nodejs-fetch-and-websocket-options.ts

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"
import { runMain } from "../../config"

async function main(): Promise<void> {
  const client = createDfuseClient({
    apiKey: process.env.DFUSE_API_KEY || "",
    network: process.env.DFUSE_API_NETWORK || "mainnet.eos.dfuse.io",
    httpClientOptions: {
      fetch: nodeFetch,
    },
    graphqlStreamClientOptions: {
      socketOptions: {
        // The WebSocket factory used for GraphQL stream must use this special protocols set
        // We intend on making the library handle this for you automatically in the future,
        // for now, it's required otherwise, the GraphQL will not connect correctly.
        webSocketFactory: (url) => webSocketFactory(url, ["graphql-ws"]),
      },
    },
    streamClientOptions: {
      socketOptions: {
        webSocketFactory: (url) => webSocketFactory(url),
      },
    },
  })

  const onMessage = (message: InboundMessage): void => {
    if (message.type === InboundMessageType.LISTENING) {
      console.log("Stream is now listening.")
    }
  }

  const stream = await client.streamActionTraces(
    {
      accounts: "eosio.token",
      action_names: "issue",
    },
    onMessage
  )

  console.log("Socket is now connected.")
  await waitFor(35000)
  await stream.close()

  client.release()
}

/**
 * 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 https://developer.mozilla.org/en-US/docs/Web/API/WebSocket/WebSocket#Parameters
 */
async function webSocketFactory(url: string, protocols: string[] = []): Promise<WebSocketClient> {
  const webSocket = new WebSocketClient(url, protocols, {
    handshakeTimeout: 30 * 1000, // 30s
    maxPayload: 10 * 1024 * 1024, // 10 MiB (max accepted value from the server)
  })

  const onUpgrade = (response: IncomingMessage): void => {
    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
}

runMain(main)