243 lines
		
	
	
		
			8.7 KiB
		
	
	
	
		
			Python
		
	
	
			
		
		
	
	
			243 lines
		
	
	
		
			8.7 KiB
		
	
	
	
		
			Python
		
	
	
| # Copyright 2015 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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| 
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| from synapse.http.server import request_handler, respond_with_json_bytes
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| from synapse.http.servlet import parse_integer
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| from synapse.api.errors import SynapseError, Codes
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| 
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| from twisted.web.resource import Resource
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| from twisted.web.server import NOT_DONE_YET
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| from twisted.internet import defer
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| 
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| 
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| from io import BytesIO
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| import json
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| import logging
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| logger = logging.getLogger(__name__)
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| 
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| 
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| class RemoteKey(Resource):
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|     """HTTP resource for retreiving the TLS certificate and NACL signature
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|     verification keys for a collection of servers. Checks that the reported
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|     X.509 TLS certificate matches the one used in the HTTPS connection. Checks
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|     that the NACL signature for the remote server is valid. Returns a dict of
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|     JSON signed by both the remote server and by this server.
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| 
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|     Supports individual GET APIs and a bulk query POST API.
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| 
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|     Requsts:
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| 
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|     GET /_matrix/key/v2/query/remote.server.example.com HTTP/1.1
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| 
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|     GET /_matrix/key/v2/query/remote.server.example.com/a.key.id HTTP/1.1
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| 
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|     POST /_matrix/v2/query HTTP/1.1
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|     Content-Type: application/json
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|     {
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|         "server_keys": {
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|             "remote.server.example.com": {
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|                 "a.key.id": {
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|                     "minimum_valid_until_ts": 1234567890123
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|                 }
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|             }
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|         }
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|     }
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| 
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|     Response:
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| 
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|     HTTP/1.1 200 OK
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|     Content-Type: application/json
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|     {
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|         "server_keys": [
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|             {
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|                 "server_name": "remote.server.example.com"
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|                 "valid_until_ts": # posix timestamp
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|                 "verify_keys": {
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|                     "a.key.id": { # The identifier for a key.
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|                         key: "" # base64 encoded verification key.
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|                     }
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|                 }
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|                 "old_verify_keys": {
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|                     "an.old.key.id": { # The identifier for an old key.
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|                         key: "", # base64 encoded key
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|                         "expired_ts": 0, # when the key stop being used.
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|                     }
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|                 }
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|                 "tls_fingerprints": [
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|                     { "sha256": # fingerprint }
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|                 ]
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|                 "signatures": {
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|                     "remote.server.example.com": {...}
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|                     "this.server.example.com": {...}
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|                 }
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|             }
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|         ]
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|     }
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|     """
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| 
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|     isLeaf = True
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| 
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|     def __init__(self, hs):
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|         self.keyring = hs.get_keyring()
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|         self.store = hs.get_datastore()
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|         self.version_string = hs.version_string
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|         self.clock = hs.get_clock()
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| 
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|     def render_GET(self, request):
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|         self.async_render_GET(request)
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|         return NOT_DONE_YET
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| 
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|     @request_handler
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|     @defer.inlineCallbacks
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|     def async_render_GET(self, request):
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|         if len(request.postpath) == 1:
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|             server, = request.postpath
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|             query = {server: {}}
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|         elif len(request.postpath) == 2:
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|             server, key_id = request.postpath
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|             minimum_valid_until_ts = parse_integer(
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|                 request, "minimum_valid_until_ts"
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|             )
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|             arguments = {}
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|             if minimum_valid_until_ts is not None:
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|                 arguments["minimum_valid_until_ts"] = minimum_valid_until_ts
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|             query = {server: {key_id: arguments}}
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|         else:
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|             raise SynapseError(
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|                 404, "Not found %r" % request.postpath, Codes.NOT_FOUND
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|             )
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|         yield self.query_keys(request, query, query_remote_on_cache_miss=True)
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| 
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|     def render_POST(self, request):
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|         self.async_render_POST(request)
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|         return NOT_DONE_YET
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| 
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|     @request_handler
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|     @defer.inlineCallbacks
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|     def async_render_POST(self, request):
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|         try:
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|             content = json.loads(request.content.read())
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|             if type(content) != dict:
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|                 raise ValueError()
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|         except ValueError:
