\"").append(QString("}")));
        return data;
    }
    QString Firebase::buildPath(int mode)
    {
        QString destination="";
        if(mode)
        {
            host.replace(QString("/").append(latestNode).append("/"),"");
            destination
                    .append(host)
                    .append("/.json");
        }
        else
        {
            destination
                    .append(host)
                    .append(currentNode)
                    .append(".json");
    
        }
        if(!firebaseToken.isEmpty())
            destination.append("?auth=").append(firebaseToken);
    
        //根据你的实际情况，写destination
        return destination;
    
    }
    QByteArray Firebase::trimValue(const QByteArray &line) const
    {
        QByteArray value;
        int index = line.indexOf(':');
        if (index > 0)
            value = line.right(line.size() - index  - 1);
        return value.trimmed();
    }

[https_github.com_clkasd_qt-firebaseapi]: https://github.com/clkasd/qt-firebaseapi