forked from LBRYCommunity/lbry-sdk
269 lines
9.1 KiB
Python
269 lines
9.1 KiB
Python
"""
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The reflector protocol (all dicts encoded in json):
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Client Handshake (sent once per connection, at the start of the connection):
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{
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'version': 0,
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}
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Server Handshake (sent once per connection, after receiving the client handshake):
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{
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'version': 0,
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}
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Client Info Request:
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{
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'blob_hash': "<blob_hash>",
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'blob_size': <blob_size>
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}
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Server Info Response (sent in response to Client Info Request):
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{
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'send_blob': True|False
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}
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If response is 'YES', client may send a Client Blob Request or a Client Info Request.
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If response is 'NO', client may only send a Client Info Request
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Client Blob Request:
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{} # Yes, this is an empty dictionary, in case something needs to go here in the future
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<raw blob_data> # this blob data must match the info sent in the most recent Client Info Request
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Server Blob Response (sent in response to Client Blob Request):
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{
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'received_blob': True
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}
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Client may now send another Client Info Request
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"""
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import json
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import logging
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from twisted.protocols.basic import FileSender
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from twisted.internet.protocol import Protocol, ClientFactory
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from twisted.internet import defer, error
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log = logging.getLogger(__name__)
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class IncompleteResponseError(Exception):
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pass
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class LBRYFileReflectorClient(Protocol):
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# Protocol stuff
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def connectionMade(self):
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self.blob_manager = self.factory.blob_manager
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self.response_buff = ''
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self.outgoing_buff = ''
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self.blob_hashes_to_send = []
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self.next_blob_to_send = None
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self.blob_read_handle = None
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self.received_handshake_response = False
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self.protocol_version = None
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self.file_sender = None
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self.producer = None
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self.streaming = False
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d = self.get_blobs_to_send(self.factory.stream_info_manager, self.factory.stream_hash)
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d.addCallback(lambda _: self.send_handshake())
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d.addErrback(lambda err: log.warning("An error occurred immediately: %s", err.getTraceback()))
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def dataReceived(self, data):
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log.debug('Recieved %s', data)
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self.response_buff += data
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try:
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msg = self.parse_response(self.response_buff)
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except IncompleteResponseError:
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pass
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else:
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self.response_buff = ''
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d = self.handle_response(msg)
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d.addCallback(lambda _: self.send_next_request())
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d.addErrback(self.response_failure_handler)
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def connectionLost(self, reason):
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if reason.check(error.ConnectionDone):
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log.debug('Finished sending data via reflector')
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self.factory.finished_deferred.callback(True)
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else:
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log.debug('reflector finished: %s', reason)
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self.factory.finished_deferred.callback(reason)
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# IConsumer stuff
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def registerProducer(self, producer, streaming):
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self.producer = producer
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self.streaming = streaming
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if self.streaming is False:
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from twisted.internet import reactor
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reactor.callLater(0, self.producer.resumeProducing)
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def unregisterProducer(self):
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self.producer = None
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def write(self, data):
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self.transport.write(data)
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if self.producer is not None and self.streaming is False:
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from twisted.internet import reactor
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reactor.callLater(0, self.producer.resumeProducing)
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def get_blobs_to_send(self, stream_info_manager, stream_hash):
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log.debug('Getting blobs from stream hash: %s', stream_hash)
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d = stream_info_manager.get_blobs_for_stream(stream_hash)
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def set_blobs(blob_hashes):
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for blob_hash, position, iv, length in blob_hashes:
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log.info("Preparing to send %s", blob_hash)
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if blob_hash is not None:
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self.blob_hashes_to_send.append(blob_hash)
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d.addCallback(set_blobs)
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d.addCallback(lambda _: stream_info_manager.get_sd_blob_hashes_for_stream(stream_hash))
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def set_sd_blobs(sd_blob_hashes):
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for sd_blob_hash in sd_blob_hashes:
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self.blob_hashes_to_send.append(sd_blob_hash)
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d.addCallback(set_sd_blobs)
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return d
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def send_handshake(self):
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log.debug('Sending handshake')
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self.write(json.dumps({'version': 0}))
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def parse_response(self, buff):
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try:
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return json.loads(buff)
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except ValueError:
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raise IncompleteResponseError()
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def response_failure_handler(self, err):
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log.warning("An error occurred handling the response: %s", err.getTraceback())
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def handle_response(self, response_dict):
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if self.received_handshake_response is False:
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return self.handle_handshake_response(response_dict)
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else:
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return self.handle_normal_response(response_dict)
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def set_not_uploading(self):
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if self.next_blob_to_send is not None:
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self.next_blob_to_send.close_read_handle(self.read_handle)
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self.read_handle = None
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self.next_blob_to_send = None
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self.file_sender = None
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return defer.succeed(None)
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def start_transfer(self):
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self.write(json.dumps({}))
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assert self.read_handle is not None, "self.read_handle was None when trying to start the transfer"
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d = self.file_sender.beginFileTransfer(self.read_handle, self)
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return d
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def handle_handshake_response(self, response_dict):
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if 'version' not in response_dict:
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raise ValueError("Need protocol version number!")
