mirror of
https://mau.dev/maunium/synapse.git
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903 lines
30 KiB
Python
903 lines
30 KiB
Python
# Copyright 2014-2016 OpenMarket Ltd
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# Copyright 2018 New Vector Ltd
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import abc
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import html
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import logging
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import types
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import urllib
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from http import HTTPStatus
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from inspect import isawaitable
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from typing import (
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TYPE_CHECKING,
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Any,
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Awaitable,
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Callable,
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Dict,
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Iterable,
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Iterator,
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List,
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NoReturn,
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Optional,
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Pattern,
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Tuple,
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Union,
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)
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import attr
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import jinja2
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from canonicaljson import encode_canonical_json
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from typing_extensions import Protocol
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from zope.interface import implementer
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from twisted.internet import defer, interfaces
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from twisted.python import failure
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from twisted.web import resource
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from twisted.web.server import NOT_DONE_YET, Request
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from twisted.web.static import File
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from twisted.web.util import redirectTo
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from synapse.api.errors import (
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CodeMessageException,
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Codes,
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RedirectException,
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SynapseError,
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UnrecognizedRequestError,
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)
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from synapse.http.site import SynapseRequest
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from synapse.logging.context import defer_to_thread, preserve_fn, run_in_background
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from synapse.logging.opentracing import active_span, start_active_span, trace_servlet
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from synapse.util import json_encoder
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from synapse.util.caches import intern_dict
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from synapse.util.iterutils import chunk_seq
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if TYPE_CHECKING:
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import opentracing
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from synapse.server import HomeServer
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logger = logging.getLogger(__name__)
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HTML_ERROR_TEMPLATE = """<!DOCTYPE html>
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<html lang=en>
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<head>
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<meta charset="utf-8">
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<title>Error {code}</title>
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</head>
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<body>
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<p>{msg}</p>
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</body>
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</html>
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"""
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def return_json_error(f: failure.Failure, request: SynapseRequest) -> None:
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"""Sends a JSON error response to clients."""
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if f.check(SynapseError):
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# mypy doesn't understand that f.check asserts the type.
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exc: SynapseError = f.value # type: ignore
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error_code = exc.code
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error_dict = exc.error_dict()
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logger.info("%s SynapseError: %s - %s", request, error_code, exc.msg)
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else:
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error_code = 500
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error_dict = {"error": "Internal server error", "errcode": Codes.UNKNOWN}
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logger.error(
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"Failed handle request via %r: %r",
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request.request_metrics.name,
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request,
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exc_info=(f.type, f.value, f.getTracebackObject()), # type: ignore[arg-type]
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)
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# Only respond with an error response if we haven't already started writing,
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# otherwise lets just kill the connection
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if request.startedWriting:
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if request.transport:
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try:
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request.transport.abortConnection()
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except Exception:
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# abortConnection throws if the connection is already closed
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pass
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else:
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respond_with_json(
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request,
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error_code,
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error_dict,
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send_cors=True,
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)
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def return_html_error(
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f: failure.Failure,
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request: Request,
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error_template: Union[str, jinja2.Template],
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) -> None:
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"""Sends an HTML error page corresponding to the given failure.
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Handles RedirectException and other CodeMessageExceptions (such as SynapseError)
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Args:
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f: the error to report
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request: the failing request
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error_template: the HTML template. Can be either a string (with `{code}`,
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`{msg}` placeholders), or a jinja2 template
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"""
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if f.check(CodeMessageException):
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# mypy doesn't understand that f.check asserts the type.
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cme: CodeMessageException = f.value # type: ignore
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code = cme.code
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msg = cme.msg
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if isinstance(cme, RedirectException):
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logger.info("%s redirect to %s", request, cme.location)
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request.setHeader(b"location", cme.location)
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request.cookies.extend(cme.cookies)
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elif isinstance(cme, SynapseError):
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logger.info("%s SynapseError: %s - %s", request, code, msg)
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else:
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logger.error(
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"Failed handle request %r",
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request,
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exc_info=(f.type, f.value, f.getTracebackObject()), # type: ignore[arg-type]
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)
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else:
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code = HTTPStatus.INTERNAL_SERVER_ERROR
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msg = "Internal server error"
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logger.error(
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"Failed handle request %r",
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request,
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exc_info=(f.type, f.value, f.getTracebackObject()), # type: ignore[arg-type]
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)
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if isinstance(error_template, str):
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body = error_template.format(code=code, msg=html.escape(msg))
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else:
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body = error_template.render(code=code, msg=msg)
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respond_with_html(request, code, body)
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def wrap_async_request_handler(
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h: Callable[["_AsyncResource", SynapseRequest], Awaitable[None]]
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) -> Callable[["_AsyncResource", SynapseRequest], "defer.Deferred[None]"]:
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"""Wraps an async request handler so that it calls request.processing.
