source: python/trunk/Doc/library/ftplib.rst

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[2]1:mod:`ftplib` --- FTP protocol client
2=====================================
3
4.. module:: ftplib
5 :synopsis: FTP protocol client (requires sockets).
6
7
8.. index::
9 pair: FTP; protocol
10 single: FTP; ftplib (standard module)
11
[391]12**Source code:** :source:`Lib/ftplib.py`
13
14--------------
15
[2]16This module defines the class :class:`FTP` and a few related items. The
17:class:`FTP` class implements the client side of the FTP protocol. You can use
18this to write Python programs that perform a variety of automated FTP jobs, such
19as mirroring other ftp servers. It is also used by the module :mod:`urllib` to
20handle URLs that use FTP. For more information on FTP (File Transfer Protocol),
21see Internet :rfc:`959`.
22
23Here's a sample session using the :mod:`ftplib` module::
24
25 >>> from ftplib import FTP
[391]26 >>> ftp = FTP('ftp.debian.org') # connect to host, default port
27 >>> ftp.login() # user anonymous, passwd anonymous@
28 '230 Login successful.'
29 >>> ftp.cwd('debian') # change into "debian" directory
30 >>> ftp.retrlines('LIST') # list directory contents
31 -rw-rw-r-- 1 1176 1176 1063 Jun 15 10:18 README
32 ...
33 drwxr-sr-x 5 1176 1176 4096 Dec 19 2000 pool
34 drwxr-sr-x 4 1176 1176 4096 Nov 17 2008 project
35 drwxr-xr-x 3 1176 1176 4096 Oct 10 2012 tools
36 '226 Directory send OK.'
[2]37 >>> ftp.retrbinary('RETR README', open('README', 'wb').write)
38 '226 Transfer complete.'
39 >>> ftp.quit()
40
[391]41
[2]42The module defines the following items:
43
44.. class:: FTP([host[, user[, passwd[, acct[, timeout]]]]])
45
46 Return a new instance of the :class:`FTP` class. When *host* is given, the
47 method call ``connect(host)`` is made. When *user* is given, additionally
48 the method call ``login(user, passwd, acct)`` is made (where *passwd* and
49 *acct* default to the empty string when not given). The optional *timeout*
50 parameter specifies a timeout in seconds for blocking operations like the
51 connection attempt (if is not specified, the global default timeout setting
52 will be used).
53
54 .. versionchanged:: 2.6
55 *timeout* was added.
56
57
[391]58.. class:: FTP_TLS([host[, user[, passwd[, acct[, keyfile[, certfile[, timeout]]]]]]])
[2]59
[391]60 A :class:`FTP` subclass which adds TLS support to FTP as described in
61 :rfc:`4217`.
62 Connect as usual to port 21 implicitly securing the FTP control connection
63 before authenticating. Securing the data connection requires the user to
64 explicitly ask for it by calling the :meth:`prot_p` method.
65 *keyfile* and *certfile* are optional -- they can contain a PEM formatted
66 private key and certificate chain file name for the SSL connection.
[2]67
[391]68 .. versionadded:: 2.7
[2]69
[391]70 Here's a sample session using the :class:`FTP_TLS` class:
[2]71
[391]72 >>> from ftplib import FTP_TLS
73 >>> ftps = FTP_TLS('ftp.python.org')
74 >>> ftps.login() # login anonymously before securing control channel
75 >>> ftps.prot_p() # switch to secure data connection
76 >>> ftps.retrlines('LIST') # list directory content securely
77 total 9
78 drwxr-xr-x 8 root wheel 1024 Jan 3 1994 .
79 drwxr-xr-x 8 root wheel 1024 Jan 3 1994 ..
