C++ Winsock下载文件截断HTTP头

#include <iostream>
#include <fstream>
#include <winsock2.h>

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

int main() {
    // 初始化Winsock
    WSADATA wsaData;
    if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0) {
        std::cerr << "Failed to initialize Winsock." << std::endl;
        return 1;
    }

    // 创建Socket
    SOCKET clientSocket = socket(AF_INET, SOCK_STREAM, 0);
    if (clientSocket == INVALID_SOCKET) {
        std::cerr << "Failed to create socket." << std::endl;
        WSACleanup();
        return 1;
    }

    // 设置服务器地址和端口
    sockaddr_in serverAddress{};
    serverAddress.sin_family = AF_INET;
    serverAddress.sin_port = htons(80);
    if (inet_pton(AF_INET, "example.com", &(serverAddress.sin_addr)) <= 0) {
        std::cerr << "Invalid address." << std::endl;
        closesocket(clientSocket);
        WSACleanup();
        return 1;
    }

    // 连接服务器
    if (connect(clientSocket, reinterpret_cast<sockaddr*>(&serverAddress), sizeof(serverAddress)) < 0) {
        std::cerr << "Failed to connect to the server." << std::endl;
        closesocket(clientSocket);
        WSACleanup();
        return 1;
    }

    // 发送HTTP请求
    const char* httpRequest = "GET /path/to/file HTTP/1.1\r\nHost: example.com\r\n\r\n";
    if (send(clientSocket, httpRequest, strlen(httpRequest), 0) < 0) {
        std::cerr << "Failed to send HTTP request." << std::endl;
        closesocket(clientSocket);
        WSACleanup();
        return 1;
    }

    // 接收HTTP响应
    char responseBuffer[4096];
    std::ofstream outputFile("file.txt", std::ios::binary);
    bool headerEnd = false;
    while (true) {
        int bytesRead = recv(clientSocket, responseBuffer, sizeof(responseBuffer), 0);
        if (bytesRead <= 0) {
            break;
        }

        if (!headerEnd) {
            // 检查是否到达HTTP头部的结束标志
            for (int i = 0; i < bytesRead - 3; i++) {
                if (responseBuffer[i] == '\r' && responseBuffer[i + 1] == '\n' &&
                    responseBuffer[i + 2] == '\r' && responseBuffer[i + 3] == '\n') {
                    headerEnd = true;
                    bytesRead -= (i + 4);
                    std::memcpy(responseBuffer, responseBuffer + i + 4, bytesRead);
                    break;
                }
            }
        }

        if (headerEnd) {
            // 写入文件内容
            outputFile.write(responseBuffer, bytesRead);
        }
    }

    // 关闭Socket和清理Winsock
    closesocket(clientSocket);
    WSACleanup();

    // 关闭文件
    outputFile.close();

    return 0;
}