756 lines
25 KiB
Python
756 lines
25 KiB
Python
# -*- coding: utf-8 -*-
|
|
# Copyright 2014-2016 OpenMarket Ltd
|
|
# Copyright 2018 New Vector Ltd
|
|
#
|
|
# Licensed under the Apache License, Version 2.0 (the "License");
|
|
# you may not use this file except in compliance with the License.
|
|
# You may obtain a copy of the License at
|
|
#
|
|
# http://www.apache.org/licenses/LICENSE-2.0
|
|
#
|
|
# Unless required by applicable law or agreed to in writing, software
|
|
# distributed under the License is distributed on an "AS IS" BASIS,
|
|
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
# See the License for the specific language governing permissions and
|
|
# limitations under the License.
|
|
|
|
import abc
|
|
import collections
|
|
import html
|
|
import logging
|
|
import types
|
|
import urllib
|
|
from http import HTTPStatus
|
|
from io import BytesIO
|
|
from typing import Any, Callable, Dict, Iterator, List, Tuple, Union
|
|
|
|
import jinja2
|
|
from canonicaljson import iterencode_canonical_json, iterencode_pretty_printed_json
|
|
from zope.interface import implementer
|
|
|
|
from twisted.internet import defer, interfaces
|
|
from twisted.python import failure
|
|
from twisted.web import resource
|
|
from twisted.web.server import NOT_DONE_YET, Request
|
|
from twisted.web.static import File, NoRangeStaticProducer
|
|
from twisted.web.util import redirectTo
|
|
|
|
import synapse.events
|
|
import synapse.metrics
|
|
from synapse.api.errors import (
|
|
CodeMessageException,
|
|
Codes,
|
|
RedirectException,
|
|
SynapseError,
|
|
UnrecognizedRequestError,
|
|
)
|
|
from synapse.http.site import SynapseRequest
|
|
from synapse.logging.context import preserve_fn
|
|
from synapse.logging.opentracing import trace_servlet
|
|
from synapse.util import json_encoder
|
|
from synapse.util.caches import intern_dict
|
|
|
|
logger = logging.getLogger(__name__)
|
|
|
|
HTML_ERROR_TEMPLATE = """<!DOCTYPE html>
|
|
<html lang=en>
|
|
<head>
|
|
<meta charset="utf-8">
|
|
<title>Error {code}</title>
|
|
</head>
|
|
<body>
|
|
<p>{msg}</p>
|
|
</body>
|
|
</html>
|
|
"""
|
|
|
|
|
|
def return_json_error(f: failure.Failure, request: SynapseRequest) -> None:
|
|
"""Sends a JSON error response to clients.
|
|
"""
|
|
|
|
if f.check(SynapseError):
|
|
error_code = f.value.code
|
|
error_dict = f.value.error_dict()
|
|
|
|
logger.info("%s SynapseError: %s - %s", request, error_code, f.value.msg)
|
|
else:
|
|
error_code = 500
|
|
error_dict = {"error": "Internal server error", "errcode": Codes.UNKNOWN}
|
|
|
|
logger.error(
|
|
"Failed handle request via %r: %r",
|
|
request.request_metrics.name,
|
|
request,
|
|
exc_info=(f.type, f.value, f.getTracebackObject()),
|
|
)
|
|
|
|
# Only respond with an error response if we haven't already started writing,
|
|
# otherwise lets just kill the connection
|
|
if request.startedWriting:
|
|
if request.transport:
|
|
try:
|
|
request.transport.abortConnection()
|
|
except Exception:
|
|
# abortConnection throws if the connection is already closed
|
|
pass
|
|
else:
|
|
respond_with_json(
|
|
request,
|
|
error_code,
|
|
error_dict,
|
|
send_cors=True,
|
|
pretty_print=_request_user_agent_is_curl(request),
|
|
)
|
|
|
|
|
|
def return_html_error(
|
|
f: failure.Failure, request: Request, error_template: Union[str, jinja2.Template],
|
|
) -> None:
|
|
"""Sends an HTML error page corresponding to the given failure.
