URLDownloadToFile dont work in worker thread

[hanhao]

URLDownloadToFile dont work in worker thread

how do i make URLDownloadToFile work in a worker thread. because this is a blocking function, i got to use a worker thread when i call it. but unforturnately when i tried to use it in a thread it doesnt even work at all. its LRESULT return value becomes like -29581853 or something like that.

also, the file never shows up in c:\abc.txt

here is the code i used

	download_result=URLDownloadToFile(NULL, yahoo_url, "C:\\abc.txt", 0, NULL);

how can i make it work in my worker thread?
ref http://msdn2.microsoft.com/en-us/library/ms918866.aspx

using vc++6.0
winxp
MFC STYLE

[vart]

something like that

Is not good enouth. Have you checked the error code with the Error Lookup utility? Does it find the message?

[hanhao]

thanks for all your help
after some playing around with URLDownloadToFile function, i discovered something about it.

if you use URLDownloadToFile in the main user interface thread, it will definately work.

if you use URLDownloadToFile in a worker thread, it may or may not work depending on your OS and your internet explorer. I am not sure which version is usable, but if your code is version dependable, its best to use another style.


here's the code by someone else that i would recommend.

	CString yahoo_url= "yahoo.com"
CString Data;
	DeleteUrlCacheEntry(yahoo_url);// delete the old stupid cache

HINTERNET IntOpen = ::InternetOpen("Sample", LOCAL_INTERNET_ACCESS, NULL, 0, 0);
HINTERNET handle = ::InternetOpenUrl(IntOpen, yahoo_url, NULL, NULL, NULL, NULL);
//HANDLE hFile	= ::CreateFile("c:\\index.txt", GENERIC_WRITE, NULL, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);

char Buffer[1024];
DWORD dwRead =0;
while(::InternetReadFile(handle, Buffer, sizeof(Buffer), &dwRead) == TRUE)
{
	if ( dwRead == 0) 
	 break;
	DWORD dwWrite = 0;
//	::WriteFile(hFile, Buffer, dwRead, &dwWrite, NULL);
	Data+=Buffer;
}

 //::CloseHandle(hFile);
::InternetCloseHandle(handle);

in order to delete cache you need the following at the top

#include "wininet.h" // for clearing URL cache DeleteUrlCacheEntry
#pragma comment(lib, "wininet.lib") // for clearing URL cache DeleteUrlCacheEntry

the reason why you should delete cache is because you would want the newest version of the page and IE would not download the newest version if it has it cached

please give me a rating if this has helped you!