Ethereum Explorer

[enoldev]

Currently, there are three modules: map_block_meta, map_filter_transaction and map_contract_events.

I've included most of the information in the README.md, but I'd like to add a section in the docs with a step-by-step guide of the source code.

[enoldev]

• General:
  • I've changed the way mods are included, but I prefer to keep a file for every Substreams module (just in case we add a few more). Let me know if the structure is something critical and I can change it
  • I haven't updated the README with the new changes yet. I'd like to confirm the code first, and then I can update the README
• map_filter_transactions
  • Now you can pass query encoded parameters (for the from , to and hash fields). For example, map_filter_transactions: "to=dac17f958d2ee523a2206206994597c13d831ec7&from=46340b20830761efd32832a74d7169b29feb9758"
  • I've included a simple validation of the parameters by checking the length of the String (64 hex characters for the transaction has and 40 for the addresses) The verification returns Vec , an error for every parameter, if exists
  • I'm also discarding transaction with status != TransactionTraceStatus::Succeeded
  • In this module I'm using String instead of Vecwhen comparing because the Transaction protobuf returns Strings (so the conversion is necessary anyway), and I think it's less overhead to do TransactionTrace fields to String (which are reused after) than External Parameters to Vec . Let me know if this is critical, and I can change it
• map_contract_events
  • I'm verifying the contract address by checking its length
  • I'm using Vec when comparing here because I compare transaction.to == contract_address , and transaction.to does not get converted to String afterwards
    • Therefore, I'm converting contract_address to Vec . This is a way I've found to handle the error, but I don't if the best:

      let contract_address_as_vec = match Hex::decode(&contract_address) {
      Ok(address) => address,
      Err(error) => return Err(Error::Unexpected(error.to_string())),
      };

[maoueh]

Here for example a re-write of map_contract_events with only:

#[substreams::handlers::map]
fn map_contract_events(contract_address: String, blk: Block) -> Result<Events, Error> {
    // Not working today, needs to update `substreams-rs` to enable the conversion out of the box
    let address = Hex::decode(&contract_address)
        .with_context(|| anyhow!("invalid param address {}", contract_address))?;

    Ok(Events {
        events: blk
            .logs()
            .filter(|log_view| log_view.address() == address)
            .map(|log_view| Event {
                address: Hex::encode(log_view.address()),
                topics: log_view.log.topics.iter().map(Hex::encode).collect(),
                tx_hash: Hex::encode(log_view.receipt.transaction.hash),
            })
            .collect(),
    })
}