|
|
|
|
Handles RedirectException and other CodeMessageExceptions (such as SynapseError)
|
|
|
|
Args:
|
|
f: the error to report
|
|
request: the failing request
|
|
error_template: the HTML template. Can be either a string (with `{code}`,
|
|
`{msg}` placeholders), or a jinja2 template
|
|
"""
|
|
if f.check(CodeMessageException):
|
|
cme = f.value
|
|
code = cme.code
|
|
msg = cme.msg
|
|
|
|
if isinstance(cme, RedirectException):
|
|
logger.info("%s redirect to %s", request, cme.location)
|
|
request.setHeader(b"location", cme.location)
|
|
request.cookies.extend(cme.cookies)
|
|
elif isinstance(cme, SynapseError):
|
|
logger.info("%s SynapseError: %s - %s", request, code, msg)
|
|
else:
|
|
logger.error(
|
|
"Failed handle request %r",
|
|
request,
|
|
exc_info=(f.type, f.value, f.getTracebackObject()),
|
|
)
|
|
else:
|
|
code = HTTPStatus.INTERNAL_SERVER_ERROR
|
|
msg = "Internal server error"
|
|
|
|
logger.error(
|
|
"Failed handle request %r",
|
|
request,
|
|
exc_info=(f.type, f.value, f.getTracebackObject()),
|
|
)
|
|
|
|
if isinstance(error_template, str):
|
|
body = error_template.format(code=code, msg=html.escape(msg))
|
|
else:
|
|
body = error_template.render(code=code, msg=msg)
|
|
|
|
respond_with_html(request, code, body)
|
|
|
|
|
|
def wrap_async_request_handler(h):
|
|
"""Wraps an async request handler so that it calls request.processing.
|
|
|
|
This helps ensure that work done by the request handler after the request is completed
|
|
is correctly recorded against the request metrics/logs.
|
|
|
|
The handler method must have a signature of "handle_foo(self, request)",
|
|
where "request" must be a SynapseRequest.
|
|
|
|
The handler may return a deferred, in which case the completion of the request isn't
|
|
logged until the deferred completes.
|
|
"""
|
|
|
|
async def wrapped_async_request_handler(self, request):
|
|
with request.processing():
|
|
await h(self, request)
|
|
|
|
# we need to preserve_fn here, because the synchronous render method won't yield for
|
|
# us (obviously)
|
|
return preserve_fn(wrapped_async_request_handler)
|
|
|
|
|
|
class HttpServer(object):
|
|
""" Interface for registering callbacks on a HTTP server
|
|
"""
|
|
|
|
def register_paths(self, method, path_patterns, callback):
|
|
""" Register a callback that gets fired if we receive a http request
|
|
with the given method for a path that matches the given regex.
|
|
|
|
If the regex contains groups these gets passed to the calback via
|
|
an unpacked tuple.
|
|
|
|
Args:
|
|
method (str): The method to listen to.
|
|
path_patterns (list<SRE_Pattern>): The regex used to match requests.
|
|
callback (function): The function to fire if we receive a matched
|
|
request. The first argument will be the request object and
|
|
subsequent arguments will be any matched groups from the regex.
|
|
This should return a tuple of (code, response).
|
|
"""
|
|
pass
|
|
|
|
|
|
class _AsyncResource(resource.Resource, metaclass=abc.ABCMeta):
|
|
"""Base class for resources that have async handlers.
|
|
|
|
Sub classes can either implement `_async_render_<METHOD>` to handle
|
|
requests by method, or override `_async_render` to handle all requests.
|
|
|
|
Args:
|
|
extract_context: Whether to attempt to extract the opentracing
|
|
context from the request the servlet is handling.
|
|
"""
|
|
|
|
def __init__(self, extract_context=False):
|
|
super().__init__()
|
|
|
|
self._extract_context = extract_context
|
|
|
|
def render(self, request):
|
|
""" This gets called by twisted every time someone sends us a request.
|
|
"""
|
|
defer.ensureDeferred(self._async_render_wrapper(request))
|
|
return NOT_DONE_YET
|
|
|
|
@wrap_async_request_handler
|
|
async def _async_render_wrapper(self, request: SynapseRequest):
|
|
"""This is a wrapper that delegates to `_async_render` and handles
|
|
exceptions, return values, metrics, etc.
