Module telnetlib :: Class Telnet
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_ClassType Telnet

Telnet interface class.

An instance of this class represents a connection to a telnet
server.  The instance is initially not connected; the open()
method must be used to establish a connection.  Alternatively, the
host name and optional port number can be passed to the
constructor, too.

Don't try to reopen an already connected instance.

This class has many read_*() methods.  Note that some of them
raise EOFError when the end of the connection is read, because
they can return an empty string for other reasons.  See the
individual doc strings.

read_until(expected, [timeout])
    Read until the expected string has been seen, or a timeout is
    hit (default is no timeout); may block.

read_all()
    Read all data until EOF; may block.

read_some()
    Read at least one byte or EOF; may block.

read_very_eager()
    Read all data available already queued or on the socket,
    without blocking.

read_eager()
    Read either data already queued or some data available on the
    socket, without blocking.

read_lazy()
    Read all data in the raw queue (processing it first), without
    doing any socket I/O.

read_very_lazy()
    Reads all data in the cooked queue, without doing any socket
    I/O.

read_sb_data()
    Reads available data between SB ... SE sequence. Don't block.

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, option)
        option will be chr(0) when there is no option.
    No other action is done afterwards by telnetlib.

Instance Methods [hide private]
 
__init__(self, host=None, port=0)
Constructor.
 
open(self, host, port=0)
Connect to a host.
 
__del__(self)
Destructor -- close the connection.
 
msg(self, msg, *args)
Print a debug message, when the debug level is > 0.
 
set_debuglevel(self, debuglevel)
Set the debug level.
 
close(self)
Close the connection.
 
get_socket(self)
Return the socket object used internally.
 
fileno(self)
Return the fileno() of the socket object used internally.
 
write(self, buffer)
Write a string to the socket, doubling any IAC characters.
 
read_until(self, match, timeout=None)
Read until a given string is encountered or until timeout.
 
read_all(self)
Read all data until EOF; block until connection closed.
 
read_some(self)
Read at least one byte of cooked data unless EOF is hit.
 
read_very_eager(self)
Read everything that's possible without blocking in I/O (eager).
 
read_eager(self)
Read readily available data.
 
read_lazy(self)
Process and return data that's already in the queues (lazy).
 
read_very_lazy(self)
Return any data available in the cooked queue (very lazy).
 
read_sb_data(self)
Return any data available in the SB ...
 
set_option_negotiation_callback(self, callback)
Provide a callback function called after each receipt of a telnet option.
 
process_rawq(self)
Transfer from raw queue to cooked queue.
 
rawq_getchar(self)
Get next char from raw queue.
 
fill_rawq(self)
Fill raw queue from exactly one recv() system call.
 
sock_avail(self)
Test whether data is available on the socket.
 
interact(self)
Interaction function, emulates a very dumb telnet client.
 
mt_interact(self)
Multithreaded version of interact().
 
listener(self)
Helper for mt_interact() -- this executes in the other thread.
 
expect(self, list, timeout=None)
Read until one from a list of a regular expressions matches.
Method Details [hide private]

__init__(self, host=None, port=0)
(Constructor)

 

Constructor.

When called without arguments, create an unconnected instance. With a hostname argument, it connects the instance; a port number is optional.

open(self, host, port=0)

 

Connect to a host.

The optional second argument is the port number, which defaults to the standard telnet port (23).

Don't try to reopen an already connected instance.

msg(self, 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.

set_debuglevel(self, debuglevel)

 

Set the debug level.

The higher it is, the more debug output you get (on sys.stdout).

write(self, buffer)

 

Write a string to the socket, doubling any IAC characters.

Can block if the connection is blocked. May raise socket.error if the connection is closed.

read_until(self, match, timeout=None)

 

Read until a given string is encountered or until timeout.

When no match is found, return whatever is available instead, possibly the empty string. Raise EOFError if the connection is closed and no cooked data is available.

read_some(self)

 

Read at least one byte of cooked data unless EOF is hit.

Return '' if EOF is hit. Block if no data is immediately available.

read_very_eager(self)

 

Read everything that's possible without blocking in I/O (eager).

Raise EOFError if connection closed and no cooked data available. Return '' if no cooked data available otherwise. Don't block unless in the midst of an IAC sequence.

read_eager(self)

 

Read readily available data.

Raise EOFError if connection closed and no cooked data available. Return '' if no cooked data available otherwise. Don't block unless in the midst of an IAC sequence.

read_lazy(self)

 

Process and return data that's already in the queues (lazy).

Raise EOFError if connection closed and no data available. Return '' if no cooked data available otherwise. Don't block unless in the midst of an IAC sequence.

read_very_lazy(self)

 

Return any data available in the cooked queue (very lazy).

Raise EOFError if connection closed and no data available. Return '' if no cooked data available otherwise. Don't block.

read_sb_data(self)

 

Return any data available in the SB ... SE queue.

Return '' if no SB ... SE available. Should only be called after seeing a SB or SE command. When a new SB command is found, old unread SB data will be discarded. Don't block.

process_rawq(self)

 

Transfer from raw queue to cooked queue.

Set self.eof when connection is closed. Don't block unless in the midst of an IAC sequence.

rawq_getchar(self)

 

Get next char from raw queue.

Block if no data is immediately available. Raise EOFError when connection is closed.

fill_rawq(self)

 

Fill raw queue from exactly one recv() system call.

Block if no data is immediately available. Set self.eof when connection is closed.

expect(self, list, timeout=None)

 

Read until one from a list of a regular expressions matches.

The first argument is a list of regular expressions, either compiled (re.RegexObject instances) or uncompiled (strings). The optional second argument is a timeout, in seconds; default is no timeout.

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 EOF is read and no text was read, raise 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 (e.g. '.*') or if more than one expression can match the same input, the results are undeterministic, and may depend on the I/O timing.