An ASP Component to Send Arbitary Large File from Server to Client

#define RETURN { hr = E_FAIL; goto Cleanup; } // don't kill me! Look at last examples of MS // under http://www.microsoft.com/data/xml // You can't catch me! :-) STDMETHODIMP CGetFile::GetFile(VARIANT vFileName) { _variant_t vReturnBuffer; LPSAFEARRAY psaFile; HANDLE hFile; DWORD dwSizeOfFile; DWORD dwNumberOfBytesRead; BOOL bResult; unsigned char *pReturnBuffer = NULL; long k; HRESULT hr = S_OK; // Create file in this case only OPENS an existing file (or fails // if the file does not exist!) hFile = ::CreateFile( vFileName.bstrVal, // name of the file GENERIC_READ, // desired access FILE_SHARE_READ, // shared access NULL, // security attributes OPEN_EXISTING, // creation disposition - open only if existing! FILE_FLAG_SEQUENTIAL_SCAN, // flag attributes NULL ); if( hFile == INVALID_HANDLE_VALUE ) { return E_FAIL; } dwSizeOfFile = ::GetFileSize( hFile, NULL ); if (dwSizeOfFile == 0xFFFFFFFF) { return E_FAIL; } try { pReturnBuffer = new unsigned char[dwSizeOfFile]; } catch( std::bad_alloc& ) { return E_FAIL; } // Get the binary content of the file bResult = ::ReadFile( hFile, pReturnBuffer, dwSizeOfFile, &dwNumberOfBytesRead, NULL ); if( FALSE == bResult ) { RETURN(E_FAIL); } psaFile = ::SafeArrayCreateVector( VT_UI1 /*unsigned char*/, 0, dwSizeOfFile ); if( !psaFile ) { RETURN(E_FAIL); } // Fill in the SAFEARRAY with the binary content of the file for( k = 0; k < (int) dwSizeOfFile; k++ ) { if( FAILED(::SafeArrayPutElement( psaFile, &k, &pReturnBuffer[k] )) ) { RETURN(E_FAIL); } } vReturnBuffer.vt = VT_ARRAY | VT_UI1; V_ARRAY(&vReturnBuffer) = psaFile; m_piResponse->BinaryWrite(vReturnBuffer); Cleanup: if( pReturnBuffer ) delete [] pReturnBuffer; return SUCCEEDED(hr) ? S_OK : E_FAIL; } As you see, the idea is simple: to read the binary content of the file, to pack it into safearray and then to pass as a parameter to IResponse::BinaryWrite(). The process is pretty straightforward

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