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This helps ensure that work done by the request handler after the request is completed
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is correctly recorded against the request metrics/logs.
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The handler method must have a signature of "handle_foo(self, request)",
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where "request" must be a SynapseRequest.
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The handler may return a deferred, in which case the completion of the request isn't
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logged until the deferred completes.
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"""
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async def wrapped_async_request_handler(
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self: "_AsyncResource", request: SynapseRequest
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) -> None:
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with request.processing():
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await h(self, request)
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# we need to preserve_fn here, because the synchronous render method won't yield for
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# us (obviously)
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return preserve_fn(wrapped_async_request_handler)
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# Type of a callback method for processing requests
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# it is actually called with a SynapseRequest and a kwargs dict for the params,
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# but I can't figure out how to represent that.
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ServletCallback = Callable[
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..., Union[None, Awaitable[None], Tuple[int, Any], Awaitable[Tuple[int, Any]]]
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]
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class HttpServer(Protocol):
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"""Interface for registering callbacks on a HTTP server"""
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def register_paths(
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self,
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method: str,
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path_patterns: Iterable[Pattern],
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callback: ServletCallback,
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servlet_classname: str,
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) -> None:
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"""Register a callback that gets fired if we receive a http request
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with the given method for a path that matches the given regex.
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If the regex contains groups these gets passed to the callback via
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an unpacked tuple.
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Args:
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method: The HTTP method to listen to.
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path_patterns: The regex used to match requests.
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callback: The function to fire if we receive a matched
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request. The first argument will be the request object and
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subsequent arguments will be any matched groups from the regex.
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This should return either tuple of (code, response), or None.
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servlet_classname (str): The name of the handler to be used in prometheus
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and opentracing logs.
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"""
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pass
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class _AsyncResource(resource.Resource, metaclass=abc.ABCMeta):
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"""Base class for resources that have async handlers.
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Sub classes can either implement `_async_render_<METHOD>` to handle
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requests by method, or override `_async_render` to handle all requests.
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Args:
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extract_context: Whether to attempt to extract the opentracing
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context from the request the servlet is handling.
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"""
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def __init__(self, extract_context: bool = False):
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super().__init__()
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self._extract_context = extract_context
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def render(self, request: SynapseRequest) -> int:
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"""This gets called by twisted every time someone sends us a request."""
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defer.ensureDeferred(self._async_render_wrapper(request))
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return NOT_DONE_YET
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@wrap_async_request_handler
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async def _async_render_wrapper(self, request: SynapseRequest) -> None:
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"""This is a wrapper that delegates to `_async_render` and handles
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exceptions, return values, metrics, etc.
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"""
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try:
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request.request_metrics.name = self.__class__.__name__
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with trace_servlet(request, self._extract_context):
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callback_return = await self._async_render(request)
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if callback_return is not None:
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code, response = callback_return
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self._send_response(request, code, response)
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except Exception:
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# failure.Failure() fishes the original Failure out
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# of our stack, and thus gives us a sensible stack
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# trace.
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f = failure.Failure()
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self._send_error_response(f, request)
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async def _async_render(self, request: SynapseRequest) -> Optional[Tuple[int, Any]]:
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"""Delegates to `_async_render_<METHOD>` methods, or returns a 400 if
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no appropriate method exists. Can be overridden in sub classes for
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different routing.
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"""
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# Treat HEAD requests as GET requests.
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request_method = request.method.decode("ascii")
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if request_method == "HEAD":
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request_method = "GET"
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method_handler = getattr(self, "_async_render_%s" % (request_method,), None)
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if method_handler:
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raw_callback_return = method_handler(request)
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# Is it synchronous? We'll allow this for now.
