INT GetData(
	LPCTSTR lpszRemoteFile,
	LPBYTE lpBuffer,
	LPDWORD lpdwLength
);

INT GetData(
	LPCTSTR lpszRemoteFile,
	HGLOBAL* lpBuffer,
	LPDWORD lpdwLength
);

INT GetData(
	LPCTSTR lpszRemoteFile,
	LPTSTR lpBuffer,
	DWORD dwMaxLength
);

INT GetData(
	LPCTSTR lpszRemoteFile,
	CString& strBuffer
);

The GetData method transfers the contents of a file on the server to the specified buffer.

Parameters

lpszRemoteFile

A pointer to a string that specifies the file on the server that will be transferred to the local system. The file naming conventions must be that of the host operating system.

lpBuffer

A pointer to a buffer which will contain the data transferred from the server. In alternate forms of the method, this argument may also be a pointer to a global memory handle or reference a CString object.

lpdwLength

A pointer to an unsigned integer which should be initialized to the maximum number of bytes that can be copied to the buffer specified by the lpBuffer parameter. If the lpBuffer parameter points to a global memory handle, the length value should be initialized to zero. When the method returns, this value will be updated with the actual length of the file that was downloaded.

dwMaxLength

An unsigned integer value which specifies the maximum number of characters can be copied into the lpBuffer string. This parameter is used with the version of the method that returns the data in a character array and includes the terminating null character. This value must be greater than one and the lpBuffer parameter cannot be NULL, otherwise the method will return an error.

Return Value

If the method succeeds, the return value is the server result code. If the method fails, the return value is FTP_ERROR. To get extended error information, call GetLastError.

Remarks

The GetData method is used to download the contents of a remote file into a local buffer. The method may be used in one of two ways, depending on the needs of the application. The first method is to pre-allocate a buffer large enough to store the contents of the file. In this case, the lpBuffer parameter will point to the buffer that was allocated, the value that the lpdwLength parameter points to should be initialized to the size of that buffer.

The second method that can be used is have the lpBuffer parameter point to a global memory handle which will contain the file data when the method returns. In this case, the value that the lpdwLength parameter points to must be initialized to zero. It is important to note that the memory handle returned by the method must be freed by the application, otherwise a memory leak will occur. See the example code below.

If the third method or fourth method is used, where the data is returned in a string buffer, the data may be modified so that the end-of-line character sequence matches the convention used by the Windows platform (a carriage return character followed by a linefeed). If Unicode is being used, the data will be converted from a byte array to a Unicode string. An application should only use these versions of the GetData method if the remote file contains text.

This method will cause the current thread to block until the file transfer completes, a timeout occurs or the transfer is canceled. During the transfer, the FTP_EVENT_PROGRESS event will be periodically fired, enabling the application to update any user interface controls. Event notification must be enabled, either by calling EnableEvents, or by registering a callback function using the RegisterEvent method.

To determine the current status of a file transfer while it is in progress, use the GetTransferStatus method.

Example

HGLOBAL hgblBuffer = (HGLOBAL)NULL;
LPBYTE lpBuffer = (LPBYTE)NULL;
DWORD cbBuffer = 0;

// Return the file data into block of global memory allocated by
// the GlobalAlloc function; the handle to this memory will be
// returned in the hgblBuffer parameter
nResult = pClient->GetData(lpszRemoteFile, &hgblBuffer, &cbBuffer);

if (nResult != FTP_ERROR)
{
    // Lock the global memory handle, returning a pointer to the
    // contents of the file data
    lpBuffer = (LPBYTE)GlobalLock(hgblBuffer);
    
    // After the data has been used, the handle must be unlocked
    // and freed, otherwise a memory leak will occur
    GlobalUnlock(hgblBuffer);
    GlobalFree(hgblBuffer);
}

Requirements

Minimum Desktop Platform: Windows 7 (Service Pack 1)
Minimum Server Platform: Windows Server 2008 R2 (Service Pack 1)
Header File: cstools10.h
Import Library: csftpv10.lib
Unicode: Implemented as Unicode and ANSI versions.

See Also

ChangeDirectory, EnableEvents, GetFile, GetTransferStatus, PutData, PutFile, RegisterEvent, SetBufferSize

Copyright © 2023 Catalyst Development Corporation. All rights reserved.