Source code for

import os.path

from pycoin.coins.bitcoin.Tx import Tx
from pycoin.encoding.hexbytes import b2h_rev

[docs]class TxDb(object): """ This object can be used in many places that expect a dict. """ def __init__(self, lookup_methods=[], read_only_paths=[], writable_cache_path=None): self.lookup_methods = lookup_methods self.read_only_paths = read_only_paths if writable_cache_path: self.read_only_paths.append(writable_cache_path) self.writable_cache_path = writable_cache_path if self.writable_cache_path and not os.path.exists(self.writable_cache_path): os.makedirs(self.writable_cache_path)
[docs] def paths_for_hash(self, hash): name = b2h_rev(hash) for base_dir in self.read_only_paths: p = os.path.join(base_dir, "%s_tx.bin" % name) if os.path.exists(p): yield p
[docs] def put(self, tx): name = b2h_rev(tx.hash()) if self.writable_cache_path: try: path = os.path.join(self.writable_cache_path, "%s_tx.bin" % name) with open(path, "wb") as f: except IOError: pass
[docs] def get(self, key): for path in self.paths_for_hash(key): try: tx = Tx.parse(open(path, "rb")) if tx and tx.hash() == key: return tx except IOError: pass for method in self.lookup_methods: try: tx = method(key) if tx and tx.hash() == key: self.put(tx) return tx except Exception: pass return None
def __getitem__(self, key): raise NotImplemented def __setitem__(self, key, val): if val.hash() != key: raise ValueError("bad key %s for %s" % (b2h_rev(key), val)) self.put(val)