createEventFilter

Creates a filter to listen for new events

Creates a filter object to receive logs matching the specified criteria.

Import

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

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

Usage

An example showing how to create an event filter for a contract and use it to fetch changes.

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")
transferTopic := common.HexToHash("0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef")

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

// Use filter.ID with GetFilterChanges to get new logs
changes, err := public.GetFilterChangesLogs(ctx, publicClient, filter.ID)

Returns

*CreateEventFilterReturnType

A filter object containing:

ID FilterID - The filter identifier
Type string - Always "event" for event filters

Parameters

Configuration options accepted by this action.

Address

Type: any (accepts common.Address, *common.Address, []common.Address, string, or []string)
Optional

The contract address(es) to filter logs from. Can be a single address or a slice of addresses.

import (
  "github.com/ethereum/go-ethereum/common"
  "github.com/ChefBingbong/viem-go/actions/public"
)

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

Topics

Type: []any
Optional

The indexed event topics to filter. Each topic can be a single value or an array of values (OR condition).

transferTopic := common.HexToHash("0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef")
filter, err := public.CreateEventFilter(ctx, publicClient, public.CreateEventFilterParameters{
  Address: contractAddr,
  Topics:  []any{transferTopic},
})

FromBlock

Type: *uint64
Optional

The block number to start filtering from. Mutually exclusive with FromBlockTag.

fromBlock := uint64(16330000)
filter, err := public.CreateEventFilter(ctx, publicClient, public.CreateEventFilterParameters{
  Address:   contractAddr,
  FromBlock: &fromBlock,
})

FromBlockTag

Type: BlockTag
Optional

The block tag to start filtering from. Mutually exclusive with FromBlock.

filter, err := public.CreateEventFilter(ctx, publicClient, public.CreateEventFilterParameters{
  Address:      contractAddr,
  FromBlockTag: public.BlockTagSafe,
})

ToBlock

Type: *uint64
Optional

The block number to stop filtering at. Mutually exclusive with ToBlockTag.

toBlock := uint64(16330050)
filter, err := public.CreateEventFilter(ctx, publicClient, public.CreateEventFilterParameters{
  Address: contractAddr,
  ToBlock: &toBlock,
})

ToBlockTag

Type: BlockTag
Optional

The block tag to stop filtering at. Mutually exclusive with ToBlock.

filter, err := public.CreateEventFilter(ctx, publicClient, public.CreateEventFilterParameters{
  Address:    contractAddr,
  ToBlockTag: public.BlockTagLatest,
})

JSON-RPC Method

Underlying JSON-RPC method used by this action.

eth_newFilter