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CFtpConnection Class

  • บทความ

Manages your FTP connection to an Internet server and allows direct manipulation of directories and files on that server.

Syntax

class CFtpConnection : public CInternetConnection

Members

Public Constructors

Name Description
CFtpConnection::CFtpConnection Constructs a CFtpConnection object.

Public Methods

Name Description
CFtpConnection::Command Sends a command directly to an FTP server.
CFtpConnection::CreateDirectory Creates a directory on the server.
CFtpConnection::GetCurrentDirectory Gets the current directory for this connection.
CFtpConnection::GetCurrentDirectoryAsURL Gets the current directory for this connection as a URL.
CFtpConnection::GetFile Gets a file from the connected server
CFtpConnection::OpenFile Opens a file on the connected server.
CFtpConnection::PutFile Places a file on the server.
CFtpConnection::Remove Removes a file from the server.
CFtpConnection::RemoveDirectory Removes the specified directory from the server.
CFtpConnection::Rename Renames a file on the server.
CFtpConnection::SetCurrentDirectory Sets the current FTP directory.

Remarks

FTP is one of the three Internet services recognized by the MFC WinInet classes.

To communicate with an FTP Internet server, you must first create an instance of CInternetSession, and then create a CFtpConnection object. You never create a CFtpConnection object directly; rather, call CInternetSession::GetFtpConnection, which creates the CFtpConnection object and returns a pointer to it.

To learn more about how CFtpConnection works with the other MFC Internet classes, see the article Internet Programming with WinInet. For more information about communicating with the other two supported services, HTTP and gopher, see the classes CHttpConnection and CGopherConnection.

Example

See the example in the CFtpFileFind class overview.

Inheritance Hierarchy

CObject

CInternetConnection

CFtpConnection

Requirements

Header: afxinet.h

CFtpConnection::CFtpConnection

This member function is called to construct a CFtpConnection object.

CFtpConnection(
    CInternetSession* pSession,
    HINTERNET hConnected,
    LPCTSTR pstrServer,
    DWORD_PTR dwContext);

CFtpConnection(
    CInternetSession* pSession,
    LPCTSTR pstrServer,
    LPCTSTR pstrUserName = NULL,
    LPCTSTR pstrPassword = NULL,
    DWORD_PTR dwContext = 0,
    INTERNET_PORT nPort = INTERNET_INVALID_PORT_NUMBER,
    BOOL bPassive = FALSE);

Parameters

pSession
A pointer to the related CInternetSession object.

hConnected
The Windows handle of the current Internet session.

pstrServer
A pointer to a string containing the FTP server name.

dwContext
The context identifier for the operation. dwContext identifies the operation's status information returned by CInternetSession::OnStatusCallback. The default is set to 1; however, you can explicitly assign a specific context ID for the operation. The object and any work it does will be associated with that context ID.

pstrUserName
Pointer to a null-terminated string that specifies the name of the user to log in. If NULL, the default is anonymous.

pstrPassword
A pointer to a null-terminated string that specifies the password to use to log in. If both pstrPassword and pstrUserName are NULL, the default anonymous password is the user's email name. If pstrPassword is NULL (or an empty string) but pstrUserName is not NULL, a blank password is used. The following table describes the behavior for the four possible settings of pstrUserName and pstrPassword:

pstrUserName pstrPassword Username sent to FTP server Password sent to FTP server
NULL or " " NULL or " " "anonymous" User's email name
Non- NULL String NULL or " " pstrUserName " "
NULL Non- NULL String ERROR ERROR
Non- NULL String Non- NULL String pstrUserName pstrPassword

nPort
A number that identifies the TCP/IP port to use on the server.

bPassive
Specifies passive or active mode for this FTP session. If set to TRUE, it sets the Win32 API dwFlag to INTERNET_FLAG_PASSIVE.

Remarks

You never create a CFtpConnection object directly. Instead, call CInternetSession::GetFtpConnection, which creates the CFptConnection object.

CFtpConnection::Command

Sends a command directly to an FTP server.

CInternetFile* Command(
    LPCTSTR pszCommand,
    CmdResponseType eResponse = CmdRespNone,
    DWORD dwFlags = FTP_TRANSFER_TYPE_BINARY,
    DWORD_PTR dwContext = 1);

Parameters

pszCommand
A pointer to a string containing the command to be sent.

eResponse
Specifies whether a response is expected from the FTP server. Can be one of the following values:

  • CmdRespNone No response is expected.
  • CmdRespRead A response is expected.
  • CmdRespWrite Not used.

