Added send_packet() method

src/engineio/asyncio_server.py

@@ -87,6 +87,16 @@ async def send(self, sid, data):
                      ``str``, ``bytes``, ``list`` or ``dict``. If a ``list``
                      or ``dict``, the data will be serialized as JSON.
 
+        Note: this method is a coroutine.
+        """
+        await self.send_packet(sid, packet.Packet(packet.MESSAGE, data=data))
+
+    async def send_packet(self, sid, pkt):
+        """Send a raw packet to a client.
+
+        :param sid: The session id of the recipient client.
+        :param pkt: The packet to send to the client.
+
         Note: this method is a coroutine.
         """
         try:
@@ -95,7 +105,7 @@ async def send(self, sid, data):
             # the socket is not available
             self.logger.warning('Cannot send to sid %s', sid)
             return
-        await socket.send(packet.Packet(packet.MESSAGE, data=data))
+        await socket.send(pkt)
 
     async def get_session(self, sid):
         """Return the user session for a client.

src/engineio/packet.py

@@ -15,6 +15,7 @@ class Packet(object):
     def __init__(self, packet_type=NOOP, data=None, encoded_packet=None):
         self.packet_type = packet_type
         self.data = data
+        self.encode_cache = None
         if isinstance(data, str):
             self.binary = False
         elif isinstance(data, binary_types):
@@ -27,7 +28,13 @@ def __init__(self, packet_type=NOOP, data=None, encoded_packet=None):
             self.decode(encoded_packet)
 
     def encode(self, b64=False):
-        """Encode the packet for transmission."""
+        """Encode the packet for transmission.
+
+        Note: as a performance optimization, subsequent calls to this method
+        will return a cached encoded packet, even if the data has changed.
+        """
+        if self.encode_cache:
+            return self.encode_cache
         if self.binary:
             if b64:
                 encoded_packet = 'b' + base64.b64encode(self.data).decode(
@@ -43,6 +50,7 @@ def encode(self, b64=False):
                                                   separators=(',', ':'))
             elif self.data is not None:
                 encoded_packet += str(self.data)
+        self.encode_cache = encoded_packet
         return encoded_packet
 
     def decode(self, encoded_packet):

src/engineio/server.py

@@ -224,13 +224,21 @@ def send(self, sid, data):
                      ``str``, ``bytes``, ``list`` or ``dict``. If a ``list``
                      or ``dict``, the data will be serialized as JSON.
         """
+        self.send_packet(sid, packet.Packet(packet.MESSAGE, data=data))
+
+    def send_packet(self, sid, pkt):
+        """Send a raw packet to a client.
+
+        :param sid: The session id of the recipient client.
+        :param pkt: The packet to send to the client.
+        """
         try:
             socket = self._get_socket(sid)
         except KeyError:
             # the socket is not available
             self.logger.warning('Cannot send to sid %s', sid)
             return
-        socket.send(packet.Packet(packet.MESSAGE, data=data))
+        socket.send(pkt)
 
     def get_session(self, sid):
         """Return the user session for a client.

tests/common/test_packet.py

@@ -134,3 +134,11 @@ def test_binary_non_message_packet(self):
     def test_decode_invalid_empty_text_packet(self):
         with pytest.raises(ValueError):
             packet.Packet(encoded_packet='')
+
+    def test_encode_cache(self):
+        pkt = packet.Packet(packet.MESSAGE, data=123)
+        assert pkt.encode() == '4123'
+        pkt.data = 456
+        assert pkt.encode() == '4123'
+        pkt.encode_cache = None
+        assert pkt.encode() == '4456'