/Doc/library/ftplib.rst

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  1. :mod:`ftplib` --- FTP protocol client
  2. =====================================
  3. .. module:: ftplib
  4. :synopsis: FTP protocol client (requires sockets).
  5. .. index::
  6. pair: FTP; protocol
  7. single: FTP; ftplib (standard module)
  8. This module defines the class :class:`FTP` and a few related items. The
  9. :class:`FTP` class implements the client side of the FTP protocol. You can use
  10. this to write Python programs that perform a variety of automated FTP jobs, such
  11. as mirroring other ftp servers. It is also used by the module :mod:`urllib` to
  12. handle URLs that use FTP. For more information on FTP (File Transfer Protocol),
  13. see Internet :rfc:`959`.
  14. Here's a sample session using the :mod:`ftplib` module::
  15. >>> from ftplib import FTP
  16. >>> ftp = FTP('ftp.cwi.nl') # connect to host, default port
  17. >>> ftp.login() # user anonymous, passwd anonymous@
  18. >>> ftp.retrlines('LIST') # list directory contents
  19. total 24418
  20. drwxrwsr-x 5 ftp-usr pdmaint 1536 Mar 20 09:48 .
  21. dr-xr-srwt 105 ftp-usr pdmaint 1536 Mar 21 14:32 ..
  22. -rw-r--r-- 1 ftp-usr pdmaint 5305 Mar 20 09:48 INDEX
  23. .
  24. .
  25. .
  26. >>> ftp.retrbinary('RETR README', open('README', 'wb').write)
  27. '226 Transfer complete.'
  28. >>> ftp.quit()
  29. The module defines the following items:
  30. .. class:: FTP([host[, user[, passwd[, acct[, timeout]]]]])
  31. Return a new instance of the :class:`FTP` class. When *host* is given, the
  32. method call ``connect(host)`` is made. When *user* is given, additionally
  33. the method call ``login(user, passwd, acct)`` is made (where *passwd* and
  34. *acct* default to the empty string when not given). The optional *timeout*
  35. parameter specifies a timeout in seconds for blocking operations like the
  36. connection attempt (if is not specified, the global default timeout setting
  37. will be used).
  38. .. versionchanged:: 2.6
  39. *timeout* was added.
  40. .. attribute:: all_errors
  41. The set of all exceptions (as a tuple) that methods of :class:`FTP`
  42. instances may raise as a result of problems with the FTP connection (as
  43. opposed to programming errors made by the caller). This set includes the
  44. four exceptions listed below as well as :exc:`socket.error` and
  45. :exc:`IOError`.
  46. .. exception:: error_reply
  47. Exception raised when an unexpected reply is received from the server.
  48. .. exception:: error_temp
  49. Exception raised when an error code in the range 400--499 is received.
  50. .. exception:: error_perm
  51. Exception raised when an error code in the range 500--599 is received.
  52. .. exception:: error_proto
  53. Exception raised when a reply is received from the server that does not
  54. begin with a digit in the range 1--5.
  55. .. seealso::
  56. Module :mod:`netrc`
  57. Parser for the :file:`.netrc` file format. The file :file:`.netrc` is typically
  58. used by FTP clients to load user authentication information before prompting the
  59. user.
  60. .. index:: single: ftpmirror.py
  61. The file :file:`Tools/scripts/ftpmirror.py` in the Python source distribution is
  62. a script that can mirror FTP sites, or portions thereof, using the :mod:`ftplib`
  63. module. It can be used as an extended example that applies this module.
  64. .. _ftp-objects:
  65. FTP Objects
  66. -----------
  67. Several methods are available in two flavors: one for handling text files and
  68. another for binary files. These are named for the command which is used
  69. followed by ``lines`` for the text version or ``binary`` for the binary version.
  70. :class:`FTP` instances have the following methods:
  71. .. method:: FTP.set_debuglevel(level)
  72. Set the instance's debugging level. This controls the amount of debugging
  73. output printed. The default, ``0``, produces no debugging output. A value of
  74. ``1`` produces a moderate amount of debugging output, generally a single line
  75. per request. A value of ``2`` or higher produces the maximum amount of
  76. debugging output, logging each line sent and received on the control connection.
