winhttp实现通过http的post方式上传文件并获取返回值

可以使用WinHTTP API来实现通过HTTP的POST方式上传文件并获取返回值。以下是一个简单的示例代码：

#include <Windows.h>
#include <WinHttp.h>
#include <iostream>

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

int main() {
    // 创建WinHTTP会话句柄
    HINTERNET hSession = WinHttpOpen(L"WinHTTP Example/1.0", WINHTTP_ACCESS_TYPE_DEFAULT_PROXY, WINHTTP_NO_PROXY_NAME, WINHTTP_NO_PROXY_BYPASS, 0);
    if (!hSession) {
        std::cerr << "Failed to create WinHTTP session.\n";
        return 1;
    }

    // 创建WinHTTP连接句柄
    HINTERNET hConnect = WinHttpConnect(hSession, L"example.com", INTERNET_DEFAULT_HTTP_PORT, 0);
    if (!hConnect) {
        std::cerr << "Failed to create WinHTTP connection.\n";
        WinHttpCloseHandle(hSession);
        return 1;
    }

    // 创建WinHTTP请求句柄
    HINTERNET hRequest = WinHttpOpenRequest(hConnect, L"POST", L"/upload", NULL, WINHTTP_NO_REFERER, NULL, 0);
    if (!hRequest) {
        std::cerr << "Failed to create WinHTTP request.\n";
        WinHttpCloseHandle(hConnect);
        WinHttpCloseHandle(hSession);
        return 1;
    }

    // 设置请求头
    LPCWSTR szHeaders = L"Content-Type: multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxkTrZu0gW";
    if (!WinHttpAddRequestHeaders(hRequest, szHeaders, wcslen(szHeaders), WINHTTP_ADDREQ_FLAG_REPLACE)) {
        std::cerr << "Failed to set request headers.\n";
        WinHttpCloseHandle(hRequest);
        WinHttpCloseHandle(hConnect);
        WinHttpCloseHandle(hSession);
        return 1;
    }

    // 读取要上传的文件
    std::ifstream file("example.txt", std::ios::binary);
    if (!file) {
        std::cerr << "Failed to open file.\n";
        WinHttpCloseHandle(hRequest);
        WinHttpCloseHandle(hConnect);
        WinHttpCloseHandle(hSession);
        return 1;
    }

    // 获取文件长度
    file.seekg(0, std::ios::end);
    int fileSize = file.tellg();
    file.seekg(0, std::ios::beg);

    // 构建POST数据
    const char* szBoundary = "----WebKitFormBoundary7MA4YWxkTrZu0gW";
    std::vector<char> postData;
    postData.reserve(fileSize + 1024);
    postData.insert(postData.end(), szBoundary, szBoundary + strlen(szBoundary));
    postData.insert(postData.end(), "\r\nContent-Disposition: form-data; name=\"file\"; filename=\"example.txt\"\r\nContent-Type: application/octet-stream\r\n\r\n", "\r\nContent-Disposition: form-data; name=\"file\"; filename=\"example.txt\"\r\nContent-Type: application/octet-stream\r\n\r\n" + 1024);
    std::copy(std::istreambuf_iterator<char>(file), std::istreambuf_iterator<char>(), std::back_inserter(postData));
    postData.insert(postData.end(), "\r\n", "\r\n" + 2);
    postData.insert(postData.end(), szBoundary, szBoundary + strlen(szBoundary));
    postData.insert(postData.end(), "--\r\n", "--\r\n" + 4);

    // 发送请求
    if (!WinHttpSendRequest(hRequest, WINHTTP_NO_ADDITIONAL_HEADERS, 0, &postData[0], postData.size(), postData.size(), 0)) {
        std::cerr << "Failed to send WinHTTP request.\n";
        WinHttpCloseHandle(hRequest);
        WinHttpCloseHandle(hConnect);
        WinHttpCloseHandle(hSession);
        return 1;
    }

    // 接收响应
    if (!WinHttpReceiveResponse(hRequest, NULL)) {
        std::cerr << "Failed to receive WinHTTP response.\n";
        WinHttpCloseHandle(hRequest);
        WinHttpCloseHandle(hConnect);
        WinHttpCloseHandle(hSession);
        return 1;
    }

    // 读取响应数据
    std::vector<char> responseData(1024);
    DWORD dwBytesRead = 0;
    while (WinHttpReadData(hRequest, &responseData[0], responseData.size(), &dwBytesRead)) {
        std::cout.write(&responseData[0], dwBytesRead);
    }

    // 关闭请求句柄、连接句柄和会话句柄
    WinHttpCloseHandle(hRequest);
    WinHttpCloseHandle(hConnect);
    WinHttpCloseHandle(hSession);

    return 0;
}

上述代码以POST方式上传名为`example.txt`的文件到`example.com`的`/upload`路径，并输出响应数据。请根据实际情况修改代码中的URL、请求头、POST数据和文件名等参数。