The CmdResponseType is a member of CFtpConnection, defined in afxinet.h.

dwFlags
A value containing the flags that control this function. For a complete list, see FTPCommand.

dwContext
A pointer to a value containing an application-defined value used to identify the application context in callbacks.

Return Value

Nonzero if successful; otherwise 0.

Remarks

This member function emulates the functionality of the FTPCommand function, as described in the Windows SDK.

If an error occurs, MFC throws an exception of type CInternetException.

CFtpConnection::CreateDirectory

Call this member function to create a directory on the connected server.

BOOL CreateDirectory(LPCTSTR pstrDirName);

Parameters

pstrDirName
A pointer to a string containing the name of the directory to create.

Return Value

Nonzero if successful; otherwise 0. If the call fails, the Windows function GetLastError may be called to determine the cause of the error.

Remarks

Use GetCurrentDirectory to determine the current working directory for this connection to the server. Do not assume that the remote system has connected you to the root directory.

The pstrDirName parameter can be either a partially or a fully qualified filename relative to the current directory. A backslash (\) or forward slash (/) can be used as the directory separator for either name. CreateDirectory translates the directory name separators to the appropriate characters before they are used.

CFtpConnection::GetCurrentDirectory

Call this member function to get the name of the current directory.

BOOL GetCurrentDirectory(CString& strDirName) const;

BOOL GetCurrentDirectory(
    LPTSTR pstrDirName,
    LPDWORD lpdwLen) const;

Parameters

strDirName
A reference to a string that will receive the name of the directory.

pstrDirName
A pointer to a string that will receive the name of the directory.

lpdwLen
A pointer to a DWORD that contains the following information:

On entry: The size of the buffer referenced by pstrDirName.

On return: The number of characters stored to pstrDirName. If the member function fails and ERROR_INSUFFICIENT_BUFFER is returned, then lpdwLen contains the number of bytes that the application must allocate in order to receive the string.

Return Value

Nonzero if successful; otherwise 0. If the call fails, the Win32 function GetLastError may be called to determine the cause of the error.

Remarks

To get the directory name as a URL instead, call GetCurrentDirectoryAsURL.

The parameters pstrDirName or strDirName can be either partially qualified filenames relative to the current directory or fully qualified. A backslash (\) or forward slash (/) can be used as the directory separator for either name. GetCurrentDirectory translates the directory name separators to the appropriate characters before they are used.

CFtpConnection::GetCurrentDirectoryAsURL

Call this member function to get the current directory's name as a URL.

BOOL GetCurrentDirectoryAsURL(CString& strDirName) const;

BOOL GetCurrentDirectoryAsURL(
    LPTSTR pstrName,
    LPDWORD lpdwLen) const;

Parameters

strDirName
A reference to a string that will receive the name of the directory.

pstrDirName
A pointer to a string that will receive the name of the directory.

lpdwLen
A pointer to a DWORD that contains the following information:

On entry: The size of the buffer referenced by pstrDirName.

On return: The number of characters stored to pstrDirName. If the member function fails and ERROR_INSUFFICIENT_BUFFER is returned, then lpdwLen contains the number of bytes that the application must allocate in order to receive the string.

Return Value

Nonzero if successful; otherwise 0. If the call fails, the Win32 function GetLastError may be called to determine the cause of the error.

Remarks

GetCurrentDirectoryAsURL behaves the same as GetCurrentDirectory

The parameter strDirName can be either partially qualified filenames relative to the current directory or fully qualified. A backslash (\) or forward slash (/) can be used as the directory separator for either name. GetCurrentDirectoryAsURL translates the directory name separators to the appropriate characters before they are used.

CFtpConnection::GetFile

Call this member function to get a file from an FTP server and store it on the local machine.

BOOL GetFile(
    LPCTSTR pstrRemoteFile,
    LPCTSTR pstrLocalFile,
    BOOL bFailIfExists = TRUE,
    DWORD dwAttributes = FILE_ATTRIBUTE_NORMAL,
    DWORD dwFlags = FTP_TRANSFER_TYPE_BINARY,
    DWORD_PTR dwContext = 1);

Parameters

pstrRemoteFile
A pointer to a null-terminated string containing the name of a file to retrieve from the FTP server.

pstrLocalFile
A pointer to a null-terminated string containing the name of the file to create on the local system.

bFailIfExists
Indicates whether the file name may already be used by an existing file. If the local file name already exists, and this parameter is TRUE, GetFile fails. Otherwise, GetFile will erase the existing copy of the file.

dwAttributes
Indicates the attributes of the file. This can be any combination of the following FILE_ATTRIBUTE_* flags.

