#include tcharh#include stdioh#include winsock2h#include stdlibh #include stringh #include Ws2tcpiph#include iostream#include fstream#pragma commentlibws2_32lib#define BUFFER_SIZE 2048#define FILE_N

#include <tchar.h> #include <stdio.h> #include <winsock2.h> #include <stdlib.h>
#include <string.h>
#include <Ws2tcpip.h> #include #include #pragma comment(lib,"ws2_32.lib")

#define BUFFER_SIZE 2048 #define FILE_NAME_MAX_SIZE 512

using namespace std; string home = "client_home/";

bool sendAll(SOCKET socket, const char* buffer, int length) { int totalSent = 0; int bytesLeft = length; int bytesSent = 0;

while (totalSent < length)
{
    bytesSent = send(socket, buffer + totalSent, bytesLeft, 0);
    if (bytesSent == SOCKET_ERROR)
    {
        return false;
    }
    totalSent += bytesSent;
    bytesLeft -= bytesSent;
}

return true;

}

bool receiveAll(SOCKET socket, char* buffer, int length) { int totalReceived = 0; int bytesLeft = length; int bytesRead = 0;

while (totalReceived < length)
{
    bytesRead = recv(socket, buffer + totalReceived, bytesLeft, 0);
    if (bytesRead == SOCKET_ERROR || bytesRead == 0)
    {
        return false;
    }
    totalReceived += bytesRead;
    bytesLeft -= bytesRead;
}

return true;

}

int main(int argc, char* argv[]) { // Initialize WSA, allowing the program to make Windows socket calls WORD sockVersion = MAKEWORD(2, 2); WSADATA wsaData; if (WSAStartup(sockVersion, &wsaData) != 0) { return 0; }

// Create client_socket and check if it is created successfully
SOCKET client_socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP); ;
if (client_socket == INVALID_SOCKET) {
    // If the created socket is invalid, exit the program
    perror("socket error !");
    return 0;
}

// Create the address structure server_addr and set the port and IP
sockaddr_in server_addr;
memset(&server_addr, 0, sizeof(server_addr));
server_addr.sin_family = AF_INET;
// Port number of the server to connect to: 8888
server_addr.sin_port = htons(8888);
// Specify the address of the server: 127.0.0.1
PCWSTR src = TEXT("127.0.0.1");
InetPton(AF_INET, src, &server_addr.sin_addr.s_addr);

// Connect the client_socket to the address server_addr
if (connect(client_socket, (SOCKADDR*)&server_addr, sizeof(SOCKADDR)))
{
    perror("connect error !\n");
    return 0;
}

cout << "Please enter the command to execute (1 for upload file, 2 for download file, 3 for view file list):" << endl;
string choice;
cin >> choice;

// Send the data in buffer to the server
if (sendAll(client_socket, choice.c_str(), BUFFER_SIZE) == false)
{
    perror("Error message: Failed to send command!");
    exit(1);
}

// Upload file
if (choice == "1")
{
    // Enter the file to upload
    memset(buffer, 0, BUFFER_SIZE);
    cout << "Please enter the name of the file to upload, e.g. test.txt:" << endl;
    string filename;
    cin >> filename;
    sendAll(client_socket, filename.c_str(), filename.length());

    // Open the file and read the file data
    string f = home + filename;
    FILE* fp;
    errno_t F_ERR = fopen_s(&fp, f.c_str(), "rb");
    string stateNum;
    if (F_ERR != 0)
    {
        cout << "Error message: File not found!" << endl;
        stateNum = "1";
        sendAll(client_socket, stateNum.c_str(), stateNum.length());
        exit(1);
    }

    stateNum = "2";
    sendAll(client_socket, stateNum.c_str(), stateNum.length());

    // Confirm the server's status and determine if the file transfer can begin
    char flag[2];
    if (receiveAll(client_socket, flag, 2) == false)
    {
        cout << "Error message: Failed to receive client status from server!" << endl;
        exit(2);
    }

    cout << "Client starts uploading file!" << endl;
    memset(buffer, 0, BUFFER_SIZE);

    int length = 0;
    // Read a segment of data and send it to the server, loop until the file is read completely
    while ((length = fread(buffer, sizeof(char), BUFFER_SIZE, fp)) > 0)
    {
        if (sendAll(client_socket, buffer, length) == false)
        {
            cout << "Error message: File upload failed!" << endl;
            break;
        }
        memset(buffer, 0, BUFFER_SIZE);
    }

    // Close the file
    fclose(fp);
    cout << "File uploaded successfully!" << endl;
}

// Download file
else if (choice == "2")
{
    // Enter the file to download
    memset(buffer, 0, BUFFER_SIZE);

    cout << "Please enter the name of the file to download, e.g. test.txt:" << endl;
    cin >> buffer;
    char file_name[FILE_NAME_MAX_SIZE + 1];
    strncpy_s(file_name, buffer, strlen(buffer) > FILE_NAME_MAX_SIZE ? FILE_NAME_MAX_SIZE : strlen(buffer));
    if (sendAll(client_socket, buffer, BUFFER_SIZE) == false)
    {
        perror("Error message: Failed to send file name!");
        exit(1);
    }

    // Receive the server's status: whether the file to download is found or not
    char stateNum[2];
    memset(stateNum, 0, 2);
    if (receiveAll(client_socket, stateNum, 2) == false)
    {
        cout << "Error message: Failed to receive server status!" << endl;
    }

    if (!strcmp(stateNum, "1"))
    {
        cout << "Error message: File name not found on server!" << endl;
        exit(2);
    }

    // Prepare to write to file
    string f = file_name;
    f = home + f;
    FILE* fp;
    errno_t F_ERR = fopen_s(&fp, f.c_str(), "wb");
    if (F_ERR != 0)
    {
        cout << "Failed to open file!" << endl;
        exit(1);
    }

    // Receive data from the server into buffer
    // Write each segment of data received to the file, loop until the file is received and written completely
    memset(buffer, 0, BUFFER_SIZE);
    cout << "Downloading file..." << endl;
    int length = 0;
    while ((length = recv(client_socket, buffer, BUFFER_SIZE, 0)) > 0)
    {
        if (fwrite(buffer, sizeof(char), length, fp) < length)
        {
            cout << "Failed to write file!" << endl;
            break;
        }
        memset(buffer, 0, BUFFER_SIZE);
    }

    // Close the file after successful reception
    cout << file_name << " downloaded successfully!" << endl;
    fclose(fp);
}

else if (choice == "3")
{
    cout << "Server file list:" << endl;
    char buffer[BUFFER_SIZE];
    memset(buffer, 0, BUFFER_SIZE);
    while (recv(client_socket, buffer, BUFFER_SIZE, 0) > 0)
    {
        cout << buffer << " ";
        memset(buffer, 0, BUFFER_SIZE);
    }
}

// Close the socket and WSA
closesocket(client_socket);
WSACleanup();
system("pause");
return 0;