80 drwxr-xr-x 2 root wheel 1024 Jan 3 1994 bin
81 drwxr-xr-x 2 root wheel 1024 Jan 3 1994 etc
82 d-wxrwxr-x 2 ftp wheel 1024 Sep 5 13:43 incoming
83 drwxr-xr-x 2 root wheel 1024 Nov 17 1993 lib
84 drwxr-xr-x 6 1094 wheel 1024 Sep 13 19:07 pub
85 drwxr-xr-x 3 root wheel 1024 Jan 3 1994 usr
86 -rw-r--r-- 1 root root 312 Aug 1 1994 welcome.msg
87 '226 Transfer complete.'
88 >>> ftps.quit()
89 >>>
[2]90
91
[391]92.. exception:: error_reply
[2]93
[391]94 Exception raised when an unexpected reply is received from the server.
[2]95
96
[391]97.. exception:: error_temp
[2]98
[391]99 Exception raised when an error code signifying a temporary error (response
100 codes in the range 400--499) is received.
[2]101
102
[391]103.. exception:: error_perm
[2]104
[391]105 Exception raised when an error code signifying a permanent error (response
106 codes in the range 500--599) is received.
[2]107
108
[391]109.. exception:: error_proto
110
111 Exception raised when a reply is received from the server that does not fit
112 the response specifications of the File Transfer Protocol, i.e. begin with a
113 digit in the range 1--5.
114
115
116.. data:: all_errors
117
118 The set of all exceptions (as a tuple) that methods of :class:`FTP`
119 instances may raise as a result of problems with the FTP connection (as
120 opposed to programming errors made by the caller). This set includes the
121 four exceptions listed above as well as :exc:`socket.error` and
122 :exc:`IOError`.
123
124
[2]125.. seealso::
126
127 Module :mod:`netrc`
[391]128 Parser for the :file:`.netrc` file format. The file :file:`.netrc` is
129 typically used by FTP clients to load user authentication information
130 before prompting the user.
[2]131
132 .. index:: single: ftpmirror.py
133
134 The file :file:`Tools/scripts/ftpmirror.py` in the Python source distribution is
135 a script that can mirror FTP sites, or portions thereof, using the :mod:`ftplib`
136 module. It can be used as an extended example that applies this module.
137
138
139.. _ftp-objects:
140
141FTP Objects
142-----------
143
144Several methods are available in two flavors: one for handling text files and
145another for binary files. These are named for the command which is used
146followed by ``lines`` for the text version or ``binary`` for the binary version.
147
148:class:`FTP` instances have the following methods:
149
150
151.. method:: FTP.set_debuglevel(level)
152
153 Set the instance's debugging level. This controls the amount of debugging
154 output printed. The default, ``0``, produces no debugging output. A value of
155 ``1`` produces a moderate amount of debugging output, generally a single line
156 per request. A value of ``2`` or higher produces the maximum amount of
157 debugging output, logging each line sent and received on the control connection.
158
159
160.. method:: FTP.connect(host[, port[, timeout]])
161
162 Connect to the given host and port. The default port number is ``21``, as
163 specified by the FTP protocol specification. It is rarely needed to specify a
164 different port number. This function should be called only once for each
165 instance; it should not be called at all if a host was given when the instance
166 was created. All other methods can only be used after a connection has been
167 made.
168
169 The optional *timeout* parameter specifies a timeout in seconds for the
170 connection attempt. If no *timeout* is passed, the global default timeout
171 setting will be used.
172
173 .. versionchanged:: 2.6
174 *timeout* was added.
175
176
177.. method:: FTP.getwelcome()
178
179 Return the welcome message sent by the server in reply to the initial
180 connection. (This message sometimes contains disclaimers or help information
181 that may be relevant to the user.)
182
183
184.. method:: FTP.login([user[, passwd[, acct]]])
185
186 Log in as the given *user*. The *passwd* and *acct* parameters are optional and
187 default to the empty string. If no *user* is specified, it defaults to
188 ``'anonymous'``. If *user* is ``'anonymous'``, the default *passwd* is
189 ``'anonymous@'``. This function should be called only once for each instance,
190 after a connection has been established; it should not be called at all if a
191 host and user were given when the instance was created. Most FTP commands are
192 only allowed after the client has logged in. The *acct* parameter supplies
193 "accounting information"; few systems implement this.
