telnetlib
— Telnet 客户端
¶
源代码： Lib/telnetlib.py
telnetlib
模块提供
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).
telnetlib.
Telnet
(
host=None
,
port=0
[
,
timeout
]
)
¶
Telnet
represents a connection to a Telnet server. The instance is initially not connected by default; 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, in which case the connection to the server will be established before the constructor returns. The optional
timeout
参数指定超时 (以秒为单位) 为阻止像连接尝试操作 (若不指定，将使用全局默认超时设置)。
Do not 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 descriptions below.
A
Telnet
object is a context manager and can be used in a
with
statement. When the
with
block ends, the
close()
method is called:
>>> from telnetlib import Telnet
>>> with Telnet('localhost', 23) as tn:
... tn.interact()
...
3.6 版改变： Context manager support added
另请参阅
Telnet
实例具有下列方法：
Telnet.
read_until
(
expected
,
timeout=None
)
¶
Read until a given byte string, expected , is encountered or until timeout seconds have passed.
When no match is found, return whatever is available instead, possibly empty bytes. Raise
EOFError
if the connection is closed and no cooked data is available.
Telnet.
read_all
(
)
¶
Read all data until EOF as bytes; block until connection closed.
Telnet.
read_some
(
)
¶
Read at least one byte of cooked data unless EOF is hit. Return
b''
if EOF is hit. Block if no data is immediately available.
Telnet.
read_very_eager
(
)
¶
Read everything that can be without blocking in I/O (eager).
引发
EOFError
if connection closed and no cooked data available. Return
b''
if no cooked data available otherwise. Do not block unless in the midst of an IAC sequence.
Telnet.
read_eager
(
)
¶
Read readily available data.
引发
EOFError
if connection closed and no cooked data available. Return
b''
if no cooked data available otherwise. Do not block unless in the midst of an IAC sequence.
Telnet.
read_lazy
(
)
¶
Process and return data already in the queues (lazy).
引发
EOFError
if connection closed and no data available. Return
b''
if no cooked data available otherwise. Do not block unless in the midst of an IAC sequence.
Telnet.
read_very_lazy
(
)
¶
Return any data available in the cooked queue (very lazy).
引发
EOFError
if connection closed and no data available. Return
b''
if no cooked data available otherwise. This method never blocks.
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.
Telnet.
open
(
host
,
port=0
[
,
timeout
]
)
¶
Connect to a host. The optional second argument is the port number, which defaults to the standard Telnet port (23). The optional timeout 参数指定超时 (以秒为单位) 为阻止像连接尝试操作 (若不指定，将使用全局默认超时设置)。
Do not try to reopen an already connected instance.
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.
Telnet.
set_debuglevel
(
debuglevel
)
¶
Set the debug level. The higher the value of
debuglevel
, the more debug output you get (on
sys.stdout
).
Telnet.
close
(
)
¶
关闭连接。
Telnet.
get_socket
(
)
¶
Return the socket object used internally.
Telnet.
fileno
(
)
¶
Return the file descriptor of the socket object used internally.
Telnet.
write
(
buffer
)
¶
Write a byte string to the socket, doubling any IAC characters. This can block if the connection is blocked. May raise
OSError
if the connection is closed.
3.3 版改变：
This method used to raise
socket.error
，现在是别名
OSError
.
Telnet.
interact
(
)
¶
Interaction function, emulates a very dumb Telnet client.
Telnet.
mt_interact
(
)
¶
Multithreaded version of
interact()
.
Telnet.
expect
(
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 ( regex objects ) or uncompiled (byte 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 bytes read up till and including the match.
If end of file is found and no bytes were read, raise
EOFError
. Otherwise, when nothing matches, return
(-1,
None,
data)
where
data
is the bytes received so far (may be empty bytes 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.
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.
A simple example illustrating typical use:
import getpass
import telnetlib
HOST = "localhost"
user = input("Enter your remote account: ")
password = getpass.getpass()
tn = telnetlib.Telnet(HOST)
tn.read_until(b"login: ")
tn.write(user.encode('ascii') + b"\n")
if password:
tn.read_until(b"Password: ")
tn.write(password.encode('ascii') + b"\n")
tn.write(b"ls\n")
tn.write(b"exit\n")
print(tn.read_all().decode('ascii'))