asyncdemo.cpp

FTP

			//write the callback information to the buffer
			sprintf(szBuffer,"%s: RECEIVEING_RESPONSE (%d)", 
				cpContext->szMemo, dwStatusInformationLength);
			break;
		case INTERNET_STATUS_RESPONSE_RECEIVED:
			//write the callback information to the buffer
			sprintf(szBuffer,"%s: RESPONSE_RECEIVED (%d)", 
				cpContext->szMemo, dwStatusInformationLength);
			break;
		case INTERNET_STATUS_REDIRECT:
			//write the callback information to the buffer
			sprintf(szBuffer,"%s: REDIRECT (%d)", 
				cpContext->szMemo, dwStatusInformationLength);
			break;
		case INTERNET_STATUS_REQUEST_COMPLETE:

			//check for errors
			if (LPINTERNET_ASYNC_RESULT(lpvStatusInformation)->dwError == 0)
			{
				//check if the completed request is from AsyncDirect
				if (strcmp(cpContext->szMemo, "AsyncDirect"))
				{
					//set the resource handle to the HINTERNET handle 
					//returned in the callback
					cpContext->hResource = HINTERNET(
						LPINTERNET_ASYNC_RESULT(lpvStatusInformation)->dwResult);

					//write the callback information to the buffer
					sprintf(szBuffer,"%s: REQUEST_COMPLETE (%d)", 
						cpContext->szMemo, dwStatusInformationLength);

					//create a thread to handle the header and 
					//resource download
					cpContext->hThread = CreateThread(NULL, 0, 
						(LPTHREAD_START_ROUTINE)Threader,LPVOID(cpContext), 0, 
						&cpContext->dwThreadID);

				}
				else
				{
					sprintf(szBuffer,"%s(%d): REQUEST_COMPLETE (%d)", 
						cpContext->szMemo,
						cpContext->nURL, dwStatusInformationLength);
				}

			}
			else
			{
				sprintf(szBuffer,
					"%s: REQUEST_COMPLETE (%d) Error (%d) encountered", 
					cpContext->szMemo, dwStatusInformationLength,
					GetLastError());
			}			
			break;
		case INTERNET_STATUS_REQUEST_SENT:
			//write the callback information to the buffer
			sprintf(szBuffer,"%s: REQUEST_SENT (%d)", 
				cpContext->szMemo, dwStatusInformationLength);
			break;
		case INTERNET_STATUS_RESOLVING_NAME:
			//write the callback information to the buffer
			sprintf(szBuffer,"%s: RESOLVING_NAME (%d)", 
				cpContext->szMemo, dwStatusInformationLength);
			break;
		case INTERNET_STATUS_SENDING_REQUEST:
			//write the callback information to the buffer
			sprintf(szBuffer,"%s: SENDING_REQUEST (%d)", 
				cpContext->szMemo, dwStatusInformationLength);
			break;
		case INTERNET_STATUS_STATE_CHANGE:
			//write the callback information to the buffer
			sprintf(szBuffer,"%s: STATE_CHANGE (%d)", 
				cpContext->szMemo, dwStatusInformationLength);
			break;
		default:
			//write the callback information to the buffer
			sprintf(szBuffer,"%s: Unknown: Status %d Given", dwInternetStatus);
			break;
	}

	//add the callback information to the callback list box
	SendDlgItemMessage(cpContext->hWindow,IDC_CallbackList,
		LB_ADDSTRING,0,(LPARAM)szBuffer);
	
}



/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

  Threader is a thread function to handle the retrieval of the header
  and resource information.  Since the WinInet functions involved in
  both of these operations work synchronously, using a separate 
  thread will help avoid any blocking.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
DWORD Threader(LPVOID lpvContext)
{
	REQUEST_CONTEXT *cpContext;
	
	//copy the pointer to a REQUEST_CONTEXT pointer to ease calls
	cpContext= (REQUEST_CONTEXT*)lpvContext;

	//set szMemo to the name of the function to be called
	sprintf(cpContext->szMemo, "Header(%d)", cpContext->nURL);

	//call the header function
	Header(cpContext->hWindow, cpContext->nHeader, -1, cpContext->hResource);

	//set szMemo to the name of the function to be called
	sprintf(cpContext->szMemo, "Dump(%d)", cpContext->nURL);

	//call the dump function
	Dump(cpContext->hWindow, cpContext->nResource, cpContext->hResource);

	return S_OK;

}


/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

  Header handles the retrieval of the HTTP header information.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
int WINAPI Header(HWND hX,int intControl, int intCustom, HINTERNET hHttp)
{
	DWORD dwHeaderType=-1;
	DWORD dwSize=0;
	LPVOID lpOutBuffer = NULL;

	char szError[80];

	//change the cursor
	SetCursor(LoadCursor(NULL,IDC_WAIT));


	//set the header type to be requested, which is all headers in
	//this case
	dwHeaderType = HTTP_QUERY_RAW_HEADERS_CRLF;	



retry:

