20.11. ftplib — FTP protocol client
This module defines the class FTP and a few related items. The
FTP class implements the client side of the FTP protocol. You can use
this to write Python programs that perform a variety of automated FTP jobs, such
as mirroring other ftp servers. It is also used by the module
urllib.request to handle URLs that use FTP. For more information on FTP
(File Transfer Protocol), see Internet RFC 959.
Here’s a sample session using the ftplib module:
>>> from ftplib import FTP
>>> ftp = FTP('ftp.cwi.nl') # connect to host, default port
>>> ftp.login() # user anonymous, passwd anonymous@
>>> ftp.retrlines('LIST') # list directory contents
drwxrwsr-x 5 ftp-usr pdmaint 1536 Mar 20 09:48 .
dr-xr-srwt 105 ftp-usr pdmaint 1536 Mar 21 14:32 ..
-rw-r--r-- 1 ftp-usr pdmaint 5305 Mar 20 09:48 INDEX
>>> ftp.retrbinary('RETR README', open('README', 'wb').write)
'226 Transfer complete.'
The module defines the following items:
class ftplib.FTP(host='', user='', passwd='', acct=''[, timeout])
- Return a new instance of the FTP class. When host is given, the
method call connect(host) is made. When user is given, additionally
the method call login(user, passwd, acct) is made (where passwd and
acct default to the empty string when not given). The optional timeout
parameter specifies a timeout in seconds for blocking operations like the
connection attempt (if is not specified, the global default timeout setting
will be used).
- Exception raised when an unexpected reply is received from the server.
- Exception raised when an error code signifying a temporary error (response
codes in the range 400–499) is received.
- Exception raised when an error code signifying a permanent error (response
codes in the range 500–599) is received.
- Exception raised when a reply is received from the server that does not fit
the response specifications of the File Transfer Protocol, i.e. begin with a
digit in the range 1–5.
- The set of all exceptions (as a tuple) that methods of FTP
instances may raise as a result of problems with the FTP connection (as
opposed to programming errors made by the caller). This set includes the
four exceptions listed above as well as socket.error and
- Module netrc
- Parser for the .netrc file format. The file .netrc is
typically used by FTP clients to load user authentication information
before prompting the user.
The file Tools/scripts/ftpmirror.py in the Python source distribution is
a script that can mirror FTP sites, or portions thereof, using the ftplib
module. It can be used as an extended example that applies this module.
20.11.1. FTP Objects
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 instances have the following methods:
- 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])
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
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.
- 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. The passwd and acct parameters are optional and
default to the empty string. If no user is specified, it defaults to
'anonymous'. If 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.
- Abort a file transfer that is in progress. Using this does not always work, but
it’s worth a try.
- Send a simple command string to the server and return the response string.
- 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 otherwise.
FTP.retrbinary(cmd, callback, blocksize=8192, rest=None)
- Retrieve a file in binary transfer mode. cmd should be an appropriate
RETR command: 'RETR filename'. The callback function is called for
each block of data received, with a single string 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
- 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, NLST or MLSD (usually just the string 'LIST').
LIST retrieves a list of files and information about those files.
NLST retrieves a list of file names. On some servers, MLSD retrieves
a machine readable list of files and information about those files. The
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.
- Enable “passive” mode if boolean is true, other disable passive mode.
Passive mode is on by default.
FTP.storbinary(cmd, file, blocksize=8192, callback=None)
- Store a file in binary transfer mode. cmd should be an appropriate
STOR command: "STOR filename". file is an open file object
which is read until EOF using its read() method in blocks of size
blocksize to provide the data to be stored. The blocksize argument
defaults to 8192. callback is an optional single parameter callable that
is called on each block of data after it is sent.
FTP.storlines(cmd, file, 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
open file object file 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.
Initiate a transfer over the data connection. If the transfer is active, send a
EPRT or PORT command and the transfer command specified by cmd, and
accept the connection. If the server is passive, send a 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 as an argument. 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
- Like 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
- 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 command.
- 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.
- Rename file fromname on the server to toname.
- 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.
- Set the current directory on the server.
- Create a new directory on the server.
- Return the pathname of the current directory on the server.
- Remove the directory named dirname on the server.
- 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.
- Send a 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).
- 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() method).