4334cdace1
Each blob requests has three parts - A request to see what blobs are available - A request to download and pay for one of those blobs - A request to negotiate data costs Before the refactoring all of the code to accomplish this was mixed into one class. They are now three seperate classes. There is still a lot of room for improvement, but it is at least better than it was.
519 lines
20 KiB
Python
519 lines
20 KiB
Python
from collections import defaultdict
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import logging
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from twisted.internet import defer
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from twisted.python.failure import Failure
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from zope.interface import implements
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from lbrynet.core.Error import PriceDisagreementError, DownloadCanceledError, InsufficientFundsError
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from lbrynet.core.Error import InvalidResponseError, RequestCanceledError, NoResponseError
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from lbrynet.core.Error import ConnectionClosedBeforeResponseError
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from lbrynet.core.client.ClientRequest import ClientRequest, ClientBlobRequest
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from lbrynet.interfaces import IRequestCreator
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log = logging.getLogger(__name__)
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def get_points(num_bytes, rate):
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return 1.0 * num_bytes * rate / 2**20
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def cache(fn):
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"""Caches the function call for each instance"""
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attr = '__{}_value'.format(fn.__name__)
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def helper(self):
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if not hasattr(self, attr):
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value = fn(self)
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setattr(self, attr, value)
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return getattr(self, attr)
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return helper
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class BlobRequester(object):
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implements(IRequestCreator)
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def __init__(self, blob_manager, peer_finder, payment_rate_manager, wallet, download_manager):
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self.blob_manager = blob_manager
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self.peer_finder = peer_finder
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self.payment_rate_manager = payment_rate_manager
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self.wallet = wallet
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self.download_manager = download_manager
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self._peers = defaultdict(int) # {Peer: score}
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self._available_blobs = defaultdict(list) # {Peer: [blob_hash]}
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self._unavailable_blobs = defaultdict(list) # {Peer: [blob_hash]}}
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self._protocol_prices = {} # {ClientProtocol: price}
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self._price_disagreements = [] # [Peer]
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self._incompatible_peers = []
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######## IRequestCreator #########
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def send_next_request(self, peer, protocol):
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"""Makes an availability request, download request and price request"""
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if not self.should_send_next_request(peer):
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return defer.succeed(False)
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return self._send_next_request(peer, protocol)
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def get_new_peers(self):
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d = self._get_hash_for_peer_search()
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d.addCallback(self._find_peers_for_hash)
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return d
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######### internal calls #########
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def should_send_next_request(self, peer):
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return (
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self._blobs_to_download() and
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self._should_send_request_to(peer)
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)
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def _send_next_request(self, peer, protocol):
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log.debug('Sending a blob request for %s and %s', peer, protocol)
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availability = AvailabilityRequest(self, peer, protocol)
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download = DownloadRequest(self, peer, protocol, self.wallet, self.payment_rate_manager)
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price = PriceRequest(self, peer, protocol)
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sent_request = False
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if availability.can_make_request():
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availability.make_request_and_handle_response()
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sent_request = True
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if download.can_make_request():
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try:
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download.make_request_and_handle_response()
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sent_request = True
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except InsufficientFundsError as err:
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return defer.fail(err)
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if sent_request and price.can_make_request():
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# TODO: document why a PriceRequest is only made if an
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# Availability or Download request was made
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price.make_request_and_handle_response()
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return defer.succeed(sent_request)
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def _get_hash_for_peer_search(self):
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r = None
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blobs_to_download = self._blobs_to_download()
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if blobs_to_download:
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blobs_without_sources = self._blobs_without_sources()
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if not blobs_without_sources:
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blob_hash = blobs_to_download[0].blob_hash
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else:
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blob_hash = blobs_without_sources[0].blob_hash
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r = blob_hash
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log.debug("Blob requester peer search response: %s", str(r))
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return defer.succeed(r)
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def _find_peers_for_hash(self, h):
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if h is None:
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return None
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else:
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d = self.peer_finder.find_peers_for_blob(h)
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def choose_best_peers(peers):
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bad_peers = self._get_bad_peers()
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return [p for p in peers if not p in bad_peers]
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d.addCallback(choose_best_peers)
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def lookup_failed(err):
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log.error("An error occurred looking up peers for a hash: %s", err.getTraceback())
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return []
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d.addErrback(lookup_failed)
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return d
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def _should_send_request_to(self, peer):
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if self._peers[peer] < -5.0:
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return False
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if peer in self._price_disagreements:
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return False
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if peer in self._incompatible_peers:
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return False
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return True
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def _get_bad_peers(self):
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return [p for p in self._peers.iterkeys() if not self._should_send_request_to(p)]
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def _hash_available(self, blob_hash):
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for peer in self._available_blobs:
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if blob_hash in self._available_blobs[peer]:
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return True
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return False
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def _hash_available_on(self, blob_hash, peer):
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if blob_hash in self._available_blobs[peer]:
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return True
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return False
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def _blobs_to_download(self):
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needed_blobs = self.download_manager.needed_blobs()
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return sorted(needed_blobs, key=lambda b: b.is_downloading())
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def _blobs_without_sources(self):
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return [
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b for b in self.download_manager.needed_blobs()
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if not self._hash_available(b.blob_hash)
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]
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def _price_settled(self, protocol):
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if protocol in self._protocol_prices:
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return True
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return False
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def _update_local_score(self, peer, amount):
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self._peers[peer] += amount
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class RequestHelper(object):
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def __init__(self, requestor, peer, protocol):
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self.requestor = requestor
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self.peer = peer
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self.protocol = protocol
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@property
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def protocol_prices(self):
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return self.requestor._protocol_prices
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@property
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def available_blobs(self):
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return self.requestor._available_blobs[self.peer]
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@property
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def unavailable_blobs(self):
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return self.requestor._unavailable_blobs[self.peer]
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def update_local_score(self, score):
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self.requestor._update_local_score(self.peer, score)
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def _request_failed(self, reason, request_type):
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if reason.check(RequestCanceledError):
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return
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if reason.check(NoResponseError):
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self.requestor._incompatible_peers.append(self.peer)
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log.warning("A request of type '%s' failed. Reason: %s, Error type: %s",
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request_type, reason.getErrorMessage(), reason.type)
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self.update_local_score(-10.0)
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if isinstance(reason, InvalidResponseError) or isinstance(reason, NoResponseError):
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self.peer.update_score(-10.0)
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else:
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self.peer.update_score(-2.0)
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if reason.check(ConnectionClosedBeforeResponseError):
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return
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return reason
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def get_and_save_rate_for_protocol(self):
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rate = self.protocol_prices.get(self.protocol)
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if rate is None:
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rate = self.requestor.payment_rate_manager.get_rate_blob_data(self.peer)
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self.protocol_prices[self.protocol] = rate
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return rate
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def _handle_incoming_blob(response_dict, peer, request):
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if not request.response_identifier in response_dict:
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return InvalidResponseError("response identifier not in response")
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if not type(response_dict[request.response_identifier]) == dict:
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return InvalidResponseError("response not a dict. got %s" %
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type(response_dict[request.response_identifier]))
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response = response_dict[request.response_identifier]
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if 'error' in response:
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# This means we're not getting our blob for some reason
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if response['error'] == "RATE_UNSET":
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# Stop the download with an error that won't penalize the peer
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request.cancel(PriceDisagreementError())
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else:
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# The peer has done something bad so we should get out of here
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return InvalidResponseError("Got an unknown error from the peer: %s" %
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(response['error'],))
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else:
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if not 'blob_hash' in response:
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return InvalidResponseError("Missing the required field 'blob_hash'")
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if not response['blob_hash'] == request.request_dict['requested_blob']:
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return InvalidResponseError(
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"Incoming blob does not match expected. Incoming: %s. Expected: %s" %
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(response['blob_hash'], request.request_dict['requested_blob'])
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)
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if not 'length' in response:
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return InvalidResponseError("Missing the required field 'length'")
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if not request.blob.set_length(response['length']):
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return InvalidResponseError("Could not set the length of the blob")
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return True
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def _handle_download_error(err, peer, blob_to_download):
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if not err.check(DownloadCanceledError, PriceDisagreementError, RequestCanceledError):
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log.warning("An error occurred while downloading %s from %s. Error: %s",
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blob_to_download.blob_hash, str(peer), err.getTraceback())
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if err.check(PriceDisagreementError):
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# Don't kill the whole connection just because a price couldn't be agreed upon.
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# Other information might be desired by other request creators at a better rate.
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return True
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return err
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class AvailabilityRequest(RequestHelper):
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"""Ask a peer what blobs it has available.
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Results are saved in `_available_blobs` and `_unavailable_blobs`
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on the parent BlobRequester.
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"""
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def can_make_request(self):
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return self.get_top_needed_blobs()
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def make_request_and_handle_response(self):
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request = self._get_request()
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self._handle_request(request)
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def _get_request(self):
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to_request = self.get_top_needed_blobs()
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if not to_request:
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raise Exception('Unable to make a request without available blobs')
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return self._make_request(to_request)
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@cache
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def get_top_needed_blobs(self, limit=20):
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all_needed = [
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b.blob_hash for b in self.requestor._blobs_to_download()
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if not self.is_available(b)
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]
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# sort them so that the peer will be asked first for blobs it
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# hasn't said it doesn't have
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sorted_needed = sorted(
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all_needed,
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key=lambda b: b in self.unavailable_blobs
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)
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return sorted_needed[:limit]
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def is_available(self, blob):
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return blob.blob_hash in self.available_blobs
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def _make_request(self, to_request):
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log.debug('Requesting blobs: %s', to_request)
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r_dict = {'requested_blobs': to_request}
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response_identifier = 'available_blobs'
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request = ClientRequest(r_dict, response_identifier)
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return request
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def _handle_request(self, a_r):
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log.debug('making an availability request')
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d1 = self.protocol.add_request(a_r)
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d1.addCallback(self._handle_availability, a_r)
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d1.addErrback(self._request_failed, "availability request")
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def _handle_availability(self, response_dict, request):
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assert request.response_identifier == 'available_blobs'
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if 'available_blobs' not in response_dict:
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raise InvalidResponseError("response identifier not in response")
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log.debug("Received a response to the availability request")
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# save available blobs
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blob_hashes = response_dict['available_blobs']
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for blob_hash in blob_hashes:
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if blob_hash in request.request_dict['requested_blobs']:
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self.process_available_blob_hash(blob_hash, request)
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# everything left in the request is missing
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for blob_hash in request.request_dict['requested_blobs']:
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self.unavailable_blobs.append(blob_hash)
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return True
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def process_available_blob_hash(self, blob_hash, request):
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log.debug("The server has indicated it has the following blob available: %s", blob_hash)
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self.available_blobs.append(blob_hash)
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self.remove_from_unavailable_blobs(blob_hash)
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request.request_dict['requested_blobs'].remove(blob_hash)
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def remove_from_unavailable_blobs(self, blob_hash):
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if blob_hash in self.unavailable_blobs:
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self.unavailable_blobs.remove(blob_hash)
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class DownloadRequest(RequestHelper):
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"""Choose a blob and download it from a peer and also pay the peer for the data."""
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def __init__(self, requestor, peer, protocol, wallet, payment_rate_manager):
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RequestHelper.__init__(self, requestor, peer, protocol)
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self.wallet = wallet
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self.payment_rate_manager = payment_rate_manager
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def can_make_request(self):
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return self.get_blob_details()
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def make_request_and_handle_response(self):
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request = self._get_request()
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self._handle_download_request(request)
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def _get_request(self):
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blob_details = self.get_blob_details()
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if not blob_details:
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raise Exception('No blobs available to download')
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return self._make_request(blob_details)
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@cache
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def get_blob_details(self):
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"""Open a blob for writing and return the details.
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If no blob can be opened, returns None.
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"""
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to_download = self.get_available_blobs()
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return self.find_blob(to_download)
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def get_available_blobs(self):
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available_blobs = [
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b for b in self.requestor._blobs_to_download()
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if self.requestor._hash_available_on(b.blob_hash, self.peer)
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]
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log.debug('available blobs: %s', available_blobs)
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return available_blobs
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def find_blob(self, to_download):
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"""Return the first blob in `to_download` that is successfully opened for write."""
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for blob in to_download:
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if blob.is_validated():
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log.debug('Skipping blob %s as its already validated', blob)
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continue
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d, write_func, cancel_func = blob.open_for_writing(self.peer)
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if d is not None:
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return BlobDownloadDetails(blob, d, write_func, cancel_func, self.peer)
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log.debug('Skipping blob %s as there was an issue opening it for writing', blob)
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return None
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def _make_request(self, blob_details):
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blob = blob_details.blob
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request = ClientBlobRequest(
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{'requested_blob': blob.blob_hash},
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'incoming_blob',
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blob_details.counting_write_func,
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blob_details.deferred,
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blob_details.cancel_func,
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blob
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)
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log.info("Requesting blob %s from %s", blob.blob_hash, self.peer)
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return request
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def _handle_download_request(self, client_blob_request):
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reserved_points = self.reserve_funds_or_cancel(client_blob_request)
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self.add_callbacks_to_download_request(client_blob_request, reserved_points)