|
|
"""
|
|
try:
|
|
request.request_metrics.name = self.__class__.__name__
|
|
|
|
with trace_servlet(request, self._extract_context):
|
|
callback_return = await self._async_render(request)
|
|
|
|
if callback_return is not None:
|
|
code, response = callback_return
|
|
self._send_response(request, code, response)
|
|
except Exception:
|
|
# failure.Failure() fishes the original Failure out
|
|
# of our stack, and thus gives us a sensible stack
|
|
# trace.
|
|
f = failure.Failure()
|
|
self._send_error_response(f, request)
|
|
|
|
async def _async_render(self, request: Request):
|
|
"""Delegates to `_async_render_<METHOD>` methods, or returns a 400 if
|
|
no appropriate method exists. Can be overriden in sub classes for
|
|
different routing.
|
|
"""
|
|
# Treat HEAD requests as GET requests.
|
|
request_method = request.method.decode("ascii")
|
|
if request_method == "HEAD":
|
|
request_method = "GET"
|
|
|
|
method_handler = getattr(self, "_async_render_%s" % (request_method,), None)
|
|
if method_handler:
|
|
raw_callback_return = method_handler(request)
|
|
|
|
# Is it synchronous? We'll allow this for now.
|
|
if isinstance(raw_callback_return, (defer.Deferred, types.CoroutineType)):
|
|
callback_return = await raw_callback_return
|
|
else:
|
|
callback_return = raw_callback_return
|
|
|
|
return callback_return
|
|
|
|
_unrecognised_request_handler(request)
|
|
|
|
@abc.abstractmethod
|
|
def _send_response(
|
|
self, request: SynapseRequest, code: int, response_object: Any,
|
|
) -> None:
|
|
raise NotImplementedError()
|
|
|
|
@abc.abstractmethod
|
|
def _send_error_response(
|
|
self, f: failure.Failure, request: SynapseRequest,
|
|
) -> None:
|
|
raise NotImplementedError()
|
|
|
|
|
|
class DirectServeJsonResource(_AsyncResource):
|
|
"""A resource that will call `self._async_on_<METHOD>` on new requests,
|
|
formatting responses and errors as JSON.
|
|
"""
|
|
|
|
def _send_response(
|
|
self, request: Request, code: int, response_object: Any,
|
|
):
|
|
"""Implements _AsyncResource._send_response
|
|
"""
|
|
# TODO: Only enable CORS for the requests that need it.
|
|
respond_with_json(
|
|
request,
|
|
code,
|
|
response_object,
|
|
send_cors=True,
|
|
pretty_print=_request_user_agent_is_curl(request),
|
|
canonical_json=self.canonical_json,
|
|
)
|
|
|
|
def _send_error_response(
|
|
self, f: failure.Failure, request: SynapseRequest,
|
|
) -> None:
|
|
"""Implements _AsyncResource._send_error_response
|
|
"""
|
|
return_json_error(f, request)
|
|
|
|
|
|
class JsonResource(DirectServeJsonResource):
|
|
""" This implements the HttpServer interface and provides JSON support for
|
|
Resources.
|
|
|
|
Register callbacks via register_paths()
|
|
|
|
Callbacks can return a tuple of status code and a dict in which case the
|
|
the dict will automatically be sent to the client as a JSON object.
|
|
|
|
The JsonResource is primarily intended for returning JSON, but callbacks
|
|
may send something other than JSON, they may do so by using the methods
|
|
on the request object and instead returning None.
|
|
"""
|
|
|
|
isLeaf = True
|
|
|
|
_PathEntry = collections.namedtuple(
|
|
"_PathEntry", ["pattern", "callback", "servlet_classname"]
|
|
)
|
|
|
|
def __init__(self, hs, canonical_json=True, extract_context=False):
|
|
super().__init__(extract_context)
|
|
|
|
self.canonical_json = canonical_json
|
|
self.clock = hs.get_clock()
|
|
self.path_regexs = {}
|
|
self.hs = hs
|
|
|
|
def register_paths(self, method, path_patterns, callback, servlet_classname):
|
|
"""
|
|
Registers a request handler against a regular expression. Later request URLs are
|
|
checked against these regular expressions in order to identify an appropriate
|
|
handler for that request.
|
|
|
|
Args:
|
|
method (str): GET, POST etc
|
|
|
|
path_patterns (Iterable[str]): A list of regular expressions to which
|
|
the request URLs are compared.
|
|
|
|
callback (function): The handler for the request. Usually a Servlet
|
|
|
|
servlet_classname (str): The name of the handler to be used in prometheus
|
|
and opentracing logs.