	//call HttpQueryInfo.
	//first time with a zero buffer size to get the size of the buffer
	//needed and to check if the header exists
	if(!HttpQueryInfo(hHttp,dwHeaderType,(LPVOID)lpOutBuffer,&dwSize,NULL))
	{
		//check if the header was not found
		if (GetLastError()==ERROR_HTTP_HEADER_NOT_FOUND)
		{
			sprintf(szError,"Error %d encountered", GetLastError());
			SetDlgItemText(hX,intControl, szError);
			SetCursor(LoadCursor(NULL,IDC_ARROW));
			return TRUE;
		}
		else
		{
			//check if the buffer was insufficient
			if (GetLastError()==ERROR_INSUFFICIENT_BUFFER)
			{
				//allocate the buffer
				lpOutBuffer = new char[dwSize+1];
				goto retry;				
			}
			else
			{
				//display other errors in header edit box
				sprintf(szError,"Error %d encountered", GetLastError());
				SetDlgItemText(hX,intControl, szError);
				SetCursor(LoadCursor(NULL,IDC_ARROW));
				return FALSE;
			}
		}
	}


	SetDlgItemText(hX,intControl,(LPSTR)lpOutBuffer);
	delete[]lpOutBuffer;
	SetCursor(LoadCursor(NULL,IDC_ARROW));
	return 1;

}	
	

/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
int WINAPI Dump(HWND hX, int intCtrlID, HINTERNET hResource)
{
	
	LPSTR	lpszData;		// buffer for the data
	DWORD	dwSize;			// size of the data available
	DWORD	dwDownloaded;	// size of the downloaded data
	DWORD	dwSizeSum=0;	// size of the data in the textbox
	LPSTR	lpszHolding;	// buffer to merge the textbox data and buffer

	char	szError[80];	// buffer for error information
	// Set the cursor to an hourglass.
	SetCursor(LoadCursor(NULL,IDC_WAIT));

	int		nCounter;		// counter used to display something while
							// I/O is pending.


	// This loop handles reading the data.  
	do
	{

try_again:
		// The call to InternetQueryDataAvailable determines the amount of 
		// data available to download.
		if (!InternetQueryDataAvailable(hResource,&dwSize,0,0))
		{
			if (GetLastError()== ERROR_IO_PENDING)
			{
				nCounter = 0;
				
				while(GetLastError()==ERROR_IO_PENDING)
				{
					nCounter++;

					if (nCounter==2000)
						break;
				}
				goto try_again;
			}
			sprintf(szError,"Error %d encountered by InternetQueryDataAvailable",
				GetLastError());
			SetDlgItemText(hX,intCtrlID, szError);
			SetCursor(LoadCursor(NULL,IDC_ARROW));
			break;
		}
		else
		{	
			// Allocates a buffer of the size returned by InternetQueryDataAvailable
			lpszData = new char[dwSize+1];

			// Reads the data from the HINTERNET handle.
			if(!InternetReadFile(hResource,(LPVOID)lpszData,dwSize,&dwDownloaded))
			{
				if (GetLastError()== ERROR_IO_PENDING)
				{
					nCounter = 0;
					
					while(GetLastError()==ERROR_IO_PENDING)
					{
						nCounter++;
					}
					goto keep_going;
				}
				sprintf(szError,"Error %d encountered by InternetReadFile",
					GetLastError());
				SetDlgItemText(hX,intCtrlID, szError);
				delete[] lpszData;
				break;
			}
			else
			{

keep_going:				
				// Adds a null terminator to the end of the data buffer
				lpszData[dwDownloaded]='\0';

				// Allocates the holding buffer
				lpszHolding = new char[dwSizeSum + dwDownloaded + 1];
				
				// Checks if there has been any data written to the textbox
				if (dwSizeSum != 0)
				{
					// Retrieves the data stored in the textbox if any
					GetDlgItemText(hX,intCtrlID,(LPSTR)lpszHolding,dwSizeSum);
					
					// Adds a null terminator at the end of the textbox data
					lpszHolding[dwSizeSum]='\0';
				}
				else
				{
					// Make the holding buffer an empty string. 
					lpszHolding[0]='\0';
				}

				// Adds the new data to the holding buffer
				strcat(lpszHolding,lpszData);

				// Writes the holding buffer to the textbox
				SetDlgItemText(hX,intCtrlID,(LPSTR)lpszHolding);

				// Delete the two buffers
				delete[] lpszHolding;
				delete[] lpszData;

				// Add the size of the downloaded data to the textbox data size
				dwSizeSum = dwSizeSum + dwDownloaded + 1;

				// Check the size of the remaining data.  If it is zero, break.
				if (dwDownloaded == 0)
					break;
			}
		}
	}
	while(TRUE);

	// Close the HINTERNET handle
	InternetCloseHandle(hResource);

	// Set the cursor back to an arrow
	SetCursor(LoadCursor(NULL,IDC_ARROW));

	// Return
	return TRUE;
}
					



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//
//
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