c++ - 如何使用套接字 c/C++ 以 block 的形式发送文件？

Question

我一直在尝试寻找如何在 C 或 C++ 中以 block 的形式发送文件我在这里查看了一些示例，但没有找到很好的示例。我对 C/C++ 中的 sockect 编程很陌生

http://beej.us/guide/bgnet/html/single/bgnet.html

我需要如何在客户端和服务器之间以 block 的形式发送文件？客户端请求文件，服务器发回。

我发现这个要发送，但不确定是否收到。

#include <sys/types.h>
#include <sys/socket.h>

int sendall(int s, char *buf, int *len)
{
    int total = 0;        // how many bytes we've sent
    int bytesleft = *len; // how many we have left to send
    int n;

    while(total < *len) {
        n = send(s, buf+total, bytesleft, 0);
        if (n == -1) { break; }
        total += n;
        bytesleft -= n;
    }

    *len = total; // return number actually sent here

    return n==-1?-1:0; // return -1 on failure, 0 on success
}

Answer 1

我刚刚编写了这段代码，用于在 Client using linux sockets in C 中接收文件。

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <fcntl.h>


#define PORT 4118

#define MaxBufferLength 1024 // set the size of data you want to recieve from Server


int main()
{
    int sockFd, bytesRead= 1, bytesSent;

    char buffer[MaxBufferLength];

    struct sockaddr_in server, client;


    server.sin_port= htons(PORT);
    server.sin_family = AF_INET;
    server.sin_addr.s_addr = inet_addr("127.0.0.1");

    sockFd = socket(AF_INET, SOCK_STREAM, 0);


    if(sockFd < 0)
        printf("Unable to open socket\n");

    int connectionSocket = connect(sockFd, (struct sockaddr *) &server, sizeof(struct sockaddr) );

    if(connectionSocket < 0)
        perror("connection not established\n");


    int fd = open("helloworlds.txt",O_CREAT | O_WRONLY,S_IRUSR | S_IWUSR);  

    if(fd == -1)
        perror("couldn't openf iel");

    while(bytesRead > 0)
    {           

        bytesRead = recv(sockFd, buffer, MaxBufferLength, 0);

        if(bytesRead == 0)
        {

            break;
        }

        printf("bytes read %d\n", bytesRead);

        printf("receivnig data\n");

        bytesSent = write(fd, buffer, bytesRead);


        printf("bytes written %d\n", bytesSent);

        if(bytesSent < 0)
            perror("Failed to send a message");

    }


    close(fd);

    close(sockFd);

    return 0;

}

希望对你有帮助