194
195
196.. method:: FTP.abort()
197
198 Abort a file transfer that is in progress. Using this does not always work, but
199 it's worth a try.
200
201
202.. method:: FTP.sendcmd(command)
203
204 Send a simple command string to the server and return the response string.
205
206
207.. method:: FTP.voidcmd(command)
208
[391]209 Send a simple command string to the server and handle the response. Return
210 nothing if a response code corresponding to success (codes in the range
211 200--299) is received. Raise :exc:`error_reply` otherwise.
[2]212
213
214.. method:: FTP.retrbinary(command, callback[, maxblocksize[, rest]])
215
216 Retrieve a file in binary transfer mode. *command* should be an appropriate
217 ``RETR`` command: ``'RETR filename'``. The *callback* function is called for
218 each block of data received, with a single string argument giving the data
219 block. The optional *maxblocksize* argument specifies the maximum chunk size to
220 read on the low-level socket object created to do the actual transfer (which
221 will also be the largest size of the data blocks passed to *callback*). A
222 reasonable default is chosen. *rest* means the same thing as in the
223 :meth:`transfercmd` method.
224
225
226.. method:: FTP.retrlines(command[, callback])
227
228 Retrieve a file or directory listing in ASCII transfer mode. *command*
229 should be an appropriate ``RETR`` command (see :meth:`retrbinary`) or a
230 command such as ``LIST``, ``NLST`` or ``MLSD`` (usually just the string
[391]231 ``'LIST'``). ``LIST`` retrieves a list of files and information about those files.
232 ``NLST`` retrieves a list of file names. On some servers, ``MLSD`` retrieves
233 a machine readable list of files and information about those files. The *callback*
234 function is called for each line with a string argument containing the line with
235 the trailing CRLF stripped. The default *callback* prints the line to ``sys.stdout``.
[2]236
237
238.. method:: FTP.set_pasv(boolean)
239
240 Enable "passive" mode if *boolean* is true, other disable passive mode. (In
241 Python 2.0 and before, passive mode was off by default; in Python 2.1 and later,
242 it is on by default.)
243
244
[391]245.. method:: FTP.storbinary(command, file[, blocksize, callback, rest])
[2]246
247 Store a file in binary transfer mode. *command* should be an appropriate
248 ``STOR`` command: ``"STOR filename"``. *file* is an open file object which is
249 read until EOF using its :meth:`read` method in blocks of size *blocksize* to
250 provide the data to be stored. The *blocksize* argument defaults to 8192.
251 *callback* is an optional single parameter callable that is called
[391]252 on each block of data after it is sent. *rest* means the same thing as in
253 the :meth:`transfercmd` method.
[2]254
255 .. versionchanged:: 2.1
256 default for *blocksize* added.
257
258 .. versionchanged:: 2.6
259 *callback* parameter added.
260
[391]261 .. versionchanged:: 2.7
262 *rest* parameter added.
[2]263
264.. method:: FTP.storlines(command, file[, callback])
265
266 Store a file in ASCII transfer mode. *command* should be an appropriate
267 ``STOR`` command (see :meth:`storbinary`). Lines are read until EOF from the
[391]268 open file object *file* using its :meth:`~file.readline` method to provide
269 the data to be stored. *callback* is an optional single parameter callable
[2]270 that is called on each line after it is sent.
271
272 .. versionchanged:: 2.6
273 *callback* parameter added.
274
275
276.. method:: FTP.transfercmd(cmd[, rest])
277
278 Initiate a transfer over the data connection. If the transfer is active, send a
279 ``EPRT`` or ``PORT`` command and the transfer command specified by *cmd*, and
280 accept the connection. If the server is passive, send a ``EPSV`` or ``PASV``
281 command, connect to it, and start the transfer command. Either way, return the
282 socket for the connection.