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if isawaitable(raw_callback_return):
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callback_return = await raw_callback_return
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else:
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callback_return = raw_callback_return # type: ignore
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return callback_return
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_unrecognised_request_handler(request)
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@abc.abstractmethod
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def _send_response(
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self,
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request: SynapseRequest,
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code: int,
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response_object: Any,
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) -> None:
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raise NotImplementedError()
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@abc.abstractmethod
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def _send_error_response(
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self,
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f: failure.Failure,
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request: SynapseRequest,
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) -> None:
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raise NotImplementedError()
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class DirectServeJsonResource(_AsyncResource):
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"""A resource that will call `self._async_on_<METHOD>` on new requests,
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formatting responses and errors as JSON.
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"""
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def __init__(self, canonical_json: bool = False, extract_context: bool = False):
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super().__init__(extract_context)
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self.canonical_json = canonical_json
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def _send_response(
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self,
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request: SynapseRequest,
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code: int,
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response_object: Any,
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) -> None:
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"""Implements _AsyncResource._send_response"""
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# TODO: Only enable CORS for the requests that need it.
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respond_with_json(
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request,
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code,
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response_object,
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send_cors=True,
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canonical_json=self.canonical_json,
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)
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def _send_error_response(
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self,
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f: failure.Failure,
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request: SynapseRequest,
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) -> None:
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"""Implements _AsyncResource._send_error_response"""
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return_json_error(f, request)
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@attr.s(slots=True, frozen=True, auto_attribs=True)
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class _PathEntry:
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pattern: Pattern
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callback: ServletCallback
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servlet_classname: str
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class JsonResource(DirectServeJsonResource):
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"""This implements the HttpServer interface and provides JSON support for
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Resources.
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Register callbacks via register_paths()
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Callbacks can return a tuple of status code and a dict in which case the
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the dict will automatically be sent to the client as a JSON object.
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The JsonResource is primarily intended for returning JSON, but callbacks
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may send something other than JSON, they may do so by using the methods
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on the request object and instead returning None.
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"""
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isLeaf = True
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def __init__(
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self,
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hs: "HomeServer",
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canonical_json: bool = True,
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extract_context: bool = False,
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):
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super().__init__(canonical_json, extract_context)
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self.clock = hs.get_clock()
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self.path_regexs: Dict[bytes, List[_PathEntry]] = {}
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self.hs = hs
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def register_paths(
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self,
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method: str,
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path_patterns: Iterable[Pattern],
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callback: ServletCallback,
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servlet_classname: str,
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) -> None:
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"""
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Registers a request handler against a regular expression. Later request URLs are
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checked against these regular expressions in order to identify an appropriate
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handler for that request.
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Args:
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method: GET, POST etc
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path_patterns: A list of regular expressions to which the request
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URLs are compared.
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callback: The handler for the request. Usually a Servlet
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servlet_classname: The name of the handler to be used in prometheus
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and opentracing logs.
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"""
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method_bytes = method.encode("utf-8")
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for path_pattern in path_patterns:
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logger.debug("Registering for %s %s", method, path_pattern.pattern)
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self.path_regexs.setdefault(method_bytes, []).append(
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_PathEntry(path_pattern, callback, servlet_classname)
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)
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def _get_handler_for_request(
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self, request: SynapseRequest
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) -> Tuple[ServletCallback, str, Dict[str, str]]:
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"""Finds a callback method to handle the given request.
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Returns:
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A tuple of the callback to use, the name of the servlet, and the
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key word arguments to pass to the callback
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"""
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# At this point the path must be bytes.
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request_path_bytes: bytes = request.path # type: ignore
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request_path = request_path_bytes.decode("ascii")
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# Treat HEAD requests as GET requests.
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request_method = request.method
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if request_method == b"HEAD":
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request_method = b"GET"
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# Loop through all the registered callbacks to check if the method
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# and path regex match
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for path_entry in self.path_regexs.get(request_method, []):
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m = path_entry.pattern.match(request_path)
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if m:
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# We found a match!
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return path_entry.callback, path_entry.servlet_classname, m.groupdict()
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# Huh. No one wanted to handle that? Fiiiiiine. Send 400.