  • FILE_ATTRIBUTE_ARCHIVE The file is an archive file. Applications use this attribute to mark files for backup or removal.

  • FILE_ATTRIBUTE_COMPRESSED The file or directory is compressed. For a file, compression means that all of the data in the file is compressed. For a directory, compression is the default for newly created files and subdirectories.

  • FILE_ATTRIBUTE_DIRECTORY The file is a directory.

  • FILE_ATTRIBUTE_NORMAL The file has no other attributes set. This attribute is valid only if used alone. All other file attributes override FILE_ATTRIBUTE_NORMAL:

  • FILE_ATTRIBUTE_HIDDEN The file is hidden. It is not to be included in an ordinary directory listing.

  • FILE_ATTRIBUTE_READONLY The file is read only. Applications can read the file but cannot write to it or delete it.

  • FILE_ATTRIBUTE_SYSTEM The file is part of or is used exclusively by the operating system.

  • FILE_ATTRIBUTE_TEMPORARY The file is being used for temporary storage. Applications should write to the file only if absolutely necessary. Most of the file's data remains in memory without being flushed to the media because the file will soon be deleted.

dwFlags
Specifies the conditions under which the transfer occurs. This parameter can be any of the dwFlags values described in FtpGetFile in the Windows SDK.

dwContext
The context identifier for the file retrieval. See Remarks for more information about dwContext.

Return Value

Nonzero if successful; otherwise 0. If the call fails, the Win32 function GetLastError may be called to determine the cause of the error.

Remarks

GetFile is a high-level routine that handles all of the overhead associated with reading a file from an FTP server and storing it locally. Applications that only retrieve file data, or that require close control over the file transfer, should use OpenFile and CInternetFile::Read instead.

If dwFlags is FILE_TRANSFER_TYPE_ASCII, translation of file data also converts control and formatting characters to Windows equivalents. The default transfer is binary mode, where the file is downloaded in the same format as it is stored on the server.

Both pstrRemoteFile and pstrLocalFile can be either partially qualified filenames relative to the current directory or fully qualified. A backslash (\) or forward slash (/) can be used as the directory separator for either name. GetFile translates the directory name separators to the appropriate characters before they are used.

Override the dwContext default to set the context identifier to a value of your choosing. The context identifier is associated with this specific operation of the CFtpConnection object created by its CInternetSession object. The value is returned to CInternetSession::OnStatusCallback to provide status on the operation with which it is identified. See the article Internet First Steps: WinInet for more information about the context identifier.

CFtpConnection::OpenFile

Call this member function to open a file located on an FTP server for reading or writing.

CInternetFile* OpenFile(
    LPCTSTR pstrFileName,
    DWORD dwAccess = GENERIC_READ,
    DWORD dwFlags = FTP_TRANSFER_TYPE_BINARY,
    DWORD_PTR dwContext = 1);

Parameters

pstrFileName
A pointer to a string containing the name of the file to be opened.

dwAccess
Determines how the file will be accessed. Can be either GENERIC_READ or GENERIC_WRITE, but not both.

dwFlags
Specifies the conditions under which subsequent transfers occur. This can be any of the following FTP_TRANSFER_* constants:

  • FTP_TRANSFER_TYPE_ASCII The file transfers using FTP ASCII (Type A) transfer method. Converts control and formatting information to local equivalents.

  • FTP_TRANSFER_TYPE_BINARY The file transfers data using FTP's Image (Type I) transfer method. The file transfers data exactly as it exists, with no changes. This is the default transfer method.

dwContext
The context identifier for opening the file. See Remarks for more information about dwContext.

Return Value

A pointer to a CInternetFile object.

Remarks

OpenFile should be used in the following situations:

  • An application has data that needs to be sent and created as a file on the FTP server, but that data is not in a local file. Once OpenFile opens a file, the application uses CInternetFile::Write to send the FTP file data to the server.

  • An application must retrieve a file from the server and place it into application-controlled memory, instead of writing it to disk. The application uses CInternetFile::Read after using OpenFile to open the file.

  • An application needs a fine level of control over a file transfer. For example, the application may want to display a progress control indicate the progress of the file transfer status while downloading a file.

After calling OpenFile and until calling CInternetFile::Close, the application can only call CInternetFile::Read, CInternetFile::Write, CInternetConnection::Close, or CFtpFileFind::FindFile. Calls to other FTP functions for the same FTP session will fail and set the error code to FTP_ETRANSFER_IN_PROGRESS.

The pstrFileName parameter can be either a partially qualified filename relative to the current directory or fully qualified. A backslash (\) or forward slash (/) can be used as the directory separator for either name. OpenFile translates the directory name separators to the appropriate characters before using it.

