getFilterChanges

Returns a list of logs or hashes based on a filter since the last time it was called

Returns a list of logs or hashes based on a filter since the last time it was called.

A filter can be created from:

Import

Import the public actions package so you can call this action.

import "github.com/ChefBingbong/viem-go/actions/public"

Usage

Event Logs

Fetch filter changes for an event filter and inspect the new logs since the last poll.

import (
  "context"
  "log"

  "github.com/ethereum/go-ethereum/common"
  "github.com/ChefBingbong/viem-go/actions/public"
  "github.com/ChefBingbong/viem-go/client"
  "github.com/ChefBingbong/viem-go/client/transport"
  "github.com/ChefBingbong/viem-go/chain/definitions"
)

ctx := context.Background()

publicClient, err := client.CreatePublicClient(client.PublicClientConfig{
  Chain:     definitions.Mainnet,
  Transport: transport.HTTP("https://eth.llamarpc.com"),
})
if err != nil {
  log.Fatal(err)
}
defer func() { _ = publicClient.Close() }()

contractAddr := common.HexToAddress("0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48")
filter, _ := public.CreateEventFilter(ctx, publicClient, public.CreateEventFilterParameters{
  Address: contractAddr,
})

logs, err := public.GetFilterChangesLogs(ctx, publicClient, filter.ID)
if err != nil {
  log.Fatal(err)
}
log.Printf("Found %d new logs", len(logs))

Block Hashes

Fetch filter changes for a block filter and inspect newly seen block hashes.

filter, _ := public.CreateBlockFilter(ctx, publicClient)

blockHashes, err := public.GetFilterChangesBlocks(ctx, publicClient, filter.ID)
if err != nil {
  log.Fatal(err)
}
log.Printf("Found %d new blocks", len(blockHashes))

Pending Transaction Hashes

Fetch filter changes for a pending transaction filter and inspect newly seen transaction hashes.

filter, _ := public.CreatePendingTransactionFilter(ctx, publicClient)

txHashes, err := public.GetFilterChangesTransactions(ctx, publicClient, filter.ID)
if err != nil {
  log.Fatal(err)
}
log.Printf("Found %d new pending transactions", len(txHashes))

Returns

The return type depends on the filter type:

[]formatters.Log - For event filters (via GetFilterChangesLogs)
[]common.Hash - For block filters (via GetFilterChangesBlocks)
[]common.Hash - For pending transaction filters (via GetFilterChangesTransactions)

Parameters

Configuration options accepted by this action.

FilterID

Type: FilterID
Required

The filter identifier returned by CreateEventFilter, CreateBlockFilter, or CreatePendingTransactionFilter.

filter, err := public.CreateEventFilter(ctx, publicClient, public.CreateEventFilterParameters{
  Address: contractAddr,
})
if err != nil {
  log.Fatal(err)
}

logs, err := public.GetFilterChangesLogs(ctx, publicClient, filter.ID)

JSON-RPC Method

Underlying JSON-RPC method used by this action.

eth_getFilterChanges