def test_previous_tx_non_existent():
"""
tests transaction update when a previous transaction does
not exist
"""
# make a synthetic previous transaction
num_prev_tx_outputs = secrets.randbelow(5) + 1
previous_tx = make_synthetic_previous_transaction(num_prev_tx_outputs)
#reflect this previous transaction in HeliumDB
ctr = 0
for vout in previous_tx["vout"]:
#pdb.set_trace()
fragment = {}
fragment["pkhash"] = vout["ScriptPubKey"][2]
fragment["spent"] = False
fragment["value"] = max(secrets.randbelow(1000000), 10)
fragment["tx_chain"] = ""
txid = previous_tx["transactionid"] + "_" + str(ctr)
chain.put_transaction( txid, fragment)
ctr += 1
# make a transaction consuming some previous transaction outputs
trx = make_synthetic_transaction(previous_tx)
trx["vin"][0]["txid"] = "bad previous tx id"
#update the Helium Chainstate
assert chain.transaction_update(trx) == False
def make_synthetic_transaction(block):
"""
makes a synthetic transaction with randomized values
"""
transaction = {}
transaction['version'] = hconfig.conf["VERSION_NO"]
transaction['transactionid'] = rcrypt.make_uuid()
transaction['locktime'] = 0
transaction['vin'] = []
transaction['vout'] = []
# make public-private key pair for the transaction
pair = rcrypt.make_ecc_keys()
tx_keys[transaction["transactionid"]] = pair
# make vin list
# genesis block does not have inputs
if block["height"] > 0:
num_inputs = secrets.randbelow(3) + 1
for ctr in range(num_inputs):
trx = make_synthetic_vin(transaction, ctr)
if trx == False: break
transaction["vin"].append(trx)
# make vout list
num_outputs = secrets.randbelow(5) + 1
ctr = 0
for ctr in range(num_outputs):
vout = make_synthetic_vout(block, transaction, ctr, pair[1])
if vout != False: transaction["vout"].append(vout)
block["tx"].append(transaction)
hchaindb.transaction_update(transaction)
return transaction
def add_block(block: "dictionary") -> "bool":
"""
add_block: adds a block to the blockchain. Receives a block.
The block attributes are checked for validity and each transaction in the block is
tested for validity. If there are no errors, the block is written to a file as a
sequence of raw bytes. Then the block is added to the blockchain.
The chainstate database and the blk_index databases are updated.
returns True if the block is added to the blockchain and False otherwise
"""
try:
# validate the received block parameters
if validate_block(block) == False:
raise(ValueError("block validation error"))
# validate the transactions in the block
# update the chainstate database
for trx in block['tx']:
# first transaction in the block is a coinbase transaction
if block["height"] == 0 or block['tx'][0] == trx: zero_inputs = True
else: zero_inputs = False
if tx.validate_transaction(trx, zero_inputs) == False:
raise(ValueError("transaction validation error"))
if hchaindb.transaction_update(trx) == False:
raise(ValueError("chainstate update transaction error"))
# serialize the block to a file
if (serialize_block(block) == False):
raise(ValueError("serialize block error"))
# add the block to the blockchain in memory
blockchain.append(block)
# update the blk_index
for transaction in block['tx']:
blockindex.put_index(transaction["transactionid"], block["height"])
except Exception as err:
print(str(err))
logging.debug('add_block: exception: ' + str(err))
return False
return True
def build_chainstate():
'''
build the Chainstate database from the blockchain files
'''
blockno = 0
tx_count = 0
try:
while True:
# test whether the block file exists
block_file = "block" + "_" + str(blockno) + ".dat"
if os.path.isfile(block_file) == False: break
# load the block file into a dictionary object
f = open(block_file, 'rb')
block = pickle.load(f)
# process the vout and vin arrays for each block transaction
for trx in block["tx"]:
ret = hchaindb.transaction_update(trx)
tx_count += 1
if ret == False:
raise (
ValueError("failed to rebuild chainstate. block no: " +
str(blockno)))
blockno += 1
except Exception as err:
print(str(err))
return False
print("transactions processed: " + str(tx_count))
print("blocks processed: " + str(blockno))
return True