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self.protocol_version = int(response_dict['version'])
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if self.protocol_version != 0:
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raise ValueError("I can't handle protocol version {}!".format(self.protocol_version))
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self.received_handshake_response = True
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return defer.succeed(True)
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def handle_normal_response(self, response_dict):
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if self.file_sender is None: # Expecting Server Info Response
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if 'send_blob' not in response_dict:
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raise ValueError("I don't know whether to send the blob or not!")
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if response_dict['send_blob'] is True:
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self.file_sender = FileSender()
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return defer.succeed(True)
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else:
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return self.set_not_uploading()
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else: # Expecting Server Blob Response
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if 'received_blob' not in response_dict:
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raise ValueError("I don't know if the blob made it to the intended destination!")
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else:
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return self.set_not_uploading()
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def open_blob_for_reading(self, blob):
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if blob.is_validated():
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read_handle = blob.open_for_reading()
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if read_handle is not None:
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log.debug('Getting ready to send %s', blob.blob_hash)
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self.next_blob_to_send = blob
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self.read_handle = read_handle
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return None
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raise ValueError("Couldn't open that blob for some reason. blob_hash: {}".format(blob.blob_hash))
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def send_blob_info(self):
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log.info("Send blob info for %s", self.next_blob_to_send.blob_hash)
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assert self.next_blob_to_send is not None, "need to have a next blob to send at this point"
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log.debug('sending blob info')
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self.write(json.dumps({
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'blob_hash': self.next_blob_to_send.blob_hash,
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'blob_size': self.next_blob_to_send.length
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}))
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def send_next_request(self):
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if self.file_sender is not None:
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# send the blob
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log.debug('Sending the blob')
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return self.start_transfer()
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elif self.blob_hashes_to_send:
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# open the next blob to send
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blob_hash = self.blob_hashes_to_send[0]
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log.debug('No current blob, sending the next one: %s', blob_hash)
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self.blob_hashes_to_send = self.blob_hashes_to_send[1:]
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d = self.blob_manager.get_blob(blob_hash, True)
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d.addCallback(self.open_blob_for_reading)
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# send the server the next blob hash + length
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d.addCallback(lambda _: self.send_blob_info())
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return d
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else:
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# close connection
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log.debug('No more blob hashes, closing connection')
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self.transport.loseConnection()
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class LBRYFileReflectorClientFactory(ClientFactory):
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protocol = LBRYFileReflectorClient
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def __init__(self, blob_manager, stream_info_manager, stream_hash):
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self.blob_manager = blob_manager
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self.stream_info_manager = stream_info_manager
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self.stream_hash = stream_hash
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self.p = None
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self.finished_deferred = defer.Deferred()
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def buildProtocol(self, addr):
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p = self.protocol()
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p.factory = self
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self.p = p
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return p
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def startFactory(self):
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log.debug('Starting reflector factory')
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ClientFactory.startFactory(self)
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def startedConnecting(self, connector):
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log.debug('Started connecting')
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def clientConnectionLost(self, connector, reason):
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"""If we get disconnected, reconnect to server."""
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log.debug("connection lost: %s", reason)
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def clientConnectionFailed(self, connector, reason):
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log.debug("connection failed: %s", reason)
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