502 lines
		
	
	
		
			17 KiB
		
	
	
	
		
			Python
		
	
	
			
		
		
	
	
			502 lines
		
	
	
		
			17 KiB
		
	
	
	
		
			Python
		
	
	
| # -*- coding: utf-8 -*-
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| # 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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| 
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| import cgi
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| import collections
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| import logging
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| 
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| from six import PY3
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| from six.moves import http_client, urllib
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| 
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| from canonicaljson import encode_canonical_json, encode_pretty_printed_json, json
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| 
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| from twisted.internet import defer
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| from twisted.python import failure
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| from twisted.web import resource, server
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| from twisted.web.server import NOT_DONE_YET
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| from twisted.web.util import redirectTo
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| 
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| import synapse.events
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| import synapse.metrics
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| from synapse.api.errors import (
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|     CodeMessageException,
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|     Codes,
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|     SynapseError,
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|     UnrecognizedRequestError,
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| )
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| from synapse.http.request_metrics import requests_counter
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| from synapse.util.caches import intern_dict
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| from synapse.util.logcontext import LoggingContext, PreserveLoggingContext
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| from synapse.util.metrics import Measure
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| 
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| logger = logging.getLogger(__name__)
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| 
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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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| 
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| 
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| def wrap_json_request_handler(h):
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|     """Wraps a request handler method with exception handling.
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| 
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|     Also adds logging as per wrap_request_handler_with_logging.
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| 
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|     The handler method must have a signature of "handle_foo(self, request)",
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|     where "self" must have a "clock" attribute (and "request" must be a
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|     SynapseRequest).
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| 
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|     The handler must return a deferred. If the deferred succeeds we assume that
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|     a response has been sent. If the deferred fails with a SynapseError we use
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|     it to send a JSON response with the appropriate HTTP reponse code. If the
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|     deferred fails with any other type of error we send a 500 reponse.
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|     """
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| 
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|     @defer.inlineCallbacks
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|     def wrapped_request_handler(self, request):
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|         try:
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|             yield h(self, request)
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|         except SynapseError as e:
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|             code = e.code
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|             logger.info(
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|                 "%s SynapseError: %s - %s", request, code, e.msg
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|             )
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|             respond_with_json(
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|                 request, code, e.error_dict(), send_cors=True,
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|                 pretty_print=_request_user_agent_is_curl(request),
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|             )
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| 
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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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|             logger.error(
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|                 "Failed handle request via %r: %r: %s",
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|                 h,
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|                 request,
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|                 f.getTraceback().rstrip(),
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|             )
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|             respond_with_json(
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|                 request,
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|                 500,
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|                 {
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|                     "error": "Internal server error",
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|                     "errcode": Codes.UNKNOWN,
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|                 },
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|                 send_cors=True,
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|                 pretty_print=_request_user_agent_is_curl(request),
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|             )
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| 
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|     return wrap_request_handler_with_logging(wrapped_request_handler)
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| 
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| 
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| def wrap_html_request_handler(h):
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|     """Wraps a request handler method with exception handling.
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| 
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|     Also adds logging as per wrap_request_handler_with_logging.
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| 
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|     The handler method must have a signature of "handle_foo(self, request)",
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|     where "self" must have a "clock" attribute (and "request" must be a
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|     SynapseRequest).
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|     """
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|     def wrapped_request_handler(self, request):
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|         d = defer.maybeDeferred(h, self, request)
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|         d.addErrback(_return_html_error, request)
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|         return d
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| 
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|     return wrap_request_handler_with_logging(wrapped_request_handler)
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| 
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| 
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| def _return_html_error(f, request):
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|     """Sends an HTML error page corresponding to the given failure
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| 
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|     Args:
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|         f (twisted.python.failure.Failure):
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|         request (twisted.web.iweb.IRequest):
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|     """
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|     if f.check(CodeMessageException):
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|         cme = f.value
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|         code = cme.code
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|         msg = cme.msg
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| 
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|         if isinstance(cme, SynapseError):
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|             logger.info(
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|                 "%s SynapseError: %s - %s", request, code, msg
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|             )
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|         else:
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|             logger.error(
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|                 "Failed handle request %r: %s",
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|                 request,
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|                 f.getTraceback().rstrip(),
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|             )
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|     else:
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|         code = http_client.INTERNAL_SERVER_ERROR
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|         msg = "Internal server error"
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| 
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|         logger.error(
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|             "Failed handle request %r: %s",
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|             request,
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|             f.getTraceback().rstrip(),
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|         )
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| 
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|     body = HTML_ERROR_TEMPLATE.format(
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|         code=code, msg=cgi.escape(msg),
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|     ).encode("utf-8")
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|     request.setResponseCode(code)
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|     request.setHeader(b"Content-Type", b"text/html; charset=utf-8")
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|     request.setHeader(b"Content-Length", b"%i" % (len(body),))
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|     request.write(body)
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|     finish_request(request)
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| 
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| 
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| def wrap_request_handler_with_logging(h):
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|     """Wraps a request handler to provide logging and metrics
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| 
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|     The handler method must have a signature of "handle_foo(self, request)",
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|     where "self" must have a "clock" attribute (and "request" must be a
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|     SynapseRequest).
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| 
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|     As well as calling `request.processing` (which will log the response and
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|     duration for this request), the wrapped request handler will insert the