283
284 If optional *rest* is given, a ``REST`` command is sent to the server, passing
285 *rest* as an argument. *rest* is usually a byte offset into the requested file,
286 telling the server to restart sending the file's bytes at the requested offset,
287 skipping over the initial bytes. Note however that RFC 959 requires only that
288 *rest* be a string containing characters in the printable range from ASCII code
289 33 to ASCII code 126. The :meth:`transfercmd` method, therefore, converts
290 *rest* to a string, but no check is performed on the string's contents. If the
291 server does not recognize the ``REST`` command, an :exc:`error_reply` exception
292 will be raised. If this happens, simply call :meth:`transfercmd` without a
293 *rest* argument.
294
295
296.. method:: FTP.ntransfercmd(cmd[, rest])
297
298 Like :meth:`transfercmd`, but returns a tuple of the data connection and the
299 expected size of the data. If the expected size could not be computed, ``None``
300 will be returned as the expected size. *cmd* and *rest* means the same thing as
301 in :meth:`transfercmd`.
302
303
304.. method:: FTP.nlst(argument[, ...])
305
[391]306 Return a list of file names as returned by the ``NLST`` command. The
307 optional *argument* is a directory to list (default is the current server
308 directory). Multiple arguments can be used to pass non-standard options to
309 the ``NLST`` command.
[2]310
311
312.. method:: FTP.dir(argument[, ...])
313
314 Produce a directory listing as returned by the ``LIST`` command, printing it to
315 standard output. The optional *argument* is a directory to list (default is the
316 current server directory). Multiple arguments can be used to pass non-standard
317 options to the ``LIST`` command. If the last argument is a function, it is used
318 as a *callback* function as for :meth:`retrlines`; the default prints to
319 ``sys.stdout``. This method returns ``None``.
320
321
322.. method:: FTP.rename(fromname, toname)
323
324 Rename file *fromname* on the server to *toname*.
325
326
327.. method:: FTP.delete(filename)
328
329 Remove the file named *filename* from the server. If successful, returns the
330 text of the response, otherwise raises :exc:`error_perm` on permission errors or
331 :exc:`error_reply` on other errors.
332
333
334.. method:: FTP.cwd(pathname)
335
336 Set the current directory on the server.
337
338
339.. method:: FTP.mkd(pathname)
340
341 Create a new directory on the server.
342
343
344.. method:: FTP.pwd()
345
346 Return the pathname of the current directory on the server.
347
348
349.. method:: FTP.rmd(dirname)
350
351 Remove the directory named *dirname* on the server.
352
353
354.. method:: FTP.size(filename)
355
356 Request the size of the file named *filename* on the server. On success, the
357 size of the file is returned as an integer, otherwise ``None`` is returned.
358 Note that the ``SIZE`` command is not standardized, but is supported by many
359 common server implementations.
360
361
362.. method:: FTP.quit()
363
364 Send a ``QUIT`` command to the server and close the connection. This is the
365 "polite" way to close a connection, but it may raise an exception if the server
366 responds with an error to the ``QUIT`` command. This implies a call to the
367 :meth:`close` method which renders the :class:`FTP` instance useless for
368 subsequent calls (see below).
369
370
371.. method:: FTP.close()
372
373 Close the connection unilaterally. This should not be applied to an already
[391]374 closed connection such as after a successful call to :meth:`~FTP.quit`.
375 After this call the :class:`FTP` instance should not be used any more (after
376 a call to :meth:`close` or :meth:`~FTP.quit` you cannot reopen the
377 connection by issuing another :meth:`login` method).
[2]378
[391]379
380FTP_TLS Objects
381---------------
382
383:class:`FTP_TLS` class inherits from :class:`FTP`, defining these additional objects:
384
385.. attribute:: FTP_TLS.ssl_version
386
387 The SSL version to use (defaults to *TLSv1*).
388
389.. method:: FTP_TLS.auth()
390
391 Set up secure control connection by using TLS or SSL, depending on what
392 specified in :meth:`ssl_version` attribute.
393
394.. method:: FTP_TLS.prot_p()
395
396 Set up secure data connection.
397
398.. method:: FTP_TLS.prot_c()
399
400 Set up clear text data connection.
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