C++ WinHttp接收大数据流的方法

在C++中，使用WinHttp库接收大数据流的方法如下：

1. 首先，包含所需的头文件并链接到WinHttp库。

#include<iostream>
#include<vector>
#include<Windows.h>
#include <Winhttp.h>
#pragma comment(lib, "winhttp")

2. 定义一个函数来初始化WinHttp会话、连接和请求。

HINTERNET InitializeWinHttp(const std::wstring& url) {
    HINTERNET hSession = WinHttpOpen(L"MyUserAgent", WINHTTP_ACCESS_TYPE_DEFAULT_PROXY, WINHTTP_NO_PROXY_NAME, WINHTTP_NO_PROXY_BYPASS, 0);
    if (!hSession) {
        return NULL;
    }

    URL_COMPONENTS urlComponents;
    ZeroMemory(&urlComponents, sizeof(urlComponents));
    urlComponents.dwStructSize = sizeof(urlComponents);
    urlComponents.dwSchemeLength = -1;
    urlComponents.dwHostNameLength = -1;
    urlComponents.dwUrlPathLength = -1;

    if (!WinHttpCrackUrl(url.c_str(), static_cast<DWORD>(url.length()), 0, &urlComponents)) {
        WinHttpCloseHandle(hSession);
        return NULL;
    }

    HINTERNET hConnect = WinHttpConnect(hSession, urlComponents.lpszHostName, urlComponents.nPort, 0);
    if (!hConnect) {
        WinHttpCloseHandle(hSession);
        return NULL;
    }

    HINTERNET hRequest = WinHttpOpenRequest(hConnect, L"GET", urlComponents.lpszUrlPath, NULL, WINHTTP_NO_REFERER, WINHTTP_DEFAULT_ACCEPT_TYPES, 0);
    if (!hRequest) {
        WinHttpCloseHandle(hSession);
        WinHttpCloseHandle(hConnect);
        return NULL;
    }

    return hRequest;
}

3. 定义一个函数来接收大数据流。

bool ReceiveLargeDataStream(const std::wstring& url, std::vector<char>& data) {
    HINTERNET hRequest = InitializeWinHttp(url);
    if (!hRequest) {
        return false;
    }

    if (!WinHttpSendRequest(hRequest, WINHTTP_NO_ADDITIONAL_HEADERS, 0, WINHTTP_NO_REQUEST_DATA, 0, 0, 0)) {
        WinHttpCloseHandle(hRequest);
        return false;
    }

    if (!WinHttpReceiveResponse(hRequest, NULL)) {
        WinHttpCloseHandle(hRequest);
        return false;
    }

    DWORD dwStatusCode = 0;
    DWORD dwSize = sizeof(dwStatusCode);
    if (!WinHttpQueryHeaders(hRequest, WINHTTP_QUERY_STATUS_CODE | WINHTTP_QUERY_FLAG_NUMBER, NULL, &dwStatusCode, &dwSize, NULL)) {
        WinHttpCloseHandle(hRequest);
        return false;
    }

    if (dwStatusCode != HTTP_STATUS_OK) {
        WinHttpCloseHandle(hRequest);
        return false;
    }

    char buffer[4096];
    DWORD dwBytesRead;
    do {
        if (!WinHttpReadData(hRequest, buffer, sizeof(buffer), &dwBytesRead)) {
            WinHttpCloseHandle(hRequest);
            return false;
        }

        if (dwBytesRead == 0) {
            break;
        }

        data.insert(data.end(), buffer, buffer + dwBytesRead);
    } while (true);

    WinHttpCloseHandle(hRequest);
    return true;
}

4. 在主函数中调用ReceiveLargeDataStream函数。

int main() {
    std::wstring url = L"https://example.com/large-data-stream";
    std::vector<char> data;

    if (ReceiveLargeDataStream(url, data)) {
        std::cout << "Received data size: "<< data.size()<< std::endl;
    } else {
        std::cerr << "Failed to receive data stream."<< std::endl;
    }

    return 0;
}

这个示例将从指定的URL接收大数据流，并将其存储在std::vector<char>中。你可以根据需要修改此代码以处理接收到的数据。