From d5611bccb64e2aa1e2c3e77d2c401f6146c8d9af Mon Sep 17 00:00:00 2001
From: Brian May <brian@linuxpenguins.xyz>
Date: Fri, 6 Jul 2018 11:26:34 +1000
Subject: [PATCH] Don't crash if connection closed before application started
 (#213)

Fixes #205.
---
 daphne/http_protocol.py | 2 +-
 daphne/server.py        | 2 ++
 daphne/ws_protocol.py   | 5 +++--
 3 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/daphne/http_protocol.py b/daphne/http_protocol.py
index 1155135..3ff10be 100755
--- a/daphne/http_protocol.py
+++ b/daphne/http_protocol.py
@@ -160,7 +160,7 @@ class WebRequest(http.Request):
                     "server": self.server_addr,
                 })
                 # Check they didn't close an unfinished request
-                if self.content.closed:
+                if self.application_queue is None or self.content.closed:
                     # Not much we can do, the request is prematurely abandoned.
                     return
                 # Run application against request
diff --git a/daphne/server.py b/daphne/server.py
index d8d43f2..63d34db 100755
--- a/daphne/server.py
+++ b/daphne/server.py
@@ -185,6 +185,8 @@ class Server(object):
         input_queue = asyncio.Queue()
         application_instance = yield deferToThread(self.application, scope=scope)
         # Run it, and stash the future for later checking
+        if protocol not in self.connections:
+            return None
         self.connections[protocol]["application_instance"] = asyncio.ensure_future(application_instance(
             receive=input_queue.get,
             send=lambda message: self.handle_reply(protocol, message),
diff --git a/daphne/ws_protocol.py b/daphne/ws_protocol.py
index 9edfce6..a7331b5 100755
--- a/daphne/ws_protocol.py
+++ b/daphne/ws_protocol.py
@@ -75,8 +75,9 @@ class WebSocketProtocol(WebSocketServerProtocol):
                 "server": self.server_addr,
                 "subprotocols": subprotocols,
             })
-            self.application_deferred.addCallback(self.applicationCreateWorked)
-            self.application_deferred.addErrback(self.applicationCreateFailed)
+            if self.application_deferred is not None:
+                self.application_deferred.addCallback(self.applicationCreateWorked)
+                self.application_deferred.addErrback(self.applicationCreateFailed)
         except Exception as e:
             # Exceptions here are not displayed right, just 500.
             # Turn them into an ERROR log.