I'm attempting to calculate slippage of the past X number of blocks to determine if a potential trade is likely to slip beyond the threshold 1% level. If it does I will cancel the trade.

To do this, I have used web3.eth.getPastLogs() and have started to receive this error:

Error: CONNECTION ERROR: Couldn't connect to node on WS.
    at Object.ConnectionError (/Users/TrentKennelly/trading_bot_V2/node_modules/web3-core-helpers/lib/errors.js:66:23)
    at Object.InvalidConnection (/Users/TrentKennelly/trading_bot_V2/node_modules/web3-core-helpers/lib/errors.js:36:21)
    at /Users/TrentKennelly/trading_bot_V2/node_modules/web3-providers-ws/lib/index.js:161:37
    at Map.forEach (<anonymous>)
    at WebsocketProvider._onClose (/Users/TrentKennelly/trading_bot_V2/node_modules/web3-providers-ws/lib/index.js:160:28)
    at W3CWebSocket._dispatchEvent [as dispatchEvent] (/Users/TrentKennelly/trading_bot_V2/node_modules/yaeti/lib/EventTarget.js:115:12)
    at W3CWebSocket.onClose (/Users/TrentKennelly/trading_bot_V2/node_modules/websocket/lib/W3CWebSocket.js:228:10)
    at WebSocketConnection.<anonymous> (/Users/TrentKennelly/trading_bot_V2/node_modules/websocket/lib/W3CWebSocket.js:201:17)
    at WebSocketConnection.emit (node:events:513:28)
    at WebSocketConnection.drop (/Users/TrentKennelly/trading_bot_V2/node_modules/websocket/lib/WebSocketConnection.js:475:14)
    at /Users/TrentKennelly/trading_bot_V2/node_modules/websocket/lib/WebSocketConnection.js:303:18
    at process.processTicksAndRejections (node:internal/process/task_queues:77:11) {
  code: 1009,
  reason: 'Frame size of 5607436 bytes exceeds maximum accepted frame size'

I have attempted to increase the maxReceivedFrameSize in my truffle-config, which is a solution offered here like so:

networks: {
    mainnet: {
      provider: () => new HDWalletProvider(mnemonic, `wss://mainnet.infura.io/ws/v3/${process.env.INFURA_API_KEY}`,
            clientConfig: {
                maxReceivedFrameSize: 100000000,
                maxReceivedMessageSize: 100000000
      network_id: '*', 
      gasPrice: 100000000000

Here is the function that is producing the error. :

const determineSlippage = async (_token0, _token1, _pairContract) => {

  console.log(`Calculating Slippage...\n`)

  const endpoint = 'https://api.thegraph.com/subgraphs/name/uniswap/uniswap-v2'

  // Set the token pair to analyze
  const token0 = _token0 
  const token1 = _token1 

  // Set the time interval to analyze (in blocks)
  const blocks = 500

async function getTradesForPair(token0, token1, blocks, uPairValue) {
  // Get the latest block number
  const latestBlockNumber = await web3.eth.getBlockNumber();

  // Determine the block range to search for trades
  const startBlockNumber = Math.max(latestBlockNumber - blocks, 0);
  const endBlockNumber = latestBlockNumber;
  const pair = _pairContract;

  const filter = {
    fromBlock: startBlockNumber,
    toBlock: endBlockNumber,
    topics: [web3.utils.sha3('Swap(address,uint256,uint256,uint256,uint256,address)')]

  // Get the past Swap events from the Uniswap pair contract
  const events = await web3.eth.getPastLogs(filter);

  // Create an array of trades from the Swap events
  const trades = events.map(event => {
  const { amount0In, amount1In, amount0Out, amount1Out } = event.returnValues;
  const { token0, token1 } = pair.options;
  const trade = { 
    inputToken: token0.options.address === token0Address ? token0 : token1,
    outputToken: token0.options.address === token0Address ? token1 : token0,
    inputAmount: web3.utils.toBN(token0.options.address === token0Address ? amount0In : amount1In),
    outputAmount: web3.utils.toBN(token0.options.address === token0Address ? amount1Out : amount0Out)

  return trade;


return trades;

As a final note, this error occurs whether blocks is 500 or 100. Doesn't seem to matter. Any thoughts?

1 Answer 1


I'm just asking for too much data at a time and have had to break it into smaller bits.

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