  77. .. method:: FTP.connect(host[, port[, timeout]])
  78. Connect to the given host and port. The default port number is ``21``, as
  79. specified by the FTP protocol specification. It is rarely needed to specify a
  80. different port number. This function should be called only once for each
  81. instance; it should not be called at all if a host was given when the instance
  82. was created. All other methods can only be used after a connection has been
  83. made.
  84. The optional *timeout* parameter specifies a timeout in seconds for the
  85. connection attempt. If no *timeout* is passed, the global default timeout
  86. setting will be used.
  87. .. versionchanged:: 2.6
  88. *timeout* was added.
  89. .. method:: FTP.getwelcome()
  90. Return the welcome message sent by the server in reply to the initial
  91. connection. (This message sometimes contains disclaimers or help information
  92. that may be relevant to the user.)
  93. .. method:: FTP.login([user[, passwd[, acct]]])
  94. Log in as the given *user*. The *passwd* and *acct* parameters are optional and
  95. default to the empty string. If no *user* is specified, it defaults to
  96. ``'anonymous'``. If *user* is ``'anonymous'``, the default *passwd* is
  97. ``'anonymous@'``. This function should be called only once for each instance,
  98. after a connection has been established; it should not be called at all if a
  99. host and user were given when the instance was created. Most FTP commands are
  100. only allowed after the client has logged in.
  101. .. method:: FTP.abort()
  102. Abort a file transfer that is in progress. Using this does not always work, but
  103. it's worth a try.
  104. .. method:: FTP.sendcmd(command)
  105. Send a simple command string to the server and return the response string.
  106. .. method:: FTP.voidcmd(command)
  107. Send a simple command string to the server and handle the response. Return
  108. nothing if a response code in the range 200--299 is received. Raise an exception
  109. otherwise.
  110. .. method:: FTP.retrbinary(command, callback[, maxblocksize[, rest]])
  111. Retrieve a file in binary transfer mode. *command* should be an appropriate
  112. ``RETR`` command: ``'RETR filename'``. The *callback* function is called for
  113. each block of data received, with a single string argument giving the data
  114. block. The optional *maxblocksize* argument specifies the maximum chunk size to
  115. read on the low-level socket object created to do the actual transfer (which
  116. will also be the largest size of the data blocks passed to *callback*). A
  117. reasonable default is chosen. *rest* means the same thing as in the
  118. :meth:`transfercmd` method.
  119. .. method:: FTP.retrlines(command[, callback])
  120. Retrieve a file or directory listing in ASCII transfer mode. *command*
  121. should be an appropriate ``RETR`` command (see :meth:`retrbinary`) or a
  122. command such as ``LIST``, ``NLST`` or ``MLSD`` (usually just the string
  123. ``'LIST'``). The *callback* function is called for each line, with the
  124. trailing CRLF stripped. The default *callback* prints the line to
  125. ``sys.stdout``.
  126. .. method:: FTP.set_pasv(boolean)
  127. Enable "passive" mode if *boolean* is true, other disable passive mode. (In
  128. Python 2.0 and before, passive mode was off by default; in Python 2.1 and later,
  129. it is on by default.)
  130. .. method:: FTP.storbinary(command, file[, blocksize, callback])
  131. Store a file in binary transfer mode. *command* should be an appropriate
  132. ``STOR`` command: ``"STOR filename"``. *file* is an open file object which is
  133. read until EOF using its :meth:`read` method in blocks of size *blocksize* to
  134. provide the data to be stored. The *blocksize* argument defaults to 8192.
  135. *callback* is an optional single parameter callable that is called
  136. on each block of data after it is sent.
  137. .. versionchanged:: 2.1
  138. default for *blocksize* added.
  139. .. versionchanged:: 2.6
  140. *callback* parameter added.
  141. .. method:: FTP.storlines(command, file[, callback])
  142. Store a file in ASCII transfer mode. *command* should be an appropriate
  143. ``STOR`` command (see :meth:`storbinary`). Lines are read until EOF from the
  144. open file object *file* using its :meth:`readline` method to provide the data to
  145. be stored. *callback* is an optional single parameter callable
  146. that is called on each line after it is sent.
