QT----简单的htttp服务器与客户端

HTTP协议学习

协议的相关学习可以参考这篇 csdn学习连接

总体流程如下

HTTP服务器

监听ip和端口,有连接时接收请求,发送回复

server.h
#pragma once
#include <QtWidgets/QMainWindow>
#include "ui_httpServer.h"
#include <QTcpServer>
#include <QTcpSocket>
#include <QtNetwork>
#include <QNetworkAccessManager>
#include <QDebug>
#include <QJsonObject>
#include <QJsonDocument>
#include <QDateTime>

class httpServer : public QMainWindow
{
    Q_OBJECT

public:
    httpServer(QWidget *parent = nullptr);
    ~httpServer();
	// 启动 HTTP 服务器，默认监听 8080 端口
	void start(quint16 port = 8080);

public slots:
	// 当有新的 TCP 连接到来时，处理连接的槽函数
	void onNewConnection();

private:
    Ui::httpServerClass ui;
};

回应使用json构建,我这边是添加了url的判断,需要在url里有/getData我才会回复对应的数据

server.cpp
#include "httpServer.h"

httpServer::httpServer(QWidget *parent)
    : QMainWindow(parent)
{
    ui.setupUi(this);
	
}

httpServer::~httpServer()
{

}

void httpServer::start(quint16 port)
{
	//创建TCP服务器实例监听
	QTcpServer* server = new QTcpServer(this);

	//有新链接时
	connect(server, &QTcpServer::newConnection, this, &httpServer::onNewConnection);

	//启动监听
	if (!server->listen(QHostAddress::Any, port)) {
		qDebug() << "Server failed to start:" << server->errorString();
	}
	else {
		qDebug() << "Server started at port" << port;
	}
}

void httpServer::onNewConnection()
{
	//获取当前触发的server对象
	QTcpServer* server = qobject_cast<QTcpServer*>(sender());

	//获取客户端的socket连接
	QTcpSocket *clientSocket = server->nextPendingConnection();

	connect(clientSocket, &QTcpSocket::readyRead, [clientSocket]()
	{
		//读取客户端发来的请求(完整的http请求)
		QByteArray request = clientSocket->readAll();
		qDebug() << "Request received:\n" << request;
		
		//构建Json对象
		QJsonObject json;
		json["time"] = QDateTime::currentDateTime().toString("yyyy-MM-dd HH:mm:ss");
		json["ocrCode"] = "ABC123456";
		json["rollCode"] = "ROLL7890";

		QJsonDocument doc(json);
		QByteArray body = doc.toJson(QJsonDocument::Compact);//压缩格式(无缩进)

		//构建http响应头

		// 构造 HTTP 响应头
		QByteArray response;
		response.append("HTTP/1.1 200 OK\r\n");
		response.append("Content-Type: application/json; charset=utf-8\r\n");
		response.append("Content-Length: " + QByteArray::number(body.size()) + "\r\n");
		response.append("Connection: close\r\n");
		response.append("\r\n");
		response.append(body);  // 加上 JSON 内容

		//发送HTTP响应
		clientSocket->write(response);
		//断开连接
		clientSocket->disconnectFromHost();
	});
}

最后在main.cpp里调用m_pServer.start(8080);启动监听端口

在HTTP头上添加上
response.append("Access-Control-Allow-Origin: *\r\n"); // 如果前端跨域请求,添加上这个网页访问也能看到可以直接用浏览器去访问查看结果

客户端

发送http请求,对服务器的回应做出json解析

client.h

#pragma once

#include <QtWidgets/QMainWindow>
#include "ui_httpclient.h"
#include <QObject>
#include <QNetworkAccessManager>
#include <QNetworkReply>
#include <QTimer>
#include <QJsonObject>
#include <QJsonDocument>
#include <QJsonParseError>

class httpclient : public QMainWindow
{
    Q_OBJECT

public:
    httpclient(QWidget *parent = nullptr);
    ~httpclient();
	// 发起 GET 请求
	void get(const QUrl &url);

private slots:
	// 网络请求完成后的处理槽函数
	void onFinished(QNetworkReply *reply);

private:
    Ui::httpclientClass ui;

	// Qt 的网络访问管理器，支持异步 HTTP 请求
	QNetworkAccessManager m_manager;

	QTimer* m_pTimer;
};

客户端实例通过get()函数发起请求

client.cpp

#include "httpclient.h"

httpclient::httpclient(QWidget *parent)
    : QMainWindow(parent)
{
    ui.setupUi(this);
	// 请求完成后触发 onFinished()
	connect(&m_manager, &QNetworkAccessManager::finished, this, &httpclient::onFinished);
	m_pTimer = new QTimer(this);
	m_pTimer->setInterval(10000);
	m_pTimer->start();
	connect(m_pTimer, &QTimer::timeout, [=]() {this->get(QUrl("http://192.168.1.168:8080/getData")); });
}

httpclient::~httpclient()
{}

//发起get请求
void httpclient::get(const QUrl & url)
{
	QNetworkRequest request(url);	//构造请求
	m_manager.get(request);			//异步发送get请求
}

//收到服务器响应后调用
void httpclient::onFinished(QNetworkReply *reply)
{
	if (reply->error() == QNetworkReply::NoError)
	{
		//读取服务器返回的内容
		QByteArray data = reply->readAll();
		qDebug() << "Response:" << data; 

		QJsonParseError err;
		QJsonDocument doc = QJsonDocument::fromJson(data, &err);
		if (err.error == QJsonParseError::NoError && doc.isObject())
		{
			QJsonObject obj = doc.object();
			QString time = obj["time"].toString();
			QString ocrCode = obj["ocrCode"].toString();
			QString rollCode = obj["rollCode"].toString();

			qDebug() << "Parsed JSON:";
			qDebug() << "  Time:" << time;
			qDebug() << "  OCR Code:" << ocrCode;
			qDebug() << "  Roll Code:" << rollCode;
			ui.textEdit->append(time);
			ui.textEdit->append(ocrCode);
			ui.textEdit->append(rollCode);
		}
		else 
		{
			qDebug() << "Invalid JSON:" << err.errorString();
			ui.textEdit->append("Invalid JSON:");
		}
	}
	else {
		qDebug() << "Error:" << reply->errorString(); // 网络错误
		ui.textEdit->append("Error:"+reply->errorString());
	}
	reply->deleteLater();	//释放资源
}