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|     request id into the logging context.
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|     """
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|     @defer.inlineCallbacks
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|     def wrapped_request_handler(self, request):
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|         """
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|         Args:
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|             self:
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|             request (synapse.http.site.SynapseRequest):
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|         """
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| 
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|         request_id = request.get_request_id()
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|         with LoggingContext(request_id) as request_context:
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|             request_context.request = request_id
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|             with Measure(self.clock, "wrapped_request_handler"):
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|                 # we start the request metrics timer here with an initial stab
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|                 # at the servlet name. For most requests that name will be
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|                 # JsonResource (or a subclass), and JsonResource._async_render
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|                 # will update it once it picks a servlet.
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|                 servlet_name = self.__class__.__name__
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|                 with request.processing(servlet_name):
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|                     with PreserveLoggingContext(request_context):
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|                         d = defer.maybeDeferred(h, self, request)
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| 
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|                         # record the arrival of the request *after*
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|                         # dispatching to the handler, so that the handler
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|                         # can update the servlet name in the request
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|                         # metrics
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|                         requests_counter.labels(request.method,
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|                                                 request.request_metrics.name).inc()
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|                         yield d
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|     return wrapped_request_handler
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| 
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| 
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| class HttpServer(object):
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|     """ Interface for registering callbacks on a HTTP server
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|     """
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| 
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|     def register_paths(self, method, path_patterns, callback):
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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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| 
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|         If the regex contains groups these gets passed to the calback via
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|         an unpacked tuple.
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| 
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|         Args:
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|             method (str): The method to listen to.
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|             path_patterns (list<SRE_Pattern>): The regex used to match requests.
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|             callback (function): 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 a tuple of (code, response).
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|         """
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|         pass
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| 
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| 
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| class JsonResource(HttpServer, resource.Resource):
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|     """ This implements the HttpServer interface and provides JSON support for
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|     Resources.
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| 
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|     Register callbacks via register_paths()
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| 
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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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| 
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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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| 
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|     isLeaf = True
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| 
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|     _PathEntry = collections.namedtuple("_PathEntry", ["pattern", "callback"])
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| 
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|     def __init__(self, hs, canonical_json=True):
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|         resource.Resource.__init__(self)
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| 
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|         self.canonical_json = canonical_json
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|         self.clock = hs.get_clock()
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|         self.path_regexs = {}
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|         self.hs = hs
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| 
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|     def register_paths(self, method, path_patterns, callback):
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|         method = method.encode("utf-8")  # method is bytes on py3
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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, []).append(
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|                 self._PathEntry(path_pattern, callback)
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|             )
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| 
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|     def render(self, request):
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|         """ This gets called by twisted every time someone sends us a request.
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|         """
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|         self._async_render(request)
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|         return server.NOT_DONE_YET
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| 
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|     @wrap_json_request_handler
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|     @defer.inlineCallbacks
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|     def _async_render(self, request):
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|         """ This gets called from render() every time someone sends us a request.
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|             This checks if anyone has registered a callback for that method and
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|             path.
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|         """
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|         callback, group_dict = self._get_handler_for_request(request)
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| 
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|         servlet_instance = getattr(callback, "__self__", None)
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|         if servlet_instance is not None:
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|             servlet_classname = servlet_instance.__class__.__name__
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|         else:
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|             servlet_classname = "%r" % callback
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|         request.request_metrics.name = servlet_classname
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| 
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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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| 
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|         def _unquote(s):
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|             if PY3:
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|                 # On Python 3, unquote is unicode -> unicode
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|                 return urllib.parse.unquote(s)
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|             else:
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|                 # On Python 2, unquote is bytes -> bytes We need to encode the
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|                 # URL again (as it was decoded by _get_handler_for request), as
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|                 # ASCII because it's a URL, and then decode it to get the UTF-8
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|                 # characters that were quoted.
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|                 return urllib.parse.unquote(s.encode('ascii')).decode('utf8')
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| 
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|         kwargs = intern_dict({
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|             name: _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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|         callback_return = yield callback(request, **kwargs)
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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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| 
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|     def _get_handler_for_request(self, request):
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|         """Finds a callback method to handle the given request
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| 
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|         Args:
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|             request (twisted.web.http.Request):
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| 
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|         Returns:
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|             Tuple[Callable, dict[unicode, unicode]]: callback method, and the
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|                 dict mapping keys to path components as specified in the
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|                 handler's path match regexp.
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| 
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|                 The callback will normally be a method registered via
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|                 register_paths, so will return (possibly via Deferred) either
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|                 None, or a tuple of (http code, response body).
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|         """
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|         if request.method == b"OPTIONS":
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|             return _options_handler, {}
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| 
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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.decode('ascii'))
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|             if m:
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|                 # We found a match!
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|                 return path_entry.callback, m.groupdict()
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| 
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|         # Huh. No one wanted to handle that? Fiiiiiine. Send 400.
