Add a limit to WebSocket message size (Fixes #193)

tests/test_websocket.py

@@ -1,8 +1,8 @@
 import asyncio
 import sys
 import unittest
-from microdot import Microdot
-from microdot.websocket import with_websocket, WebSocket
+from microdot import Microdot, Request
+from microdot.websocket import with_websocket, WebSocket, WebSocketError
 from microdot.test_client import TestClient
 
 
@@ -17,6 +17,7 @@ class TestWebSocket(unittest.TestCase):
         return self.loop.run_until_complete(coro)
 
     def test_websocket_echo(self):
+        WebSocket.max_message_length = 65537
         app = Microdot()
 
         @app.route('/echo')
@@ -26,34 +27,10 @@ class TestWebSocket(unittest.TestCase):
                 data = await ws.receive()
                 await ws.send(data)
 
-        results = []
-
-        def ws():
-            data = yield 'hello'
-            results.append(data)
-            data = yield b'bye'
-            results.append(data)
-            data = yield b'*' * 300
-            results.append(data)
-            data = yield b'+' * 65537
-            results.append(data)
-
-        client = TestClient(app)
-        res = self._run(client.websocket('/echo', ws))
-        self.assertIsNone(res)
-        self.assertEqual(results, ['hello', b'bye', b'*' * 300, b'+' * 65537])
-
-    @unittest.skipIf(sys.implementation.name == 'micropython',
-                     'no support for async generators in MicroPython')
-    def test_websocket_echo_async_client(self):
-        app = Microdot()
-
-        @app.route('/echo')
+        @app.route('/divzero')
         @with_websocket
-        async def index(req, ws):
-            while True:
-                data = await ws.receive()
-                await ws.send(data)
+        async def divzero(req, ws):
+            1 / 0
 
         results = []
 
@@ -72,6 +49,35 @@ class TestWebSocket(unittest.TestCase):
         self.assertIsNone(res)
         self.assertEqual(results, ['hello', b'bye', b'*' * 300, b'+' * 65537])
 
+        res = self._run(client.websocket('/divzero', ws))
+        self.assertIsNone(res)
+        WebSocket.max_message_length = -1
+
+    @unittest.skipIf(sys.implementation.name == 'micropython',
+                     'no support for async generators in MicroPython')
+    def test_websocket_large_message(self):
+        saved_max_body_length = Request.max_body_length
+        Request.max_body_length = 10
+        app = Microdot()
+
+        @app.route('/echo')
+        @with_websocket
+        async def index(req, ws):
+            data = await ws.receive()
+            await ws.send(data)
+
+        results = []
+
+        async def ws():
+            data = yield '0123456789abcdef'
+            results.append(data)
+
+        client = TestClient(app)
+        res = self._run(client.websocket('/echo', ws))
+        self.assertIsNone(res)
+        self.assertEqual(results, [])
+        Request.max_body_length = saved_max_body_length
+
     def test_bad_websocket_request(self):
         app = Microdot()
 
@@ -106,7 +112,7 @@ class TestWebSocket(unittest.TestCase):
                          (None, 'foo'))
         self.assertEqual(ws._process_websocket_frame(WebSocket.BINARY, b'foo'),
                          (None, b'foo'))
-        self.assertRaises(OSError, ws._process_websocket_frame,
+        self.assertRaises(WebSocketError, ws._process_websocket_frame,
                           WebSocket.CLOSE, b'')
         self.assertEqual(ws._process_websocket_frame(WebSocket.PING, b'foo'),
                          (WebSocket.PONG, b'foo'))