C++ 下载文件 - 如果不可用，增加 RAM 使用率 1mb/s

Question

如果无法下载文件，我的代码会不断填充 RAM。(禁用网络进行测试)如何在超时后停止下载？

这里是下载的主要部分:

int WINAPI WinMain(HINSTANCE instanceHandle, HINSTANCE, char*, int)
{
    using namespace std;
    std::wstring loadme = targetfolder;
    loadme += L"\\filename.txt";
    std::wstring url1(L"fileurl");
    HRESULT hr1 = URLDownloadToFile(NULL, (url1.c_str()), (loadme.c_str()), 0, NULL); //Download-Start
}

Answer 1

您可以使用 WinINet 函数检查互联网是否可用，检查 url 链接是否可用，并报告进度。需要“wininet.lib”

WinINet Reference

#include <windows.h>
#include <wininet.h>
#include <fstream>

void geturl(const wchar_t *url)
{
    std::ofstream file("c:\\test\\test.htm");
    HINTERNET hopen = InternetOpen(L"myAppName",INTERNET_OPEN_TYPE_PRECONFIG,NULL,NULL,0);
    if (hopen)
    {
        HINTERNET hurl = InternetOpenUrl(hopen,url,NULL,0,INTERNET_FLAG_DONT_CACHE,0);
        if (hurl)
        {
            DWORD received;
            const int bufsize = 1024;
            char buf[bufsize];
            while (InternetReadFile(hurl, buf, bufsize, &received))
            {
                //progress...
                if (!received) break;
                file.write(buf, received);
            }
            InternetCloseHandle(hurl);
        }
        InternetCloseHandle(hopen);
    }
}