lbolla · March 21, 2013 15:28 · Mar 21, 2013
diff --git a/chat.py b/chat.py
@@ -0,0 +1,46 @@
+import sys
+import tornado.ioloop
+import psycopg2
+import psycopg2.extensions
+
+io_loop = tornado.ioloop.IOLoop.instance()
+conn = psycopg2.connect('dbname=mytest user=lbolla password=secret')
+conn.set_isolation_level(psycopg2.extensions.ISOLATION_LEVEL_AUTOCOMMIT)
+
+
+def listen(ch):
+    '''Listen to a channel.'''
+    curs = conn.cursor()
+    curs.execute("LISTEN %s;" % ch)
+
+
+def receive(fd, events):
+    '''Receive a notify message from the channel we are listening.'''
+    state = conn.poll()
+    if state == psycopg2.extensions.POLL_OK:
+        if conn.notifies:
+            notify = conn.notifies.pop()
+            print(notify.payload)
+io_loop.add_handler(conn.fileno(), receive, io_loop.READ)
+
+
+def talk(who, ch):
+    # Connections are thread-safe, but cursors are not
+    curs = conn.cursor()
+
+    def _talk():
+        while True: 
+            what = input()
+            msg = '[%s] %s: %s' % (ch, who, what)
+            # Notify all of what you just said
+            curs.execute("NOTIFY %s, '%s';" % (ch, msg))
+    # Run in a separate thread: we could also monitor stdin into the IOLoop...
+    threading.Thread(target=_talk).start()
+
+
+if __name__ == '__main__':
+    who, ch = sys.argv[1:3]
+    # Always listen before talk!
+    listen(ch)
+    talk(who, ch)
+    io_loop.start()