[VC++] Socket Programming 파일 전송(Server → Client)

Server.cpp

#pragma comment(lib, "ws2_32.lib")

#include <stdio.h>
#include <stdlib.h>
#include <tchar.h>
#include <WinSock2.h>

#define BUFSIZE 512

int main(int argc, char *argv[]) {
	WSADATA	wsaData;
	SOCKET	ConnectSocket = INVALID_SOCKET;
	SOCKADDR_IN	addrinfo;
	int iResult;

	if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0)
		return 1;

	if ((ConnectSocket = socket(AF_INET, SOCK_STREAM, 0)) == INVALID_SOCKET)
		return 1;

	ZeroMemory(&addrinfo, sizeof(addrinfo));
	addrinfo.sin_family = AF_INET;
	addrinfo.sin_port = htons(atoi(argv[2]));
	addrinfo.sin_addr.s_addr = inet_addr(argv[1]);

	if (connect(ConnectSocket, (SOCKADDR *)&addrinfo, sizeof(addrinfo)) == SOCKET_ERROR)
		return 1;

	FILE *fp = fopen(argv[3], "rb");
	if (fp == NULL) {
		printf("File I/O error\n");
		return 1;
	}

	// Send filename
	char filename[256];
	ZeroMemory(filename, 256);
	sprintf(filename, argv[3]);
	if (send(ConnectSocket, filename, 256, 0) == SOCKET_ERROR)
		return 1;

	// Get file size
	fseek(fp, 0, SEEK_END);
	int filesize = ftell(fp);

	// Send file size
	if (send(ConnectSocket, (char *)&filesize, sizeof(filesize), 0) == SOCKET_ERROR)
		return 1;

	char buf[BUFSIZE];
	int read;
	int total = 0;

	// Send file contents
	rewind(fp);
	while (1) {
		read = fread(buf, 1, BUFSIZE, fp);
		if (read > 0) {
			iResult = send(ConnectSocket, buf, read, 0);
			if (iResult == SOCKET_ERROR)
				break;
			total += read;
		} else if (read == 0 && total == filesize) {
			printf("File transmission complete: %d bytes\n", filesize);
			break;
		} else {
			printf("File I/O error\n");
			break;
		}
	}
	fclose(fp);

	closesocket(ConnectSocket);
	WSACleanup();
	return 0;
}

Client.cpp

#pragma comment(lib, "ws2_32.lib")

#include <stdio.h>
#include <stdlib.h>
#include <tchar.h>
#include <WinSock2.h>

#define BUFSIZE 512

int recvn(SOCKET socket, char *buf, int len, int flags) {
	int		iResult;
	char	*ptr = buf;
	int		left = len;

	while (left > 0) {
		iResult = recv(socket, ptr, left, flags);
		if (iResult == SOCKET_ERROR)
			return SOCKET_ERROR;
		else if (iResult == 0)
			break;

		left -= iResult;
		ptr += iResult;
	}

	return (len - left);
}

int main(int argc, char *argv[]) {
	WSADATA	wsaData;
	SOCKET	ListenSocket = INVALID_SOCKET;
	SOCKADDR_IN addrinfo;
	int iResult;

	if (WSAStartup(MAKEWORD(2, 2),	 &wsaData) != 0)
		return 1;

	if ((ListenSocket = socket(AF_INET, SOCK_STREAM, 0)) == INVALID_SOCKET)
		return 1;
	
	ZeroMemory(&addrinfo, sizeof(addrinfo));
	addrinfo.sin_family = AF_INET;
	addrinfo.sin_port = htons(atoi(argv[2]));
	addrinfo.sin_addr.s_addr = htonl(INADDR_ANY);

	if (bind(ListenSocket, (SOCKADDR *)&addrinfo, sizeof(addrinfo)) == SOCKET_ERROR)
		return 1;

	if (listen(ListenSocket, SOMAXCONN) == SOCKET_ERROR)
		return 1;
	printf("Listen!\n");

	SOCKET	SenderSocket;
	SOCKADDR_IN	senderinfo;
	int		addrlen;
	char	buf[BUFSIZE];

	while (1) {
		addrlen = sizeof(senderinfo);
		SenderSocket = accept(ListenSocket, (SOCKADDR *)&senderinfo, &addrlen);
		if (SenderSocket == INVALID_SOCKET)
			continue;

		printf("File Sender: %s(%d)\n", inet_ntoa(senderinfo.sin_addr), ntohs(senderinfo.sin_port));

		// Receive filename from server
		char filename[256];
		ZeroMemory(filename, sizeof(filename));
		iResult = recvn(SenderSocket, filename, 256, 0);
		if (iResult == SOCKET_ERROR) {
			printf("Receive filename failed\n");
			closesocket(SenderSocket);
			continue;
		}
		printf("\tFilename: %s\n", filename);

		// Receive file size from server
		int filesize;
		iResult = recvn(SenderSocket, (char *)&filesize, sizeof(filesize), 0);
		if (iResult == SOCKET_ERROR) {
			closesocket(SenderSocket);
			continue;
		}
		printf("\tFile size: %d\n", filesize);

		// File open
		FILE *fp = fopen(filename, "wb");
		if (fp == NULL) {
			closesocket(SenderSocket);
			continue;
		}

		// Receive file contents
		int	total = 0;
		while (1) {
			ZeroMemory(buf, sizeof(buf));
			iResult = recvn(SenderSocket, buf, BUFSIZE, 0);
			if (iResult == SOCKET_ERROR) {
				break;
			} else if (iResult == 0) {
				break;
			} else {
				fwrite(buf, 1, iResult, fp);
				if (ferror(fp)) {
					printf("File I/O error\n");
					break;
				}
				total += iResult;
			}
		}
		fclose(fp);

		// File size check
		if (total == filesize)
			printf("File download success\n");
		else
			printf("File download failed\n");

		closesocket(SenderSocket);
	}

	closesocket(ListenSocket);
	WSACleanup();
	return 0;
}