class Block:
"""This class encapsulates the logic to create blocks.
Note:
Methods of this class will be executed in different processes.
"""
def __init__(self):
"""Initialize the Block creator"""
self.bigchain = Bigchain()
self.txs = []
def filter_tx(self, tx):
"""Filter a transaction.
Args:
tx (dict): the transaction to process.
Returns:
The transaction if assigned to the current node,
``None`` otherwise.
"""
if tx['assignee'] == self.bigchain.me:
tx.pop('assignee')
tx.pop('assignment_timestamp')
return tx
def validate_tx(self, tx):
"""Validate a transaction.
Also checks if the transaction already exists in the blockchain. If it
does, or it's invalid, it's deleted from the backlog immediately.
Args:
tx (dict): the transaction to validate.
Returns:
The transaction if valid, ``None`` otherwise.
"""
if self.bigchain.transaction_exists(tx['id']):
# if the transaction already exists, we must check whether
# it's in a valid or undecided block
tx, status = self.bigchain.get_transaction(tx['id'],
include_status=True)
if status == self.bigchain.TX_VALID \
or status == self.bigchain.TX_UNDECIDED:
# if the tx is already in a valid or undecided block,
# then it no longer should be in the backlog, or added
# to a new block. We can delete and drop it.
r.table('backlog').get(tx['id']) \
.delete(durability='hard') \
.run(self.bigchain.conn)
return None
tx_validated = self.bigchain.is_valid_transaction(tx)
if tx_validated:
return tx
else:
# if the transaction is not valid, remove it from the
# backlog
r.table('backlog').get(tx['id']) \
.delete(durability='hard') \
.run(self.bigchain.conn)
return None
def create(self, tx, timeout=False):
"""Create a block.
This method accumulates transactions to put in a block and outputs
a block when one of the following conditions is true:
- the size limit of the block has been reached, or
- a timeout happened.
Args:
tx (dict): the transaction to validate, might be None if
a timeout happens.
timeout (bool): ``True`` if a timeout happened
(Default: ``False``).
Returns:
The block, if a block is ready, or ``None``.
"""
if tx:
self.txs.append(tx)
if len(self.txs) == 1000 or (timeout and self.txs):
block = self.bigchain.create_block(self.txs)
self.txs = []
return block
def write(self, block):
"""Write the block to the Database.
Args:
block (dict): the block of transactions to write to the database.
Returns:
The block.
"""
logger.info('Write new block %s with %s transactions',
block['id'],
len(block['block']['transactions']))
self.bigchain.write_block(block)
return block
def delete_tx(self, block):
"""Delete transactions.
Args:
block (dict): the block containg the transactions to delete.
Returns:
The block.
"""
r.table('backlog')\
.get_all(*[tx['id'] for tx in block['block']['transactions']])\
.delete(durability='hard')\
.run(self.bigchain.conn)
return block
from bigchaindb import Bigchain
import writeout
b = Bigchain()
for x in range(1,8):
tx_signed = writeout.importData("user"+str(x)+"vote")
tx_retrieved = b.get_transaction(tx_signed['id'])
print(b.transaction_exists(tx_retrieved['id']))
class Block:
"""This class encapsulates the logic to create blocks.
Note:
Methods of this class will be executed in different processes.
"""
def __init__(self):
"""Initialize the Block creator"""
self.bigchain = Bigchain()
self.txs = []
def filter_tx(self, tx):
"""Filter a transaction.
Args:
tx (dict): the transaction to process.
Returns:
The transaction if assigned to the current node,
``None`` otherwise.
"""
if tx['assignee'] == self.bigchain.me:
tx.pop('assignee')
tx.pop('assignment_timestamp')
return tx
def validate_tx(self, tx):
"""Validate a transaction.
Also checks if the transaction already exists in the blockchain. If it
does, or it's invalid, it's deleted from the backlog immediately.
Args:
tx (dict): the transaction to validate.
Returns:
The transaction if valid, ``None`` otherwise.
"""
if self.bigchain.transaction_exists(tx['id']):
# if the transaction already exists, we must check whether
# it's in a valid or undecided block
tx, status = self.bigchain.get_transaction(tx['id'],
include_status=True)
if status == self.bigchain.TX_VALID \
or status == self.bigchain.TX_UNDECIDED:
# if the tx is already in a valid or undecided block,
# then it no longer should be in the backlog, or added
# to a new block. We can delete and drop it.
r.table('backlog').get(tx['id']) \
.delete(durability='hard') \
.run(self.bigchain.conn)
return None
tx_validated = self.bigchain.is_valid_transaction(tx)
if tx_validated:
return tx
else:
# if the transaction is not valid, remove it from the
# backlog
r.table('backlog').get(tx['id']) \
.delete(durability='hard') \
.run(self.bigchain.conn)
return None
def create(self, tx, timeout=False):
"""Create a block.
This method accumulates transactions to put in a block and outputs
a block when one of the following conditions is true:
- the size limit of the block has been reached, or
- a timeout happened.
Args:
tx (dict): the transaction to validate, might be None if
a timeout happens.
timeout (bool): ``True`` if a timeout happened
(Default: ``False``).
Returns:
The block, if a block is ready, or ``None``.
"""
if tx:
self.txs.append(tx)
if len(self.txs) == 1000 or (timeout and self.txs):
block = self.bigchain.create_block(self.txs)
self.txs = []
return block
def write(self, block):
"""Write the block to the Database.
Args:
block (dict): the block of transactions to write to the database.
Returns:
The block.
"""
logger.info('Write new block %s with %s transactions',
block['id'],
len(block['block']['transactions']))
self.bigchain.write_block(block)
return block
def delete_tx(self, block):
"""Delete transactions.
Args:
block (dict): the block containg the transactions to delete.
Returns:
The block.
"""
r.table('backlog')\
.get_all(*[tx['id'] for tx in block['block']['transactions']])\
.delete(durability='hard')\
.run(self.bigchain.conn)
return block
from bigchaindb import Bigchain
import writeout
b = Bigchain()
for x in range(1, 8):
tx_signed = writeout.importData("user" + str(x) + "vote")
tx_retrieved = b.get_transaction(tx_signed['id'])
print(b.transaction_exists(tx_retrieved['id']))
