如何利用C++ WinHttp进行文件上传

要使用C++和WinHttp库进行文件上传，请按照以下步骤操作：

包含所需的头文件：

#include<iostream>#include<windows.h>#include <winhttp.h>#include <fstream>#pragma comment(lib, "winhttp")

定义一个函数来执行文件上传：

bool UploadFile(const std::wstring& url, const std::wstring& filePath) {    // 初始化WinHttp会话    HINTERNET hSession = WinHttpOpen(L"MyUserAgent", WINHTTP_ACCESS_TYPE_DEFAULT_PROXY, WINHTTP_NO_PROXY_NAME, WINHTTP_NO_PROXY_BYPASS, 0);    if (!hSession) {        std::cerr << "Error opening session"<< std::endl;        return false;    }    // 连接到服务器    HINTERNET hConnect = WinHttpConnect(hSession, url.c_str(), INTERNET_DEFAULT_HTTPS_PORT, 0);    if (!hConnect) {        std::cerr << "Error connecting to server"<< std::endl;        WinHttpCloseHandle(hSession);        return false;    }    // 打开请求    HINTERNET hRequest = WinHttpOpenRequest(hConnect, L"POST", url.c_str(), NULL, WINHTTP_NO_REFERER, WINHTTP_DEFAULT_ACCEPT_TYPES, WINHTTP_FLAG_SECURE);    if (!hRequest) {        std::cerr << "Error opening request"<< std::endl;        WinHttpCloseHandle(hConnect);        WinHttpCloseHandle(hSession);        return false;    }    // 设置请求头    if (!WinHttpAddRequestHeaders(hRequest, L"Content-Type: multipart/form-data; boundary=----MyBoundary\r\n", -1, WINHTTP_ADDREQ_FLAG_ADD)) {        std::cerr << "Error adding headers"<< std::endl;        WinHttpCloseHandle(hRequest);        WinHttpCloseHandle(hConnect);        WinHttpCloseHandle(hSession);        return false;    }    // 读取文件内容    std::ifstream file(filePath, std::ios::binary | std::ios::ate);    if (!file.is_open()) {        std::cerr << "Error opening file"<< std::endl;        WinHttpCloseHandle(hRequest);        WinHttpCloseHandle(hConnect);        WinHttpCloseHandle(hSession);        return false;    }    int fileSize = file.tellg();    file.seekg(0, std::ios::beg);    char* buffer = new char[fileSize];    file.read(buffer, fileSize);    file.close();    // 构建请求体    std::string requestBody = "------MyBoundary\r\nContent-Disposition: form-data; name=\"file\"; filename=\"" + std::string(filePath.begin(), filePath.end()) + "\"\r\nContent-Type: application/octet-stream\r\n\r\n";    requestBody += std::string(buffer, fileSize);    requestBody += "\r\n------MyBoundary--\r\n";    delete[] buffer;    // 发送请求    if (!WinHttpSendRequest(hRequest, WINHTTP_NO_ADDITIONAL_HEADERS, 0, (LPVOID)requestBody.c_str(), requestBody.size(), requestBody.size(), 0)) {        std::cerr << "Error sending request"<< std::endl;        WinHttpCloseHandle(hRequest);        WinHttpCloseHandle(hConnect);        WinHttpCloseHandle(hSession);        return false;    }    // 接收响应    if (!WinHttpReceiveResponse(hRequest, NULL)) {        std::cerr << "Error receiving response"<< std::endl;        WinHttpCloseHandle(hRequest);        WinHttpCloseHandle(hConnect);        WinHttpCloseHandle(hSession);        return false;    }    // 获取响应状态码    DWORD statusCode = 0;    DWORD statusCodeSize = sizeof(statusCode);    if (!WinHttpQueryHeaders(hRequest, WINHTTP_QUERY_STATUS_CODE | WINHTTP_QUERY_FLAG_NUMBER, NULL, &statusCode, &statusCodeSize, NULL)) {        std::cerr << "Error querying headers"<< std::endl;        WinHttpCloseHandle(hRequest);        WinHttpCloseHandle(hConnect);        WinHttpCloseHandle(hSession);        return false;    }    // 关闭句柄    WinHttpCloseHandle(hRequest);    WinHttpCloseHandle(hConnect);    WinHttpCloseHandle(hSession);    // 检查状态码    if (statusCode != 200) {        std::cerr << "Server returned status code: "<< statusCode<< std::endl;        return false;    }    return true;}

在主函数中调用UploadFile函数：

int main() {    std::wstring url = L"https://example.com/upload";    std::wstring filePath = L"C:\\path\\to\\your\\file.txt";    if (UploadFile(url, filePath)) {        std::cout << "File uploaded successfully!"<< std::endl;    } else {        std::cerr << "Error uploading file"<< std::endl;    }    return 0;}

这个示例将文件上传到指定的URL。请确保将url和filePath变量更改为实际值。注意，这个示例仅适用于Windows平台。