Support Ethereum-style JSON-RPC interface

[ychiaoli18]

Motivations

FVM’s M2.1 aims to support the EVM and the existing EVM ecosystem out of the box. Currently, the EVM’s existing developer tools and decentralized apps utilize Ethereum-style JSON-RPC APIs to interact with blockchains. Filecoin’s implementations, such as Lotus or Forest, do not speak those APIs now. For the existing EVM-based tools to support Filecoin with minimal change, Filecoin’s implementations have to implement the Ethereum-style JSON-RPC APIs.

This discussion aims to provide a prioritized list of the JSON-RPC methods that Filecoin should implement. We researched how Hardhat, Remix, and Alchemy use each method to understand their importance. The methods are ranked based on the following criteria:

• Nodes are not expected to hold keys, so the methods requiring the nodes to have private key information are excluded, such as eth_accounts, eth_signTransaction, eth_sign, etc.
• Nodes are not expected to provide any mining capabilities, so the methods related to mining are excluded, such as eth_hashrate, eth_getWork, eth_submitWork, etc.
• Nodes are not expected to provide information about uncle blocks, so methods like eth_getUncleByBlockHashAndIndex are excluded.
• Methods used by Hardhat and Remix are a high priority.
• Methods used by logs and events are a medium priority. Part of the reason is that the implementation detail of logs and events on FVM is currently under discussion.
• The rest of the methods are a low priority.
• Complexity is provided based on the FVM team’s experience on Lotus.

Specification

Included Methods

The methods are sorted according to the order of implementation priority.

Method	Importance	Complexity	Description
eth_blockNumber	High	Low	Returns the number of most recent block.
eth_getBlockByHash	High	Low	Returns information about a block by hash.
eth_getBlockByNumber	High	Low	Returns information about a block by number.
eth_getTransactionByHash	High	Low	Returns the information about a transaction requested by transaction hash.
eth_getTransactionCount	High	Low	Returns the number of transactions sent from an address.
eth_getTransactionReceipt	High	Low	Returns the receipt of a transaction by transaction hash.
eth_getTransactionByBlockHashAndIndex	High	Low	Returns information about a transaction by block hash and transaction index position.
eth_getTransactionByBlockNumberAndIndex	High	Low	Returns information about a transaction by block number and transaction index position.
eth_sendRawTransaction	High	Low	Submits a raw transaction.
eth_getBalance	High	Low	Returns the balance of the account of given address.
eth_gasPrice	High	Low	Returns the current price per gas in wei.
eth_chainId	High	Low	Returns the chain ID of the current network.
net_version	High	Low	Returns the current network id.
net_listening	High	Low	Returns true if client is actively listening for network connections.
eth_getCode	High	Medium	Returns code at a given address.
eth_call	High	High	Executes a new message call immediately without creating a transaction on the block chain.
eth_subscribe	High	High	Ethereum API - Subscribe to different event types like newHeads, logs, and pendingTransactions using websockets.
eth_unsubscribe	High	High	Subscriptions are cancelled with a regular RPC call with eth_unsubscribe as method and the subscription id as first parameter.
eth_estimateGas	High	Not sure	Generates and returns an estimate of how much gas is necessary to allow the transaction to complete.
eth_getStorageAt	Medium	Medium	Returns the value from a storage position at a given address.
eth_getLogs	Medium	High	Returns an array of all logs matching filter with given id.
eth_getFilterChanges	Medium	High	Polling method for a filter, which returns an array of logs which occurred since last poll.
eth_getFilterLogs	Medium	High	Returns an array of all logs matching filter with given id.
eth_newBlockFilter	Medium	High	Creates a filter in the node, to notify when a new block arrives.
eth_newFilter	Medium	High	Creates a filter object, based on filter options, to notify when the state changes (logs).
eth_newPendingTransactionFilter	Medium	High	Creates a filter in the node, to notify when new pending transactions arrive.
eth_uninstallFilter	Medium	High	Uninstalls a filter with given id.
eth_feeHistory	Medium	High	Transaction fee history
eth_getBlockTransactionCountByHash	Low	Low	Returns the number of transactions in a block from a block matching the given block hash.
eth_getBlockTransactionCountByNumber	Low	Low	Returns the number of transactions in a block matching the given block number.
eth_protocolVersion	Low	Low	Returns the current Ethereum protocol version.
eth_getBlockReceipts	Low	Medium	Get all transaction receipts for a given block on Ethereum.
eth_getProof	Low	Not sure	Returns the merkle proof for a given account and optionally some storage keys.
eth_maxPriorityFeePerGas	Low	Not sure	Returns a fee per gas that is an estimate of how much you can pay as a priority fee, or "tip", to get a transaction included in the current block.

Note: description field is adapted from Ethereum's API Spec and Alchemy's API Doc

Excluded Methods

Method	Description
eth_accounts	Returns a list of addresses owned by client.
eth_sign	Returns an EIP-191 signature over the provided data.
eth_signTransaction	Returns an RLP encoded transaction signed by the specified account.
eth_sendTransaction	Signs and submits a transaction.
eth_getUncleByBlockHashAndIndex	Returns information about an uncle of a block by hash and uncle index position.
eth_getUncleByBlockNumberAndIndex	Returns information about an uncle of a block by number and uncle index position.
eth_getUncleCountByBlockHash	Returns the number of uncles in a block from a block matching the given block hash.
eth_getUncleCountByBlockNumber	Returns the number of transactions in a block matching the given block number.
eth_syncing	Returns an object with data about the sync status or false.
eth_coinbase	Returns the client coinbase address.
eth_mining	Returns whether the client is actively mining new blocks.
eth_hashrate	Returns the number of hashes per second that the node is mining with.
eth_getWork	Returns the hash of the current block, the seedHash, and the boundary condition to be met (“target”).
eth_submitWork	Used for submitting a proof-of-work solution.
eth_submitHashrate	Used for submitting mining hashrate.

[mriise]

Events are still in spec land: https://github.com/filecoin-project/fvm-specs/issues/98

[Stebalien]

eth_sendRawTransaction

This has High complexity as we'll need to re-wrap the transaction as a Filecoin message (for vaildiation via an abstract ETH account: #388).