Fixed #229: Allow bytes headers only

Previously Daphne was too lax and would happily accept strings too.

daphne/server.py

@@ -211,9 +211,28 @@ class Server(object):
         # Don't do anything if the connection is closed
         if self.connections[protocol].get("disconnected", None):
             return
+        self.check_headers_type(message)
         # Let the protocol handle it
         protocol.handle_reply(message)
 
+    @staticmethod
+    def check_headers_type(message):
+        if not message["type"] == "http.response.start":
+            return
+        for k, v in message.get("headers", []):
+            if not isinstance(k, bytes):
+                raise ValueError(
+                    "Header name '{}' expected to be `bytes`, but got `{}`".format(
+                        k, type(k)
+                    )
+                )
+            if not isinstance(v, bytes):
+                raise ValueError(
+                    "Header value '{}' expected to be `bytes`, but got `{}`".format(
+                        v, type(v)
+                    )
+                )
+
     ### Utility
 
     def application_checker(self):

tests/http_base.py

@@ -37,12 +37,10 @@ class DaphneTestCase(unittest.TestCase):
             if params:
                 path += "?" + parse.urlencode(params, doseq=True)
             conn.putrequest(method, path, skip_accept_encoding=True, skip_host=True)
-            # Manually send over headers (encoding any non-safe values as best we can)
+            # Manually send over headers
             if headers:
                 for header_name, header_value in headers:
-                    conn.putheader(
-                        header_name.encode("utf8"), header_value.encode("utf8")
-                    )
+                    conn.putheader(header_name, header_value)
             # Send body if provided.
             if body:
                 conn.putheader("Content-Length", str(len(body)))
@@ -140,19 +138,19 @@ class DaphneTestCase(unittest.TestCase):
             headers = []
         headers.extend(
             [
-                ("Host", "example.com"),
-                ("Upgrade", "websocket"),
-                ("Connection", "Upgrade"),
-                ("Sec-WebSocket-Key", "x3JJHMbDL1EzLkh9GBhXDw=="),
-                ("Sec-WebSocket-Version", "13"),
-                ("Origin", "http://example.com"),
+                (b"Host", b"example.com"),
+                (b"Upgrade", b"websocket"),
+                (b"Connection", b"Upgrade"),
+                (b"Sec-WebSocket-Key", b"x3JJHMbDL1EzLkh9GBhXDw=="),
+                (b"Sec-WebSocket-Version", b"13"),
+                (b"Origin", b"http://example.com"),
             ]
         )
         if subprotocols:
-            headers.append(("Sec-WebSocket-Protocol", ", ".join(subprotocols)))
+            headers.append((b"Sec-WebSocket-Protocol", ", ".join(subprotocols)))
         if headers:
             for header_name, header_value in headers:
-                conn.putheader(header_name.encode("utf8"), header_value.encode("utf8"))
+                conn.putheader(header_name, header_value)
         conn.endheaders()
         # Read out the response
         try:

tests/http_strategies.py

@@ -92,7 +92,7 @@ def header_name():
     """
     return strategies.text(
         alphabet=string.ascii_letters + string.digits + "-", min_size=1, max_size=30
-    )
+    ).map(lambda s: s.encode("utf-8"))
 
 
 def header_value():
@@ -102,7 +102,8 @@ def header_value():
     "For example, the Apache 2.3 server by default limits the size of each field to 8190 bytes"
     https://en.wikipedia.org/wiki/List_of_HTTP_header_fields
     """
-    return strategies.text(
+    return (
+        strategies.text(
             alphabet=string.ascii_letters
             + string.digits
             + string.punctuation.replace(",", "")
@@ -110,7 +111,10 @@ def header_value():
             min_size=1,
             average_size=40,
             max_size=8190,
-    ).filter(lambda s: len(s.encode("utf8")) < 8190)
+        )
+        .map(lambda s: s.encode("utf-8"))
+        .filter(lambda s: len(s) < 8190)
+    )
 
 
 def headers():

