21.13. ftplib — FTP 协议客户端 ¶

>>> from ftplib import FTP
>>> ftp = FTP('ftp.debian.org')     # connect to host, default port
>>> ftp.login()                     # user anonymous, passwd anonymous@
'230 Login successful.'
>>> ftp.cwd('debian')               # change into "debian" directory
>>> ftp.retrlines('LIST')           # list directory contents
-rw-rw-r--    1 1176     1176         1063 Jun 15 10:18 README
...
drwxr-sr-x    5 1176     1176         4096 Dec 19  2000 pool
drwxr-sr-x    4 1176     1176         4096 Nov 17  2008 project
drwxr-xr-x    3 1176     1176         4096 Oct 10  2012 tools
'226 Directory send OK.'
>>> ftp.retrbinary('RETR README', open('README', 'wb').write)
'226 Transfer complete.'
>>> ftp.quit()
							

21.13.1. FTP 对象 ¶

Several methods are available in two flavors: one for handling text files and another for binary files. These are named for the command which is used followed by lines for the text version or binary for the binary version.

FTP 实例具有下列方法：

FTP. set_debuglevel ( level ) ¶

Set the instance’s debugging level. This controls the amount of debugging output printed. The default, 0 , produces no debugging output. A value of 1 produces a moderate amount of debugging output, generally a single line per request. A value of 2 or higher produces the maximum amount of debugging output, logging each line sent and received on the control connection.

FTP. connect ( host='' , port=0 , timeout=None , source_address=None ) ¶

Connect to the given host and port. The default port number is 21 , as specified by the FTP protocol specification. It is rarely needed to specify a different port number. This function should be called only once for each instance; it should not be called at all if a host was given when the instance was created. All other methods can only be used after a connection has been made. The optional timeout parameter specifies a timeout in seconds for the connection attempt. If no timeout is passed, the global default timeout setting will be used. source_address is a 2-tuple (host, port) for the socket to bind to as its source address before connecting.

3.3 版改变： source_address 参数被添加。

FTP. getwelcome ( ) ¶

Return the welcome message sent by the server in reply to the initial connection. (This message sometimes contains disclaimers or help information that may be relevant to the user.)

FTP. login ( user='anonymous' , passwd='' , acct='' ) ¶

Log in as the given user 。 passwd and acct parameters are optional and default to the empty string. If no user is specified, it defaults to 'anonymous' 。若 user is 'anonymous' , the default passwd is 'anonymous@' . This function should be called only once for each instance, after a connection has been established; it should not be called at all if a host and user were given when the instance was created. Most FTP commands are only allowed after the client has logged in. The acct parameter supplies “accounting information”; few systems implement this.

FTP. abort ( ) ¶

Abort a file transfer that is in progress. Using this does not always work, but it’s worth a try.

FTP. sendcmd ( cmd ) ¶

Send a simple command string to the server and return the response string.

FTP. voidcmd ( cmd ) ¶

Send a simple command string to the server and handle the response. Return nothing if a response code corresponding to success (codes in the range 200–299) is received. Raise error_reply 否则。

FTP. retrbinary ( cmd , callback , blocksize=8192 , rest=None ) ¶

Retrieve a file in binary transfer mode. cmd should be an appropriate RETR 命令： 'RETR filename' 。 callback function is called for each block of data received, with a single bytes argument giving the data block. The optional blocksize argument specifies the maximum chunk size to read on the low-level socket object created to do the actual transfer (which will also be the largest size of the data blocks passed to callback ). A reasonable default is chosen. rest means the same thing as in the transfercmd() 方法。

FTP. retrlines ( cmd , callback=None ) ¶

Retrieve a file or directory listing in ASCII transfer mode. cmd should be an appropriate RETR command (see retrbinary() ) or a command such as LIST or NLST (usually just the string 'LIST' ). LIST retrieves a list of files and information about those files. NLST retrieves a list of file names. callback function is called for each line with a string argument containing the line with the trailing CRLF stripped. The default callback prints the line to sys.stdout .

FTP. set_pasv ( val ) ¶

Enable “passive” mode if val is true, otherwise disable passive mode. Passive mode is on by default.

FTP. storbinary ( cmd , fp , blocksize=8192 , callback=None , rest=None ) ¶

Store a file in binary transfer mode. cmd should be an appropriate STOR 命令： "STOR filename" . fp 是 文件对象 (opened in binary mode) which is read until EOF using its read() method in blocks of size blocksize to provide the data to be stored. blocksize argument defaults to 8192. callback is an optional single parameter callable that is called on each block of data after it is sent. rest means the same thing as in the transfercmd() 方法。

3.2 版改变： rest 参数被添加。

FTP. storlines ( cmd , fp , callback=None ) ¶

Store a file in ASCII transfer mode. cmd should be an appropriate STOR command (see storbinary() ). Lines are read until EOF from the 文件对象 fp (opened in binary mode) using its readline() method to provide the data to be stored. callback is an optional single parameter callable that is called on each line after it is sent.

