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import { createDfuseClient, InboundMessage, InboundMessageType, waitFor } from "@dfuse/client"
import { IncomingMessage } from "http"
* In this example, we will showcase how to avoid polluting the global
* scope to configure the `fetch` and `WebSocket` values.
* Indeed, polluting the global scope is not a recommended practicte,
* especially when alternatives are present to handle those cases.
* We will configure the `DfuseClient` instance when creating it via
* the factory to pass the `fetch` and `WebSocket options directly.
* **Note** This example completely avoids importing `../config` to ensure
* we really do not pollute the global scope. Ensures you have the
* appropriate environment variables set.
// We add the example imports here to make the example clearer, in your
// own code, group them with yours.
import nodeFetch from "node-fetch"
import WebSocketClient from "ws"
async function main() {
const client = createDfuseClient({
apiKey: process.env.DFUSE_API_KEY!,
network: process.env.DFUSE_API_NETWORK || "mainnet",
httpClientOptions: {
fetch: nodeFetch
streamClientOptions: {
socketOptions: {
* The factory receives the full resolved URL, API token included,
* of the remote endpoint to connect to.
* When using the Node.js enviroment in your own
* factory, it is here that you can customize the WebSocket client instance.
* In the factory below, we jump the `maxPayload` size to 200M,
* which can be useful when streaming really big tables like the
* `voters` table on EOS.
* We also add error logging for errors occurring at the HTTP Upgrade
* level before turning the connection into a WebSocket connection. This
* can happen when authorization happens with your API token.
* **Note** Don't try to override the `onOpen`, `onClose`, `onError`
* and `onMessage` handler, they are overwritten by the `Socket` instance
* for its own usage.
* **Important Web Browser Usage Notice**
* We are in a Node.js context here, the `WebSocketClient` is a
* Node.js implementation of WebSocket Protocol. It does not have
* quite the same API interface. The configuration done below
* will not work in a Browser environment! Check W3C Browser
* WebSocket API to see what is accepted as it's second argument.
* @see
webSocketFactory: async (url: string) => {
const webSocket = new WebSocketClient(url, {
handshakeTimeout: 30 * 1000, // 30s
maxPayload: 200 * 1024 * 1000 * 1000 // 200Mb
const onUpgrade = (response: IncomingMessage) => {
console.log("Socket upgrade response status code.", response.statusCode)
// You need to remove the listener at some point since this factory
// is called at each reconnection with the remote endpoint!
webSocket.removeListener("upgrade", onUpgrade)
webSocket.on("upgrade", onUpgrade)
return webSocket
const onMessage = (message: InboundMessage) => {
if (message.type === InboundMessageType.LISTENING) {
console.log("Stream is now listening.")
const stream = await client.streamActionTraces(
accounts: "eosio.token",
action_names: "issue"
console.log("Socket is now connected.")
await waitFor(35000)
await stream.close()
.then(() => {
console.log("Example completed.")
.catch((error) => {
console.log("An untrapped error occurred.", error)
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