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return _unrecognised_request_handler, "unrecognised_request_handler", {}
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async def _async_render(self, request: SynapseRequest) -> Tuple[int, Any]:
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callback, servlet_classname, group_dict = self._get_handler_for_request(request)
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# Make sure we have an appropriate name for this handler in prometheus
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# (rather than the default of JsonResource).
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request.request_metrics.name = servlet_classname
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# Now trigger the callback. If it returns a response, we send it
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# here. If it throws an exception, that is handled by the wrapper
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# installed by @request_handler.
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kwargs = intern_dict(
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{
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name: urllib.parse.unquote(value) if value else value
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for name, value in group_dict.items()
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}
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)
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raw_callback_return = callback(request, **kwargs)
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# Is it synchronous? We'll allow this for now.
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if isinstance(raw_callback_return, (defer.Deferred, types.CoroutineType)):
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callback_return = await raw_callback_return
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else:
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callback_return = raw_callback_return # type: ignore
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return callback_return
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class DirectServeHtmlResource(_AsyncResource):
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"""A resource that will call `self._async_on_<METHOD>` on new requests,
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formatting responses and errors as HTML.
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"""
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# The error template to use for this resource
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ERROR_TEMPLATE = HTML_ERROR_TEMPLATE
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def _send_response(
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self,
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request: SynapseRequest,
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code: int,
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response_object: Any,
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) -> None:
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"""Implements _AsyncResource._send_response"""
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# We expect to get bytes for us to write
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assert isinstance(response_object, bytes)
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html_bytes = response_object
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respond_with_html_bytes(request, 200, html_bytes)
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def _send_error_response(
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self,
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f: failure.Failure,
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request: SynapseRequest,
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) -> None:
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"""Implements _AsyncResource._send_error_response"""
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return_html_error(f, request, self.ERROR_TEMPLATE)
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class StaticResource(File):
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"""
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A resource that represents a plain non-interpreted file or directory.
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Differs from the File resource by adding clickjacking protection.
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"""
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def render_GET(self, request: Request) -> bytes:
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set_clickjacking_protection_headers(request)
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return super().render_GET(request)
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|
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def _unrecognised_request_handler(request: Request) -> NoReturn:
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"""Request handler for unrecognised requests
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This is a request handler suitable for return from
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_get_handler_for_request. It actually just raises an
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UnrecognizedRequestError.
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Args:
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request: Unused, but passed in to match the signature of ServletCallback.
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"""
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raise UnrecognizedRequestError()
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class RootRedirect(resource.Resource):
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"""Redirects the root '/' path to another path."""
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def __init__(self, path: str):
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super().__init__()
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self.url = path
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def render_GET(self, request: Request) -> bytes:
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return redirectTo(self.url.encode("ascii"), request)
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def getChild(self, name: str, request: Request) -> resource.Resource:
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if len(name) == 0:
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return self # select ourselves as the child to render
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return super().getChild(name, request)
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|
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class OptionsResource(resource.Resource):
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"""Responds to OPTION requests for itself and all children."""
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|
|
def render_OPTIONS(self, request: Request) -> bytes:
|
|
request.setResponseCode(204)
|
|
request.setHeader(b"Content-Length", b"0")
|
|
|
|
set_cors_headers(request)
|
|
|
|
return b""
|
|
|
|
def getChildWithDefault(self, path: str, request: Request) -> resource.Resource:
|
|
if request.method == b"OPTIONS":
|
|
return self # select ourselves as the child to render
|
|
return super().getChildWithDefault(path, request)
|
|
|
|
|
|
class RootOptionsRedirectResource(OptionsResource, RootRedirect):
|
|
pass
|
|
|
|
|
|
@implementer(interfaces.IPushProducer)
|
|
class _ByteProducer:
|
|
"""
|
|
Iteratively write bytes to the request.
