Windows network programming winsock file transfer example

This paper illustrates the method of file transfer in winsock in Windows network programming, which is useful for winsock network programming under Windows.

The program code is mainly based on the winsock network file transfer example of TCP stream protocol, using the C language under Windows. Can achieve the file transfer function of passing any format file.

The specific implementation code is as follows:

The Server code is as follows:

 
 
#include <stdio.h> 
#include <stdlib.h> 
#include <string.h> 
#include <WinSock2.h> 
 
#define PORT 8087 
#define SERVER_IP "127.0.0.1" 
#define BUFFER_SIZE 1024 
#define FILE_NAME_MAX_SIZE 512 
#pragma comment(lib, "WS2_32") 
 
int main() 
{ 
  //Declare and initialize a server-side (local) address structure
  sockaddr_in server_addr; 
  server_addr.sin_family = AF_INET; 
  server_addr.sin_addr.S_un.S_addr = INADDR_ANY; 
  server_addr.sin_port = htons(PORT); 
 
  //Initializes the socket DLL
  WSADATA wsaData; 
  WORD socketVersion = MAKEWORD(2, 0); 
  if(WSAStartup(socketVersion, &wsaData) != 0) 
  { 
    printf("Init socket dll error!"); 
    exit(1); 
  } 
 
  //Create a socket
  SOCKET m_Socket = socket(AF_INET, SOCK_STREAM, 0); 
    if (SOCKET_ERROR == m_Socket) 
    { 
      printf("Create Socket Error!"); 
    exit(1); 
    } 
 
  //Bind socket and server (local) addresses
  if (SOCKET_ERROR == bind(m_Socket, (LPSOCKADDR)&server_addr, sizeof(server_addr))) 
  { 
    printf("Server Bind Failed: %d", WSAGetLastError()); 
    exit(1); 
  } 
 
  //Listening to the
  if (SOCKET_ERROR == listen(m_Socket, 10)) 
  { 
    printf("Server Listen Failed: %d", WSAGetLastError()); 
    exit(1); 
  } 
 
 
  while(1) 
  { 
    printf("Listening To Client...n"); 
 
    sockaddr_in client_addr; 
    int client_addr_len = sizeof(client_addr); 
 
    SOCKET m_New_Socket = accept(m_Socket, (sockaddr *)&client_addr, &client_addr_len); 
    if (SOCKET_ERROR == m_New_Socket) 
    { 
      printf("Server Accept Failed: %d", WSAGetLastError()); 
      break; 
    } 
 
 char buffer[BUFFER_SIZE]; 
 memset(buffer, 0, BUFFER_SIZE); 
    if (recv(m_New_Socket, buffer, BUFFER_SIZE, 0) < 0) 
    { 
      printf("Server Receive Data Failed!"); 
      break; 
    } 
 
    char file_name[FILE_NAME_MAX_SIZE+1]; 
    memset(file_name, 0, FILE_NAME_MAX_SIZE+1); 
    strncpy(file_name, buffer, strlen(buffer)>FILE_NAME_MAX_SIZE ? FILE_NAME_MAX_SIZE:strlen(buffer)); 
    printf("%sn", file_name); 
 
    FILE * fp = fopen(file_name, "rb"); //Under Windows is "rb", which means to open a read-only binary
    if (NULL == fp) 
    { 
      printf("File: %s Not Foundn", file_name); 
    } 
        else 
    { 
      memset(buffer, 0, BUFFER_SIZE); 
      int length = 0; 
 
      while ((length = fread(buffer, sizeof(char), BUFFER_SIZE, fp)) > 0) 
      { 
        if (send(m_New_Socket, buffer, length, 0) < 0) 
        { 
          printf("Send File: %s Failedn", file_name); 
          break; 
        } 
        memset(buffer, 0, BUFFER_SIZE); 
      } 
 
      fclose(fp); 
      printf("File: %s Transfer Successful!n", file_name); 
    } 
    closesocket(m_New_Socket); 
  } 
 
  closesocket(m_Socket); 
  //Release of the winsock library
  WSACleanup(); 
  return 0; 
} 

The Client code is as follows:

 
 
#include <stdio.h> 
#include <stdlib.h> 
#include <string.h> 
#include <WinSock2.h> 
 
#define PORT 8087 
#define SERVER_IP "127.0.0.1" 
#define BUFFER_SIZE 1024 
#define FILE_NAME_MAX_SIZE 512 
#pragma comment(lib, "WS2_32") 
 
int main() 
{ 
  //Initializes the socket DLL
  WSADATA wsaData; 
  WORD socketVersion = MAKEWORD(2, 0); 
  if(WSAStartup(socketVersion, &wsaData) != 0) 
  { 
    printf("Init socket dll error!"); 
    exit(1); 
  } 
 
  //Create a socket
  SOCKET c_Socket = socket(AF_INET, SOCK_STREAM, 0); 
  if (SOCKET_ERROR == c_Socket) 
  { 
    printf("Create Socket Error!"); 
    system("pause"); 
    exit(1); 
  } 
 
  //Specify the address of the server
  sockaddr_in server_addr; 
  server_addr.sin_family = AF_INET; 
  server_addr.sin_addr.S_un.S_addr = inet_addr(SERVER_IP); 
  server_addr.sin_port = htons(PORT); 
 
  if (SOCKET_ERROR == connect(c_Socket, (LPSOCKADDR)&server_addr, sizeof(server_addr))) 
  { 
    printf("Can Not Connect To Server IP!n"); 
    system("pause"); 
    exit(1); 
  } 
 
  //Input file name
  char file_name[FILE_NAME_MAX_SIZE+1]; 
  memset(file_name, 0, FILE_NAME_MAX_SIZE+1); 
  printf("Please Input File Name On Server: "); 
  scanf("%s", &file_name); 
 
  char buffer[BUFFER_SIZE]; 
  memset(buffer, 0, BUFFER_SIZE); 
  strncpy(buffer, file_name, strlen(file_name)>BUFFER_SIZE ? BUFFER_SIZE:strlen(file_name)); 
 
  //Send the file name to the server
  if(send(c_Socket, buffer, BUFFER_SIZE, 0) < 0) 
  { 
    printf("Send File Name Failedn"); 
    system("pause"); 
    exit(1); 
  } 
 
  //Open the file and prepare to write
  FILE * fp = fopen(file_name, "wb"); //Under Windows is "wb", which means to open a write-only binary
  if(NULL == fp) 
  { 
    printf("File: %s Can Not Open To Writen", file_name); 
    system("pause"); 
    exit(1); 
  } 
  else 
  { 
    memset(buffer, 0, BUFFER_SIZE); 
    int length = 0; 
    while ((length = recv(c_Socket, buffer, BUFFER_SIZE, 0)) > 0) 
    { 
      if (fwrite(buffer, sizeof(char), length, fp) < length) 
      { 
        printf("File: %s Write Failedn", file_name); 
        break; 
      } 
      memset(buffer, 0, BUFFER_SIZE); 
    } 
 
    printf("Receive File: %s From Server Successful!n", file_name); 
  } 
 
  fclose(fp); 
  closesocket(c_Socket); 
   
  //Release of the winsock library
  WSACleanup(); 
 
  system("pause"); 
  return 0; 
} 

The program has more detailed comments, I believe you are not difficult to understand. Interested friends can according to their own needs to improve the program to make it more powerful.