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)

    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

    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)

    def refresh(self):
        """ Even though blocks never change, you freshly obtain its contents
            from an API with this method
        """
        block = self.blockchain.rpc.get_block_header(self.identifier)
        if not block:
            raise BlockDoesNotExistsException
        super(BlockHeader, self).__init__(
            block, blockchain_instance=self.blockchain, use_cache=self._use_cache
        )

    def time(self):
        """ Return a datatime instance for the timestamp of this block
        """
        return parse_time(self["timestamp"])