Solana: I need help filtering Solana transactions from QuickNode flows. Retrieve the amount of SOL sent and change the direction

I can guide you through setting up a solution for filtering and extracting specific information from your Solana transactions using QuickNode.

Prerequisites

• You have a QuickNode stream set up that is feeding live Solana transactions.

• Your QuickNode setup allows streaming raw payload block data. If not, you’ll need to implement this feature or use an alternative method to obtain the transaction data.

• You want to extract specific information from each transaction, such as:

– The amount of SOL sent.

– The direction (buy/sell) of the swap.

Solution Overview

To achieve your goal, we will utilize QuickNode’s streaming capabilities along with Solana’s built-in transaction filtering features. We’ll also use JavaScript for this example, but you can adapt it to other languages if needed.

Step 1: Set up a basic workflow in QuickNode

First, ensure that QuickNode is configured to stream data from your Solana node. This typically involves creating a stream listener and setting it to listen on the solana topic with a specific block number range (in this case, the latest 100 blocks). You can use libraries like quicknode-streams or create your own custom implementation.

Here’s a basic example of how you might set up such a listener in JavaScript using QuickNode Streams:

const { StreamListener } = require('quicknode-streams');


// Create a stream listener

const streamListener = new StreamListener({

  topic: 'solana',

  startBlockNumber: 100, // Start from the latest 100 blocks

  endBlockNumber: Infinity,

});


streamListener.on('block', (block) => {

  // Do something with each block's data

  console.log(block.data);

});

Step 2: Use a library to filter transactions

Now that we have our stream listener set up, let’s create a function that filters the transactions based on the amount of SOL sent and the direction of swap. For this example, I’ll use solana-stream-filter which is a popular JavaScript library for filtering Solana transaction data.

First, install the required library:

npm install solana-stream-filter

Then, create a new file (e.g., filterTransactions.js) and add the following code:

const { StreamFilter } = require('solana-stream-filter');


// Function to filter transactions based on SOL amount and direction

async function filterTransactions(transaction) {

  const solAmount = transaction.amount;

  const swapDirection = transaction.direction;


  // Assuming we have a list of acceptable amounts or directions

  if (

    !acceptableAmounts.includes(solAmount) ||

    (swapDirection === 'buy' && solAmount > acceptableAmounts[0]) ||

    (swapDirection === 'sell' && solAmount < acceptableAmounts[1])

  ) {

    return false;

  }


  return true;

}


// List of acceptable amounts

const acceptableAmounts = [10, 20]; // Replace with your preferred SOL amounts


// Create a stream filter

const filter = new StreamFilter({

  transaction,

  filters: { amount: acceptableAmounts },

});


// Use the filter in our QuickNode listener

streamListener.on('block', (block) => {

  const transactions = block.transactions;

  for (const transaction of transactions) {

    if (!filter.transaction(transaction)) {

      console.log(Filtered out ${transaction.address}:${transaction.amount} - ${transaction.direction});

      // Remove or log the filtered transaction

      filter.remove(transaction);

    }

  }

});

This example assumes you have a predefined list of acceptable amounts and directions for filtering. You can replace this with your own logic based on your specific requirements.

Step 3: Integrate the solution into QuickNode

After implementing the filtering step, integrate it back into your existing QuickNode setup.