get_almost_latest_block_number

Documentation for eth_defi.provider.broken_provider.get_almost_latest_block_number function.

get_almost_latest_block_number(web3)

Get the latest block number with workarounds for low quality JSON-RPC service providers.

Use this method instead of web3.eth.block_number.

Because low quality providers may lose the block of this block number on the subsequent API calls, we add some number of delay or confirmations to the chain tip, specified by get_block_tip_latency().

Includes a monotonicity safety check: if the block number drops by more than MAX_BLOCK_REGRESSION blocks compared to the last observed value, raises BlockNumberOutOfRange. This catches scenarios where the RPC provider silently starts returning data for the wrong chain after a failover.

Providers with known issues

  • LlamaNodes

  • Ankr

Example:

from eth_defi.provider.broken_provider import get_almost_latest_block_number

# We cannot query the chain head on Ankr or LlamaNodes,
# so get the almost head
if not block_number:
    block_number = get_almost_latest_block_number(web3)

timestamp = fetch_block_timestamp(web3, block_number)

token = fetch_erc20_details(web3, asset.address)
amount = token.fetch_balance_of(address, block_identifier=block_number)
Raises

BlockNumberOutOfRange – If the block number regresses by more than MAX_BLOCK_REGRESSION.

Parameters

web3 (web3.main.Web3) –

Return type

int