eth_getFilterChanges
methodeth_getFilterChanges
method is a standard RPC call used across EVM-compatible blockchains. Its primary purpose is to retrieve changes or updates that occurred concerning a previously set filter. In simpler terms, once a filter is set to watch for a specific event, the eth_getFilterChanges
method can fetch any new occurrences. Learn more about eth_getFilterChanges.
However, developers might occasionally encounter the “Filter Not Found” error while working with this method.
eth_newBlockFilter
method. This filter watches for new blocks on the blockchain.
eth_getFilterChanges
eth_getFilterChanges
, passing the filter ID to retrieve changes matching the filter’s criteria:
eth_getFilterChanges
.
Ethereum nodes keep filters for 5 minutes, according to the Go Ethereum (Geth) GitHub page. If you wait too long to check for changes, or a situation listed in the previous paragraph happens, the filter may no longer exist, returning Filter Not Found
.
get_filter_changes
method from web3.py immediately. Implementing error handling at this stage can prevent potential issues:
try-except
block is instrumental in identifying and managing errors during the get_filter_changes
invocation. By examining the error message for filter not found
, we can specifically address this error. For other discrepancies, a generic error message aids in debugging.
new_filter
once more and preserving the new filter ID:
web3.py
.
eth_getFilterChanges
. Each filter possesses a unique ID, and discrepancies in using the correct ID will inevitably trigger the “Filter Not Found” error.
Ethereum’s inherent design includes a brief filter expiration duration. While this can be a source of the “Filter Not Found” error, adept error handling can substantially reduce its adverse effects, paving the way for a resilient Ethereum-based application.