FTP. transfercmd ( cmd , rest=None ) ¶

Initiate a transfer over the data connection. If the transfer is active, send an EPRT or PORT command and the transfer command specified by cmd , and accept the connection. If the server is passive, send an EPSV or PASV command, connect to it, and start the transfer command. Either way, return the socket for the connection.

If optional rest is given, a REST command is sent to the server, passing rest 作为自变量。 rest is usually a byte offset into the requested file, telling the server to restart sending the file’s bytes at the requested offset, skipping over the initial bytes. Note however that RFC 959 requires only that rest be a string containing characters in the printable range from ASCII code 33 to ASCII code 126. The transfercmd() method, therefore, converts rest to a string, but no check is performed on the string’s contents. If the server does not recognize the REST command, an error_reply exception will be raised. If this happens, simply call transfercmd() without a rest 自变量。

FTP. ntransfercmd ( cmd , rest=None ) ¶

像 transfercmd() , but returns a tuple of the data connection and the expected size of the data. If the expected size could not be computed, None will be returned as the expected size. cmd and rest means the same thing as in transfercmd() .

FTP. mlsd ( path="" , facts=[] ) ¶

List a directory in a standardized format by using MLSD command ( RFC 3659 )。若 path is omitted the current directory is assumed. facts is a list of strings representing the type of information desired (e.g. ["type", "size", "perm"] ). Return a generator object yielding a tuple of two elements for every file found in path. First element is the file name, the second one is a dictionary containing facts about the file name. Content of this dictionary might be limited by the facts argument but server is not guaranteed to return all requested facts.

3.3 版新增。

FTP. nlst ( argument [ , ... ] ) ¶

Return a list of file names as returned by the NLST command. The optional argument is a directory to list (default is the current server directory). Multiple arguments can be used to pass non-standard options to the NLST 命令。

注意

若服务器支持命令， mlsd() 提供了更好的 API。

FTP. dir ( argument [ , ... ] ) ¶

Produce a directory listing as returned by the LIST command, printing it to standard output. The optional argument is a directory to list (default is the current server directory). Multiple arguments can be used to pass non-standard options to the LIST command. If the last argument is a function, it is used as a callback function as for retrlines() ; the default prints to sys.stdout . This method returns None .

注意

若服务器支持命令， mlsd() 提供了更好的 API。

FTP. rename ( fromname , toname ) ¶

Rename file fromname on the server to toname .

FTP. delete ( filename ) ¶

Remove the file named filename from the server. If successful, returns the text of the response, otherwise raises error_perm on permission errors or error_reply on other errors.

FTP. cwd ( pathname ) ¶

Set the current directory on the server.

FTP. mkd ( pathname ) ¶

Create a new directory on the server.

FTP. pwd ( ) ¶

Return the pathname of the current directory on the server.

FTP. rmd ( dirname ) ¶

Remove the directory named dirname on the server.

FTP. size ( filename ) ¶

Request the size of the file named filename on the server. On success, the size of the file is returned as an integer, otherwise None is returned. Note that the SIZE command is not standardized, but is supported by many common server implementations.

FTP. quit ( ) ¶

发送 QUIT command to the server and close the connection. This is the “polite” way to close a connection, but it may raise an exception if the server responds with an error to the QUIT command. This implies a call to the close() method which renders the FTP instance useless for subsequent calls (see below).

FTP. close ( ) ¶

Close the connection unilaterally. This should not be applied to an already closed connection such as after a successful call to quit() . After this call the FTP instance should not be used any more (after a call to close() or quit() you cannot reopen the connection by issuing another login() 方法)。

21.13.2. FTP_TLS 对象 ¶

FTP_TLS 类继承自 FTP ，定义了这些额外对象：

FTP_TLS. ssl_version ¶

要使用的 SSL 版本 (默认为 ssl.PROTOCOL_SSLv23 ).

FTP_TLS. auth ( ) ¶

Set up a secure control connection by using TLS or SSL, depending on what is specified in the ssl_version 属性。

3.4 版改变： The method now supports hostname check with ssl.SSLContext.check_hostname and Server Name Indication (见 ssl.HAS_SNI ).

FTP_TLS. ccc ( ) ¶

Revert control channel back to plaintext. This can be useful to take advantage of firewalls that know how to handle NAT with non-secure FTP without opening fixed ports.

3.3 版新增。

FTP_TLS. prot_p ( ) ¶

建立安全数据连接。

FTP_TLS. prot_c ( ) ¶

建立明文数据连接。