Question

我已经创建了一个Socket服务器和客户端。客户端选择pdf文件并将其发送到服务器。此代码在本地计算机上运行完美，即服务器和客户端在同一主机上运行，文件在服务器端传输，打开内容，但当我在不同的主机上运行服务器和客户端时，我遇到以下问题，服务器无法退出，文件传输被覆盖在服务器端，因此无法显示文件内容，如果我发送一个来自客户端的240 kb文件在服务器上接收的文件是2 GB。我在qt creator中编程，客户端是一个Gui应用程序，它也运行Socket客户端代码，而服务器是一个控制台项目。

This is server.cpp
#include <QtCore/QCoreApplication>
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#define Size 2048

    int main(int argc, char *argv[])
    {
        QCoreApplication a(argc, argv);
        int s, fd, len;
        struct sockaddr_in my_addr;
        struct sockaddr_in remote_addr;
        socklen_t sin_size;
        char buf[BUFSIZ];
        FILE *fp = fopen("/home/D.A.D19/Desktop/Filecopy/Q7Basic_essentials.pdf","a+");
        memset(&my_addr, 0, sizeof(my_addr));
        my_addr.sin_family = AF_INET;
        my_addr.sin_addr.s_addr = inet_addr("192.168.103.128");
        my_addr.sin_port = htons(8000);
        if ((s = socket(AF_INET, SOCK_STREAM, 0)) < 0)
        {
        qWarning("socket");

        return 1;
        }
        if (bind(s,(struct sockaddr *)&my_addr,sizeof(struct sockaddr))<0)
        {
        qWarning("bind");
        return 1;
        }
        listen(s, 5);
        sin_size = sizeof(struct sockaddr_in);
        if ((fd =accept(s,(struct sockaddr *)&remote_addr,&sin_size)) < 0)
        {
        qWarning("accepted client %s\n", inet_ntoa(remote_addr.sin_addr));
        return 1;
        }

        len = send(fd, "Welcome to my server\n", 21, 0);

            while(1)
            {
                len = recv(fd,buf,Size,0);

问题出在这里

                 if (strcmp(buf,"quit") == 0){
                    qWarning("Connection terminated");
                    break;

                }

                fwrite(buf,Size,1, fp);
                memset(buf,0,Size);
            }


        fclose(fp);
        close(fd);
        close(s);

        return a.exec();
    }

    This is Client.cpp

    #include "mainwindow.h"
    #include "ui_mainwindow.h"
    #include <QLabel>
    #include <QPushButton>
    #include <QFileDialog>
    #include <QLineEdit>
    #include <QString>
    #include <QtCore/QCoreApplication>
    #include <stdio.h>
    #include <sys/types.h>
    #include <sys/socket.h>
    #include <netinet/in.h>
    #include <arpa/inet.h>
    #define SIZE 2048

    QString Path;
    MainWindow::MainWindow(QWidget *parent) :
        QMainWindow(parent),
        ui(new Ui::MainWindow)
    {
        ui->setupUi(this);

        QLabel *label1 = new QLabel(this);
        label1->setText("FileName");
        label1->setGeometry(15,25,70,30);
        label1->show();


        QPushButton *pushbutton = new QPushButton(this);
        pushbutton->setText("Browse");
        pushbutton->setGeometry(180,28,90,25);
        pushbutton->show();

        QObject::connect(pushbutton,SIGNAL(clicked()),this, SLOT(browse()));

    }

    MainWindow::~MainWindow()
    {
        delete ui;
    }

    void MainWindow::browse()
    {
        int s, len;
            struct sockaddr_in remote_addr;
            char buf[BUFSIZ];
            memset(&remote_addr, 0, sizeof(remote_addr));

            remote_addr.sin_family = AF_INET;
            remote_addr.sin_addr.s_addr = inet_addr("192.168.103.128");
            remote_addr.sin_port = htons(8000);

        QLineEdit *line = new  QLineEdit(this);
        line->setGeometry(82,28,90,25);
        QString  filename = QFileDialog::getOpenFileName(this,tr("Find files"),
                                                         "/home/D.A.D19/Desktop");
        line->setText(filename);
        line->show();



        if ((s = socket(AF_INET, SOCK_STREAM, 0)) < 0)
        {
            qWarning("socket");
            //return 1;
        }


        if (::connect(s, (struct sockaddr *)&remote_addr, sizeof(struct sockaddr)) < 0)
        {
            qWarning("connect");
            //return 1;
        }



       qWarning("connected to server \n");
       len = recv(s, buf, BUFSIZ, 0);
       qWarning("%s \n",buf);
       buf[len] = '\0';

        sprintf(buf, "%s", qPrintable(filename));

        FILE *fp = fopen(buf,"r");

            while(1)
            {
                if(feof(fp))
                {
                    strcpy(buf,"quit");
                    send(s,buf,SIZE,0);
                    break;
                }
                if(!feof(fp))
                {
                int count = fread(buf,SIZE,1,fp);
                len = send(s, buf,SIZE, 0);
                memset(buf,0,SIZE);
                }




            }

            fclose(fp);
            ::close(s);
            return;


    }

Answer 1

当您输入字符串退出时，它也会有\n。

因此，当您比较字符串时，请按照以下方式进行比较：

     if (strcmp(buf,"quit\n") == 0)

然后执行代码。现在字符串将被匹配，连接将被终止。

C套接字服务器无法终止连接？

1 个答案: