243 lines
7.2 KiB
ReStructuredText
243 lines
7.2 KiB
ReStructuredText
|
|
:mod:`telnetlib` --- Telnet client
|
|
==================================
|
|
|
|
.. module:: telnetlib
|
|
:synopsis: Telnet client class.
|
|
.. sectionauthor:: Skip Montanaro <skip@pobox.com>
|
|
|
|
|
|
.. index:: single: protocol; Telnet
|
|
|
|
The :mod:`telnetlib` module provides a :class:`Telnet` class that implements the
|
|
Telnet protocol. See :rfc:`854` for details about the protocol. In addition, it
|
|
provides symbolic constants for the protocol characters (see below), and for the
|
|
telnet options. The symbolic names of the telnet options follow the definitions
|
|
in ``arpa/telnet.h``, with the leading ``TELOPT_`` removed. For symbolic names
|
|
of options which are traditionally not included in ``arpa/telnet.h``, see the
|
|
module source itself.
|
|
|
|
The symbolic constants for the telnet commands are: IAC, DONT, DO, WONT, WILL,
|
|
SE (Subnegotiation End), NOP (No Operation), DM (Data Mark), BRK (Break), IP
|
|
(Interrupt process), AO (Abort output), AYT (Are You There), EC (Erase
|
|
Character), EL (Erase Line), GA (Go Ahead), SB (Subnegotiation Begin).
|
|
|
|
|
|
.. class:: Telnet([host[, port[, timeout]]])
|
|
|
|
:class:`Telnet` represents a connection to a Telnet server. The instance is
|
|
initially not connected by default; the :meth:`open` method must be used to
|
|
establish a connection. Alternatively, the host name and optional port
|
|
number can be passed to the constructor, to, in which case the connection to
|
|
the server will be established before the constructor returns. The optional
|
|
*timeout* parameter specifies a timeout in seconds for blocking operations
|
|
like the connection attempt (if not specified, the global default timeout
|
|
setting will be used).
|
|
|
|
Do not reopen an already connected instance.
|
|
|
|
This class has many :meth:`read_\*` methods. Note that some of them raise
|
|
:exc:`EOFError` when the end of the connection is read, because they can return
|
|
an empty string for other reasons. See the individual descriptions below.
|
|
|
|
.. versionchanged:: 2.6
|
|
*timeout* was added.
|
|
|
|
|
|
.. seealso::
|
|
|
|
:rfc:`854` - Telnet Protocol Specification
|
|
Definition of the Telnet protocol.
|
|
|
|
|
|
.. _telnet-objects:
|
|
|
|
Telnet Objects
|
|
--------------
|
|
|
|
:class:`Telnet` instances have the following methods:
|
|
|
|
|
|
.. method:: Telnet.read_until(expected[, timeout])
|
|
|
|
Read until a given string, *expected*, is encountered or until *timeout* seconds
|
|
have passed.
|
|
|
|
When no match is found, return whatever is available instead, possibly the empty
|
|
string. Raise :exc:`EOFError` if the connection is closed and no cooked data is
|
|
available.
|
|
|
|
|
|
.. method:: Telnet.read_all()
|
|
|
|
Read all data until EOF; block until connection closed.
|
|
|
|
|
|
.. method:: Telnet.read_some()
|
|
|
|
Read at least one byte of cooked data unless EOF is hit. Return ``''`` if EOF is
|
|
hit. Block if no data is immediately available.
|
|
|
|
|
|
.. method:: Telnet.read_very_eager()
|
|
|
|
Read everything that can be without blocking in I/O (eager).
|
|
|
|
Raise :exc:`EOFError` if connection closed and no cooked data available. Return
|
|
``''`` if no cooked data available otherwise. Do not block unless in the midst
|
|
of an IAC sequence.
|
|
|
|
|
|
.. method:: Telnet.read_eager()
|
|
|
|
Read readily available data.
|
|
|
|
Raise :exc:`EOFError` if connection closed and no cooked data available. Return
|
|
``''`` if no cooked data available otherwise. Do not block unless in the midst
|
|
of an IAC sequence.
|
|
|
|
|
|
.. method:: Telnet.read_lazy()
|
|
|
|
Process and return data already in the queues (lazy).
|
|
|
|
Raise :exc:`EOFError` if connection closed and no data available. Return ``''``
|
|
if no cooked data available otherwise. Do not block unless in the midst of an
|
|
IAC sequence.
|
|
|
|
|
|
.. method:: Telnet.read_very_lazy()
|
|
|
|
Return any data available in the cooked queue (very lazy).
