401 lines
		
	
	
		
			14 KiB
		
	
	
	
		
			Python
		
	
	
			
		
		
	
	
			401 lines
		
	
	
		
			14 KiB
		
	
	
	
		
			Python
		
	
	
# -*- coding: utf-8 -*-
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# Copyright 2014-2016 OpenMarket 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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from synapse.api.errors import (
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    cs_exception, SynapseError, CodeMessageException, UnrecognizedRequestError, Codes
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)
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from synapse.util.logcontext import LoggingContext, PreserveLoggingContext
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import synapse.metrics
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import synapse.events
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from canonicaljson import (
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    encode_canonical_json, encode_pretty_printed_json
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)
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from twisted.internet import defer
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from twisted.web import server, resource
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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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import collections
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import logging
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import urllib
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import ujson
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logger = logging.getLogger(__name__)
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metrics = synapse.metrics.get_metrics_for(__name__)
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incoming_requests_counter = metrics.register_counter(
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    "requests",
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    labels=["method", "servlet", "tag"],
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)
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outgoing_responses_counter = metrics.register_counter(
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    "responses",
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    labels=["method", "code"],
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)
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response_timer = metrics.register_distribution(
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    "response_time",
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    labels=["method", "servlet", "tag"]
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)
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response_ru_utime = metrics.register_distribution(
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    "response_ru_utime", labels=["method", "servlet", "tag"]
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)
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response_ru_stime = metrics.register_distribution(
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    "response_ru_stime", labels=["method", "servlet", "tag"]
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)
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response_db_txn_count = metrics.register_distribution(
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    "response_db_txn_count", labels=["method", "servlet", "tag"]
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)
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response_db_txn_duration = metrics.register_distribution(
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    "response_db_txn_duration", labels=["method", "servlet", "tag"]
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)
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_next_request_id = 0
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def request_handler(request_handler):
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    """Wraps a method that acts as a request handler with the necessary logging
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    and exception handling.
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    The method must have a signature of "handle_foo(self, request)". The
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    argument "self" must have "version_string" and "clock" attributes. The
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    argument "request" must be a twisted HTTP request.
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    The method 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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    We insert a unique request-id into the logging context for this request and
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    log the response and duration for this request.
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    """
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    @defer.inlineCallbacks
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    def wrapped_request_handler(self, request):
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        global _next_request_id
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        request_id = "%s-%s" % (request.method, _next_request_id)
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        _next_request_id += 1
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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 request.processing():
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                try:
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                    with PreserveLoggingContext(request_context):
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                        yield request_handler(self, request)
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                except CodeMessageException as e:
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                    code = e.code
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                    if isinstance(e, SynapseError):
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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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                    else:
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                        logger.exception(e)
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                    outgoing_responses_counter.inc(request.method, str(code))
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                    respond_with_json(
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                        request, code, cs_exception(e), send_cors=True,
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                        pretty_print=_request_user_agent_is_curl(request),
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                        version_string=self.version_string,
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                    )
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                except:
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                    logger.exception(
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                        "Failed handle request %s.%s on %r: %r",
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                        request_handler.__module__,
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                        request_handler.__name__,
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                        self,
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                        request
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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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                    )
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    return wrapped_request_handler
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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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    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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        If the regex contains groups these gets passed to the calback via
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        an unpacked tuple.
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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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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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    Register callbacks via register_path()
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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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    _PathEntry = collections.namedtuple("_PathEntry", ["pattern", "callback"])
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    def __init__(self, hs, canonical_json=True):
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        resource.Resource.__init__(self)
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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.version_string = hs.version_string
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        self.hs = hs
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    def register_paths(self, method, path_patterns, callback):
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        for path_pattern in path_patterns:
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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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    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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    @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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        start = self.clock.time_msec()
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        if request.method == "OPTIONS":
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            self._send_response(request, 200, {})
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            return
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        start_context = LoggingContext.current_context()
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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 not m:
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                continue
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            # We found a match! Trigger callback and then return the
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            # returned response. We pass both the request and any
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            # matched groups from the regex to the callback.
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            callback = path_entry.callback
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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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            args = [
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                urllib.unquote(u).decode("UTF-8") if u else u for u in m.groups()
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            ]
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            callback_return = yield callback(request, *args)
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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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            try:
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                context = LoggingContext.current_context()
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                tag = ""
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                if context:
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                    tag = context.tag
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                    if context != start_context:
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                        logger.warn(
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                            "Context have unexpectedly changed %r, %r",
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                            context, self.start_context
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                        )
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                        return
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                incoming_requests_counter.inc(request.method, servlet_classname, tag)
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                response_timer.inc_by(
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                    self.clock.time_msec() - start, request.method,
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                    servlet_classname, tag
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                )
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                ru_utime, ru_stime = context.get_resource_usage()
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                response_ru_utime.inc_by(
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                    ru_utime, request.method, servlet_classname, tag
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                )
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                response_ru_stime.inc_by(
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                    ru_stime, request.method, servlet_classname, tag
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                )
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                response_db_txn_count.inc_by(
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                    context.db_txn_count, request.method, servlet_classname, tag
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                )
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                response_db_txn_duration.inc_by(
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                    context.db_txn_duration, request.method, servlet_classname, tag
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                )
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            except:
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                pass
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            return
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        # Huh. No one wanted to handle that? Fiiiiiine. Send 400.
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        raise UnrecognizedRequestError()
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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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        # 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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        outgoing_responses_counter.inc(request.method, str(code))
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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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            version_string=self.version_string,
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            canonical_json=self.canonical_json,
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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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    def __init__(self, path):
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        resource.Resource.__init__(self)
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        self.url = path
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    def render_GET(self, request):
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        return redirectTo(self.url, request)
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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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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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                      version_string="", canonical_json=True):
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    if pretty_print:
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        json_bytes = encode_pretty_printed_json(json_object) + "\n"
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    else:
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        if canonical_json or synapse.events.USE_FROZEN_DICTS:
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            json_bytes = encode_canonical_json(json_object)
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        else:
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            # ujson doesn't like frozen_dicts.
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            json_bytes = ujson.dumps(json_object, ensure_ascii=False)
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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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        version_string=version_string
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    )
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def respond_with_json_bytes(request, code, json_bytes, send_cors=False,
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                            version_string="", response_code_message=None):
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    """Sends encoded JSON in response to the given request.
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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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    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"Server", version_string)
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    request.setHeader(b"Content-Length", b"%d" % (len(json_bytes),))
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    if send_cors:
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        request.setHeader("Access-Control-Allow-Origin", "*")
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        request.setHeader("Access-Control-Allow-Methods",
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                          "GET, POST, PUT, DELETE, OPTIONS")
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        request.setHeader("Access-Control-Allow-Headers",
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                          "Origin, X-Requested-With, Content-Type, Accept")
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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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def finish_request(request):
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    """ Finish writing the response to the request.
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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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    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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def _request_user_agent_is_curl(request):
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    user_agents = request.requestHeaders.getRawHeaders(
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        "User-Agent", default=[]
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    )
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    for user_agent in user_agents:
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        if "curl" in user_agent:
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            return True
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    return False
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