feat(anvil): expose api to query blobs on anvil

[Thegaram]

Component

Anvil

Describe the feature you would like

• Add an option in anvil to store and index blob sidecars.
• Add an API to retrieve blobs. E.g. anvil_getBlobByHash (by blobVersionedHash), or anvil_getBlobsByTransactionHash (by transactionHash).

Additional context

Many rollup teams use anvil as a convenient tool for running devnets, mainnet shadowfork tests, etc. In this setup, the rollup node produces an L2 chain and sends blob transactions to L1 (anvil). This is already possible today.

Some aspects of rollups (e.g. chain derivation) require L2 nodes to query blobs and decode them. This is currently not possible because anvil does not persist blobs and does not provide an API to query them (see previous discussion).

As an example, Scroll's node currently supports 4 types of blob sources:

• Beacon API "/eth/v1/beacon/blob_sidecars". This takes the slot as its argument, so probably not suitable for Anvil.
• Blobscan API: https://api.blobscan.com/#/blobs/blob-getByBlobId
• BlockNative API: https://docs.blocknative.com/blocknative-data-archive/blob-archive
• AWS S3.

If Anvil exposed an API similar to Blobscan's, it would be easy for our team to add a new anvil blob source and use that on devnets.

[mattsse]

I do think we keep the sidecar so these additional endpoints would make sense

I believe if you query the raw blob tx then this should return the full 4844 tx with sidecar

but these additional endpoints to query the blobs by hash also make sense

maybe @Soubhik-10 or @Rimeeeeee want to look into this :)

[Soubhik-10]

May I take it..@Rimeeeeee ?

[Rimeeeeee]

May I take it..@Rimeeeeee ?

Sure :)

[Thegaram]

I believe if you query the raw blob tx then this should return the full 4844 tx with sidecar

@mattsse do you mean via eth_getTransactionByHash or eth_getRawTransactionByHash? I don't think that's the case, since the blob sidecars are not part of the JSON-RPC spec.

I just tested by running an anvil mainnet fork and querying a pre-fork 4844 transaction, the response did not include the blob sidecars. Not sure it this would be different if I sent a 4844 tx to anvil and then queried it.

[mattsse]

eth_getRawTransactionByHash

[mattsse]

@Soubhik-10 we should ensure that we store the sidecars when we mine a block

foundry/crates/anvil/core/src/eth/block.rs

Line 21 in 6d1d624

pub transactions: Vec<Transaction>,

and then the additional endpoints would need to just scan all blocks+4844 txs which should be reasonably fast