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trezor-firmware/trezorlib/tx_api.py
2018-08-13 18:22:19 +02:00

145 lines
5.1 KiB
Python

# This file is part of the Trezor project.
#
# Copyright (C) 2012-2018 SatoshiLabs and contributors
#
# This library is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License version 3
# as published by the Free Software Foundation.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the License along with this library.
# If not, see <https://www.gnu.org/licenses/lgpl-3.0.html>.
import binascii
import json
from decimal import Decimal
import requests
from . import messages as proto
cache_dir = None
class TxApi(object):
def __init__(self, network, url=None):
self.network = network
self.url = url
def get_url(self, resource, resourceid):
url = "%s%s/%s" % (self.url, resource, resourceid)
return url
def current_height(self):
r = requests.get(self.url + "/status?q=getBlockCount")
j = r.json(parse_float=str)
block_height = j["info"]["blocks"]
return block_height
def get_block_hash(self, block_number):
r = requests.get(self.url + "/block-index/" + str(block_number))
j = r.json(parse_float=str)
block_hash = binascii.unhexlify(j["blockHash"])
return block_hash
def fetch_json(self, resource, resourceid):
global cache_dir
if cache_dir:
cache_file = "%s/%s_%s_%s.json" % (
cache_dir,
self.network,
resource,
resourceid,
)
try: # looking into cache first
j = json.load(open(cache_file), parse_float=str)
return j
except Exception:
pass
if not self.url:
raise RuntimeError("No URL specified and tx not in cache")
try:
url = self.get_url(resource, resourceid)
r = requests.get(url, headers={"User-agent": "Mozilla/5.0"})
j = r.json(parse_float=str)
except Exception:
raise RuntimeError("URL error: %s" % url)
if cache_dir and cache_file:
try: # saving into cache
json.dump(j, open(cache_file, "w"))
except Exception:
pass
return j
def get_tx(self, txhash):
raise NotImplementedError
class TxApiInsight(TxApi):
def __init__(self, network, url=None, zcash=None, bip115=False):
super().__init__(network, url)
self.zcash = zcash
self.bip115 = bip115
if url:
prefix, suffix = url.rsplit("/", maxsplit=1)
self.pushtx_url = prefix + "/tx/send"
def get_tx(self, txhash):
data = self.fetch_json("tx", txhash)
t = proto.TransactionType()
t.version = data["version"]
t.lock_time = data["locktime"]
for vin in data["vin"]:
i = t._add_inputs()
if "coinbase" in vin.keys():
i.prev_hash = b"\0" * 32
i.prev_index = 0xffffffff # signed int -1
i.script_sig = binascii.unhexlify(vin["coinbase"])
i.sequence = vin["sequence"]
else:
i.prev_hash = binascii.unhexlify(vin["txid"])
i.prev_index = vin["vout"]
i.script_sig = binascii.unhexlify(vin["scriptSig"]["hex"])
i.sequence = vin["sequence"]
for vout in data["vout"]:
o = t._add_bin_outputs()
o.amount = int(Decimal(vout["value"]) * 100000000)
o.script_pubkey = binascii.unhexlify(vout["scriptPubKey"]["hex"])
if self.bip115 and o.script_pubkey[-1] == 0xb4:
# Verify if coin implements replay protection bip115 and script includes checkblockatheight opcode. 0xb4 - is op_code (OP_CHECKBLOCKATHEIGHT)
# <OP_32> <32-byte block hash> <OP_3> <3-byte block height> <OP_CHECKBLOCKATHEIGHT>
tail = o.script_pubkey[-38:]
o.block_hash = tail[1:33] # <32-byte block hash>
o.block_height = int.from_bytes(
tail[34:37], byteorder="little"
) # <3-byte block height>
if self.zcash:
t.overwintered = data.get("fOverwintered", False)
t.expiry = data.get("nExpiryHeight", False)
if t.version >= 2:
joinsplit_cnt = len(data["vjoinsplit"])
if joinsplit_cnt == 0:
t.extra_data = b"\x00"
else:
if joinsplit_cnt >= 253:
# we assume cnt < 253, so we can treat varIntLen(cnt) as 1
raise ValueError("Too many joinsplits")
extra_data_len = 1 + joinsplit_cnt * 1802 + 32 + 64
raw = self.fetch_json("rawtx", txhash)
raw = binascii.unhexlify(raw["rawtx"])
t.extra_data = raw[-extra_data_len:]
return t