EventFetcher

Event fetching and parsing utilities for the Arbitrum SDK.

This module provides classes for fetching and parsing blockchain events/logs in a structured way, similar to the TypeScript EventFetcher implementation.

class arbitrum_py.utils.event_fetcher.FetchedEvent(*, event, topic, name, block_number, block_hash, transaction_hash, address, topics, data)

Bases: CaseDict

A structured representation of an Ethereum event/log.

This class represents a parsed blockchain event, containing both the decoded data (event arguments) and the raw log information. It’s the Python equivalent of the TypeScript FetchedEvent<TEvent> type.

Variables:

• event (Dict[str, Any]) – The decoded event arguments

• topic (Optional[str]) – The primary topic (event signature)

• name (str) – The event name (e.g., “MessageDelivered”)

• block_number (int) – Block number containing the event

• block_hash (str) – Hash of the block containing the event

• transaction_hash (str) – Hash of the transaction containing the event

• address (str) – Contract address that emitted the event

• topics (List[str]) – All topics from the log

• data (Optional[str]) – Raw data from the log

__init__(*, event, topic, name, block_number, block_hash, transaction_hash, address, topics, data)

Initialize a FetchedEvent instance.

Parameters:

• event (Dict[str, Any]) – The decoded event arguments

• topic (Optional[str]) – Primary topic (event signature) if any

• name (str) – Event name (e.g., “MessageDelivered”)

• block_number (int) – Block number containing the event

• block_hash (str) – Hash of the block containing the event

• transaction_hash (str) – Hash of the transaction containing the event

• address (NewType()(ChecksumAddress, NewType()(HexAddress, NewType()(HexStr, str)))) – Contract address that emitted the event

• topics (List[str]) – All topics from the log

• data (Optional[str]) – Raw data from the log

class arbitrum_py.utils.event_fetcher.EventFetcher(provider)

Bases: object

A utility class for fetching and parsing blockchain events.

This class provides functionality to: 1. Query blockchain logs using various filters 2. Parse the logs into structured FetchedEvent objects 3. Handle different provider types (Web3, SignerOrProvider, ArbitrumProvider)

It’s the Python equivalent of the TypeScript EventFetcher class.

__init__(provider)

Initialize an EventFetcher instance.

Parameters:

provider (Union[Web3, SignerOrProvider, ArbitrumProvider]) – The provider to use for fetching logs. Can be: - A Web3 instance - A SignerOrProvider instance - An ArbitrumProvider instance

Raises:

ArbSdkError – If the provider is invalid or missing

get_events(contract_factory, event_name, argument_filters=None, filter=None, is_classic=False)

Fetch and parse blockchain events.

This method: 1. Sets up the contract interface 2. Creates an event filter 3. Fetches matching logs 4. Parses them into FetchedEvent objects

Parameters:

• contract_factory (Union[str, Contract]) – Either a contract name string or Contract instance

• event_name (str) – Name of the event to fetch (e.g., ‘MessageDelivered’)

• argument_filters (Optional[Dict[str, Any]]) – Filters for specific event argument values

• filter (Optional[FilterParams]) – Block range and address filters containing: - fromBlock: Starting block number - toBlock: Ending block number - address: Contract address (optional)

• is_classic (bool) – Whether to use classic or nitro contract version

Returns:

The fetched and parsed events

Return type:

List[FetchedEvent]

Raises:

ArbSdkError – If contract or event cannot be found/accessed

Example

>>> fetcher = EventFetcher(web3)
>>> events = fetcher.get_events(
...     contract_factory='Bridge',
...     event_name='MessageDelivered',
...     filter={'fromBlock': 1000000, 'toBlock': 'latest'}
... )