  147. .. versionchanged:: 2.6
  148. *callback* parameter added.
  149. .. method:: FTP.transfercmd(cmd[, rest])
  150. Initiate a transfer over the data connection. If the transfer is active, send a
  151. ``EPRT`` or ``PORT`` command and the transfer command specified by *cmd*, and
  152. accept the connection. If the server is passive, send a ``EPSV`` or ``PASV``
  153. command, connect to it, and start the transfer command. Either way, return the
  154. socket for the connection.
  155. If optional *rest* is given, a ``REST`` command is sent to the server, passing
  156. *rest* as an argument. *rest* is usually a byte offset into the requested file,
  157. telling the server to restart sending the file's bytes at the requested offset,
  158. skipping over the initial bytes. Note however that RFC 959 requires only that
  159. *rest* be a string containing characters in the printable range from ASCII code
  160. 33 to ASCII code 126. The :meth:`transfercmd` method, therefore, converts
  161. *rest* to a string, but no check is performed on the string's contents. If the
  162. server does not recognize the ``REST`` command, an :exc:`error_reply` exception
  163. will be raised. If this happens, simply call :meth:`transfercmd` without a
  164. *rest* argument.
  165. .. method:: FTP.ntransfercmd(cmd[, rest])
  166. Like :meth:`transfercmd`, but returns a tuple of the data connection and the
  167. expected size of the data. If the expected size could not be computed, ``None``
  168. will be returned as the expected size. *cmd* and *rest* means the same thing as
  169. in :meth:`transfercmd`.
  170. .. method:: FTP.nlst(argument[, ...])
  171. Return a list of files as returned by the ``NLST`` command. The optional
  172. *argument* is a directory to list (default is the current server directory).
  173. Multiple arguments can be used to pass non-standard options to the ``NLST``
  174. command.
  175. .. method:: FTP.dir(argument[, ...])
  176. Produce a directory listing as returned by the ``LIST`` command, printing it to
  177. standard output. The optional *argument* is a directory to list (default is the
  178. current server directory). Multiple arguments can be used to pass non-standard
  179. options to the ``LIST`` command. If the last argument is a function, it is used
  180. as a *callback* function as for :meth:`retrlines`; the default prints to
  181. ``sys.stdout``. This method returns ``None``.
  182. .. method:: FTP.rename(fromname, toname)
  183. Rename file *fromname* on the server to *toname*.
  184. .. method:: FTP.delete(filename)
  185. Remove the file named *filename* from the server. If successful, returns the
  186. text of the response, otherwise raises :exc:`error_perm` on permission errors or
  187. :exc:`error_reply` on other errors.
  188. .. method:: FTP.cwd(pathname)
  189. Set the current directory on the server.
  190. .. method:: FTP.mkd(pathname)
  191. Create a new directory on the server.
  192. .. method:: FTP.pwd()
  193. Return the pathname of the current directory on the server.
  194. .. method:: FTP.rmd(dirname)
  195. Remove the directory named *dirname* on the server.
  196. .. method:: FTP.size(filename)
  197. Request the size of the file named *filename* on the server. On success, the
  198. size of the file is returned as an integer, otherwise ``None`` is returned.
  199. Note that the ``SIZE`` command is not standardized, but is supported by many
  200. common server implementations.
  201. .. method:: FTP.quit()
  202. Send a ``QUIT`` command to the server and close the connection. This is the
  203. "polite" way to close a connection, but it may raise an exception if the server
  204. responds with an error to the ``QUIT`` command. This implies a call to the
  205. :meth:`close` method which renders the :class:`FTP` instance useless for
  206. subsequent calls (see below).
  207. .. method:: FTP.close()
  208. Close the connection unilaterally. This should not be applied to an already
  209. closed connection such as after a successful call to :meth:`quit`. After this
  210. call the :class:`FTP` instance should not be used any more (after a call to
  211. :meth:`close` or :meth:`quit` you cannot reopen the connection by issuing
  212. another :meth:`login` method).