The Ethereum Explorer consists of several Substreams modules showcasing the most basic operations that you can perform with Substreams on the Ethereum blockchain.

Before You Begin

Make sure you have the Substreams CLI installed, and you know the basic structure of a Substreams module. You must also provide an authentication token.

Modules

The modules in this repository answer some interesting questions when developing a blockchain application:

How Can You Get the Basic Information of a Block?

For every block, the map_block_meta module retrieves the most relevant information of the block (number, hash, and parent hash).

How Can You Retrieve a Specific Transaction By Its Hash?

Given a transaction hash parameter (tx_hash), the map_filter_transaction filters a transaction among all transactions in the blockchain. This involves:

Iterating over all the transactions.
Filter the transactions, where the hash field is equal to the hash parameter (hash == tx_hash).

How Can You Retrieve All the Events for a Specific Smart Contract?

Given a smart contract address parameter (contract_address), the map_contract_events module retrieves all the events related to a specific smart contract. This involves:

Iterating over all the smart contract transactions,
Filtering the transactions, where the to field is equal to the smart contract address parameter (to == contract_address).
For every filtered transaction, retrieve the logs.

Running the Substreams

First, generate the Protobuf code, which are the outputs of the Substreams:

> make protogen

Then, build the Rust code using the cargo command-line tool:

> make build

Now, you are ready to run the Substreams. The Substreams contained in this project are independent of each other, so you must specify which Substreams module you want to run.

Running the "map_block_meta" Module

In the following command, you retrieve the metadata of the block with number 17712040. You specify the starting block by using the --start-block parameter.

> substreams run -e mainnet.eth.streamingfast.io:443 substreams.yaml map_block_meta --start-block 17712040 --stop-block +1
Connected (trace ID e98f04cd7ebb6191befbbf2e6668eafc)
Progress messages received: 0 (0/sec)
Backprocessing history up to requested target block 17712040:
(hit 'm' to switch mode)

----------- BLOCK #17,712,040 (31ad07fed936990d3c75314589b15cbdec91e4cc53a984a43de622b314c38d0b) ---------------
{
  "@module": "map_block_meta",
  "@block": 17712040,
  "@type": "eth.block_meta.v1.BlockMeta",
  "@data": {
    "number": "17712040",
    "hash": "31ad07fed936990d3c75314589b15cbdec91e4cc53a984a43de622b314c38d0b",
    "parentHash": "1385f853d28b16ad7ebc5d51b6f2ef6d43df4b57bd4c6fe4ef8ccb6f266d8b91"
  }
}

all done

Running the "map_filter_transaction" Module

To run this module, you must provide a transaction hash, so that Substreams can filter the transactions accordingly. The Substreams manifest (substreams.yaml) contains a default transaction hash (4faa877df84080a9d98b1e28294c4680bb141ec27a1a5dee009c3e02dfa65ab7) in the params section, which you can update.

The 4faa877df84080a9d98b1e28294c4680bb141ec27a1a5dee009c3e02dfa65ab7 transaction is at block number 17712040. In order to avoid iterating over the full blockchain, the following command starts searching at block number 17712038.

> substreams run -e mainnet.eth.streamingfast.io:443 substreams.yaml map_filter_transactions --start-block 17712038 --stop-block +10
Connected (trace ID 9dce06621a0ec353213adeaf9f10ef79)
Progress messages received: 0 (0/sec)
Backprocessing history up to requested target block 17712038:
(hit 'm' to switch mode)

----------- BLOCK #17,712,038 (b96fc7e71c0daf69b19211c45fbb5c201f4356fb2b5607500b7d88d298599f5b) ---------------
----------- BLOCK #17,712,039 (1385f853d28b16ad7ebc5d51b6f2ef6d43df4b57bd4c6fe4ef8ccb6f266d8b91) ---------------
----------- BLOCK #17,712,040 (31ad07fed936990d3c75314589b15cbdec91e4cc53a984a43de622b314c38d0b) ---------------
{
  "@module": "map_filter_transaction",
  "@block": 17712040,
  "@type": "eth.transaction.v1.TransactionOption",
  "@data": {
    "transaction": {
      "from": "e93685f3bba03016f02bd1828badd6195988d950",
      "to": "902f09715b6303d4173037652fa7377e5b98089e",
      "hash": "4faa877df84080a9d98b1e28294c4680bb141ec27a1a5dee009c3e02dfa65ab7"
    }
  }
}

