debug_traceBlockByHash | Ethereum

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Parameters

• hash — the hash of the block to be traced.
• tracer — an object identifying the type of tracer and its configuration:
  • 4byteTracer — tracer that captures the function signatures and call data sizes for all functions executed during a transaction, creating a map that links each selector and size combination to the number of times it occurred. This provides valuable information about the frequency and usage of each function within the transaction.
  • callTracer — tracer that captures information on all call frames executed during a transaction. The resulting nested list of call frames is organized into a tree structure that reflects the way the Ethereum Virtual Machine works and can be used for debugging and analysis purposes.
  • prestateTracer — tracer with two modes: prestate and diff, where the former returns the accounts needed to execute a transaction, and the latter returns the differences between the pre and post-states of the transaction. The tracer operates by re-executing the transaction and tracking every state change made, resulting in an object with the account addresses as keys and the corresponding trie leaves as values.
  • flatCallTracer — tracer that returns call traces in the flat, Parity-style format used by the trace_* namespace, as a flattened list of call frames rather than a nested tree.
  • muxTracer — tracer that runs several native tracers in a single pass, configured via a tracerConfig object keyed by tracer name, returning each tracer’s output under its own key.
  • erc7562Tracer — tracer that enforces the ERC-7562 account-abstraction validation rules, tracking opcode and storage access during the validation phase of an ERC-4337 user operation.

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Response types

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4byteTracer response

• object — the 4byteTracer traces object:
  • result — a map of the function signature, the call data size, and how many times the function was called.

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callTracer response

• object — the callTracer traces object:
  • from — the address of the sender who initiated the transaction.
  • gas — the units of gas included in the transaction by the sender.
  • gasused — the total used gas by the call. Encoded as hexadecimal.
  • to — the address of the recipient of the transaction if it was a transaction to an address. For contract creation transactions, this field is null.
  • input — the optional input data sent with the transaction, usually used to interact with smart contracts.
  • output — the return value of the call, encoded as a hexadecimal string.
  • error — an error message in case the execution failed.
  • revertReason — the reason why the transaction was reverted, returned by the smart contract if any.
  • calls — a list of sub-calls made by the contract during the call, each represented as a nested call frame object.

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prestateTracer response

• object — the prestateTracer traces object:
  • smart contract address — the address of the smart contract associated with the result.
    • balance — the balance of the contract, expressed in wei and encoded as a hexadecimal string.
    • code — the bytecode of the contract, encoded as a hexadecimal string.
    • nonce — the nonce of the account associated with the contract, represented as an unsigned integer.
    • storage — a map of key-value pairs representing the storage slots of the contract. The keys and values are both encoded as hexadecimal strings.

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debug_traceBlockByHash code examples

const ethers = require("ethers");

// Create a ChainstackProvider instance for Ethereum mainnet
const chainstack = new ethers.ChainstackProvider("mainnet");

const traceBlockByHash = async (blockHash) => {
  // Specify the type of tracer: 4byteTracer, callTracer, prestateTracer, or muxTracer
  const tracer = { tracer: "4byteTracer" };
  const traces = await chainstack.send("debug_traceBlockByHash", [
    blockHash,
    tracer,
  ]);
  console.log(traces);
};

traceBlockByHash(
  "0x4725335feac695de65deb8662235f52692522d4f623a81468cc6479b43dc9782"
);

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Use case

const ethers = require("ethers");

// Create a ChainstackProvider instance for Ethereum mainnet
const chainstack = new ethers.ChainstackProvider("mainnet");

async function traceTransferFunction(blockHash) {
    try {
      // Specify the type of tracer: 4byteTracer, callTracer, prestateTracer, or muxTracer
      const tracer = { tracer: "4byteTracer" };
      const response = await chainstack.send("debug_traceBlockByHash", [
        blockHash,
        tracer,
      ]);

      let sum = 0;
      for (let obj of response) {

        for (let key in obj.result) {

          const signature = key.split('-')[0];

          // Look for transfer function signatures
          if (signature === "0xa9059cbb") {
            const timesCalled = obj.result[key]
            sum += timesCalled
          }
        }
      }

      console.log(`In this block the transfer function was called ${sum} times!`)
    } catch (err) {
      console.error(`Error in traceBlockByHash: ${err.message}`);
    }
  }

  traceTransferFunction("0x4725335feac695de65deb8662235f52692522d4f623a81468cc6479b43dc9782");