c++ 使用WinHTTP实现文件下载功能

admin1

因为要项目中要想要实现一个软件自动更新的功能，之前是使用socket直接下载。但切换下载源的时候很麻烦。所以换用http方式。
网上找了很多资料，基本上就是下面几种：
1.curllib //功能强大太但太麻烦而且没必要
2.MFC自带的功能 // 项目不是使用的MFC所以舍
3.IE控件下载 // 没办法获取到进度，而且因为不能获取到总大小所以很容易下载的资源不完整。

思来想去，最后还是使用WinHTTP，比较简单快捷，而且功能上基本上都能够满足。

#include <stdio.h>
#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, 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;

                // 写入文件
                WriteFile(hFile, pBuffer, dwReadBytes, &dwReadBytes, NULL);
                // 进度回调
                Func(dwContentSize, ReadedLen);

        }

        CloseHandle(hFile);
        delete pBuffer;


        /*
        // 一次性写入整个文件
        BYTE *pBuffer = NULL;

        pBuffer = new BYTE[dwContentSize];
        ZeroMemory(pBuffer, dwContentSize);
        //do{
                WinHttpReadData(hRequest, pBuffer, dwContentSize, &dwReadBytes);
                Func(dwContentSize, dwReadBytes);
        //} while (dwReadBytes == 0);
       

        HANDLE hFile = CreateFileW(FileName, GENERIC_WRITE, FILE_SHARE_READ, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
        WriteFile(hFile, pBuffer, dwContentSize, &dwReadBytes, NULL);
        CloseHandle(hFile);

        delete pBuffer;
        */
        WinHttpCloseHandle(hRequest);
        WinHttpCloseHandle(hConnect);
        WinHttpCloseHandle(hSession);

       
}



int main(int argc, char* argv[])
{
        download(L"http://sw.bos.baidu.com/sw-search-sp/software/58d7820029ae7/BaiduMusic_10.1.7.7_setup.exe", L"./BaiduMusic_10.1.7.7_setup.exe", &dcallback);
        system("pause");
}