add basic gateway logic

Pipfile

@@ -9,6 +9,7 @@ itsdangerous = "==0.24"
 asyncpg = "==0.16.0"
 websockets = "==5.0.1"
 Quart = "==0.6.0"
+Earl-ETF = "==2.1.2"
 
 [dev-packages]
 

Pipfile.lock

@@ -1,7 +1,7 @@
 {
     "_meta": {
         "hash": {
-            "sha256": "e37a82fc53dadfc4b8ebbded3bb043d686fa5c2cde07b11589430586e236386b"
+            "sha256": "f4558d5a01c7a8954d1b4f60042c3599189df0e720c235c89bb41facb9d704ab"
         },
         "host-environment-markers": {
             "implementation_name": "cpython",
@@ -9,9 +9,9 @@
             "os_name": "posix",
             "platform_machine": "x86_64",
             "platform_python_implementation": "CPython",
-            "platform_release": "4.16.13-2-ARCH",
+            "platform_release": "4.17.2-1-ARCH",
             "platform_system": "Linux",
-            "platform_version": "#1 SMP PREEMPT Fri Jun 1 18:46:11 UTC 2018",
+            "platform_version": "#1 SMP PREEMPT Sat Jun 16 11:08:59 UTC 2018",
             "python_full_version": "3.6.5",
             "python_version": "3.6",
             "sys_platform": "linux"
@@ -53,6 +53,10 @@
             "hashes": [],
             "version": "==6.7"
         },
+        "earl-etf": {
+            "hashes": [],
+            "version": "==2.1.2"
+        },
         "h11": {
             "hashes": [],
             "version": "==0.7.0"

litecord/gateway/errors.py

@@ -0,0 +1,17 @@
+from ..errors import WebsocketClose
+
+
+class UnknownOPCode(WebsocketClose):
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+
+        # hacky solution to
+        # decrease code repetition
+        self.args = [4001, self.args[0]]
+
+
+class DecodeError(WebsocketClose):
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+
+        self.args = [4002, self.args[0]]

litecord/gateway/gateway.py

@@ -1,4 +1,5 @@
 import urllib.parse
+from .websocket import GatewayWebsocket
 
 
 async def websocket_handler(ws, url):
@@ -26,5 +27,6 @@ async def websocket_handler(ws, url):
     if gw_compress and gw_compress not in ('zlib-stream',):
         return await ws.close(1000, 'Invalid gateway compress')
 
-    await ws.close(code=1000, reason='ass')
-    return
+    gws = GatewayWebsocket(ws, v=gw_version,
+                           encoding=gw_encoding, compress=gw_compress)
+    await gws.run()

litecord/gateway/opcodes.py

@@ -0,0 +1,14 @@
+class OP:
+    """Gateway OP codes."""
+    DISPATCH = 0
+    HEARTBEAT = 1
+    IDENTIFY = 2
+    STATUS_UPDATE = 3
+    VOICE_UPDATE = 4
+    VOICE_PING = 5
+    RESUME = 6
+    RECONNECT = 7
+    REQ_GUILD_MEMBERS = 8
+    INVALID_SESSION = 9
+    HELLO = 10
+    HEARTBEAT_ACK = 11

litecord/gateway/state.py

@@ -0,0 +1,7 @@
+class GatewayState:
+    """Main websocket state.
+
+    Used to store all information tied to the websocket's session.
+    """
+    def __init__(self, **kwargs):
+        pass

litecord/gateway/websocket.py

@@ -0,0 +1,100 @@
+import json
+
+import earl
+
+from ..errors import WebsocketClose
+from .errors import DecodeError, UnknownOPCode
+from .opcodes import OP
+
+
+def encode_json(payload) -> str:
+    return json.dumps(payload)
+
+
+def decode_json(data: str):
+    return json.loads(data)
+
+
+def encode_etf(payload) -> str:
+    return earl.pack(payload)
+
+
+def decode_etf(data):
+    return earl.unpack(data)
+
+
+class GatewayWebsocket:
+    """Main gateway websocket logic."""
+    def __init__(self, ws, **kwargs):
+        self.ws = ws
+        self.version = kwargs.get('v', 6)
+        self.encoding = kwargs.get('encoding', 'json')
+        self.compress = kwargs.get('compress', None)
+
+        self.set_encoders()
+
+    def set_encoders(self):
+        encoding = self.encoding
+
+        encodings = {
+            'json': (encode_json, decode_json),
+            'etf': (encode_etf, decode_etf),
+        }
+
+        self.encoder, self.decoder = encodings[encoding]
+
+    async def send(self, payload):
+        encoded = self.encoder(payload)
+
+        # TODO: compression
+
+        await self.ws.send(encoded)
+
+    async def send_hello(self):
+        """Send the OP 10 Hello"""
+        await self.send({
+            'op': OP.HELLO,
+            'd': {
+                'heartbeat_interval': 45000,
+                '_trace': [
+                    'despacito'
+                ],
+            }
+        })
+
+    async def handle_0(self, payload):
+        pass
+
+    async def process_message(self, payload):
+        """Process a single message coming in from the client."""
+        try:
+            op_code = payload['op']
+        except KeyError:
+            raise UnknownOPCode('No OP code')
+
+        try:
+            handler = getattr(self, f'handle_{op_code}')
+        except AttributeError:
+            raise UnknownOPCode('Bad OP code')
+
+        await handler(payload)
+
+    async def listen_messages(self):
+        """Listen for messages coming in from the websocket."""
+        while True:
+            message = await self.ws.recv()
+            if len(message) > 4096:
+                raise DecodeError('Payload length exceeded')
+
+            payload = self.decoder(message)
+            await self.process_message(payload)
+
+    async def run(self):
+        """Wrap listen_messages inside
+        a try/except block for WebsocketClose handling."""
+        try:
+            await self.send_hello()
+            await self.listen_messages()
+        except WebsocketClose as err:
+            await self.ws.close(code=err.code,
+                                reason=err.reason)