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|             raise SynapseError(
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|                 400, "Content must be JSON object.", errcode=Codes.NOT_JSON
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|             )
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| 
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|         query = content["server_keys"]
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| 
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|         yield self.query_keys(request, query, query_remote_on_cache_miss=True)
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| 
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|     @defer.inlineCallbacks
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|     def query_keys(self, request, query, query_remote_on_cache_miss=False):
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|         logger.info("Handling query for keys %r", query)
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|         store_queries = []
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|         for server_name, key_ids in query.items():
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|             if not key_ids:
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|                 key_ids = (None,)
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|             for key_id in key_ids:
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|                 store_queries.append((server_name, key_id, None))
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| 
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|         cached = yield self.store.get_server_keys_json(store_queries)
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| 
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|         json_results = set()
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| 
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|         time_now_ms = self.clock.time_msec()
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| 
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|         cache_misses = dict()
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|         for (server_name, key_id, from_server), results in cached.items():
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|             results = [
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|                 (result["ts_added_ms"], result) for result in results
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|             ]
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| 
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|             if not results and key_id is not None:
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|                 cache_misses.setdefault(server_name, set()).add(key_id)
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|                 continue
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| 
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|             if key_id is not None:
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|                 ts_added_ms, most_recent_result = max(results)
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|                 ts_valid_until_ms = most_recent_result["ts_valid_until_ms"]
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|                 req_key = query.get(server_name, {}).get(key_id, {})
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|                 req_valid_until = req_key.get("minimum_valid_until_ts")
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|                 miss = False
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|                 if req_valid_until is not None:
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|                     if ts_valid_until_ms < req_valid_until:
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|                         logger.debug(
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|                             "Cached response for %r/%r is older than requested"
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|                             ": valid_until (%r) < minimum_valid_until (%r)",
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|                             server_name, key_id,
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|                             ts_valid_until_ms, req_valid_until
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|                         )
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|                         miss = True
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|                     else:
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|                         logger.debug(
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|                             "Cached response for %r/%r is newer than requested"
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|                             ": valid_until (%r) >= minimum_valid_until (%r)",
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|                             server_name, key_id,
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|                             ts_valid_until_ms, req_valid_until
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|                         )
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|                 elif (ts_added_ms + ts_valid_until_ms) / 2 < time_now_ms:
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|                     logger.debug(
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|                         "Cached response for %r/%r is too old"
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|                         ": (added (%r) + valid_until (%r)) / 2 < now (%r)",
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|                         server_name, key_id,
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|                         ts_added_ms, ts_valid_until_ms, time_now_ms
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|                     )
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|                     # We more than half way through the lifetime of the
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|                     # response. We should fetch a fresh copy.
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|                     miss = True
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|                 else:
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|                     logger.debug(
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|                         "Cached response for %r/%r is still valid"
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|                         ": (added (%r) + valid_until (%r)) / 2 < now (%r)",
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|                         server_name, key_id,
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|                         ts_added_ms, ts_valid_until_ms, time_now_ms
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|                     )
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| 
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|                 if miss:
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|                     cache_misses.setdefault(server_name, set()).add(key_id)
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|                 json_results.add(bytes(most_recent_result["key_json"]))
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|             else:
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|                 for ts_added, result in results:
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|                     json_results.add(bytes(result["key_json"]))
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| 
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|         if cache_misses and query_remote_on_cache_miss:
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|             for server_name, key_ids in cache_misses.items():
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|                 try:
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|                     yield self.keyring.get_server_verify_key_v2_direct(
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|                         server_name, key_ids
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|                     )
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|                 except:
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|                     logger.exception("Failed to get key for %r", server_name)
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|                     pass
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|             yield self.query_keys(
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|                 request, query, query_remote_on_cache_miss=False
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|             )
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|         else:
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|             result_io = BytesIO()
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|             result_io.write(b"{\"server_keys\":")
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|             sep = b"["
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|             for json_bytes in json_results:
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|                 result_io.write(sep)
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|                 result_io.write(json_bytes)
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|                 sep = b","
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|             if sep == b"[":
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|                 result_io.write(sep)
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|             result_io.write(b"]}")
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| 
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|             respond_with_json_bytes(
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|                 request, 200, result_io.getvalue(),
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|                 version_string=self.version_string
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|             )
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