|
|
"""
|
|
method = method.encode("utf-8") # method is bytes on py3
|
|
|
|
for path_pattern in path_patterns:
|
|
logger.debug("Registering for %s %s", method, path_pattern.pattern)
|
|
self.path_regexs.setdefault(method, []).append(
|
|
self._PathEntry(path_pattern, callback, servlet_classname)
|
|
)
|
|
|
|
def _get_handler_for_request(
|
|
self, request: SynapseRequest
|
|
) -> Tuple[Callable, str, Dict[str, str]]:
|
|
"""Finds a callback method to handle the given request.
|
|
|
|
Returns:
|
|
A tuple of the callback to use, the name of the servlet, and the
|
|
key word arguments to pass to the callback
|
|
"""
|
|
# Treat HEAD requests as GET requests.
|
|
request_path = request.path.decode("ascii")
|
|
request_method = request.method
|
|
if request_method == b"HEAD":
|
|
request_method = b"GET"
|
|
|
|
# Loop through all the registered callbacks to check if the method
|
|
# and path regex match
|
|
for path_entry in self.path_regexs.get(request_method, []):
|
|
m = path_entry.pattern.match(request_path)
|
|
if m:
|
|
# We found a match!
|
|
return path_entry.callback, path_entry.servlet_classname, m.groupdict()
|
|
|
|
# Huh. No one wanted to handle that? Fiiiiiine. Send 400.
|
|
return _unrecognised_request_handler, "unrecognised_request_handler", {}
|
|
|
|
async def _async_render(self, request):
|
|
callback, servlet_classname, group_dict = self._get_handler_for_request(request)
|
|
|
|
# Make sure we have an appopriate name for this handler in prometheus
|
|
# (rather than the default of JsonResource).
|
|
request.request_metrics.name = servlet_classname
|
|
|
|
# Now trigger the callback. If it returns a response, we send it
|
|
# here. If it throws an exception, that is handled by the wrapper
|
|
# installed by @request_handler.
|
|
kwargs = intern_dict(
|
|
{
|
|
name: urllib.parse.unquote(value) if value else value
|
|
for name, value in group_dict.items()
|
|
}
|
|
)
|
|
|
|
raw_callback_return = callback(request, **kwargs)
|
|
|
|
# Is it synchronous? We'll allow this for now.
|
|
if isinstance(raw_callback_return, (defer.Deferred, types.CoroutineType)):
|
|
callback_return = await raw_callback_return
|
|
else:
|
|
callback_return = raw_callback_return
|
|
|
|
return callback_return
|
|
|
|
|
|
class DirectServeHtmlResource(_AsyncResource):
|
|
"""A resource that will call `self._async_on_<METHOD>` on new requests,
|
|
formatting responses and errors as HTML.
|
|
"""
|
|
|
|
# The error template to use for this resource
|
|
ERROR_TEMPLATE = HTML_ERROR_TEMPLATE
|
|
|
|
def _send_response(
|
|
self, request: SynapseRequest, code: int, response_object: Any,
|
|
):
|
|
"""Implements _AsyncResource._send_response
|
|
"""
|
|
# We expect to get bytes for us to write
|
|
assert isinstance(response_object, bytes)
|
|
html_bytes = response_object
|
|
|
|
respond_with_html_bytes(request, 200, html_bytes)
|
|
|
|
def _send_error_response(
|
|
self, f: failure.Failure, request: SynapseRequest,
|
|
) -> None:
|
|
"""Implements _AsyncResource._send_error_response
|
|
"""
|
|
return_html_error(f, request, self.ERROR_TEMPLATE)
|
|
|
|
|
|
class StaticResource(File):
|
|
"""
|
|
A resource that represents a plain non-interpreted file or directory.
|
|
|
|
Differs from the File resource by adding clickjacking protection.
|
|
"""
|
|
|
|
def render_GET(self, request: Request):
|
|
set_clickjacking_protection_headers(request)
|
|
return super().render_GET(request)
|
|
|
|
|
|
def _unrecognised_request_handler(request):
|
|
"""Request handler for unrecognised requests
|
|
|
|
This is a request handler suitable for return from
|
|
_get_handler_for_request. It actually just raises an
|
|
UnrecognizedRequestError.
|
|
|
|
Args:
|
|
request (twisted.web.http.Request):
|
|
"""
|
|
raise UnrecognizedRequestError()
|
|
|
|
|
|
class RootRedirect(resource.Resource):
|
|
"""Redirects the root '/' path to another path."""
