GetBdnFlashBlockStream

Name: GetBdnFlashBlockStream The GetBdnFlashBlockStream stream provides low-latency access to newly produced Flashblocks on the Base network. Flashblocks are pre-confirmation blocks available before they are finalized on-chain and may differ from the final canonical chain. This is a real-time WS/gRPC, raw Flashblocks data stream.

This stream is available to Enterprise Elite and Ultra tier users.

Example: WebSocket using CLI

wscat -H "Authorization: <AUTH_HEADER>" \
  -c wss://base.blxrbdn.com:5005/ws \
  --wait 1000 \
  --execute '{"jsonrpc": "2.0", "id": 1, "method": "subscribe", "params": [  "GetBdnFlashBlockStream", {} ]}'

Example: Test with grpcurl

grpcurl -H "Authorization: <AUTH_HEADER>" \
  -H "Content-Type: application/grpc" \
  -d '{}' \
  base.blxrbdn.com:443 \
  streamerapi.Api/GetBdnFlashBlockStream

Example: Golang

package main

import (
	"encoding/json"
	"net/http"
	"net/url"

	"github.com/gorilla/websocket"
	"github.com/rs/zerolog/log"
)

const (
	BxAuthHeader = "PUT_YOUR_AUTH_HEADER"
)

type Result struct {
	BdnFlashBlock []byte `json:"bdnFlashBlock"`
}

type Params struct {
	Subscription string `json:"subscription"`
	Result       Result `json:"result"`
}

type Response struct {
	JsonRPC string `json:"jsonrpc"`
	Method  string `json:"method"`
	Params  Params `json:"params"`
}

func main() {
	u, err := url.Parse("wss://base.blxrbdn.com:5005/ws")
	if err != nil {
		log.Fatal().Err(err).Msg("Invalid WebSocket URL: ")
	}

	log.Info().Str("url", u.String()).Msg("Connecting...")
	conn, _, err := websocket.DefaultDialer.Dial(u.String(), http.Header{
		"Authorization": []string{BxAuthHeader},
	})
	if err != nil {
		log.Fatal().Err(err).Msg("WebSocket connection failed: ")
	}
	defer conn.Close()

	request := []byte(`{"jsonrpc": "2.0", "id": 1, "method": "subscribe", "params": [ "GetBdnFlashBlockStream", {} ]}`)
	err = conn.WriteMessage(websocket.TextMessage, request)
	if err != nil {
		log.Fatal().Err(err).Msg("Error sending message: ")
	}

	log.Info().Msg("Connected! Listening for Flashblocks...")
	for {
		msgType, msg, err := conn.ReadMessage()
		if err != nil {
			log.Error().Err(err).Msg("Read error: ")
			continue
		}

		if msgType != websocket.TextMessage {
			log.Error().Err(err).Int("msgType", msgType).Msg("Skipping non-text message: ")
			continue
		}

		var response *Response
		err = json.Unmarshal(msg, &response)
		if err != nil {
			log.Error().Err(err).Msg("Failed to unmarshal response: ")
			continue
		}

		if response.Params.Result.BdnFlashBlock == nil { // Expected for the first update
			log.Warn().Msg("BdnFlashBlock is nil")
			continue
		}

		// Use the Brotli-compressed Flashblock...
		log.Info().Msg("Got Flashblock")
	}
}