[Python telnetlib read_until recv problem]

Question

[Python telnetlib read_until recv problem]

“read_until”函数返回带有长命令的cut off字符串命令运行完美，但没有显示完整的文本我怎样才能解决这个问题？请帮忙。

＃my code

tn = telnetlib.Telnet(ip, 23, 5)
prompt = ']# '
tn.write('echo "this is a long command for the test purpose... > test.txt"\n')
print tn.read_until(prompt, 1)

#debug output

Telnet（192.168.220.4,23）：发送'echo'这是一个用于测试目的的长命令...＆gt; test.txt“\ n'

Telnet（192.168.220.4,23）：recv'echo“这是一个l'
Telnet（192.168.220.4,23）：用于测试目的的recv'ong命令...＆gt; te \ r \ x00＆lt;他是' Telnet（192.168.220.4,23）：recv'用于测试目的的长命令...＆gt; tes' Telnet（192.168.220.4,23）：recv'\ x08 \ x08 \ x08 \ x08 \ x08 \ x08 \ x08 \ x08 \ x08 \ x08 \ x08 \ x08 \ x08 \ x08 \ x08 \ x08 \ x08 \ x08 \ x08 \ X08 \ X08 \ X08 \ X08 \ X08 \ X0 8t.txt“'
Telnet（192.168.220.4,23）：recv'\ r \ n这是一个用于测试目的的长命令...＆gt;'
Telnet（192.168.220.4,23）：recv'test.txt \ r \ n [root @ RHEL6-5 tmp]＃'

#real output

＆lt;他是一个长期的测试目的...＆gt; test.txt的“
这是测试目的的长命令...＆gt; test.txt的
[root @ RHEL6-5 tmp]＃

Answer 1

由于换行，问题似乎正在发生。我找到了一个解决方案，其中将窗口大小宽度设置为接近最大值允许接收长行而不使用telnet服务器应用的换行。

（有关设置选项https://www.ietf.org/rfc/rfc1073.txt的详细信息，请参阅窗口大小选项 RFC）

import telnetlib
import struct
from telnetlib import DO, DONT, IAC, WILL, WONT, NAWS, SB, SE

MAX_WINDOW_WIDTH = 65000  # Max Value: 65535
MAX_WINDOW_HEIGHT = 5000


def set_max_window_size(tsocket, command, option):
    """
    Set Window size to resolve line width issue
    Set Windows size command: IAC SB NAWS <16-bit value> <16-bit value> IAC SE
    --> inform the Telnet server of the window width and height.
    Refer to https://www.ietf.org/rfc/rfc1073.txt
    :param tsocket: telnet socket object
    :param command: telnet Command
    :param option: telnet option
    :return: None
    """
    if option == NAWS:
        width = struct.pack('H', MAX_WINDOW_WIDTH)
        height = struct.pack('H', MAX_WINDOW_HEIGHT)
        tsocket.send(IAC + WILL + NAWS)
        tsocket.send(IAC + SB + NAWS + width + height + IAC + SE)
    # -- below code taken from telnetlib source
    elif command in (DO, DONT):
        tsocket.send(IAC + WONT + option)
    elif command in (WILL, WONT):
        tsocket.send(IAC + DONT + option)

ip = 'x.x.x.x'
tn = telnetlib.Telnet(ip, 23, timeout=5)
tn.set_option_negotiation_callback(set_max_window_size)

tn.write('echo "this is a long command for the test purpose... > test.txt"\n')

prompt = ']# '
print tn.read_until(prompt, timeout=1)

Answer 2

为我工作。

def set_max_window_size(tsocket, command, option):
"""
Set Window size to resolve line width issue
Set Windows size command: IAC SB NAWS <16-bit value> <16-bit value> IAC SE
--> inform the Telnet server of the window width and height.
Refer to https://www.ietf.org/rfc/rfc1073.txt
:param tsocket: telnet socket object
:param command: telnet Command
:param option: telnet option
:return: None
"""
if option == NAWS:
    naws_command = struct.pack('!BBBHHBB',
    255, 250, 31, # IAC SB NAWS
    50, 100, #width, height
    255, 240) # IAC SE
    tsocket.send(naws_command)
# -- below code taken from telnetlib source
elif command in (DO, DONT):
    tsocket.send(IAC + WONT + option)
elif command in (WILL, WONT):
    tsocket.send(IAC + DONT + option)

ip = 'x.x.x.x'
tn = telnetlib.Telnet(ip, 23, timeout=5)
socket = tn.get_socket()
tn.set_option_negotiation_callback(set_max_window_size)

tn.write('echo "this is a long command for the test purpose... > test.txt"\n')

prompt = ']# '
print tn.read_until(prompt, timeout=1)

Python telnetlib read_until返回cut off string

[Python telnetlib read_until recv problem]

2 个答案: