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get_transaction to ignore invalid blocks

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ryan 2016-05-05 10:31:40 +02:00
parent b69a897b26
commit 3121c9498a
1 changed files with 34 additions and 10 deletions
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44
bigchaindb/core.py
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@ -130,7 +130,6 @@ class Bigchain(object):
response = r.table('backlog').insert(signed_transaction, durability=durability).run(self.conn)
return response
# TODO: the same `txid` can be in two different blocks
def get_transaction(self, txid):
"""Retrieve a transaction with `txid` from bigchain.
@ -145,16 +144,41 @@ class Bigchain(object):
If no transaction with that `txid` was found it returns `None`
"""
response = r.table('bigchain').concat_map(lambda doc: doc['block']['transactions'])\
.filter(lambda transaction: transaction['id'] == txid).run(self.conn)
# First, get information on all blocks which contain this transaction
response = r.table('bigchain').get_all(txid, index='transaction_id')\
.pluck('votes', 'id', {'block': ['voters']}).run(self.conn)
blocks = list(response)
if blocks:
# Determine the election status of each block
validity = {block['id']: self.block_election_status(block) for block in blocks}
# Disregard invalid blocks, and return if there are no valid or undecided blocks
validity = {_id: status for _id, status in validity.items() if status != 'invalid'}
if not validity:
return None
# If there are multiple valid blocks with this transaction, something has gone wrong
if list(validity.values()).count('valid') > 1:
raise Exception('Transaction {tx} is present in multiple valid blocks: {block_ids}'
.format(tx=txid,
block_ids=str([block for block in validity if validity[block] == 'valid'])))
# If the transaction is in a valid or any undecided block, return it. Does not check
# if transactions in undecided blocks are consistent, but selects the valid block before
# undecided ones
for _id in validity:
target_block_id = _id
if validity[_id] == 'valid':
break
# Query the transaction in the target block and return
response = r.table('bigchain').filter(lambda block: block['id'] == target_block_id).nth(0)\
.get_field('block').get_field('transactions').filter(lambda tx: tx['id'] == txid).run(self.conn)
return response[0]
# transaction ids should be unique
transactions = list(response)
if transactions:
if len(transactions) != 1:
raise Exception('Transaction ids should be unique. There is a problem with the chain')
else:
return transactions[0]
else:
return None