|
|
"""
|
|
|
|
# The minimum number of bytes for each chunk. Note that the last chunk will
|
|
# usually be smaller than this.
|
|
min_chunk_size = 1024
|
|
|
|
def __init__(
|
|
self,
|
|
request: Request,
|
|
iterator: Iterator[bytes],
|
|
):
|
|
self._request: Optional[Request] = request
|
|
self._iterator = iterator
|
|
self._paused = False
|
|
|
|
try:
|
|
self._request.registerProducer(self, True)
|
|
except AttributeError as e:
|
|
# Calling self._request.registerProducer might raise an AttributeError since
|
|
# the underlying Twisted code calls self._request.channel.registerProducer,
|
|
# however self._request.channel will be None if the connection was lost.
|
|
logger.info("Connection disconnected before response was written: %r", e)
|
|
|
|
# We drop our references to data we'll not use.
|
|
self._request = None
|
|
self._iterator = iter(())
|
|
else:
|
|
# Start producing if `registerProducer` was successful
|
|
self.resumeProducing()
|
|
|
|
def _send_data(self, data: List[bytes]) -> None:
|
|
"""
|
|
Send a list of bytes as a chunk of a response.
|
|
"""
|
|
if not data or not self._request:
|
|
return
|
|
self._request.write(b"".join(data))
|
|
|
|
def pauseProducing(self) -> None:
|
|
self._paused = True
|
|
|
|
def resumeProducing(self) -> None:
|
|
# We've stopped producing in the meantime (note that this might be
|
|
# re-entrant after calling write).
|
|
if not self._request:
|
|
return
|
|
|
|
self._paused = False
|
|
|
|
# Write until there's backpressure telling us to stop.
|
|
while not self._paused:
|
|
# Get the next chunk and write it to the request.
|
|
#
|
|
# The output of the JSON encoder is buffered and coalesced until
|
|
# min_chunk_size is reached. This is because JSON encoders produce
|
|
# very small output per iteration and the Request object converts
|
|
# each call to write() to a separate chunk. Without this there would
|
|
# be an explosion in bytes written (e.g. b"{" becoming "1\r\n{\r\n").
|
|
#
|
|
# Note that buffer stores a list of bytes (instead of appending to
|
|
# bytes) to hopefully avoid many allocations.
|
|
buffer = []
|
|
buffered_bytes = 0
|
|
while buffered_bytes < self.min_chunk_size:
|
|
try:
|
|
data = next(self._iterator)
|
|
buffer.append(data)
|
|
buffered_bytes += len(data)
|
|
except StopIteration:
|
|
# The entire JSON object has been serialized, write any
|
|
# remaining data, finalize the producer and the request, and
|
|
# clean-up any references.
|
|
self._send_data(buffer)
|
|
self._request.unregisterProducer()
|
|
self._request.finish()
|
|
self.stopProducing()
|
|
return
|
|
|
|
self._send_data(buffer)
|
|
|
|
def stopProducing(self) -> None:
|
|
# Clear a circular reference.
|
|
self._request = None
|
|
|
|
|
|
def _encode_json_bytes(json_object: Any) -> bytes:
|
|
"""
|
|
Encode an object into JSON. Returns an iterator of bytes.
|
|
"""
|
|
return json_encoder.encode(json_object).encode("utf-8")
|
|
|
|
|
|
def respond_with_json(
|
|
request: SynapseRequest,
|
|
code: int,
|
|
json_object: Any,
|
|
send_cors: bool = False,
|
|
canonical_json: bool = True,
|
|
) -> Optional[int]:
|
|
"""Sends encoded JSON in response to the given request.
|
|
|
|
Args:
|
|
request: The http request to respond to.
|
|
code: The HTTP response code.
|
|
json_object: The object to serialize to JSON.
|
|
send_cors: Whether to send Cross-Origin Resource Sharing headers
|
|
https://fetch.spec.whatwg.org/#http-cors-protocol
|
|
canonical_json: Whether to use the canonicaljson algorithm when encoding
|
|
the JSON bytes.
|
|
|
|
Returns:
|
|
twisted.web.server.NOT_DONE_YET if the request is still active.