----------- BLOCK #17,712,041 (1af541642176c51580b54de214e955fba8bf1b82af569b81d4038956f2402a41) ---------------
----------- BLOCK #17,712,042 (43c6ebe5b89dd689a9f07468a04d0faf5274a46d0763056ea53b8b1e5ac32148) ---------------
----------- BLOCK #17,712,043 (2457f742913dbbdb171a8d8cc3b1ef8a383f8f547982700a646aa97581bfaeb8) ---------------
----------- BLOCK #17,712,044 (af7abef4f80d7c6f3111e761bb86f305e9847e544fb36b55ba5b64e6103bd5d3) ---------------
----------- BLOCK #17,712,045 (db4664944f7ca8aed5de798bf74ebbdbbeda60e58316b4291bfec61c7287fb17) ---------------
----------- BLOCK #17,712,046 (d9bce9b9210b7deb746720435d1eca99b87fe17aaf7d5055fcd54959e0c9932e) ---------------
----------- BLOCK #17,712,047 (3a5ffab8dacbaf89e10b66e9d2f7ebe65bddae4dcb5e5e8739f8b938f16f98ec) ---------------
all done

As you can see, the Substreams does not provide an output for the blocks where the transaction is not present. You can check out the transaction at Etherscan.

Running the "map_filter_transaction" Module

To run this module, you must provide the address of a smart contract. By default, the params section of the Substreams manifest contains the bc4ca0eda7647a8ab7c2061c2e118a18a936f13d address, corresponding to the Bore Yacht Club smart contract. You can change this address to track any smart contract.

The logs of a smart contract might be split across thousands of Ethereum blocks, so for testing purposes, and to avoid iterating over the full blockchain, the following command limits starts searching at block number 17717995.

> substreams run -e mainnet.eth.streamingfast.io:443 substreams.yaml map_contract_events --start-block 17717995 --stop-block +10
Connected (trace ID 834915f19a2b07a8a3aa0159cbbf56da)
Progress messages received: 0 (0/sec)
Backprocessing history up to requested target block 17717995:
(hit 'm' to switch mode)

----------- BLOCK #17,717,995 (bfecb26963a2cd77700754612185e0074fc9589d2d73abb90e362fe9e7969451) ---------------
----------- BLOCK #17,717,996 (7bf431a4f9df67e1d7e385d9a6cba41c658e66a77f0eb926163a7bbf6619ce20) ---------------
----------- BLOCK #17,717,997 (fa5a57231348f1f138cb71207f0cdcc4a0a267e2688aa63ebff14265b8dae275) ---------------
map_contract_events: log: //////////////////
{
  "@module": "map_contract_events",
  "@block": 17717997,
  "@type": "eth.event.v1.Events",
  "@data": {
    "events": [
      {
        "address": "bc4ca0eda7647a8ab7c2061c2e118a18a936f13d",
        "topics": [
          "8c5be1e5ebec7d5bd14f71427d1e84f3dd0314c0f7b2291e5b200ac8c7c3b925",
          "000000000000000000000000e2a83b15fc300d8457eb9e176f98d92a8ff40a49",
          "0000000000000000000000000000000000000000000000000000000000000000",
          "00000000000000000000000000000000000000000000000000000000000026a7"
        ],
        "txHash": "f18291982e955f3c2112de58c1d0a08b79449fb473e58b173de7e0e189d34939"
      },
      {
        "address": "bc4ca0eda7647a8ab7c2061c2e118a18a936f13d",
        "topics": [
          "ddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef",
          "000000000000000000000000e2a83b15fc300d8457eb9e176f98d92a8ff40a49",
          "000000000000000000000000c67db0df922238979da0fd00d46016e8ae14cecb",
          "00000000000000000000000000000000000000000000000000000000000026a7"
        ],
        "txHash": "f18291982e955f3c2112de58c1d0a08b79449fb473e58b173de7e0e189d34939"
      }
    ]
  }
}

----------- BLOCK #17,717,998 (372ff635821a434c81759b3b23e8dac59393fc27a7ebb88b561c1e5da3c4643a) ---------------
----------- BLOCK #17,717,999 (43f0878e119836cc789ecaf12c3280b82dc49567600cc44f6a042149e2a03779) ---------------
----------- BLOCK #17,718,000 (439efaf9cc0059890a09d34b4cb5a3fe4b61e8ef96ee67673c060d58ff951d4f) ---------------
----------- BLOCK #17,718,001 (c97ca5fd26db28128b0ec2483645348bbfe998e9a6e19e3a442221198254c9ea) ---------------
----------- BLOCK #17,718,002 (9398569e46a954378b16e0e7ce95e49d0f21e6119ed0e3ab84f1c91f16c0c30e) ---------------
----------- BLOCK #17,718,003 (80bcd4c1131c35a413c32903ffa52a14f8c8fe712492a8f6a0feddbb03b10bba) ---------------
----------- BLOCK #17,718,004 (d27309ac29fe47f09fa4987a318818c325403863a53eec6a3676c2c2f8c069d9) ---------------
all done

The block number 17717997 contains a transaction (f18291982e955f3c2112de58c1d0a08b79449fb473e58b173de7e0e189d34939) that executes a method of the smart contract, so the Substreams retrieves the corresponding logs. You can check out the logs at Etherscan and verify that topics are correct.