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|         return _unrecognised_request_handler, {}
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| 
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|     def _send_response(self, request, code, response_json_object,
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|                        response_code_message=None):
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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, code, response_json_object,
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|             send_cors=True,
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|             response_code_message=response_code_message,
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|             pretty_print=_request_user_agent_is_curl(request),
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|             canonical_json=self.canonical_json,
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|         )
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| 
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| 
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| def _options_handler(request):
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|     """Request handler for OPTIONS requests
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| 
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|     This is a request handler suitable for return from
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|     _get_handler_for_request. It returns a 200 and an empty body.
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| 
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|     Args:
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|         request (twisted.web.http.Request):
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| 
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|     Returns:
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|         Tuple[int, dict]: http code, response body.
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|     """
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|     return 200, {}
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| 
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| 
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| def _unrecognised_request_handler(request):
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|     """Request handler for unrecognised requests
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| 
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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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| 
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|     Args:
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|         request (twisted.web.http.Request):
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|     """
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|     raise UnrecognizedRequestError()
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| 
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| 
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| class RootRedirect(resource.Resource):
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|     """Redirects the root '/' path to another path."""
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| 
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|     def __init__(self, path):
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|         resource.Resource.__init__(self)
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|         self.url = path
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| 
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|     def render_GET(self, request):
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|         return redirectTo(self.url.encode('ascii'), request)
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| 
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|     def getChild(self, name, request):
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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 resource.Resource.getChild(self, name, request)
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| 
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| 
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| def respond_with_json(request, code, json_object, send_cors=False,
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|                       response_code_message=None, pretty_print=False,
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|                       canonical_json=True):
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|     # could alternatively use request.notifyFinish() and flip a flag when
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|     # the Deferred fires, but since the flag is RIGHT THERE it seems like
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|     # a waste.
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|     if request._disconnected:
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|         logger.warn(
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|             "Not sending response to request %s, already disconnected.",
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|             request)
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|         return
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| 
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|     if pretty_print:
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|         json_bytes = (encode_pretty_printed_json(json_object) + "\n"
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|                       ).encode("utf-8")
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|     else:
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|         if canonical_json or synapse.events.USE_FROZEN_DICTS:
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|             # canonicaljson already encodes to bytes
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|             json_bytes = encode_canonical_json(json_object)
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|         else:
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|             json_bytes = json.dumps(json_object).encode("utf-8")
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| 
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|     return respond_with_json_bytes(
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|         request, code, json_bytes,
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|         send_cors=send_cors,
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|         response_code_message=response_code_message,
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|     )
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| 
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| 
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| def respond_with_json_bytes(request, code, json_bytes, send_cors=False,
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|                             response_code_message=None):
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|     """Sends encoded JSON in response to the given request.
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| 
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|     Args:
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|         request (twisted.web.http.Request): The http request to respond to.
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|         code (int): The HTTP response code.
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|         json_bytes (bytes): The json bytes to use as the response body.
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|         send_cors (bool): Whether to send Cross-Origin Resource Sharing headers
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|             http://www.w3.org/TR/cors/
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|     Returns:
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|         twisted.web.server.NOT_DONE_YET"""
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| 
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|     request.setResponseCode(code, message=response_code_message)
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|     request.setHeader(b"Content-Type", b"application/json")
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|     request.setHeader(b"Content-Length", b"%d" % (len(json_bytes),))
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|     request.setHeader(b"Cache-Control", b"no-cache, no-store, must-revalidate")
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| 
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|     if send_cors:
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|         set_cors_headers(request)
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| 
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|     request.write(json_bytes)
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|     finish_request(request)
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|     return NOT_DONE_YET
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| 
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| 
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| def set_cors_headers(request):
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|     """Set the CORs headers so that javascript running in a web browsers can
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|     use this API
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| 
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|     Args:
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|         request (twisted.web.http.Request): The http request to add CORs to.
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|     """
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|     request.setHeader("Access-Control-Allow-Origin", "*")
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|     request.setHeader(
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|         "Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS"
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|     )
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|     request.setHeader(
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|         "Access-Control-Allow-Headers",
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|         "Origin, X-Requested-With, Content-Type, Accept, Authorization"
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|     )
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| 
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| 
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| def finish_request(request):
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|     """ Finish writing the response to the request.
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| 
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|     Twisted throws a RuntimeException if the connection closed before the
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|     response was written but doesn't provide a convenient or reliable way to
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|     determine if the connection was closed. So we catch and log the RuntimeException
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| 
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|     You might think that ``request.notifyFinish`` could be used to tell if the
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|     request was finished. However the deferred it returns won't fire if the
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|     connection was already closed, meaning we'd have to have called the method
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|     right at the start of the request. By the time we want to write the response
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|     it will already be too late.
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|     """
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|     try:
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|         request.finish()
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|     except RuntimeError as e:
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|         logger.info("Connection disconnected before response was written: %r", e)
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| 
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| 
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| def _request_user_agent_is_curl(request):
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|     user_agents = request.requestHeaders.getRawHeaders(
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|         b"User-Agent", default=[]
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|     )
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|     for user_agent in user_agents:
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|         if b"curl" in user_agent:
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|             return True
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|     return False
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