342 lines
8.7 KiB
Python
342 lines
8.7 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright 2017 Vector Creations 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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"""Defines the various valid commands
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The VALID_SERVER_COMMANDS and VALID_CLIENT_COMMANDS define which commands are
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allowed to be sent by which side.
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"""
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import logging
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import ujson as json
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logger = logging.getLogger(__name__)
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class Command(object):
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"""The base command class.
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All subclasses must set the NAME variable which equates to the name of the
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command on the wire.
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A full command line on the wire is constructed from `NAME + " " + to_line()`
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The default implementation creates a command of form `<NAME> <data>`
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"""
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NAME = None
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def __init__(self, data):
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self.data = data
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@classmethod
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def from_line(cls, line):
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"""Deserialises a line from the wire into this command. `line` does not
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include the command.
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"""
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return cls(line)
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def to_line(self):
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"""Serialises the comamnd for the wire. Does not include the command
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prefix.
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"""
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return self.data
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class ServerCommand(Command):
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"""Sent by the server on new connection and includes the server_name.
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Format::
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SERVER <server_name>
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"""
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NAME = "SERVER"
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class RdataCommand(Command):
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"""Sent by server when a subscribed stream has an update.
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Format::
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RDATA <stream_name> <token> <row_json>
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The `<token>` may either be a numeric stream id OR "batch". The latter case
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is used to support sending multiple updates with the same stream ID. This
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is done by sending an RDATA for each row, with all but the last RDATA having
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a token of "batch" and the last having the final stream ID.
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The client should batch all incoming RDATA with a token of "batch" (per
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stream_name) until it sees an RDATA with a numeric stream ID.
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`<token>` of "batch" maps to the instance variable `token` being None.
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An example of a batched series of RDATA::
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RDATA presence batch ["@foo:example.com", "online", ...]
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RDATA presence batch ["@bar:example.com", "online", ...]
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RDATA presence 59 ["@baz:example.com", "online", ...]
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"""
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NAME = "RDATA"
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def __init__(self, stream_name, token, row):
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self.stream_name = stream_name
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self.token = token
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self.row = row
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@classmethod
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def from_line(cls, line):
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stream_name, token, row_json = line.split(" ", 2)
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return cls(
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stream_name,
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None if token == "batch" else int(token),
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json.loads(row_json)
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)
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def to_line(self):
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return " ".join((
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self.stream_name,
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str(self.token) if self.token is not None else "batch",
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json.dumps(self.row),
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))
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class PositionCommand(Command):
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"""Sent by the client to tell the client the stream postition without
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needing to send an RDATA.
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"""
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NAME = "POSITION"
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def __init__(self, stream_name, token):
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self.stream_name = stream_name
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self.token = token
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@classmethod
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def from_line(cls, line):
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stream_name, token = line.split(" ", 1)
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return cls(stream_name, int(token))
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def to_line(self):
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return " ".join((self.stream_name, str(self.token),))
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class ErrorCommand(Command):
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"""Sent by either side if there was an ERROR. The data is a string describing
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the error.
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"""
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NAME = "ERROR"
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class PingCommand(Command):
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"""Sent by either side as a keep alive. The data is arbitary (often timestamp)
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"""
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NAME = "PING"
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class NameCommand(Command):
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"""Sent by client to inform the server of the client's identity. The data
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is the name
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"""
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NAME = "NAME"
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class ReplicateCommand(Command):
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"""Sent by the client to subscribe to the stream.
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Format::
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REPLICATE <stream_name> <token>
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Where <token> may be either:
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* a numeric stream_id to stream updates from
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* "NOW" to stream all subsequent updates.
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The <stream_name> can be "ALL" to subscribe to all known streams, in which
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case the <token> must be set to "NOW", i.e.::
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REPLICATE ALL NOW
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"""
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NAME = "REPLICATE"
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def __init__(self, stream_name, token):
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self.stream_name = stream_name
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self.token = token
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@classmethod
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def from_line(cls, line):
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stream_name, token = line.split(" ", 1)
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if token in ("NOW", "now"):
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token = "NOW"
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else:
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token = int(token)
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return cls(stream_name, token)
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def to_line(self):
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return " ".join((self.stream_name, str(self.token),))
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class UserSyncCommand(Command):
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"""Sent by the client to inform the server that a user has started or
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stopped syncing. Used to calculate presence on the master.