|
|
"""
|
|
# could alternatively use request.notifyFinish() and flip a flag when
|
|
# the Deferred fires, but since the flag is RIGHT THERE it seems like
|
|
# a waste.
|
|
if request._disconnected:
|
|
logger.warning(
|
|
"Not sending response to request %s, already disconnected.", request
|
|
)
|
|
return None
|
|
|
|
if canonical_json:
|
|
encoder = encode_canonical_json
|
|
else:
|
|
encoder = _encode_json_bytes
|
|
|
|
request.setResponseCode(code)
|
|
request.setHeader(b"Content-Type", b"application/json")
|
|
request.setHeader(b"Cache-Control", b"no-cache, no-store, must-revalidate")
|
|
|
|
if send_cors:
|
|
set_cors_headers(request)
|
|
|
|
run_in_background(
|
|
_async_write_json_to_request_in_thread, request, encoder, json_object
|
|
)
|
|
return NOT_DONE_YET
|
|
|
|
|
|
def respond_with_json_bytes(
|
|
request: Request,
|
|
code: int,
|
|
json_bytes: bytes,
|
|
send_cors: bool = False,
|
|
) -> Optional[int]:
|
|
"""Sends encoded JSON in response to the given request.
|
|
|
|
Args:
|
|
request: The http request to respond to.
|
|
code: The HTTP response code.
|
|
json_bytes: The json bytes to use as the response body.
|
|
send_cors: Whether to send Cross-Origin Resource Sharing headers
|
|
https://fetch.spec.whatwg.org/#http-cors-protocol
|
|
|
|
Returns:
|
|
twisted.web.server.NOT_DONE_YET if the request is still active.
|
|
"""
|
|
if request._disconnected:
|
|
logger.warning(
|
|
"Not sending response to request %s, already disconnected.", request
|
|
)
|
|
return None
|
|
|
|
request.setResponseCode(code)
|
|
request.setHeader(b"Content-Type", b"application/json")
|
|
request.setHeader(b"Content-Length", b"%d" % (len(json_bytes),))
|
|
request.setHeader(b"Cache-Control", b"no-cache, no-store, must-revalidate")
|
|
|
|
if send_cors:
|
|
set_cors_headers(request)
|
|
|
|
_write_bytes_to_request(request, json_bytes)
|
|
return NOT_DONE_YET
|
|
|
|
|
|
async def _async_write_json_to_request_in_thread(
|
|
request: SynapseRequest,
|
|
json_encoder: Callable[[Any], bytes],
|
|
json_object: Any,
|
|
) -> None:
|
|
"""Encodes the given JSON object on a thread and then writes it to the
|
|
request.
|
|
|
|
This is done so that encoding large JSON objects doesn't block the reactor
|
|
thread.
|
|
|
|
Note: We don't use JsonEncoder.iterencode here as that falls back to the
|
|
Python implementation (rather than the C backend), which is *much* more
|
|
expensive.
|
|
"""
|
|
|
|
def encode(opentracing_span: "Optional[opentracing.Span]") -> bytes:
|
|
# it might take a while for the threadpool to schedule us, so we write
|
|
# opentracing logs once we actually get scheduled, so that we can see how
|
|
# much that contributed.
|
|
if opentracing_span:
|
|
opentracing_span.log_kv({"event": "scheduled"})
|
|
res = json_encoder(json_object)
|
|
if opentracing_span:
|
|
opentracing_span.log_kv({"event": "encoded"})
|
|
return res
|
|
|
|
with start_active_span("encode_json_response"):
|
|
span = active_span()
|
|
json_str = await defer_to_thread(request.reactor, encode, span)
|
|
|
|
_write_bytes_to_request(request, json_str)
|
|
|
|
|
|
def _write_bytes_to_request(request: Request, bytes_to_write: bytes) -> None:
|
|
"""Writes the bytes to the request using an appropriate producer.
|
|
|
|
Note: This should be used instead of `Request.write` to correctly handle
|
|
large response bodies.
|
|
"""
|
|
|
|
# The problem with dumping all of the response into the `Request` object at
|
|
# once (via `Request.write`) is that doing so starts the timeout for the
|
|
# next request to be received: so if it takes longer than 60s to stream back
|
|
# the response to the client, the client never gets it.
|
|
#
|
|
# The correct solution is to use a Producer; then the timeout is only
|
|
# started once all of the content is sent over the TCP connection.
|
|
|
|
# To make sure we don't write all of the bytes at once we split it up into
|
|
# chunks.
|
|
chunk_size = 4096
|
|
bytes_generator = chunk_seq(bytes_to_write, chunk_size)
|
|
|
|
# We use a `_ByteProducer` here rather than `NoRangeStaticProducer` as the
|
|
# unit tests can't cope with being given a pull producer.
|
|
_ByteProducer(request, bytes_generator)
|
|
|
|
|
|
def set_cors_headers(request: Request) -> None:
|
|
"""Set the CORS headers so that javascript running in a web browsers can
|
|
use this API
|
|
|
|
Args:
|
|
request: The http request to add CORS to.
