C++通过套接字发送文件和文本

Question

我试图使用套接字发送图像，但我也必须发送文件名。即时通讯使用我发送文件的代码，但是当我发送文件名时，我在客户端收到一些奇怪的字符。

客户：

#define PORT 20000 
#define LENGTH 512 

int main(int argc, char *argv[]){ 
int sockfd; 
int nsockfd; 
char revbuf[LENGTH]; 
struct sockaddr_in remote_addr; 

/* Get the Socket file descriptor */ 
if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) 
{ 
    fprintf(stderr, "ERROR: Failed to obtain Socket Descriptor! (errno = %d)\n",errno); 
    exit(1); 
} 

/* Fill the socket address struct */ 
remote_addr.sin_family = AF_INET; 
remote_addr.sin_port = htons(PORT); 
inet_pton(AF_INET, "127.0.0.1", &remote_addr.sin_addr); 
bzero(&(remote_addr.sin_zero), 8); 

/* Try to connect the remote */ 
if (connect(sockfd, (struct sockaddr *)&remote_addr, sizeof(struct sockaddr)) == -1) 
{ 
    fprintf(stderr, "ERROR: Failed to connect to the host! (errno = %d)\n",errno); 
    exit(1); 
} 
else 
    printf("[Client] Connected to server at port %d...ok!\n", PORT); 

/* Send File to Server */ 
//if(!fork()) 
//{ 
    char* fs_name = "house.jpg"; 
    char sdbuf[LENGTH]; 

      char buffer[256]; 
      int n; 
      fgets(buffer,255,stdin); 
      bzero(buffer,256); 
      n = write(sockfd,buffer, strlen(buffer)); 
      if(n<0) printf("Error: sending filename"); 

    printf("[Client] Sending %s to the Server... ", fs_name); 
    FILE *fs = fopen(fs_name, "r"); 
    if(fs == NULL) 
    { 
     printf("ERROR: File %s not found.\n", fs_name); 
     exit(1); 
    } 

    bzero(sdbuf, LENGTH); 
    int fs_block_sz; 
    while((fs_block_sz = fread(sdbuf, sizeof(char), LENGTH, fs)) > 0) 
    { 
     if(send(sockfd, sdbuf, fs_block_sz, 0) < 0) 
     { 
      fprintf(stderr, "ERROR: Failed to send file %s. (errno = %d)\n", fs_name, errno); 
      break; 
     } 
     bzero(sdbuf, LENGTH); 
    } 
    printf("Ok File %s from Client was Sent!\n", fs_name); 
//} 


close (sockfd); 
printf("[Client] Connection lost.\n"); 
return (0); 
} 

客户端的一部分发送文本：

char buffer[256]; 
int n; 
fgets(buffer,255,stdin); 
bzero(buffer,256); 
n = write(sockfd,buffer, strlen(buffer)); 
if(n<0) printf("Error: sending filename"); 

服务器：

#define PORT 20000 
#define BACKLOG 5 
#define LENGTH 512 

int main() 
{ 
int sockfd; 
int nsockfd; 
int num; 
int sin_size; 
struct sockaddr_in addr_local; /* client addr */ 
struct sockaddr_in addr_remote; /* server addr */ 
char revbuf[LENGTH]; 

/* Get the Socket file descriptor */ 
if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) 
{ 
    fprintf(stderr, "ERROR: Failed to obtain Socket Descriptor. (errno = %d)\n", errno); 
    exit(1); 
} 
else 
    printf("[Server] Obtaining socket descriptor successfully.\n"); 

/* Fill the client socket address struct */ 
addr_local.sin_family = AF_INET; // Protocol Family 
addr_local.sin_port = htons(PORT); // Port number 
addr_local.sin_addr.s_addr = INADDR_ANY; // AutoFill local address 
bzero(&(addr_local.sin_zero), 8); // Flush the rest of struct 

/* Bind a special Port */ 
if(bind(sockfd, (struct sockaddr*)&addr_local, sizeof(struct sockaddr)) == -1) 
{ 
    fprintf(stderr, "ERROR: Failed to bind Port. (errno = %d)\n", errno); 
    exit(1); 
} 
else 
    printf("[Server] Binded tcp port %d in addr 127.0.0.1 sucessfully.\n",PORT); 

/* Listen remote connect/calling */ 
if(listen(sockfd,BACKLOG) == -1) 
{ 
    fprintf(stderr, "ERROR: Failed to listen Port. (errno = %d)\n", errno); 
    exit(1); 
} 
else 
    printf ("[Server] Listening the port %d successfully.\n", PORT); 

int success = 0; 
while(success == 0) 
{ 
    sin_size = sizeof(struct sockaddr_in); 

    /* Wait a connection, and obtain a new socket file despriptor for single connection */ 
    if ((nsockfd = accept(sockfd, (struct sockaddr *)&addr_remote, &sin_size)) == -1) 
    { 
     fprintf(stderr, "ERROR: Obtaining new Socket Despcritor. (errno = %d)\n", errno); 
     exit(1); 
    } 
    else 
     printf("[Server] Server has got connected from %s.\n", inet_ntoa(addr_remote.sin_addr)); 


      char buffer[256]; 
      bzero(buffer,256); 
      int n = 0; 
      n = read(nsockfd, buffer, 255); 
      if (n < 0) error("ERROR reading from socket"); 
      printf("msg: %s\n",buffer); 

    /*Receive File from Client */ 
    char* fr_name = "/house.jpg"; 
    FILE *fr = fopen(fr_name, "a"); 
    if(fr == NULL) 
     printf("File %s Cannot be opened file on server.\n", fr_name); 
    else 
    { 
     bzero(revbuf, LENGTH); 
     int fr_block_sz = 0; 
     while((fr_block_sz = recv(nsockfd, revbuf, LENGTH, 0)) > 0) 
     { 
      int write_sz = fwrite(revbuf, sizeof(char), fr_block_sz, fr); 
      if(write_sz < fr_block_sz) 
      { 
       error("File write failed on server.\n"); 
      } 
      bzero(revbuf, LENGTH); 
      if (fr_block_sz == 0 || fr_block_sz != 512) 
      { 
       break; 
      } 
     } 
     if(fr_block_sz < 0) 
     { 
      if (errno == EAGAIN) 
      { 
       printf("recv() timed out.\n"); 
      } 
      else 
      { 
       fprintf(stderr, "recv() failed due to errno = %d\n", errno); 
       exit(1); 
      } 
     } 
     printf("Ok received from client!\n"); 
     fclose(fr); 
    } 
} 

}服务器的

部分接收的文字：

char buffer[256]; 
bzero(buffer,256); 
int n = 0; 
n = read(nsockfd, buffer, 255); 
if (n < 0) error("ERROR reading from socket"); 
printf("msg: %s\n",buffer); 

需要一些帮助。谢谢...

Answer 1

在这段代码在客户端：

 char buffer[256]; 
     int n; 
     fgets(buffer,255,stdin); 
     bzero(buffer,256); 
     n = write(sockfd,buffer, strlen(buffer)); 

它看起来像你正试图从stdin读取的文件名，并把它的sockfd。但。您在发送之前将缓冲区清零。