clearSubscriptions | Avalanche

Use eth_clearSubscriptions on Avalanche via ethers.js to remove all active WebSocket subscriptions from your Chainstack node connection at once.

The subscriptions available using the provider.on method are:

subscribe('newBlockHeaders')

subscribe('pendingTransactions')

subscribe('logs')

subscribe('syncing')

Get your own node endpoint today

Start for free and get your app to production levels immediately. No credit card required.

You can sign up with your GitHub, X, Google, or Microsoft account.

Parameters

boolean — keep the subscribe(“syncing”) subscription if true.

Response

boolean — the boolean value indicating if the subscriptions were removed successfully. true if removed successfully, false if not.

clearSubscriptions code example

index.js

const { ethers } = require("ethers");
const NODE_URL = "CHAINSTACK_WSS_URL";
const provider = new ethers.WebSocketProvider(NODE_URL);

async function clearSubscriptions() {
    try {
      await provider.removeAllListeners();
      console.log("Subscriptions were canceled successfully");
      return process.exit(1)

    } catch (error) {
      console.error("Failed to cancel subscriptions:", error);
      return process.exit(1)
    }
  }

clearSubscriptions()

Use case

A way to use the clearSubscriptions method is to place it in a timer to clear all of the subscriptions after a pre-determined about.

The following code is an example using the subscribe(“newBlockHeaders”) method, which will be stopped and removed after one minute using clearSubscriptions:

index.js

const { ethers } = require("ethers");
const NODE_URL = "CHAINSTACK_WSS_URL";
const provider = new ethers.WebSocketProvider(NODE_URL);

async function subscribeToNewBlocks() {
    try {
        // Create a new subscription to the 'block' event
        provider.on("block", handleNewBlock);

        // Attach an event listener for any provider errors
        provider.on("error", handleError);

        console.log("New subscription created");
    } catch (error) {
        console.error(`Error subscribing to new blocks: ${error}`);
    }
}

/* Fallback functions to react to the different events */

// Event listener that logs the received block number
function handleNewBlock(blockNumber) {
    console.log(blockNumber);
}

// Event listener that logs any errors that occur
function handleError(error) {
    console.error(`Error receiving new blocks: ${error}`);
}

async function clearSubscriptions() {
    try {
        await provider.removeAllListeners();
        console.log("Subscriptions were canceled successfully");
        return process.exit(1)

    } catch (error) {
        console.error("Failed to cancel subscriptions:", error);
        return process.exit(1)
    }
}

async function main() {

    subscribeToNewBlocks();

    // Run clearSubscriptions() once after 60 seconds
    setTimeout(clearSubscriptions, 60000);
}

main()

The code starts by defining an async function called subscribeToNewBlocks that creates a new subscription to the block event using the provider.on method. This method attaches event listeners to the provider for different events, such as block and error. The code defines two event listener functions handleNewBlock and handleError that log messages to the console when these events occur.

The subscribeToNewBlocks function is called from the main function, which is also defined in the code. The main function calls subscribeToNewBlocks to create a new subscription and then schedules the clearSubscriptions function to run once after 60 seconds using the setTimeout function. The clearSubscriptions function uses the provider.removeAllListeners method to cancel any existing subscriptions and log a message to the console if the cancellation was successful.