fetch_erc20_details

Documentation for eth_defi.token.fetch_erc20_details function.

fetch_erc20_details(web3, token_address, max_str_length=256, raise_on_error=True, contract_name='ERC20MockDecimals.json', cache=LRUCache({}, maxsize=1024, currsize=0), chain_id=None, cause_diagnostics_message=None)

Read token details from on-chain data.

Connect to Web3 node and do RPC calls to extract the token info. We apply some sanitazation for incoming data, like length checks and removal of null bytes.

The function should not raise an exception as long as the underlying node connection does not fail.

Note

Always give chain_id when possible. Otherwise the caching of data is inefficient.

Example:

details = fetch_erc20_details(web3, token_address)
assert details.name == "Hentai books token"
assert details.decimals == 6
Parameters

  • web3 (web3.main.Web3) – Web3 instance

  • token_address (Union[eth_typing.evm.HexAddress, str]) – ERC-20 contract address:

  • max_str_length (int) – For input sanitisation

  • raise_on_error – If set, raise TokenDetailError on any error instead of silently ignoring in and setting details to None.

  • contract_name –

    Contract ABI file to use.

    The default is ERC20MockDecimals.json. For USDC use centre/FiatToken.json.

  • cache (dict | None) –

    Use this cache for cache token detail calls.

    The main purpose is to easily reduce JSON-RPC API call count.

    By default, we use LRU cache of 1024 entries.

    Set to None to disable the cache.

    Instance of cachetools.Cache. See cachetools documentation for details.

  • chain_id (int) –

    Chain id hint for the cache.

    If not given do eth_chainId RPC call to figure out.

  • cause_diagnostics_message (str | None) – Log in Python logging subsystem why this fetch was done to debug RPC overuse.

Returns

Sanitised token info

Return type

eth_defi.token.TokenDetails