Override the dwContext default to set the context identifier to a value of your choosing. The context identifier is associated with this specific operation of the CFtpConnection object created by its CInternetSession object. The value is returned to CInternetSession::OnStatusCallback to provide status on the operation with which it is identified. See the article Internet First Steps: WinInet for more information about the context identifier.

CFtpConnection::PutFile

Call this member function to store a file on an FTP server.

BOOL PutFile(
    LPCTSTR pstrLocalFile,
    LPCTSTR pstrRemoteFile,
    DWORD dwFlags = FTP_TRANSFER_TYPE_BINARY,
    DWORD_PTR dwContext = 1);

Parameters

pstrLocalFile
A pointer to a string containing the name of the file to send from the local system.

pstrRemoteFile
A pointer to a string containing the name of the file to create on the FTP server.

dwFlags
Specifies the conditions under which the transfer of the file occurs. Can be any of the FTP_TRANSFER_* constants described in OpenFile.

dwContext
The context identifier for placing the file. See Remarks for more information about dwContext.

Return Value

Nonzero if successful; otherwise 0. If the call fails, the Win32 function GetLastError may be called to determine the cause of the error.

Remarks

PutFile is a high-level routine that handles all of the operations associated with storing a file on an FTP server. Applications that only send data, or that require closer control over the file transfer, should use OpenFile and CInternetFile::Write.

Override the dwContext default to set the context identifier to a value of your choosing. The context identifier is associated with this specific operation of the CFtpConnection object created by its CInternetSession object. The value is returned to CInternetSession::OnStatusCallback to provide status on the operation with which it is identified. See the article Internet First Steps: WinInet for more information about the context identifier.

CFtpConnection::Remove

Call this member function to delete the specified file from the connected server.

BOOL Remove(LPCTSTR pstrFileName);

Parameters

pstrFileName
A pointer to a string containing the file name to remove.

Return Value

Nonzero if successful; otherwise 0. If the call fails, the Win32 function GetLastError may be called to determine the cause of the error.

Remarks

The pstrFileName parameter can be either a partially qualified filename relative to the current directory or fully qualified. A backslash (\) or forward slash (/) can be used as the directory separator for either name. The Remove function translates the directory name separators to the appropriate characters before they are used.

CFtpConnection::RemoveDirectory

Call this member function to remove the specified directory from the connected server.

BOOL RemoveDirectory(LPCTSTR pstrDirName);

Parameters

pstrDirName
A pointer to a string containing the directory to be removed.

Return Value

Nonzero if successful; otherwise 0. If the call fails, the Win32 function GetLastError may be called to determine the cause of the error.

Remarks

Use GetCurrentDirectory to determine the server's current working directory. Do not assume that the remote system has connected you to the root directory.

The pstrDirName parameter can be either a partially or fully qualified filename relative to the current directory. A backslash (\) or forward slash (/) can be used as the directory separator for either name. RemoveDirectory translates the directory name separators to the appropriate characters before they are used.

CFtpConnection::Rename

Call this member function to rename the specified file on the connected server.

BOOL Rename(
    LPCTSTR pstrExisting,
    LPCTSTR pstrNew);

Parameters

pstrExisting
A pointer to a string containing the current name of the file to be renamed.

pstrNew
A pointer to a string containing the file's new name.

Return Value

Nonzero if successful; otherwise 0. If the call fails, the Win32 function GetLastError may be called to determine the cause of the error.

Remarks

The pstrExisting and pstrNew parameters can be either a partially qualified filename relative to the current directory or fully qualified. A backslash (\) or forward slash (/) can be used as the directory separator for either name. Rename translates the directory name separators to the appropriate characters before they are used.

CFtpConnection::SetCurrentDirectory

Call this member function to change to a different directory on the FTP server.

BOOL SetCurrentDirectory(LPCTSTR pstrDirName);

Parameters

pstrDirName
A pointer to a string containing the name of the directory.

Return Value

Nonzero if successful; otherwise 0. If the call fails, the Win32 function GetLastError may be called to determine the cause of the error.

Remarks

The pstrDirName parameter can be either a partially or fully qualified filename relative to the current directory. A backslash (\) or forward slash (/) can be used as the directory separator for either name. SetCurrentDirectory translates the directory name separators to the appropriate characters before they are used.

Use GetCurrentDirectory to determine an FTP server's current working directory. Do not assume that the remote system has connected you to the root directory.

See also

CInternetConnection Class
Hierarchy Chart
CInternetConnection Class
CInternetSession Class