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Format::
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USER_SYNC <user_id> <state>
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Where <state> is either "start" or "stop"
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"""
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NAME = "USER_SYNC"
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def __init__(self, user_id, is_syncing):
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self.user_id = user_id
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self.is_syncing = is_syncing
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@classmethod
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def from_line(cls, line):
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user_id, state = line.split(" ", 1)
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if state not in ("start", "end"):
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raise Exception("Invalid USER_SYNC state %r" % (state,))
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return cls(user_id, state == "start")
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def to_line(self):
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return " ".join((self.user_id, "start" if self.is_syncing else "end"))
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class FederationAckCommand(Command):
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"""Sent by the client when it has processed up to a given point in the
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federation stream. This allows the master to drop in-memory caches of the
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federation stream.
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This must only be sent from one worker (i.e. the one sending federation)
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Format::
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FEDERATION_ACK <token>
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"""
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NAME = "FEDERATION_ACK"
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def __init__(self, token):
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self.token = token
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@classmethod
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def from_line(cls, line):
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return cls(int(line))
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def to_line(self):
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return str(self.token)
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class SyncCommand(Command):
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"""Used for testing. The client protocol implementation allows waiting
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on a SYNC command with a specified data.
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"""
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NAME = "SYNC"
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class RemovePusherCommand(Command):
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"""Sent by the client to request the master remove the given pusher.
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Format::
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REMOVE_PUSHER <app_id> <push_key> <user_id>
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"""
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NAME = "REMOVE_PUSHER"
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def __init__(self, app_id, push_key, user_id):
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self.user_id = user_id
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self.app_id = app_id
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self.push_key = push_key
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@classmethod
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def from_line(cls, line):
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app_id, push_key, user_id = line.split(" ", 2)
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return cls(app_id, push_key, user_id)
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def to_line(self):
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return " ".join((self.app_id, self.push_key, self.user_id))
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class InvalidateCacheCommand(Command):
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"""Sent by the client to invalidate an upstream cache.
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THIS IS NOT RELIABLE, AND SHOULD *NOT* BE USED ACCEPT FOR THINGS THAT ARE
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NOT DISASTROUS IF WE DROP ON THE FLOOR.
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Mainly used to invalidate destination retry timing caches.
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Format::
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INVALIDATE_CACHE <cache_func> <keys_json>
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Where <keys_json> is a json list.
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"""
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NAME = "INVALIDATE_CACHE"
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def __init__(self, cache_func, keys):
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self.cache_func = cache_func
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self.keys = keys
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@classmethod
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def from_line(cls, line):
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cache_func, keys_json = line.split(" ", 1)
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return cls(cache_func, json.loads(keys_json))
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def to_line(self):
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return " ".join((self.cache_func, json.dumps(self.keys)))
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# Map of command name to command type.
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COMMAND_MAP = {
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cmd.NAME: cmd
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for cmd in (
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ServerCommand,
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RdataCommand,
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PositionCommand,
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ErrorCommand,
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PingCommand,
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NameCommand,
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ReplicateCommand,
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UserSyncCommand,
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FederationAckCommand,
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SyncCommand,
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RemovePusherCommand,
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InvalidateCacheCommand,
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)
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}
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# The commands the server is allowed to send
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VALID_SERVER_COMMANDS = (
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ServerCommand.NAME,
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RdataCommand.NAME,
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PositionCommand.NAME,
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ErrorCommand.NAME,
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PingCommand.NAME,
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SyncCommand.NAME,
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)
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# The commands the client is allowed to send
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VALID_CLIENT_COMMANDS = (
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NameCommand.NAME,
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ReplicateCommand.NAME,
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PingCommand.NAME,
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UserSyncCommand.NAME,
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FederationAckCommand.NAME,
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RemovePusherCommand.NAME,
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InvalidateCacheCommand.NAME,
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ErrorCommand.NAME,
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)
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