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self.create_add_blob_request(client_blob_request)
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def reserve_funds_or_cancel(self, client_blob_request):
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reserved_points = self._reserve_points(client_blob_request.max_pay_units)
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if reserved_points is not None:
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return reserved_points
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client_blob_request.cancel(InsufficientFundsError())
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client_blob_request.finished_deferred.addErrback(lambda _: True)
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raise InsufficientFundsError()
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def add_callbacks_to_download_request(self, client_blob_request, reserved_points):
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# Note: The following three callbacks will be called when the blob has been
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# fully downloaded or canceled
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client_blob_request.finished_deferred.addCallbacks(
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self._download_succeeded,
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self._download_failed,
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callbackArgs=(client_blob_request.blob,),
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)
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client_blob_request.finished_deferred.addBoth(
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self._pay_or_cancel_payment, reserved_points, client_blob_request.blob)
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client_blob_request.finished_deferred.addErrback(
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_handle_download_error, self.peer, client_blob_request.blob)
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def _pay_or_cancel_payment(self, arg, reserved_points, blob):
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if self._can_pay_peer(blob, arg):
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self._pay_peer(blob.length, reserved_points)
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else:
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self._cancel_points(reserved_points)
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return arg
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def _can_pay_peer(self, blob, arg):
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return (
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blob.length != 0 and
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(not isinstance(arg, Failure) or arg.check(DownloadCanceledError))
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)
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def _pay_peer(self, num_bytes, reserved_points):
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assert num_bytes != 0
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rate = self.get_and_save_rate_for_protocol()
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point_amount = get_points(num_bytes, rate)
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self.wallet.send_points(reserved_points, point_amount)
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self.payment_rate_manager.record_points_paid(point_amount)
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def _cancel_points(self, reserved_points):
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self.wallet.cancel_point_reservation(reserved_points)
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def create_add_blob_request(self, client_blob_request):
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d = self.protocol.add_blob_request(client_blob_request)
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# Note: The following two callbacks will be called as soon as the peer sends its
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# response, which will be before the blob has finished downloading, but may be
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# after the blob has been canceled. For example,
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# 1) client sends request to Peer A
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# 2) the blob is finished downloading from peer B, and therefore this one is canceled
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# 3) client receives response from Peer A
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# Therefore, these callbacks shouldn't rely on there being a blob about to be
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# downloaded.
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d.addCallback(_handle_incoming_blob, self.peer, client_blob_request)
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d.addErrback(self._request_failed, "download request")
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def _reserve_points(self, num_bytes):
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# jobevers: there was an assertion here, but I don't think it
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# was a valid assertion to make. It is possible for a rate to
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# not yet been set for this protocol or for it to have been
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# removed so instead I switched it to check if a rate has been set
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# and calculate it if it has not
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rate = self.get_and_save_rate_for_protocol()
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points_to_reserve = get_points(num_bytes, rate)
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return self.wallet.reserve_points(self.peer, points_to_reserve)
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def _download_succeeded(self, arg, blob):
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log.info("Blob %s has been successfully downloaded from %s", blob, self.peer)
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self.update_local_score(5.0)
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self.peer.update_stats('blobs_downloaded', 1)
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self.peer.update_score(5.0)
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self.requestor.blob_manager.blob_completed(blob)
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return arg
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def _download_failed(self, reason):
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if not reason.check(DownloadCanceledError, PriceDisagreementError):
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self.update_local_score(-10.0)
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return reason
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class BlobDownloadDetails(object):
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"""Contains the information needed to make a ClientBlobRequest from an open blob"""
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def __init__(self, blob, deferred, write_func, cancel_func, peer):
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self.blob = blob
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self.deferred = deferred
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self.write_func = write_func
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self.cancel_func = cancel_func
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self.peer = peer
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def counting_write_func(self, data):
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self.peer.update_stats('blob_bytes_downloaded', len(data))
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return self.write_func(data)
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class PriceRequest(RequestHelper):
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"""Ask a peer if a certain price is acceptable"""
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def can_make_request(self):
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return self.get_and_save_rate_for_protocol() is not None
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def make_request_and_handle_response(self):
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request = self._get_price_request()
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self._handle_price_request(request)
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def _get_price_request(self):
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rate = self.get_and_save_rate_for_protocol()
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|
if rate is None:
|
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raise Exception('Cannot make a price request without a payment rate')
|
|
request_dict = {'blob_data_payment_rate': rate}
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return ClientRequest(request_dict, 'blob_data_payment_rate')
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|
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def _handle_price_request(self, price_request):
|
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d = self.protocol.add_request(price_request)
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d.addCallback(self._handle_price_response, price_request)
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d.addErrback(self._request_failed, "price request")
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|
|
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def _handle_price_response(self, response_dict, request):
|
|
assert request.response_identifier == 'blob_data_payment_rate'
|
|
if 'blob_data_payment_rate' not in response_dict:
|
|
return InvalidResponseError("response identifier not in response")
|
|
assert self.protocol in self.protocol_prices
|
|
response = response_dict['blob_data_payment_rate']
|
|
if response == "RATE_ACCEPTED":
|
|
return True
|
|
else:
|
|
del self.protocol_prices[self.protocol]
|
|
self.requestor._price_disagreements.append(self.peer)
|
|
return True
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