python 处理telnet返回的More，以及get想要的那个参数

问题：

需要循环获取网元返回的某个参数，并计算出平均值。

解决方案：

通过expect解决返回More的问题。

通过具体的参数位置，精确获取到参数。

讨论：

参数位置固定，不好复用。

#! usr/bin/env python

# -*- coding: utf-8 -*-

import telnetlib
import math
import time

def get_param(b):
    "获取相应的参数，返回float型参数组"
    c = []
    b = list(b)
    length = len(b)
    print length
    for x in b:
        c.append(float(x))
    print c
    return c

def get_avg(a):
    "获取平均值"
    length = len(a)
    sum = 0
    for x in a:
        sum += x
    avg = sum/length
    return avg

def get_telnet(tn):
    "获取telnet数据"
    for command in commands:  
        tn.write('%s\n' % command)
        time.sleep(0.5)
##        result = tn.read_very_eager() # 不用read_all()，不能处理More
        print "**************"
        a = []
        a.append('More')
        print a
        result = str()
        while True:
            b,c,d = tn.expect(a,timeout=1)
            print b # 有More为0，无More为-1
            print 'cccccccccccccccccccccccccccccccccccccccccccc'
            print c
            print 'dddddddddddddddddddddddddddddddddddddddddddd'
            print d
            result += d
            if 0 == b:
                print "There has 'More'!!!"
                tn.write(r' ') #不用\r\n来继续
            else:
                break
        print 'get result success!'
        print result #获取到带More的所有返回结果        
        a = result.split('\r\n') # 不要加r
        length = len(a)
        print length
        b = a[1].split(' ')
        print b
        print a[32]
        c = a[32]
        d = c.split(' ')
        print d
        length = len(d)
        print d[8]
        e = d[8].split('(')
        print e[0]
    return e[0]    

def close_telnet(tn):
    "执行完毕后，终止Telnet连接（或输入exit退出）"
    tn.write('exit\n')
    tn.close()
 
def open_telnet(Host, username, password, finish, commands):  
    "Telnet远程登录"
    # 连接Telnet服务器  
    tn = telnetlib.Telnet(Host, port=23, timeout=10)  
    tn.set_debuglevel(2)
    # 输入登录用户名  
    tn.read_until('Username:')  
    tn.write(username + '\n')  
    # 输入登录密码  
    tn.read_until('Password:')  

    tn.write(password + '\n')

    # 登录完毕后执行命令  
    tn.read_until(finish)   
    return tn
 
if __name__=='__main__': 
    Host = ''   # Telnet服务器IP
    username = ''   # 登录用户名  
    password = ''   # 登录密码  
    finish = '#'       # 命令提示符
    param = []

    commands = ['sho optical-module-info xgei-1/3/1']
    tn = open_telnet(Host, username, password, finish, commands)
    for i in range(1,10):
        param.append(get_telnet(tn))
    close_telnet(tn)
    print param
    print get_avg(get_param(param))
    

'''

运行结果：

37
['Optical', 'Module', 'Position', ':', 'xgei-1/3/1']
Bias-Upper       : 131(mA)                Bias-Lower       : 0(mA)
['Bias-Upper', '', '', '', '', '', '', ':', '131(mA)', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', 'Bias-Lower', '', '', '', '', '', '', ':', '0(mA)']
131(mA)
131
Telnet(172.10.1.123,23): send 'exit\n'
['131', '131', '131', '131', '131', '131', '131', '131', '131']
9
[131.0, 131.0, 131.0, 131.0, 131.0, 131.0, 131.0, 131.0, 131.0]
131.0
>>>
'''