Decoding MsgPayForBlobs

Developers
1

Hi!
I’m writing client library in Python and I can’t decode Celestia specific MsgPayForBlobs message. Other (cosmos) messages seems to decode just fine.

...
import src.celestia_proto.ibc.core.channel.v1.tx_pb2
import src.celestia_proto.ibc.lightclients.tendermint.v1.tendermint_pb2
import src.celestia_proto.cosmos.staking.v1beta1.tx_pb2
from src.celestia_proto.cosmos.base.tendermint.v1beta1 import query_pb2
from src.celestia_proto.cosmos.base.tendermint.v1beta1 import query_pb2_grpc
...

candidate_messages = [
        cosmos_tx_tx_pb2.Tx,
        celestia_blob_tx_pb2.MsgPayForBlobs,
    ]
    for msg in candidate_messages:
        try:
            tx = msg()
            tx.ParseFromString(tx_bytes)
            logger.info(f"Decoded transaction with message type: {msg.DESCRIPTOR.name}")
            break
        except DecodeError:
            logger.warning(f"Failed to decode transaction with message type: {msg.DESCRIPTOR.name}", exc_info=True)
            continue
    else:
        raise DecodeError(f"Failed to decode transaction: {tx_bytes}")

# Output: google.protobuf.message.DecodeError: Failed to decode transaction: b'\n\x94\x03\n\xe5\x01\n\xe2\x01\n /celestia.blob.v1.MsgPayForBlobs\x12\xbd...'
2

yo gm,

where are you querying from?

1 Like
3

I’m querying from my local machine.
Sorry, I’ll post full code sample here

import grpc
import logging
import sys
import src.celestia_proto.cosmos.crypto.secp256k1.keys_pb2
import src.celestia_proto.cosmos.distribution.v1beta1.distribution_pb2
import src.celestia_proto.cosmos.distribution.v1beta1.tx_pb2
import src.celestia_proto.ibc.core.client.v1.client_pb2
import src.celestia_proto.ibc.core.client.v1.tx_pb2
import src.celestia_proto.ibc.core.channel.v1.channel_pb2
import src.celestia_proto.ibc.core.channel.v1.tx_pb2
import src.celestia_proto.ibc.lightclients.tendermint.v1.tendermint_pb2
import src.celestia_proto.cosmos.staking.v1beta1.tx_pb2
from src.celestia_proto.cosmos.base.tendermint.v1beta1 import query_pb2
from src.celestia_proto.cosmos.base.tendermint.v1beta1 import query_pb2_grpc


from google.protobuf.message import DecodeError
from src.celestia_proto.cosmos.tx.v1beta1 import tx_pb2 as cosmos_tx_tx_pb2
from src.celestia_proto.celestia.blob.v1 import tx_pb2 as celestia_blob_tx_pb2


logging.basicConfig(level=logging.INFO, stream=sys.stdout, format="%(levelname)s: %(message)s")
logger = logging.getLogger(__name__)


def decoded_transaction(tx_bytes: bytes) -> dict:
    candidate_messages = [
        cosmos_tx_tx_pb2.Tx,
        celestia_blob_tx_pb2.MsgPayForBlobs,
    ]
    for msg in candidate_messages:
        try:
            tx = msg()
            tx.ParseFromString(tx_bytes)
            logger.info(f"Decoded transaction with message type: {msg.DESCRIPTOR.name}")
            break
        except DecodeError:
            logger.warning(f"Failed to decode transaction with message type: {msg.DESCRIPTOR.name}", exc_info=True)
            continue
    else:
        raise DecodeError(f"Failed to decode transaction: {tx_bytes}")

    logger.info(f"Decodec tx: {tx}")
    # Convert basic transaction info to dict
    tx_data = {
        ...
    }
    return tx_data


def main():
    block_number = 3805069
    with grpc.insecure_channel("celestia-rpc.brightlystake.com:9090") as channel:
        stub = query_pb2_grpc.ServiceStub(channel)
        request = query_pb2.GetBlockByHeightRequest(height=block_number)
        response = stub.GetBlockByHeight(request)

    txs = response.block.data.txs
    logger.info(f"Number of transactions in block {block_number}: {len(txs)}")

    for i, tx_bytes in enumerate(txs):
        try:
            logger.info(f"Decoding transaction {i}")
            tx_data = decoded_transaction(tx_bytes)
            logger.info(str(tx_data)[:100])
        except Exception:
            logger.error(f"Failed to parse transaction {i}", exc_info=True)
            raise Exception("Failed to parse transaction")


if __name__ == '__main__':
    main()
1 Like
4

Here are the latest version of package I’m building on.
I’ve tried to use /cosmos/tx/v1beta1/service.proto.Service:GetBlockWithTxs at first, which was suppose to return already decoded transactions, but it can’t handle celestia specific MsgPayForBlobs type.
So I’ve switched to cosmos.base.tendermint.v1beta1.query_pb2_grpc.ServiceStub:GetBlockByHeight
which returns response just fine, but with encoded transactions.
Then, in the code, I’m iterating through each tx in attempt to decode it.
Cosmos transactions are being decoded with no problem, but
/celestia.blob.v1.MsgPayForBlobs
raises an exception “google.protobuf.message.DecodeError”

I’m guessing that approach should be to decode MsgPayForBlobs transaction with other message type first and after that parse it with MsgPayForBlobs type?
I just don’t know which message type I should use to parse it with. “Any” type seems to not work as well for some reason.

5

Thanks for your reply at Discord!

For everyone else: you can find blob definitions here.