|
|
|
|
def __init__(self, path):
|
|
resource.Resource.__init__(self)
|
|
self.url = path
|
|
|
|
def render_GET(self, request):
|
|
return redirectTo(self.url.encode("ascii"), request)
|
|
|
|
def getChild(self, name, request):
|
|
if len(name) == 0:
|
|
return self # select ourselves as the child to render
|
|
return resource.Resource.getChild(self, name, request)
|
|
|
|
|
|
class OptionsResource(resource.Resource):
|
|
"""Responds to OPTION requests for itself and all children."""
|
|
|
|
def render_OPTIONS(self, request):
|
|
request.setResponseCode(204)
|
|
request.setHeader(b"Content-Length", b"0")
|
|
|
|
set_cors_headers(request)
|
|
|
|
return b""
|
|
|
|
def getChildWithDefault(self, path, request):
|
|
if request.method == b"OPTIONS":
|
|
return self # select ourselves as the child to render
|
|
return resource.Resource.getChildWithDefault(self, path, request)
|
|
|
|
|
|
class RootOptionsRedirectResource(OptionsResource, RootRedirect):
|
|
pass
|
|
|
|
|
|
@implementer(interfaces.IPullProducer)
|
|
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 = request
|
|
self._iterator = iterator
|
|
|
|
def start(self) -> None:
|
|
self._request.registerProducer(self, False)
|
|
|
|
def _send_data(self, data: List[bytes]) -> None:
|
|
"""
|
|
Send a list of strings as a response to the request.
|
|
"""
|
|
if not data:
|
|
return
|
|
self._request.write(b"".join(data))
|
|
|
|
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
|
|
|
|
# Get the next chunk and write it to the request.
|
|
#
|
|
# The output of the JSON encoder is coalesced until min_chunk_size is
|
|
# reached. (This is because JSON encoders produce a very small output
|
|
# per iteration.)
|
|
#
|
|
# 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:
|
|
self._request = None
|
|
|
|
|
|
def _encode_json_bytes(json_object: Any) -> Iterator[bytes]:
|
|
"""
|
|
Encode an object into JSON. Returns an iterator of bytes.
|
|
"""
|
|
for chunk in json_encoder.iterencode(json_object):
|
|
yield chunk.encode("utf-8")
|
|
|
|
|
|
def respond_with_json(
|
|
request: Request,
|
|
code: int,
|
|
json_object: Any,
|
|
send_cors: bool = False,
|
|
pretty_print: bool = False,
|
|
canonical_json: bool = True,
|
|
):
|
|
"""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
|
|
pretty_print: Whether to include indentation and line-breaks in the
|
|
resulting JSON bytes.
|
|
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 pretty_print:
|
|
encoder = iterencode_pretty_printed_json
|
|
else:
|
|
if canonical_json or synapse.events.USE_FROZEN_DICTS:
|
|
encoder = iterencode_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)
|
|
|
|
producer = _ByteProducer(request, encoder(json_object))
|
|
producer.start()
|
|
return NOT_DONE_YET
|
|
|
|
|
|
def respond_with_json_bytes(
|
|
request: Request, code: int, json_bytes: bytes, send_cors: bool = False,
|
|
):
|
|
"""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.
|
|
"""
|
|
|
|
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)
|
|
|
|
# note that this is zero-copy (the bytesio shares a copy-on-write buffer with
|
|
# the original `bytes`).
|
|
bytes_io = BytesIO(json_bytes)
|
|
|
|
producer = NoRangeStaticProducer(request, bytes_io)
|
|
producer.start()
|
|
return NOT_DONE_YET
|
|
|
|
|
|
def set_cors_headers(request: Request):
|
|
"""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"Origin, X-Requested-With, Content-Type, Accept, Authorization",
|
|
)
|
|
|
|
|
|
def respond_with_html(request: Request, code: int, html: str):
|
|
"""
|
|
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):
|
|
"""
|
|
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
|
|
|
|
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):
|
|
"""
|
|
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 finish_request(request: Request):
|
|
""" 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)
|
|
|
|
|
|
def _request_user_agent_is_curl(request: Request) -> bool:
|
|
user_agents = request.requestHeaders.getRawHeaders(b"User-Agent", default=[])
|
|
for user_agent in user_agents:
|
|
if b"curl" in user_agent:
|
|
return True
|
|
return False
|