C/C++ winhttp 下载文件

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偷自网上

#include <thread>
#include <string>
#include <windows.h>
#include <winhttp.h>
#pragma comment(lib, "winhttp.lib")

typedef void(*DownLoadCallback)(int ContentSize, int CUR_LEN);

typedef struct _URL_INFO
{
    WCHAR szScheme[512];
    WCHAR szHostName[512];
    WCHAR szUserName[512];
    WCHAR szPassword[512];
    WCHAR szUrlPath[512];
    WCHAR szExtraInfo[512];
}URL_INFO, *PURL_INFO;


void dcallback(int ContentSize, int file_size)
{
    //printf("count:%d,size:%d\n", ContentSize, file_size);
}

void download(const wchar_t *Url, const wchar_t *FileName,QByteArray &byt, DownLoadCallback Func)
{
    URL_INFO url_info = { 0 };
    URL_COMPONENTSW lpUrlComponents = { 0 };
    lpUrlComponents.dwStructSize = sizeof(lpUrlComponents);
    lpUrlComponents.lpszExtraInfo = url_info.szExtraInfo;
    lpUrlComponents.lpszHostName = url_info.szHostName;
    lpUrlComponents.lpszPassword = url_info.szPassword;
    lpUrlComponents.lpszScheme = url_info.szScheme;
    lpUrlComponents.lpszUrlPath = url_info.szUrlPath;
    lpUrlComponents.lpszUserName = url_info.szUserName;

    lpUrlComponents.dwExtraInfoLength =
        lpUrlComponents.dwHostNameLength =
        lpUrlComponents.dwPasswordLength =
        lpUrlComponents.dwSchemeLength =
        lpUrlComponents.dwUrlPathLength =
        lpUrlComponents.dwUserNameLength = 512;

    WinHttpCrackUrl(Url, 0, ICU_ESCAPE, &lpUrlComponents);

    // 创建一个会话
    HINTERNET hSession = WinHttpOpen(NULL, WINHTTP_ACCESS_TYPE_NO_PROXY, NULL, NULL, 0);
    DWORD dwReadBytes, dwSizeDW = sizeof(dwSizeDW), dwContentSize, dwIndex = 0;
    // 创建一个连接
    HINTERNET hConnect = WinHttpConnect(hSession, lpUrlComponents.lpszHostName, lpUrlComponents.nPort, 0);
    // 创建一个请求，先查询内容的大小
    HINTERNET hRequest = WinHttpOpenRequest(hConnect, L"HEAD", lpUrlComponents.lpszUrlPath, L"HTTP/1.1", WINHTTP_NO_REFERER, WINHTTP_DEFAULT_ACCEPT_TYPES, WINHTTP_FLAG_REFRESH);
    WinHttpSendRequest(hRequest, WINHTTP_NO_ADDITIONAL_HEADERS, 0, WINHTTP_NO_REQUEST_DATA, 0, 0, 0);
    WinHttpReceiveResponse(hRequest, 0);
    WinHttpQueryHeaders(hRequest, WINHTTP_QUERY_CONTENT_LENGTH | WINHTTP_QUERY_FLAG_NUMBER, NULL, &dwContentSize, &dwSizeDW, &dwIndex);
    WinHttpCloseHandle(hRequest);

    // 创建一个请求，获取数据
    hRequest = WinHttpOpenRequest(hConnect, L"GET", lpUrlComponents.lpszUrlPath, L"HTTP/1.1", WINHTTP_NO_REFERER, WINHTTP_DEFAULT_ACCEPT_TYPES, WINHTTP_FLAG_REFRESH);
    WinHttpSendRequest(hRequest, WINHTTP_NO_ADDITIONAL_HEADERS, 0, WINHTTP_NO_REQUEST_DATA, 0, 0, 0);
    WinHttpReceiveResponse(hRequest, 0);

    // 分段回调显示进度
    DWORD BUF_LEN = 1024, ReadedLen = 0;
    BYTE *pBuffer = NULL;
    pBuffer = new BYTE[BUF_LEN];

    HANDLE hFile = CreateFileW(FileName, GENERIC_WRITE, FILE_SHARE_READ, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);

    while (dwContentSize > ReadedLen)
    {
        ZeroMemory(pBuffer, BUF_LEN);
        WinHttpReadData(hRequest, pBuffer, BUF_LEN, &dwReadBytes);
        ReadedLen += dwReadBytes;

        byt.append((const char*)pBuffer,dwReadBytes);
        // 写入文件
        WriteFile(hFile, pBuffer, dwReadBytes, &dwReadBytes, NULL);
        // 进度回调
        Func(dwContentSize, ReadedLen);
    }

    CloseHandle(hFile);
    delete []pBuffer;

    WinHttpCloseHandle(hRequest);
    WinHttpCloseHandle(hConnect);
    WinHttpCloseHandle(hSession);
}

与QtWebEngine一起用会出你想都想不到的错误，Qt中不建议用这个。