Added expect() method which takes a list of regular expressions and an

optional timeout.  Also moved some imports around.

diff --git a/Lib/telnetlib.py b/Lib/telnetlib.py
index 0f20fb4cc0d9a277ba3e0ce471e77a3ff48679ca..1a1c75edfdeb249dcd6d9959e81e7027dc2eb8bd 100644 (file)
--- a/Lib/telnetlib.py
+++ b/Lib/telnetlib.py
@@ -30,11 +30,14 @@ Bugs:
 
 To do:
 - option negotiation
+- timeout should be intrinsic to the connection object instead of an
+  option on one of the read calls only
 
 """
 
 
 # Imported modules
+import sys
 import socket
 import select
 import string
@@ -371,7 +374,6 @@ class Telnet:
 
     def interact(self):
        """Interaction function, emulates a very dumb telnet client."""
-       import sys, select
        while 1:
            rfd, wfd, xfd = select.select([self, sys.stdin], [], [])
            if sys.stdin in rfd:
@@ -388,6 +390,55 @@ class Telnet:
                    sys.stdout.flush()
        self.close()
 
+    def 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.
+
+       """
+       re = None
+       list = list[:]
+       indices = range(len(list))
+       for i in indices:
+           if not hasattr(list[i], "search"):
+               if not re: import re
+               list[i] = re.compile(list[i])
+       while 1:
+           self.process_rawq()
+           for i in indices:
+               m = list[i].search(self.cookedq)
+               if m:
+                   e = m.end()
+                   text = self.cookedq[:e]
+                   self.cookedq = self.cookedq[e:]
+                   return (i, m, text)
+           if self.eof:
+               break
+           if timeout is not None:
+               r, w, x = select.select([self.fileno()], [], [], timeout)
+               if not r:
+                   break
+           self.fill_rawq()
+       text = self.read_very_lazy()
+       if not text and self.eof:
+           raise EOFError
+       return (-1, None, text)
 
 
 def test():
@@ -398,7 +449,6 @@ def test():
     Default host is localhost; default port is 23.
 
     """
-    import sys
     debuglevel = 0
     while sys.argv[1:] and sys.argv[1] == '-d':
        debuglevel = debuglevel+1