Discover WIN32. How to use a sync/async retrieve HTTP content in your ASP & VB projects.

// RetrievePage1.cpp : Implementation of CRetrievePageApp and DLL registration.

#include "stdafx.h"
#include "RetrievePage.h"
#include "RetrievePage1.h"

//#include <wininet.h>
#include <afxinet.h>


/////////////////////////////////////////////////////////////////////////////
// CMyObjectTemplate

IMPLEMENT_SERIAL(CHTTPpage, CObject, 0)

CHTTPpage::CHTTPpage()
{
}

CHTTPpage::~CHTTPpage()
{
}

void CHTTPpage::FormatMyObject(CString& str)
{
	str.Format(_T("{%i, %s}"), iDone, (LPCTSTR)sBody);
}

void CHTTPpage::Serialize(CArchive& ar)
{
	WORD w;
	if (ar.IsStoring())
	{
		w = (WORD)iDone;
		ar << w;
		ar << sBody;
	}
	else
	{
		ar >> w;
		iDone = w;
		ar >> sBody;
	}
}
// END CMyObjectTemplate
/////////////////////////////////////////////////////////////////////////////

/////////////////////////////////////////////////////////////////////////////
//

STDMETHODIMP RetrievePage::InterfaceSupportsErrorInfo(REFIID riid)
{
	static const IID* arr[] = 
	{
		&IID_IRetrievePage,
	};

	for (int i=0;i<sizeof(arr)/sizeof(arr[0]);i++)
	{
		if (InlineIsEqualGUID(*arr[i],riid))
			return S_OK;
	}
	return S_FALSE;
}

STDMETHODIMP RetrievePage::Retrieve(BSTR newVal, BSTR *parOut)
{
	AFX_MANAGE_STATE(AfxGetStaticModuleState())

	// TODO: Add your implementation code here
	CString		sBody;
	CString		sURL;

	sURL	= CString(newVal);
	  
	//no thread
	if ( GetPage(sURL, sBody) )
	{
		CComBSTR bstrTemp;
		
		bstrTemp.Append( sBody ); 
		*parOut = bstrTemp.Detach();
	
	}
	else
	{
		CComBSTR bstrTemp;
		bstrTemp.Append( m_sError ); 
		*parOut = bstrTemp.Detach();
		
	}
	

	return S_OK;
}

UINT MyThreadGetPage(LPVOID pParam)
{
	CString		sKey;
	CString		sBody;

	RetrievePage* pObject = (RetrievePage*)pParam;
//'	if (pObject == NULL )
//		return 0;   // if pObject is not valid

	sKey			= pObject->m_sURL;

	CHTTPpage		*oHTTPpage;
	//tre sa vedem daca nu cumva avem deja object la sKey
	oHTTPpage		= pObject->m_MapStringToHTTPpage[sKey];

	
	if ( pObject->GetPage(sKey, sBody) )
	{
		
		oHTTPpage->iDone				= 1;
		oHTTPpage->sBody				= sBody;
		
		pObject->m_MapStringToHTTPpage[sKey]		= oHTTPpage;
		
		return 1;   // thread completed successfully
	}
	else
	{
		oHTTPpage->iDone				= 0;
		oHTTPpage->sBody				= "";
		
		pObject->m_MapStringToHTTPpage[sKey]		= oHTTPpage;
		return 0;   // thread completed UNsuccessfully
	}
	
	
}

//bool RetrievePage::GetPage(CString URL)
bool RetrievePage::GetPage(CString sURL, CString& sBody)
{
	sURL.TrimLeft();
	sURL.TrimRight();
	
	char *location;
	char pagina[100000];
	
	
	LPTSTR	ppp	= sURL.GetBuffer(sURL.GetLength());
	location	= ppp;
	if (strnicmp(location, "http://",7)==0)
	{
		HINTERNET internet=InternetOpen("Daemon", INTERNET_OPEN_TYPE_PRECONFIG , NULL, NULL, NULL);
		if (internet)
		{
			/*HINTERNET file_handle=InternetOpenUrl(internet,
				location, NULL, 0,
				INTERNET_FLAG_KEEP_CONNECTION & INTERNET_FLAG_DONT_CACHE & INTERNET_FLAG_RELOAD, 0);
			*/
			