|
|
|
|
Raise :exc:`EOFError` if connection closed and no data available. Return ``''``
|
|
if no cooked data available otherwise. This method never blocks.
|
|
|
|
|
|
.. method:: Telnet.read_sb_data()
|
|
|
|
Return the data collected between a SB/SE pair (suboption begin/end). The
|
|
callback should access these data when it was invoked with a ``SE`` command.
|
|
This method never blocks.
|
|
|
|
.. versionadded:: 2.3
|
|
|
|
|
|
.. method:: Telnet.open(host[, port[, timeout]])
|
|
|
|
Connect to a host. The optional second argument is the port number, which
|
|
defaults to the standard Telnet port (23). The optional *timeout* parameter
|
|
specifies a timeout in seconds for blocking operations like the connection
|
|
attempt (if not specified, the global default timeout setting will be used).
|
|
|
|
Do not try to reopen an already connected instance.
|
|
|
|
.. versionchanged:: 2.6
|
|
*timeout* was added.
|
|
|
|
|
|
.. method:: Telnet.msg(msg[, *args])
|
|
|
|
Print a debug message when the debug level is ``>`` 0. If extra arguments are
|
|
present, they are substituted in the message using the standard string
|
|
formatting operator.
|
|
|
|
|
|
.. method:: Telnet.set_debuglevel(debuglevel)
|
|
|
|
Set the debug level. The higher the value of *debuglevel*, the more debug
|
|
output you get (on ``sys.stdout``).
|
|
|
|
|
|
.. method:: Telnet.close()
|
|
|
|
Close the connection.
|
|
|
|
|
|
.. method:: Telnet.get_socket()
|
|
|
|
Return the socket object used internally.
|
|
|
|
|
|
.. method:: Telnet.fileno()
|
|
|
|
Return the file descriptor of the socket object used internally.
|
|
|
|
|
|
.. method:: Telnet.write(buffer)
|
|
|
|
Write a string to the socket, doubling any IAC characters. This can block if the
|
|
connection is blocked. May raise :exc:`socket.error` if the connection is
|
|
closed.
|
|
|
|
|
|
.. method:: Telnet.interact()
|
|
|
|
Interaction function, emulates a very dumb Telnet client.
|
|
|
|
|
|
.. method:: Telnet.mt_interact()
|
|
|
|
Multithreaded version of :meth:`interact`.
|
|
|
|
|
|
.. method:: Telnet.expect(list[, timeout])
|
|
|
|
Read until one from a list of a regular expressions matches.
|
|
|
|
The first argument is a list of regular expressions, either compiled
|
|
(:class:`re.RegexObject` instances) or uncompiled (strings). The optional second
|
|
argument is a timeout, in seconds; the default is to block indefinitely.
|
|
|
|
Return a tuple of three items: the index in the list of the first regular
|
|
expression that matches; the match object returned; and the text read up till
|
|
and including the match.
|
|
|
|
If end of file is found and no text was read, raise :exc:`EOFError`. Otherwise,
|
|
when nothing matches, return ``(-1, None, text)`` where *text* is the text
|
|
received so far (may be the empty string if a timeout happened).
|
|
|
|
If a regular expression ends with a greedy match (such as ``.*``) or if more
|
|
than one expression can match the same input, the results are
|
|
non-deterministic, and may depend on the I/O timing.
|
|
|
|
|
|
.. method:: Telnet.set_option_negotiation_callback(callback)
|
|
|
|
Each time a telnet option is read on the input flow, this *callback* (if set) is
|
|
called with the following parameters : callback(telnet socket, command
|
|
(DO/DONT/WILL/WONT), option). No other action is done afterwards by telnetlib.
|
|
|
|
|
|
.. _telnet-example:
|
|
|
|
Telnet Example
|
|
--------------
|
|
|
|
.. sectionauthor:: Peter Funk <pf@artcom-gmbh.de>
|
|
|
|
|
|
A simple example illustrating typical use::
|
|
|
|
import getpass
|
|
import sys
|
|
import telnetlib
|
|
|
|
HOST = "localhost"
|
|
user = raw_input("Enter your remote account: ")
|
|
password = getpass.getpass()
|
|
|
|
tn = telnetlib.Telnet(HOST)
|
|
|
|
tn.read_until("login: ")
|
|
tn.write(user + "\n")
|
|
if password:
|
|
tn.read_until("Password: ")
|
|
tn.write(password + "\n")
|
|
|
|
tn.write("ls\n")
|
|
tn.write("exit\n")
|
|
|
|
print tn.read_all()
|
|
|