Fix binary over http protocol to use the actually selected protocol v…

…ersion in the response `content-type` header (#7701)

Currently the `content-type` header of the response for the binary over
http protocol, always contains the latest protocol version supported by
the server, even if the client requested an older protocol version and
the response data actually being encoded using that requested version.

The current edgedb-js client which still uses protocol v1, just happens
to work despite this bug, as it also has a bug that results in it
ignoring the incorrect protocol version header from the server and
assuming it's the version requested. (Will be fixed in
geldata/gel-js#710)

edb/server/protocol/protocol.pyx

@@ -586,6 +586,16 @@ cdef class HttpProtocol:
                         int(ver_m.group(2).decode()),
                     )
 
+                    if proto_ver < edbdef.MIN_PROTOCOL:
+                        return self._bad_request(
+                            request,
+                            response,
+                            message="requested protocol version is too old and "
+                                "no longer supported",
+                        )
+                    if proto_ver > edbdef.CURRENT_PROTOCOL:
+                        proto_ver = edbdef.CURRENT_PROTOCOL
+
                     params = request.params
                     if params is None:
                         conn_params = {}
@@ -609,7 +619,10 @@ cdef class HttpProtocol:
                         tcp_transport=self.transport,
                     )
                     response.status = http.HTTPStatus.OK
-                    response.content_type = PROTO_MIME
+                    response.content_type = (
+                        f'application/x.edgedb.v_'
+                        f'{proto_ver[0]}_{proto_ver[1]}.binary'
+                    ).encode()
                     response.close_connection = True
 
             else:

tests/test_http_auth.py

@@ -243,6 +243,125 @@ async def test_http_auth_scram_cors(self):
                     headers['access-control-expose-headers']
                 )
 
+    def test_http_binary_proto_too_old(self):
+        args = self.get_connect_args()
+        (token, _, status, _, _) = self._scram_auth(
+            args["user"], args["password"]
+        )
+
+        proto_ver = (0, 1)
+        proto_ver_str = f"v_{proto_ver[0]}_{proto_ver[1]}"
+        mime_type = f"application/x.edgedb.{proto_ver_str}.binary"
+
+        with self.http_con() as con:
+            content, _, status = self.http_con_request(
+                con,
+                method="POST",
+                path=f"db/{args["database"]}",
+                prefix="",
+                body=protocol.Execute(
+                    annotations=[],
+                    allowed_capabilities=protocol.Capability.ALL,
+                    compilation_flags=protocol.CompilationFlag(0),
+                    implicit_limit=0,
+                    command_text="SELECT 42",
+                    output_format=protocol.OutputFormat.JSON,
+                    expected_cardinality=protocol.Cardinality.AT_MOST_ONE,
+                    input_typedesc_id=b"\0" * 16,
+                    output_typedesc_id=b"\0" * 16,
+                    state_typedesc_id=b"\0" * 16,
+                    arguments=b"",
+                    state_data=b"",
+                ).dump() + protocol.Sync().dump(),
+                headers={
+                    "Content-Type": mime_type,
+                    "X-EdgeDB-User": args["user"],
+                    "Authorization": f"Bearer {token.decode("ascii")}"
+                },
+            )
+
+        self.assertEqual(status, 400)
+        self.assertEqual(
+            content,
+            b"requested protocol version is too old and no longer supported"
+        )
+
+    def test_http_binary_proto_old_supported(self):
+        args = self.get_connect_args()
+        (token, _, status, _, _) = self._scram_auth(
+            args["user"], args["password"]
+        )
+
+        proto_ver = (edbdef.CURRENT_PROTOCOL[0] - 1, edbdef.CURRENT_PROTOCOL[1])
+        proto_ver_str = f"v_{proto_ver[0]}_{proto_ver[1]}"
+        mime_type = f"application/x.edgedb.{proto_ver_str}.binary"
+
+        with self.http_con() as con:
+            _, headers, status = self.http_con_request(
+                con,
+                method="POST",
+                path=f"db/{args["database"]}",
+                prefix="",
+                body=protocol.Execute(
+                    annotations=[],
+                    allowed_capabilities=protocol.Capability.ALL,
+                    compilation_flags=protocol.CompilationFlag(0),
+                    implicit_limit=0,
+                    command_text="SELECT 42",
+                    output_format=protocol.OutputFormat.JSON,
+                    expected_cardinality=protocol.Cardinality.AT_MOST_ONE,
+                    input_typedesc_id=b"\0" * 16,
+                    output_typedesc_id=b"\0" * 16,
+                    state_typedesc_id=b"\0" * 16,
+                    arguments=b"",
+                    state_data=b"",
+                ).dump() + protocol.Sync().dump(),
+                headers={
+                    "Content-Type": mime_type,
+                    "X-EdgeDB-User": args["user"],
+                    "Authorization": f"Bearer {token.decode("ascii")}"
+                },
+            )
+
+        self.assertEqual(status, 200)
+        self.assertEqual(headers, headers | {"content-type": mime_type})
+
+    def test_http_binary_proto_too_new(self):
+        args = self.get_connect_args()
+        (token, _, status, _, _) = self._scram_auth(
+            args["user"], args["password"]
+        )
+        self.assertEqual(status, 200)
+
+        proto_ver = (edbdef.CURRENT_PROTOCOL[0] + 1, edbdef.CURRENT_PROTOCOL[1])
+
+        expect_proto_ver = edbdef.CURRENT_PROTOCOL
+        proto_ver_str = f"v_{expect_proto_ver[0]}_{expect_proto_ver[1]}"
+
+        with self.http_con() as con:
+            msgs, headers, status = self.http_con_binary_request(
+                con,
+                "SELECT 42",
+                proto_ver=proto_ver,
+                bearer_token=token.decode("ascii"),
+                user=args["user"],
+                database=args["database"],
+            )
+        self.assertEqual(status, 200)
+        self.assertEqual(headers, headers | {
+            "content-type": f"application/x.edgedb.{proto_ver_str}.binary"
+        })
+        self.assertIsInstance(msgs[0], protocol.CommandDataDescription)
+        self.assertIsInstance(msgs[1], protocol.Data)
+        self.assertEqual(bytes(msgs[1].data[0].data), b"42")
+        self.assertIsInstance(msgs[2], protocol.CommandComplete)
+        self.assertEqual(msgs[2].status, "SELECT")
+        self.assertIsInstance(msgs[3], protocol.ReadyForCommand)
+        self.assertEqual(
+            msgs[3].transaction_state,
+            protocol.TransactionState.NOT_IN_TRANSACTION,
+        )
+
 
 class TestHttpAuthSystem(BaseTestHttpAuth):