Merge pull request #404 from janoliver/master

If imaplib2 is installed use the IDLE feature of IMAP to avoid polling

i3pystatus/mail/imap.py

@@ -1,9 +1,62 @@
-import imaplib
+try:
+    from imaplib2 import IMAP4, IMAP4_SSL
+    use_idle = True
+except:
+    from imaplib import IMAP4, IMAP4_SSL
+    use_idle = False
 import socket
+from threading import *
 
 from i3pystatus.mail import Backend
 
 
+# This is the threading object that does all the waiting on
+# the event
+class Idler(object):
+    def __init__(self, conn, callback, callback_reconnect):
+        self.thread = Thread(target=self.idle)
+        self.M = conn
+        self.callback_reconnect = callback_reconnect
+        self.event = Event()
+        self.callback = callback
+
+    def start(self):
+        self.thread.start()
+
+    def stop(self):
+        self.event.set()
+
+    def join(self):
+        self.thread.join()
+
+    def idle(self):
+
+        while True:
+            if self.event.isSet():
+                return
+
+            self.needsync = False
+
+            def callback(args):
+                if not self.event.isSet():
+                    self.needsync = True
+                    self.event.set()
+
+            try:
+                self.M.idle(callback=callback)
+                self.event.wait()
+
+                if self.needsync:
+                    self.event.clear()
+                    self.callback()
+            except:
+                break
+
+        self.M = self.callback_reconnect()
+        self.stop()
+        self.start()
+
+
 class IMAP(Backend):
     """
     Checks for mail on a IMAP server
@@ -23,13 +76,19 @@ class IMAP(Backend):
     ssl = True
     mailbox = "INBOX"
 
-    imap_class = imaplib.IMAP4
+    imap_class = IMAP4
     connection = None
     last = 0
 
     def init(self):
         if self.ssl:
-            self.imap_class = imaplib.IMAP4_SSL
+            self.imap_class = IMAP4_SSL
+
+        self.conn = self.get_connection()
+
+        if use_idle:
+            idler = Idler(self.conn, self.count_new_mail, self.get_connection)
+            idler.start()
 
     def get_connection(self):
         if self.connection:
@@ -52,6 +111,9 @@ class IMAP(Backend):
 
         return self.connection
 
+    def count_new_mail(self):
+        self.last = len(self.conn.search(None, "UnSeen")[1][0].split())
+
     @property
     def unread(self):
         try:
@@ -61,7 +123,8 @@ class IMAP(Backend):
         else:
             self.last = len(conn.search(None, "UnSeen")[1][0].split())
         finally:
+            if not use_idle:
+                self.count_new_mail()
             return self.last
 
-
 Backend = IMAP