UE上传文件到HTTP服务器C++代码

在C++中，使用C++标准库`std::ifstream`、`std::ofstream`以及`boost::asio`库来处理HTTP上传文件到服务器的情况是比较常见的。这里是一个简单的示例，展示如何使用C++和Asio库发送POST请求上传文件：

#include <iostream>
#include <fstream>
#include <boost/asio.hpp>

// 假设我们有一个HTTP客户端上下文
struct HttpClient {
    boost::asio::ip::tcp::socket socket_;
    boost::asio::io_service& io_service_;

public:
    explicit HttpClient(boost::asio::io_service& io_service)
        : socket_(io_service),
          io_service_(io_service)
    {}

    void uploadFile(const std::string& filename, const std::string& url) {
        // 打开文件
        std::ifstream file(filename, std::ios::binary);
        if (!file.is_open()) {
            throw std::runtime_error("Failed to open file");
        }

        // 获取文件大小
        std::streampos fileSize(file.tellg());
        file.seekg(0, std::ios_base::end);
        fileSize += file.tellg();
        file.seekg(0);

        // 创建HTTP POST请求头
        std::string boundary = "---------------------------" + std::to_string(std::hash<std::string>()("boundary"));
        std::stringstream headers;
        headers << "POST " << url << " HTTP/1.1\r\n";
        headers << "Host: your_server_url\r\n";
        headers << "Content-Type: multipart/form-data; boundary=" << boundary << "\r\n";
        headers << "Content-Length: " << fileSize << "\r\n";
        headers << "\r\n";

        // 发送请求头
        boost::array<char, 1024> sendBuffer;
        boost::asio::write(socket_, boost::asio::buffer(headers.str(), headers.tellp()), net::transfer_all());

        // 读取并发送文件内容
        char buffer[1024];
        while (file.read(buffer, sizeof(buffer))) {
            boost::asio::write(socket_, boost::asio::buffer(buffer, file.gcount()));
        }
        boost::asio::write(socket_, boost::asio::buffer("\r\n", 2));

        // 发送文件结束标识符
        std::stringstream footer;
        footer << "--" << boundary << "--\r\n";
        boost::asio::write(socket_, boost::asio::buffer(footer.str(), footer.tellp()));

        // 关闭文件
        file.close();

        // 等待服务器响应
        // 这里通常会解析响应，但在简化示例中略过
        // boost::beast::http::response response;
        // readResponse(response);
    }
};

int main() {
    try {
        auto io_service = boost::asio::io_service{};
        HttpClient client(io_service);
        client.uploadFile("path_to_your_file.txt", "http://your_server.com/upload_endpoint");
    } catch (const std::exception& e) {
        std::cerr << "Error: " << e.what() << '\n';
    }
    return 0;
}