c++ - TCP/IP 文件传输 C++

Question

我是 C++ 编程的初学者，有一点 Java 经验。 我的目标是在服务器和客户端(在两个不同的文件夹中)之间传输文件(在本地主机中)。

我在网上找到这段代码对我来说效果很好，它打开套接字并在服务器和客户端之间建立连接，您可以发送在终端中键入的消息。

我在 INTERNET 上尝试了很多不同的代码，但要么无法编译，要么不是我需要的。

这是我发现的用于传输消息的代码。

服务器.cpp文件

enter code here
/* A simple server in the internet domain using TCP
The port number is passed as an argument */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h> 
#include <sys/socket.h>
#include <netinet/in.h>

void error(const char *msg)
{
perror(msg);
exit(1);
}

int main(int argc, char *argv[])
{
 int sockfd, newsockfd, portno;
 socklen_t clilen;
 char buffer[256];
 struct sockaddr_in serv_addr, cli_addr;
 int n;
 if (argc < 2) {
     fprintf(stderr,"ERROR, no port provided\n");
     exit(1);
 }
 sockfd = socket(AF_INET, SOCK_STREAM, 0);
 if (sockfd < 0) {
    error("ERROR opening socket");
exit(1);
    }
 bzero((char *) &serv_addr, sizeof(serv_addr));
 portno = atoi(argv[1]);
 serv_addr.sin_family = AF_INET;
 serv_addr.sin_addr.s_addr = INADDR_ANY;
 serv_addr.sin_port = htons(portno);
 if (bind(sockfd, (struct sockaddr *) &serv_addr,sizeof(serv_addr)) < 0)             { 
error("ERROR on binding");
}
 listen(sockfd,1);
 clilen = sizeof(cli_addr);
 newsockfd = accept(sockfd, 
             (struct sockaddr *) &cli_addr, 
             &clilen);
 if (newsockfd < 0) 
      error("ERROR on accept");
 bzero(buffer,256);
 n = read(newsockfd,buffer,255);
 if (n < 0) error("ERROR reading from socket");
 printf("Here is the message: %s\n",buffer);
 n = write(newsockfd,"I got your message",18);
 if (n < 0) error("ERROR writing to socket");
 close(newsockfd);
 close(sockfd);
 return 0; 
 }

客户端.cpp文件

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h> 

void error(const char *msg)
{
perror(msg);
exit(0);
}

int main(int argc, char *argv[])
{
int sockfd, portno, n;
struct sockaddr_in serv_addr;
struct hostent *server;

char buffer[256];
if (argc < 3) {
   fprintf(stderr,"usage %s hostname port\n", argv[0]);
   exit(0);
}
portno = atoi(argv[2]);
sockfd = socket(AF_INET, SOCK_STREAM, 0);
if (sockfd < 0) 
    error("ERROR opening socket");
server = gethostbyname(argv[1]);
if (server == NULL) {
    fprintf(stderr,"ERROR, no such host\n");
    exit(0);
}
bzero((char *) &serv_addr, sizeof(serv_addr));
serv_addr.sin_family = AF_INET;
bcopy((char *)server->h_addr, 
     (char *)&serv_addr.sin_addr.s_addr,
     server->h_length);
serv_addr.sin_port = htons(portno);
if (connect(sockfd,(struct sockaddr *) &serv_addr,sizeof(serv_addr)) < 0) 
    error("ERROR connecting");
printf("Please enter the message: ");
bzero(buffer,256);
fgets(buffer,255,stdin);
n = write(sockfd,buffer,strlen(buffer));
if (n < 0) 
     error("ERROR writing to socket");
bzero(buffer,256);
n = read(sockfd,buffer,255);
if (n < 0) 
     error("ERROR reading from socket");
printf("%s\n",buffer);
close(sockfd);
return 0;
}

我在 ubuntu 中使用 g++ 进行编译。

如果你能帮助我至少能够从客户端发送一个 txt 文件或从服务器下载一个文件，我会很高兴，一旦我尝试在此代码中添加功能就不再起作用了，也许我'从一个坏例子开始？

Answer 1

你应该试试这个例子，它对我很有用

接收:

size_t datasize;
FILE* fd = fopen(filename, "wb");
while (!received)
{
    datasize = recv(connection, text, sizeof(text), 0);
    fwrite(&text, 1, datasize, fd);
}
fclose(fd);

发送:

FILE *fd = fopen(filename, "rb");
size_t rret, wret;
int bytes_read;
while (!feof(fd)) {
    if ((bytes_read = fread(&buffer, 1, BUFFER_SIZE, fd)) > 0)
        send(sock, buffer, bytes_read, 0);
    else
        break;
}
    fclose(fd);

祝你好运:)