tests/test_http_request.py

@@ -63,8 +63,8 @@ class TestHTTPRequest(DaphneTestCase):
             transformed_scope_headers[name].append(value)
         transformed_request_headers = collections.defaultdict(list)
         for name, value in headers or []:
-            expected_name = name.lower().strip().encode("ascii")
-            expected_value = value.strip().encode("ascii")
+            expected_name = name.lower().strip()
+            expected_value = value.strip()
             transformed_request_headers[expected_name].append(expected_value)
         for name, value in transformed_request_headers.items():
             self.assertIn(name, transformed_scope_headers)
@@ -209,7 +209,7 @@ class TestHTTPRequest(DaphneTestCase):
         """
         Make sure headers are normalized as the spec says they are.
         """
-        headers = [("MYCUSTOMHEADER", "   foobar    ")]
+        headers = [(b"MYCUSTOMHEADER", b"   foobar    ")]
         scope, messages = self.run_daphne_request("GET", "/", headers=headers)
         self.assert_valid_http_scope(scope, "GET", "/", headers=headers)
         self.assert_valid_http_request_message(messages[0], body=b"")
@@ -237,7 +237,7 @@ class TestHTTPRequest(DaphneTestCase):
         """
         Make sure that, by default, X-Forwarded-For is ignored.
         """
-        headers = [["X-Forwarded-For", "10.1.2.3"], ["X-Forwarded-Port", "80"]]
+        headers = [[b"X-Forwarded-For", b"10.1.2.3"], [b"X-Forwarded-Port", b"80"]]
         scope, messages = self.run_daphne_request("GET", "/", headers=headers)
         self.assert_valid_http_scope(scope, "GET", "/", headers=headers)
         self.assert_valid_http_request_message(messages[0], body=b"")
@@ -248,7 +248,7 @@ class TestHTTPRequest(DaphneTestCase):
         """
         When X-Forwarded-For is enabled, make sure it is respected.
         """
-        headers = [["X-Forwarded-For", "10.1.2.3"], ["X-Forwarded-Port", "80"]]
+        headers = [[b"X-Forwarded-For", b"10.1.2.3"], [b"X-Forwarded-Port", b"80"]]
         scope, messages = self.run_daphne_request("GET", "/", headers=headers, xff=True)
         self.assert_valid_http_scope(scope, "GET", "/", headers=headers)
         self.assert_valid_http_request_message(messages[0], body=b"")
@@ -260,7 +260,7 @@ class TestHTTPRequest(DaphneTestCase):
         When X-Forwarded-For is enabled but only the host is passed, make sure
         that at least makes it through.
         """
-        headers = [["X-Forwarded-For", "10.1.2.3"]]
+        headers = [[b"X-Forwarded-For", b"10.1.2.3"]]
         scope, messages = self.run_daphne_request("GET", "/", headers=headers, xff=True)
         self.assert_valid_http_scope(scope, "GET", "/", headers=headers)
         self.assert_valid_http_request_message(messages[0], body=b"")

tests/test_http_response.py

@@ -19,10 +19,16 @@ class TestHTTPResponse(DaphneTestCase):
             [
                 (name.lower(), value.strip())
                 for name, value in headers
-                if name.lower() != "transfer-encoding"
+                if name.lower() != b"transfer-encoding"
             ]
         )
 
+    def encode_headers(self, headers):
+        def encode(s):
+            return s if isinstance(s, bytes) else s.encode("utf-8")
+
+        return [[encode(k), encode(v)] for k, v in headers]
+
     def test_minimal_response(self):
         """
         Smallest viable example. Mostly verifies that our response building works.
@@ -124,6 +130,42 @@ class TestHTTPResponse(DaphneTestCase):
         )
         # Check headers in a sensible way. Ignore transfer-encoding.
         self.assertEqual(
-            self.normalize_headers(response.getheaders()),
+            self.normalize_headers(self.encode_headers(response.getheaders())),
             self.normalize_headers(headers),
         )
+
+    def test_headers_type(self):
+        """
+        Headers should be `bytes`
+        """
+        with self.assertRaises(ValueError) as context:
+            self.run_daphne_response(
+                [
+                    {
+                        "type": "http.response.start",
+                        "status": 200,
+                        "headers": [["foo", b"bar"]],
+                    },
+                    {"type": "http.response.body", "body": b""},
+                ]
+            )
+        self.assertEqual(
+            str(context.exception),
+            "Header name 'foo' expected to be `bytes`, but got `<class 'str'>`",
+        )
+
+        with self.assertRaises(ValueError) as context:
+            self.run_daphne_response(
+                [
+                    {
+                        "type": "http.response.start",
+                        "status": 200,
+                        "headers": [[b"foo", True]],
+                    },
+                    {"type": "http.response.body", "body": b""},
+                ]
+            )
+        self.assertEqual(
+            str(context.exception),
+            "Header value 'True' expected to be `bytes`, but got `<class 'bool'>`",
+        )

tests/test_websocket.py

@@ -56,8 +56,8 @@ class TestWebsocket(DaphneTestCase):
                     transformed_scope_headers[name].append(bit.strip())
         transformed_request_headers = collections.defaultdict(list)
         for name, value in headers or []:
-            expected_name = name.lower().strip().encode("ascii")
-            expected_value = value.strip().encode("ascii")
+            expected_name = name.lower().strip()
+            expected_value = value.strip()
             # Make sure to split out any headers collapsed with commas
             transformed_request_headers.setdefault(expected_name, [])
             for bit in expected_value.split(b","):