|
|
"""
|
|
request.setHeader(b"Access-Control-Allow-Origin", b"*")
|
|
request.setHeader(
|
|
b"Access-Control-Allow-Methods", b"GET, HEAD, POST, PUT, DELETE, OPTIONS"
|
|
)
|
|
request.setHeader(
|
|
b"Access-Control-Allow-Headers",
|
|
b"X-Requested-With, Content-Type, Authorization, Date",
|
|
)
|
|
|
|
|
|
def respond_with_html(request: Request, code: int, html: str) -> None:
|
|
"""
|
|
Wraps `respond_with_html_bytes` by first encoding HTML from a str to UTF-8 bytes.
|
|
"""
|
|
respond_with_html_bytes(request, code, html.encode("utf-8"))
|
|
|
|
|
|
def respond_with_html_bytes(request: Request, code: int, html_bytes: bytes) -> None:
|
|
"""
|
|
Sends HTML (encoded as UTF-8 bytes) as the response to the given request.
|
|
|
|
Note that this adds clickjacking protection headers and finishes the request.
|
|
|
|
Args:
|
|
request: The http request to respond to.
|
|
code: The HTTP response code.
|
|
html_bytes: The HTML bytes to use as the response body.
|
|
"""
|
|
# could alternatively use request.notifyFinish() and flip a flag when
|
|
# the Deferred fires, but since the flag is RIGHT THERE it seems like
|
|
# a waste.
|
|
if request._disconnected:
|
|
logger.warning(
|
|
"Not sending response to request %s, already disconnected.", request
|
|
)
|
|
return None
|
|
|
|
request.setResponseCode(code)
|
|
request.setHeader(b"Content-Type", b"text/html; charset=utf-8")
|
|
request.setHeader(b"Content-Length", b"%d" % (len(html_bytes),))
|
|
|
|
# Ensure this content cannot be embedded.
|
|
set_clickjacking_protection_headers(request)
|
|
|
|
request.write(html_bytes)
|
|
finish_request(request)
|
|
|
|
|
|
def set_clickjacking_protection_headers(request: Request) -> None:
|
|
"""
|
|
Set headers to guard against clickjacking of embedded content.
|
|
|
|
This sets the X-Frame-Options and Content-Security-Policy headers which instructs
|
|
browsers to not allow the HTML of the response to be embedded onto another
|
|
page.
|
|
|
|
Args:
|
|
request: The http request to add the headers to.
|
|
"""
|
|
request.setHeader(b"X-Frame-Options", b"DENY")
|
|
request.setHeader(b"Content-Security-Policy", b"frame-ancestors 'none';")
|
|
|
|
|
|
def respond_with_redirect(request: Request, url: bytes) -> None:
|
|
"""Write a 302 response to the request, if it is still alive."""
|
|
logger.debug("Redirect to %s", url.decode("utf-8"))
|
|
request.redirect(url)
|
|
finish_request(request)
|
|
|
|
|
|
def finish_request(request: Request) -> None:
|
|
"""Finish writing the response to the request.
|
|
|
|
Twisted throws a RuntimeException if the connection closed before the
|
|
response was written but doesn't provide a convenient or reliable way to
|
|
determine if the connection was closed. So we catch and log the RuntimeException
|
|
|
|
You might think that ``request.notifyFinish`` could be used to tell if the
|
|
request was finished. However the deferred it returns won't fire if the
|
|
connection was already closed, meaning we'd have to have called the method
|
|
right at the start of the request. By the time we want to write the response
|
|
it will already be too late.
|
|
"""
|
|
try:
|
|
request.finish()
|
|
except RuntimeError as e:
|
|
logger.info("Connection disconnected before response was written: %r", e)
|