From f39b8b32f70445e80c63a236bf227c1694e3a05b Mon Sep 17 00:00:00 2001
From: Adam Hopkins <admhpkns@gmail.com>
Date: Mon, 21 Jun 2021 14:39:06 +0300
Subject: [PATCH] Make sure ASGI ws subprotocols is a list (#2127)

* Ensure protocols is a list for ASGI

* Subprotocol updates
---
 sanic/app.py       | 21 ++++++++++++---------
 sanic/asgi.py      |  1 -
 sanic/websocket.py | 23 +++++++++++++++++++----
 tests/test_asgi.py |  8 ++++----
 4 files changed, 35 insertions(+), 18 deletions(-)

diff --git a/sanic/app.py b/sanic/app.py
index 1d08f02e..002c92dc 100644
--- a/sanic/app.py
+++ b/sanic/app.py
@@ -585,7 +585,12 @@ class Sanic(BaseSanic):
             # determine if the parameter supplied by the caller
             # passes the test in the URL
             if param_info.pattern:
-                passes_pattern = param_info.pattern.match(supplied_param)
+                pattern = (
+                    param_info.pattern[1]
+                    if isinstance(param_info.pattern, tuple)
+                    else param_info.pattern
+                )
+                passes_pattern = pattern.match(supplied_param)
                 if not passes_pattern:
                     if param_info.cast != str:
                         msg = (
@@ -593,13 +598,13 @@ class Sanic(BaseSanic):
                             f"for parameter `{param_info.name}` does "
                             "not match pattern for type "
                             f"`{param_info.cast.__name__}`: "
-                            f"{param_info.pattern.pattern}"
+                            f"{pattern.pattern}"
                         )
                     else:
                         msg = (
                             f'Value "{supplied_param}" for parameter '
                             f"`{param_info.name}` does not satisfy "
-                            f"pattern {param_info.pattern.pattern}"
+                            f"pattern {pattern.pattern}"
                         )
                     raise URLBuildError(msg)
 
@@ -740,17 +745,14 @@ class Sanic(BaseSanic):
 
             if response:
                 response = await request.respond(response)
-            else:
+            elif not hasattr(handler, "is_websocket"):
                 response = request.stream.response  # type: ignore
-            # Make sure that response is finished / run StreamingHTTP callback
 
+            # Make sure that response is finished / run StreamingHTTP callback
             if isinstance(response, BaseHTTPResponse):
                 await response.send(end_stream=True)
             else:
-                try:
-                    # Fastest method for checking if the property exists
-                    handler.is_websocket  # type: ignore
-                except AttributeError:
+                if not hasattr(handler, "is_websocket"):
                     raise ServerError(
                         f"Invalid response type {response!r} "
                         "(need HTTPResponse)"
@@ -777,6 +779,7 @@ class Sanic(BaseSanic):
 
         if self.asgi:
             ws = request.transport.get_websocket_connection()
+            await ws.accept(subprotocols)
         else:
             protocol = request.transport.get_protocol()
             protocol.app = self
diff --git a/sanic/asgi.py b/sanic/asgi.py
index be598ec1..5765a5cd 100644
--- a/sanic/asgi.py
+++ b/sanic/asgi.py
@@ -140,7 +140,6 @@ class ASGIApp:
                 instance.ws = instance.transport.create_websocket_connection(
                     send, receive
                 )
-                await instance.ws.accept()
             else:
                 raise ServerError("Received unknown ASGI scope")
 
diff --git a/sanic/websocket.py b/sanic/websocket.py
index c4bdd580..b5600ed7 100644
--- a/sanic/websocket.py
+++ b/sanic/websocket.py
@@ -41,7 +41,7 @@ class WebSocketProtocol(HttpProtocol):
         websocket_write_limit=2 ** 16,
         websocket_ping_interval=20,
         websocket_ping_timeout=20,
-        **kwargs
+        **kwargs,
     ):
         super().__init__(*args, **kwargs)
         self.websocket = None
@@ -154,7 +154,7 @@ class WebSocketConnection:
     ) -> None:
         self._send = send
         self._receive = receive
-        self.subprotocols = subprotocols or []
+        self._subprotocols = subprotocols or []
 
     async def send(self, data: Union[str, bytes], *args, **kwargs) -> None:
         message: Dict[str, Union[str, bytes]] = {"type": "websocket.send"}
@@ -178,13 +178,28 @@ class WebSocketConnection:
 
     receive = recv
 
-    async def accept(self) -> None:
+    async def accept(self, subprotocols: Optional[List[str]] = None) -> None:
+        subprotocol = None
+        if subprotocols:
+            for subp in subprotocols:
+                if subp in self.subprotocols:
+                    subprotocol = subp
+                    break
+
         await self._send(
             {
                 "type": "websocket.accept",
-                "subprotocol": ",".join(list(self.subprotocols)),
+                "subprotocol": subprotocol,
             }
         )
 
     async def close(self) -> None:
         pass
+
+    @property
+    def subprotocols(self):
+        return self._subprotocols
+
+    @subprotocols.setter
+    def subprotocols(self, subprotocols: Optional[List[str]] = None):
+        self._subprotocols = subprotocols or []
diff --git a/tests/test_asgi.py b/tests/test_asgi.py
index a4632537..5be3fd26 100644
--- a/tests/test_asgi.py
+++ b/tests/test_asgi.py
@@ -218,7 +218,7 @@ async def test_websocket_accept_with_no_subprotocols(
 
     message = message_stack.popleft()
     assert message["type"] == "websocket.accept"
-    assert message["subprotocol"] == ""
+    assert message["subprotocol"] is None
     assert "bytes" not in message
 
 
@@ -227,7 +227,7 @@ async def test_websocket_accept_with_subprotocol(send, receive, message_stack):
     subprotocols = ["graphql-ws"]
 
     ws = WebSocketConnection(send, receive, subprotocols)
-    await ws.accept()
+    await ws.accept(subprotocols)
 
     assert len(message_stack) == 1
 
@@ -244,13 +244,13 @@ async def test_websocket_accept_with_multiple_subprotocols(
     subprotocols = ["graphql-ws", "hello", "world"]
 
     ws = WebSocketConnection(send, receive, subprotocols)
-    await ws.accept()
+    await ws.accept(["hello", "world"])
 
     assert len(message_stack) == 1
 
     message = message_stack.popleft()
     assert message["type"] == "websocket.accept"
-    assert message["subprotocol"] == "graphql-ws,hello,world"
+    assert message["subprotocol"] == "hello"
     assert "bytes" not in message