Support HTTP response without Content-Length.

Fix #1531.

src/websockets/asyncio/connection.py

@@ -1060,13 +1060,22 @@ def eof_received(self) -> None:
         # Feed the end of the data stream to the connection.
         self.protocol.receive_eof()
 
-        # This isn't expected to generate events.
-        assert not self.protocol.events_received()
+        # This isn't expected to raise an exception.
+        events = self.protocol.events_received()
 
         # There is no error handling because send_data() can only write
         # the end of the data stream here and it shouldn't raise errors.
         self.send_data()
 
+        # This code path is triggered when receiving an HTTP response
+        # without a Content-Length header. This is the only case where
+        # reading until EOF generates an event; all other events have
+        # a known length. Ignore for coverage measurement because tests
+        # are in test_client.py rather than test_connection.py.
+        for event in events:  # pragma: no cover
+            # This isn't expected to raise an exception.
+            self.process_event(event)
+
         # The WebSocket protocol has its own closing handshake: endpoints close
         # the TCP or TLS connection after sending and receiving a close frame.
         # As a consequence, they never need to write after receiving EOF, so

src/websockets/legacy/exceptions.py

@@ -50,7 +50,7 @@ def __init__(
         headers: datastructures.HeadersLike,
         body: bytes = b"",
     ) -> None:
-        # If a user passes an int instead of a HTTPStatus, fix it automatically.
+        # If a user passes an int instead of an HTTPStatus, fix it automatically.
         self.status = http.HTTPStatus(status)
         self.headers = datastructures.Headers(headers)
         self.body = body

src/websockets/sync/connection.py

@@ -696,13 +696,22 @@ def recv_events(self) -> None:
                 # Feed the end of the data stream to the protocol.
                 self.protocol.receive_eof()
 
-                # This isn't expected to generate events.
-                assert not self.protocol.events_received()
+                # This isn't expected to raise an exception.
+                events = self.protocol.events_received()
 
                 # There is no error handling because send_data() can only write
                 # the end of the data stream here and it handles errors itself.
                 self.send_data()
 
+            # This code path is triggered when receiving an HTTP response
+            # without a Content-Length header. This is the only case where
+            # reading until EOF generates an event; all other events have
+            # a known length. Ignore for coverage measurement because tests
+            # are in test_client.py rather than test_connection.py.
+            for event in events:  # pragma: no cover
+                # This isn't expected to raise an exception.
+                self.process_event(event)
+
         except Exception as exc:
             # This branch should never run. It's a safety net in case of bugs.
             self.logger.error("unexpected internal error", exc_info=True)

tests/asyncio/test_client.py

@@ -401,6 +401,36 @@ def close_connection(self, request):
                 "connection closed while reading HTTP status line",
             )
 
+    async def test_http_response(self):
+        """Client reads HTTP response."""
+
+        def http_response(connection, request):
+            return connection.respond(http.HTTPStatus.OK, "👌")
+
+        async with serve(*args, process_request=http_response) as server:
+            with self.assertRaises(InvalidStatus) as raised:
+                async with connect(get_uri(server)):
+                    self.fail("did not raise")
+
+        self.assertEqual(raised.exception.response.status_code, 200)
+        self.assertEqual(raised.exception.response.body.decode(), "👌")
+
+    async def test_http_response_without_content_length(self):
+        """Client reads HTTP response without a Content-Length header."""
+
+        def http_response(connection, request):
+            response = connection.respond(http.HTTPStatus.OK, "👌")
+            del response.headers["Content-Length"]
+            return response
+
+        async with serve(*args, process_request=http_response) as server:
+            with self.assertRaises(InvalidStatus) as raised:
+                async with connect(get_uri(server)):
+                    self.fail("did not raise")
+
+        self.assertEqual(raised.exception.response.status_code, 200)
+        self.assertEqual(raised.exception.response.body.decode(), "👌")
+
     async def test_junk_handshake(self):
         """Client closes the connection when receiving non-HTTP response from server."""
 

tests/sync/test_client.py

@@ -1,3 +1,4 @@
+import http
 import logging
 import socket
 import socketserver
@@ -6,7 +7,7 @@
 import time
 import unittest
 
-from websockets.exceptions import InvalidHandshake, InvalidURI
+from websockets.exceptions import InvalidHandshake, InvalidStatus, InvalidURI
 from websockets.extensions.permessage_deflate import PerMessageDeflate
 from websockets.sync.client import *
 
@@ -156,6 +157,36 @@ def close_connection(self, request):
                 "connection closed while reading HTTP status line",
             )
 
+    def test_http_response(self):
+        """Client reads HTTP response."""
+
+        def http_response(connection, request):
+            return connection.respond(http.HTTPStatus.OK, "👌")
+
+        with run_server(process_request=http_response) as server:
+            with self.assertRaises(InvalidStatus) as raised:
+                with connect(get_uri(server)):
+                    self.fail("did not raise")
+
+        self.assertEqual(raised.exception.response.status_code, 200)
+        self.assertEqual(raised.exception.response.body.decode(), "👌")
+
+    def test_http_response_without_content_length(self):
+        """Client reads HTTP response without a Content-Length header."""
+
+        def http_response(connection, request):
+            response = connection.respond(http.HTTPStatus.OK, "👌")
+            del response.headers["Content-Length"]
+            return response
+
+        with run_server(process_request=http_response) as server:
+            with self.assertRaises(InvalidStatus) as raised:
+                with connect(get_uri(server)):
+                    self.fail("did not raise")
+
+        self.assertEqual(raised.exception.response.status_code, 200)
+        self.assertEqual(raised.exception.response.body.decode(), "👌")
+
     def test_junk_handshake(self):
         """Client closes the connection when receiving non-HTTP response from server."""