diff -r ac176a69d188 Lib/imaplib.py
--- a/Lib/imaplib.py	Sun Dec 28 22:14:23 2014 -0600
+++ b/Lib/imaplib.py	Mon Dec 29 16:25:38 2014 +0100
@@ -1,6 +1,6 @@
 """IMAP4 client.
 
-Based on RFC 2060.
+Based on RFC 2060, RFC 2177.
 
 Public class:           IMAP4
 Public variable:        Debug
@@ -22,7 +22,7 @@
 
 __version__ = "2.58"
 
-import binascii, errno, random, re, socket, subprocess, sys, time, calendar
+import binascii, errno, random, re, select, socket, subprocess, sys, time, calendar
 from datetime import datetime, timezone, timedelta
 from io import DEFAULT_BUFFER_SIZE
 
@@ -65,6 +65,7 @@
         'CREATE':       ('AUTH', 'SELECTED'),
         'DELETE':       ('AUTH', 'SELECTED'),
         'DELETEACL':    ('AUTH', 'SELECTED'),
+        'DONE':         ('IDLE'),
         'EXAMINE':      ('AUTH', 'SELECTED'),
         'EXPUNGE':      ('SELECTED',),
         'FETCH':        ('SELECTED',),
@@ -72,6 +73,7 @@
         'GETANNOTATION':('AUTH', 'SELECTED'),
         'GETQUOTA':     ('AUTH', 'SELECTED'),
         'GETQUOTAROOT': ('AUTH', 'SELECTED'),
+        'IDLE':         ('AUTH', 'SELECTED'),
         'MYRIGHTS':     ('AUTH', 'SELECTED'),
         'LIST':         ('AUTH', 'SELECTED'),
         'LOGIN':        ('NONAUTH',),
@@ -828,6 +830,88 @@
             name = 'FETCH'
         return self._untagged_response(typ, dat, name)
 
+    def idle(self):
+        """Implements IMAP IDLE extension as described in RFC 2177.
+        
+        This commands enters the idle mode and changes the state to IDLING.
+        It parses the continuation response as well as update messages from the
+        server. To check for update messages or leave the idle mode,
+        use idle_poll(), idle_wait() or idle_done().
+
+        (typ, {data}) = <instance>.idle(timeout)
+
+        Returns typ 'IDLING' and the untagged responses received from the server.
+        """
+        if not "IDLE" in self.capabilities:
+            raise self.error("server does not support IDLE command.")
+
+        self.untagged_responses = {}
+        self.__idle_tag = self._command("IDLE")
+        self._get_response() # read continuation response + update messages
+        self.__state_before_idle = self.state # store previous state
+        self.state = 'IDLE'
+        return 'IDLING', self.untagged_responses
+
+    def idle_poll(self):
+        """Implements IMAP IDLE extension as described in RFC 2177.
+        
+        Retrieves any update messages that have been received during this idle
+        session since the last call to idle_poll(). The update messages are
+        cleared after each poll, thus they are not aggregated.
+        This method asserts that the client is in idle mode, i.e. that idle()
+        was called and neither idle_wait() or idle_done() has been called since.
+        
+        (typ, {data}) = <instance>.idle_poll()
+        
+        Returns typ 'IDLING' and the untagged responses received from the server.
+        """
+        assert(self.state == 'IDLE')
+        self.untagged_responses = {}
+        while True:
+        	# check if something arrived, do not block!
+            s,_,_ = select.select([self.sock],[],[],0)
+            if len(s) == 0: break
+            self._get_response()
+        return 'IDLING', self.untagged_responses
+    
+    def idle_wait(self, timeout = 29 * 60):
+        """Implements IMAP IDLE extension as described in RFC 2177.
+        
+        Blocks until an update message is received from the server or the
+        timeout is reached. The default timeout is 29 minutes, being the
+        maximum idle time advised by RFC 2177. Then, it calls idle_done() and
+        passes on its result.
+        This method asserts that the client is in idle mode, i.e. that idle()
+        was called and neither idle_wait() or idle_done() has been called since.
+
+        (typ, {data}) = <instance>.idle_wait()
+        
+        Returns typ 'IDLING' and the untagged responses received from the server.
+        """
+        assert(self.state == 'IDLE')
+        # block until something happens
+        select.select([self.sock],[],[],timeout)
+        return self.idle_done()
+    
+    def idle_done(self):
+        """Implements IMAP IDLE extension as described in RFC 2177.
+        
+        Executes DONE to leave the idle mode.
+        The state that the client was in before entering the idle mode is
+        restored. Parses all update messages from the server and returns them.
+        This method asserts that the client is in idle mode, i.e. that idle()
+        was called and neither idle_wait() or idle_done() has been called since.
+
+        (typ, {data}) = <instance>.idle_done()
+        
+        Returns the untagged responses received from the server.
+        """
+        assert(self.state == 'IDLE')
+        self.untagged_responses = {}
+        self.send(b"DONE" + CRLF) # send raw bytes "DONE"
+        typ,data = self._command_complete("IDLE", self.__idle_tag)
+        self.state = self.__state_before_idle # restore state
+        return typ, self.untagged_responses
 
     def unsubscribe(self, mailbox):
         """Unsubscribe from old mailbox.