better handling of packets with no data

socketio/packet.py

@@ -88,9 +88,9 @@ class Packet(object):
         self.namespace = None
         self.data = None
         ep = ep[1:]
-        dash = (ep + '-').find('-')
+        dash = ep.find('-')
         attachment_count = 0
-        if ep[0:dash].isdigit():
+        if dash > 0 and ep[0:dash].isdigit():
             attachment_count = int(ep[0:dash])
             ep = ep[dash + 1:]
         if ep and ep[0:1] == '/':
@@ -106,7 +106,7 @@ class Packet(object):
                 self.namespace = self.namespace[0:q]
         if ep and ep[0].isdigit():
             self.id = 0
-            while ep[0].isdigit():
+            while ep and ep[0].isdigit():
                 self.id = self.id * 10 + int(ep[0])
                 ep = ep[1:]
         if ep:

tests/test_packet.py

@@ -146,6 +146,18 @@ class TestPacket(unittest.TestCase):
         self.assertEqual(pkt.id, 123)
         self.assertEqual(pkt.encode(), '2123["foo"]')
 
+    def test_encode_id_no_data(self):
+        pkt = packet.Packet(packet_type=packet.EVENT, id=123)
+        self.assertEqual(pkt.id, 123)
+        self.assertIsNone(pkt.data)
+        self.assertEqual(pkt.encode(), '2123')
+
+    def test_decode_id_no_data(self):
+        pkt = packet.Packet(encoded_packet='2123')
+        self.assertEqual(pkt.id, 123)
+        self.assertIsNone(pkt.data)
+        self.assertEqual(pkt.encode(), '2123')
+
     def test_encode_namespace_and_id(self):
         pkt = packet.Packet(packet_type=packet.EVENT,
                             data=[six.text_type('foo')], namespace='/bar',