ChildToParentMessageNitro

arbitrum_py.message.child_to_parent_message_nitro.get_child_block_range_cache_key(child_chain_id, l1_block_number)

Create a unique cache key for the child block range lookup.

Parameters:

• child_chain_id (int) – The chain ID of the child chain

• l1_block_number (int) – The L1 block number to create a cache key for

Return type:

str

Returns:

A unique string key combining chain ID and block number

arbitrum_py.message.child_to_parent_message_nitro.set_child_block_range_cache(key, value)

Cache the child block range under the given key.

Parameters:

• key (str) – The cache key to store the value under

• value (List[Optional[int]]) – The block range values to cache

Return type:

None

arbitrum_py.message.child_to_parent_message_nitro.get_block_ranges_for_l1_block_with_cache(parent_provider, child_provider, for_l1_block)

Get block ranges for an L1 block using a shared cache to avoid repeated calls.

Parameters:

• parent_provider (Web3) – Web3 provider instance for the parent chain

• child_provider (Web3) – Web3 provider instance for the child chain

• for_l1_block (int) – The L1 block number to get ranges for

Return type:

List[Optional[int]]

Returns:

List of block ranges, where each element can be None

class arbitrum_py.message.child_to_parent_message_nitro.ChildToParentMessageNitro(event)

Bases: object

Base functionality for ‘nitro’ child->parent messages.

This class provides the core functionality for handling messages sent from a child chain to its parent chain in the Arbitrum Nitro protocol.

__init__(event)

Initialize a new ChildToParentMessageNitro instance.

Parameters:

event (dict) – The ChildToParentTx event dictionary from the child chain

classmethod from_event(parent_signer_or_provider, event, parent_provider=None)

Create a message reader or writer based on the provided signer/provider.

Parameters:

• parent_signer_or_provider (Web3) – Signer or provider for the parent chain

• event (dict) – The event data containing message details

• parent_provider (Optional[Web3]) – Optional override provider for the parent chain

Return type:

Union[ChildToParentMessageReaderNitro, ChildToParentMessageWriterNitro]

Returns:

Either a reader or writer instance based on input type

static get_child_to_parent_events(child_provider, filter_dict, position=None, destination=None, hash=None)

Fetch Child->Parent events from the child chain.

Parameters:

• child_provider (Web3) – Web3 provider for the child chain

• filter_dict (dict) – Dictionary containing filter parameters (fromBlock, toBlock)

• position (Optional[int]) – Optional position to filter events by

• destination (Optional[str]) – Optional destination address to filter events by

• hash (Optional[str]) – Optional hash to filter events by

Return type:

List[dict]

Returns:

List of matching event dictionaries

class arbitrum_py.message.child_to_parent_message_nitro.ChildToParentMessageReaderNitro(parent_provider, event)

Bases: ChildToParentMessageNitro

Read-only logic for child->parent messages in Nitro. Replaces L2ToL1MessageReaderNitro.

__init__(parent_provider, event)

Initialize a new ChildToParentMessageNitro instance.

Parameters:

event (CaseDict) – The ChildToParentTx event dictionary from the child chain

get_outbox_proof(child_provider)

Equivalent to getOutboxProof in the TS code. Constructs a proof to execute the message.

Parameters:

child_provider (Web3) – Web3 provider for the child chain

Return type:

List[bytes]

Returns:

The outbox proof

has_executed(child_provider)

Checks if the message is already executed by calling Outbox.isSpent(position).

Parameters:

child_provider (Web3) – Web3 provider for the child chain

Return type:

bool

Returns:

Whether the message has been executed

status(child_provider)

Returns the status of this message (UNCONFIRMED, CONFIRMED, or EXECUTED).

Parameters:

child_provider (Web3) – Web3 provider for the child chain

Return type:

ChildToParentMessageStatus

Returns:

The status of the message

parse_node_created_assertion(fetched_event)

For a classic RollupUserLogic NodeCreated event. Replaces parseNodeCreatedAssertion from TS code.

Parameters:

fetched_event (FetchedEvent) – The event data

Return type:

Dict[str, Dict[str, bytes]]

Returns:

The parsed assertion data

parse_assertion_created_event(fetched_event)

For a BoldRollupUserLogic AssertionCreated event (BoLD). Replaces parseAssertionCreatedEvent from TS code.

Parameters:

fetched_event – The event data

Returns:

The parsed assertion data

is_assertion_created_log(fetched_event)

Distinguishes between NodeCreated (legacy) vs. AssertionCreated (BoLD). In TS, we look for ‘event.challengeManager != undefined’.

Parameters:

fetched_event (dict) – The event data

Return type:

bool

Returns:

Whether the event is an AssertionCreated log

get_block_from_assertion_log(child_provider, fetched_event=None)

Merges logic from getBlockFromNodeLog + getBlockFromAssertionLog in TS.

Parameters:

• child_provider (Web3) – Web3 provider for the child chain

• fetched_event (Optional[FetchedEvent]) – The event data

Return type:

AttributeDict

Returns:

The block data

get_block_from_assertion_id(rollup_contract, assertion_id, child_provider)

Merges getBlockFromNodeNum with the BoLD path using getAssertion. In TS, we do rollup.getNode(…) vs rollup.getAssertion(…).

Parameters:

• rollup_contract – The rollup contract instance

• assertion_id – The assertion ID

• child_provider – Web3 provider for the child chain

Returns:

The block data

get_batch_number(child_provider)

findBatchContainingBlock parallels TS logic, but might fail if the block doesn’t exist yet.

Parameters:

child_provider – Web3 provider for the child chain

Return type:

Optional[int]

Returns:

The batch number

get_send_props(child_provider)

Merges logic from getSendProps in TS: checks whether the node is confirmed or not. If so, we store sendRootSize, sendRootHash, sendRootConfirmed, etc.

Parameters:

child_provider (Web3) – Web3 provider for the child chain

Return type:

Dict[str, Union[int, str, bool, None]]

Returns:

The send properties

wait_until_ready_to_execute(child_provider, retry_delay=1000)

Wait repeatedly until the outbox entry (assertion) is confirmed, so the message can be executed.

Warning

This operation may take a very long time (1 week+) as outbox entries are only created when the corresponding node is confirmed.

Parameters:

• child_provider (Web3) – Web3 provider for the child chain

• retry_delay (int) – Milliseconds to wait between status checks

Return type:

ChildToParentMessageStatus

Returns:

Final message status (either EXECUTED or CONFIRMED)

get_first_executable_block(child_provider)

getFirstExecutableBlock from the TS code: - If message can be or is already executed, return None - Otherwise, find the earliest block in which it can be executed

Parameters:

child_provider – Web3 provider for the child chain

Return type:

Optional[NewType()(BlockNumber, int)]

Returns:

The first executable block number

class arbitrum_py.message.child_to_parent_message_nitro.ChildToParentMessageWriterNitro(parent_signer, event, parent_provider=None)

Bases: ChildToParentMessageReaderNitro

Read+Write access for nitro Child->Parent messages. Replaces L2ToL1MessageWriterNitro.

__init__(parent_signer, event, parent_provider=None)

Initialize a new ChildToParentMessageNitro instance.

Parameters:

event (CaseDict) – The ChildToParentTx event dictionary from the child chain

execute(child_provider, overrides=None)

Executes the Child->Parent message on the parent chain once the outbox entry is confirmed. Throws if message is not yet CONFIRMED.

Parameters:

• child_provider (Web3) – Web3 provider for the child chain

• overrides (None) – Optional transaction overrides

Return type:

AttributeDict

Returns:

The transaction receipt