Source code for graphenecommon.block
# -*- coding: utf-8 -*-
from .blockchainobject import BlockchainObject
from .exceptions import BlockDoesNotExistsException
from .utils import parse_time
from .instance import AbstractBlockchainInstanceProvider
class Block(BlockchainObject, AbstractBlockchainInstanceProvider):
"""Read a single block from the chain
:param int block: block number
:param instance blockchain_instance: instance to use when accesing a RPC
:param bool lazy: Use lazy loading
Instances of this class are dictionaries that come with additional
methods (see below) that allow dealing with a block and it's
corresponding functions.
.. code-block:: python
from block import Block
block = Block(1)
print(block)
.. note:: This class comes with its own caching function to reduce the
load on the API server. Instances of this class can be
refreshed with ``Account.refresh()``.
"""
type_id = "n/a"
def __init__(self, *args, use_cache=False, **kwargs):
# We allow to hand over use_cache be default, but here,
# we want to change the default to *false* so we don't cache every
# block all the time for eternity
kwargs["use_cache"] = use_cache
BlockchainObject.__init__(self, *args, **kwargs)
[docs] def refresh(self):
"""Even though blocks never change, you freshly obtain its contents
from an API with this method
"""
identifier = self.identifier
block = self.blockchain.rpc.get_block(self.identifier)
if not block:
raise BlockDoesNotExistsException
super(Block, self).__init__(
block, blockchain_instance=self.blockchain, use_cache=self._use_cache
)
# block does not contain an id and thus identifier gets overwritten
self.identifier = identifier
[docs] def time(self):
"""Return a datatime instance for the timestamp of this block"""
return parse_time(self["timestamp"])
class BlockHeader(BlockchainObject, AbstractBlockchainInstanceProvider):
type_id = "n/a"
def __init__(self, *args, use_cache=False, **kwargs):
# We allow to hand over use_cache be default, but here,
# we want to change the default to *false* so we don't cache every
# block all the time for eternity
kwargs["use_cache"] = use_cache
BlockchainObject.__init__(self, *args, **kwargs)