ethereum.homestead.blocksethereum.dao_fork.blocks

A Block is a single link in the chain that is Ethereum. Each Block contains a Header and zero or more transactions. Each Header contains associated metadata like the block number, parent block hash, and how much gas was consumed by its transactions.

Together, these blocks form a cryptographically secure journal recording the history of all state transitions that have happened since the genesis of the chain.

Header

Header portion of a block on the chain, containing metadata and cryptographic commitments to the block's contents.

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@slotted_freezable
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@dataclass
class Header:

parent_hash

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    parent_hash: Hash32

ommers_hash

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    ommers_hash: Hash32

coinbase

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    coinbase: Address

state_root

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    state_root: Root

transactions_root

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    transactions_root: Root

receipt_root

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    receipt_root: Root

bloom

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    bloom: Bloom

difficulty

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    difficulty: Uint

number

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    number: Uint

gas_limit

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    gas_limit: Uint

gas_used

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    gas_used: Uint

timestamp

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    timestamp: U256

extra_data

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    extra_data: Bytes

mix_digest

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    mix_digest: Bytes32

nonce

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    nonce: Bytes8

Block

A complete block on Ethereum, which is composed of a block header, a list of transactions, and a list of ommers (also known as uncle blocks).

The block header includes PoW-specific fields such as difficulty, nonce, and ommersHash, which relate to the mining process. The coinbase field denotes the address receiving mining and transaction fees.

The header also contains commitments to the current state (stateRoot), the transactions (transactionsRoot), and the transaction receipts (receiptsRoot). It also includes a bloom filter which summarizes log data from the transactions.

Ommers are used to provide rewards for near-valid mined blocks that didn't become part of the canonical chain.

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@slotted_freezable
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@dataclass
class Block:

header

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    header: Header

transactions

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    transactions: Tuple[Transaction, ...]

ommers

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    ommers: Tuple[Header, ...]

Log

Data record produced during the execution of a transaction. Logs are used by smart contracts to emit events (using the EVM log opcodes (LOG0, LOG1, LOG2, LOG3 and LOG4), which can be efficiently searched using the bloom filter in the block header.

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@slotted_freezable
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@dataclass
class Log:

address

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    address: Address

topics

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    topics: Tuple[Hash32, ...]

data

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    data: Bytes

Receipt

Result of a transaction execution. Receipts are included in the receipts trie.

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@slotted_freezable
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@dataclass
class Receipt:

post_state

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    post_state: Root

cumulative_gas_used

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    cumulative_gas_used: Uint

bloom

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    bloom: Bloom

logs

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    logs: Tuple[Log, ...]