			HINTERNET file_handle=InternetOpenUrl(internet,
				location, NULL, 0,
				INTERNET_FLAG_RELOAD, 0);
			

			if (file_handle)
			{
				DWORD bytes_read=0;
				
				//Beep(200, 200);
				InternetReadFile(file_handle, pagina, 100000, &bytes_read);
				
				//in pagina am &bytes_read bytes de pe internet
				//tre sa bag pagina in sBody			
				/*FILE *fp;
				if ((fp=fopen("C:\\HTTPFILE.TXT","wb")) !=NULL)
				{
					fwrite(pagina, bytes_read, 1, fp);
					fclose(fp);
				}*/
				
				sBody	= CString (pagina);
				sBody	= sBody.Left(bytes_read);

				long lll= sBody.GetLength();

				//Sleep(0);
				//AfxMessageBox("GetPage:  "+ sURL + "   "+ sBody);
			}
			else
			{
				m_sError = "Is not possible to connect to internet";
				return FALSE;
			}
		}
		else
		{
			m_sError	= "The sURL location must contain 'http://' string";
			return FALSE;
		}
		
		InternetCloseHandle(internet);
	}	
	
	return true;
}


STDMETHODIMP RetrievePage::RetrieveAsync(BSTR newVal, BSTR *parOut)
{
	AFX_MANAGE_STATE(AfxGetStaticModuleState())
		
		// TODO: Add your implementation code here
	CString			sURL;
	sURL			= CString(newVal);
	
	CComBSTR		bstrTemp;

	CHTTPpage		*oHTTPpage		= NULL;
	
	//tre sa vedem daca nu cumva avem deja object la sKey
	if ( !m_MapStringToHTTPpage.Lookup(sURL, oHTTPpage) )
		oHTTPpage		= new CHTTPpage;					//object nou
	
	if (oHTTPpage != NULL)
	{
		oHTTPpage->iDone				= 0;
		oHTTPpage->sBody				= "";
		
		m_MapStringToHTTPpage[sURL]		= oHTTPpage;
		
		m_sURL							= sURL;
		if ( AfxBeginThread( MyThreadGetPage , this, THREAD_PRIORITY_NORMAL ) )
		{
			bstrTemp.Append( "ok" ); 
			*parOut = bstrTemp.Detach();
		}
		else
		{
			bstrTemp.Append( m_sError ); 
			*parOut = bstrTemp.Detach();
		}
	}
	else
	{
		bstrTemp.Append( "Memory Error" ); 
		*parOut = bstrTemp.Detach();
	}

	return S_OK;
}


STDMETHODIMP RetrievePage::RetrieveAsyncCompleted(BSTR newVal, int *parOut)
{
	AFX_MANAGE_STATE(AfxGetStaticModuleState())

	// TODO: Add your implementation code here

	CString			sKey	= CString(newVal);

	CHTTPpage		*oHTTPpage = NULL;//	= new CHTTPpage;;

	if (m_MapStringToHTTPpage.Lookup(sKey, oHTTPpage))
	{
		if ( oHTTPpage != NULL )
			*parOut				= oHTTPpage->iDone;
		else
			*parOut				= -1;
	}
	else	//nu mai exista cheia
		*parOut				= -1;

	
	//delete oHTTPpage;

	return S_OK;
}

STDMETHODIMP RetrievePage::RetrieveAsyncPage(BSTR newVal, BSTR *parOut)
{
	AFX_MANAGE_STATE(AfxGetStaticModuleState())

	// TODO: Add your implementation code here
	CString			sKey			= CString(newVal);
	CString			sToken;
	CComBSTR		bstrTemp("");
 
	CHTTPpage		*oHTTPpage	= NULL;//	= new CHTTPpage;
	
	if (m_MapStringToHTTPpage.Lookup(sKey, oHTTPpage))
	{
		if (oHTTPpage != NULL)
		{
			sToken		= oHTTPpage->sBody;
			bstrTemp.Append( sToken );
			//AfxMessageBox(sToken);
			
			*parOut				= bstrTemp;
		}
		else
		{
			bstrTemp.Append( "" );
			*parOut				= bstrTemp;
		}
	}
	else
	{
		bstrTemp.Append( "" );
		*parOut				= bstrTemp;
	}

	//delete oHTTPpage;

	return S_OK;
}