InternetOpenUrl - urgent help needed

YaronNir

i use InternetOpenUrl (as async) to receive a file from a url. this is the code i use : BOOL CMyCode::RequestFile( LPCTSTR lpszUrl ) { m_hInternet = InternetOpen(_T("MyCode"), INTERNET_OPEN_TYPE_DIRECT, NULL, NULL, INTERNET_FLAG_ASYNC); if (!m_hInternet) { return FALSE; } InternetSetStatusCallback(m_hInternet, CMyCode::InternetStatusCallback); InternetOpenUrl(m_hInternet, lpszUrl, NULL, 0, INTERNET_FLAG_RELOAD | INTERNET_FLAG_PRAGMA_NOCACHE | INTERNET_FLAG_NO_CACHE_WRITE, (DWORD) this); return TRUE; } void __stdcall CMyCode::InternetStatusCallback (HINTERNET hSession, DWORD Context, DWORD Status, LPVOID pInformation, DWORD InfoLength) { CMyCode* pThis = (CMyCode*) Context; if (!pThis) { return; } switch (Status) { case INTERNET_STATUS_RESPONSE_RECEIVED: m_dwNumytes2Read = (*(DWORD *)pInformation); break; case INTERNET_STATUS_HANDLE_CREATED: m_hHttpSession = * (HINTERNET *) pInformation; // Copy break; case INTERNET_STATUS_REQUEST_COMPLETE: CompleteRequest(); break; case INTERNET_STATUS_HANDLE_CLOSING: break; default: ATLTRACE(_T("Status is %ld\n"), Status); break; } } void CMyCode::CompleteRequest() { LPBYTE pBuff = new BYTE[m_dwNumytes2Read]; ZeroMemory(pBuff, m_dwNumytes2Read); DWORD dwBytesRead(0); BOOL bOK(TRUE); while (bOK) { bOK = InternetReadFile (m_hHttpSession, pBuff, m_dwNumytes2Read, &dwBytesRead); if (!dwBytesRead) bOK = FALSE; // .. progress handling } if (pBuff) delete []pBuff; Abort(); //... done } the code works ok only i have 2 major problems: 1. the file is received in a chunks of 267/268 Bytes each time i call InternetReadFile???? 2. the CPU reaches 80% until the file is download completely can any1 help me here? thanks in advanced

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_Superman_

You can try URLDownloadToFile function.

«_Superman_» I love work. It gives me something to do between weekends.
Microsoft MVP (Visual C++)

YaronNir

thanks for the reply... i can not use other methods other than what i've posted in my code (for stupid reasons go figure) so i would still like any help regarding my issues thanks again

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Lost User

Have you checked the value of m_dwNumytes2Read bfore your call to InternetReadFile()?

YaronNir

what do you mean? can you give an example

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Lost User

You have the following code (btw could you edit your original message and put the code between <pre></pre> tags):

case INTERNET_STATUS_RESPONSE_RECEIVED:
m_dwNumytes2Read = (*(DWORD *)pInformation);
break;
// intermediate lines omitted

void CMyCode::CompleteRequest()
{
LPBYTE pBuff = new BYTE[m_dwNumytes2Read];
ZeroMemory(pBuff, m_dwNumytes2Read);

DWORD dwBytesRead(0);
BOOL bOK(TRUE);
while (bOK)
{
bOK = InternetReadFile (m\_hHttpSession, pBuff, m\_dwNumytes2Read, &dwBytesRead);
// intermediate lines omitted

}

The value of m_dwNumytes2Read is set when you process the INTERNET_STATUS_RESPONSE_RECEIVED message and is relevant to the status information, so it is probably less than the amount of data that may be available. Try resetting it to some bigger value before calling InternetReadFile() for example:

dwNumytes2Read = 2048;
LPBYTE pBuff = new BYTE\[m\_dwNumytes2Read\];
DWORD dwBytesRead;
BOOL bOK(TRUE);
while (bOK)
{
bOK = InternetReadFile (m\_hHttpSession, pBuff, m\_dwNumytes2Read, &dwBytesRead);
// ...

YaronNir

thanks for the reply - it did solve the problem now the chunck are 2048 bytes each time - good! the second problem still remains - high CPU about 80% - how can i solve this? thanks again for your kind reply

Interface basics click here : http://www.codeproject.com/com/COMBasics.asp don't forget to vote :)

Lost User

First thing is to run some tests with different buffer sizes to see how that affects performance, 2048 was just a number plucked from the air. Looking at your code I notice that you use ZeroMemory on the input buffer just before reading data into it; this is wasteful and serves no purpose, just allocate it with the new call. Alternatively you could allocate your buffer at the beginning of the program, either via new or as a static data area. This would save repeated new delete[] pairs, and the consequent garbage collection code. There may be other issues in the rest of your code, but I leave that for you to investigate.

YaronNir

once again - thank you!

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Bram van Kampen

YaronNir wrote:

i can not use other methods other than what i've posted in my code (for stupid reasons go figure) so i would still like any help regarding my issues

Then You're at a dead end! We cannot help you any further!(for stupid reasons go figure). :) :)

Bram van Kampen

YaronNir

this sort of reply is in appropriate, if you can see below i got a really good reply who took my question seriously shame on you....

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