#!/usr/local/bin/python
""" Telnet scripting interface
This class supports simple scripting of a telnet session. When
created, it takes the name of the host and an optional dictionary.
Scripts are passed to the object's RunScript method as a list of
strings. Here is an example script:
ru Login:
w %(user)s
ru Password:
w %(pwd)s
w cd ~/branches/HEAD
w %(cvslogin)s
w %(cvsup)s
# Should do something useful here
w exit
c
Which means:
Read until "Login:"
Write the value associated with the key "user" in the dictionary
Read until "Password:"
Write value of key "password"
Change to $HOME/branches/HEAD
Write the value of key "cvslogin" (this happens to contain a cvs
login command w/ -d option)
Write the value of key "cvsup" (likewise, a cvs up command)
(Do nothing, comment)
Exit the telnet shell
Close the telnet session
Each command is one or two characters, followed by whitespace, followed by
an optional string that serves as a parameter to the command. (Some commands,
eg Read All, do not have commands. For a list of commands that telnetscript
supports, see the definition of self.__functable in the __init__ method
below.
Lines that are blank are ignored, as are lines that begin with "#".
When RunScript returns, it returns a buffer (string) that contains all
the stuff that was read during the session.
Final note: I commonly assign variables that the script is going to
expect within the calling namespace, and then pass all local variables
to the script object using vars().
"""
import telnetlib, re
class telnetscript:
parserx = re.compile( '^\s*(\w+)(?:\s+)?(.*)' )
fmtrx = re.compile( '(%[^%])' )
commentrx = re.compile( '^\s+#' )
def __init__( self, server, data={} ):
host = telnetlib.Telnet( server )
self.__host = host
self.__buffer = ''
self.__data = data
self.__functable = { 'ru': host.read_until,
'ra': host.read_all,
'rs': host.read_some,
'rve': host.read_very_eager,
're': host.read_eager,
'rl': host.read_lazy,
'rvl': host.read_very_lazy,
'cl': host.close,
'w': self.write }
def TelnetObject( self ):
""" Return the underlying telnet object contained by the script class """
return self.__host
def RunScript( self, script ):
""" script is a list of strings """
rBuffer = ''
for line in script:
# cull out blank lines and comments
if (not line.strip()) or self.commentrx.search( line ): continue
m = self.parserx.search( line ).groups()
if not m: raise 'Badly-formatted script line: %s' % line
if m[1]:
# If we find a % not followed by another %, apply formatting
if self.fmtrx.search( m[1] ):
arg = m[1] % self.__data
else:
arg = m[1]
buff = apply( self.__functable[ m[0] ], arg )
else:
buff = apply( self.__functable[ m[0] ])
if buff: rBuffer += buff
return rBuffer
def write( self, text ):
"""Use this instead of directly calling write so we can insert newline"""
self.__host.write( '%s\n' % text
