EIP 695: Create `eth_chainId` method for JSON-RPC

Author	Isaac Ardis, Wei Tang, Fan Torchz
Status	Draft
Type	Standards Track
Category	Interface
Created	2017-08-21

Simple Summary

Include eth_chainId method in eth_-namespaced JSON-RPC methods.

Abstract

The eth_chainId method should return a single STRING result for an integer value in hexadecimal format, describing the currently configured “Chain Id” value used for signing replay-protected transactions, introduced via EIP-155.

Motivation

Currently although we can use net_version RPC call to get the current network ID, there’s no RPC for querying the chain ID. This makes it impossible to determine the current actual blockchain using the RPC.

Specification

eth_chainId

Returns the currently configured chain id, a value used in replay-protected transaction signing as introduced by EIP-155.

Parameters

none

Returns

QUANTITY - integer of the current chain id. Defaults are mainnet=61, morden=62.

Example

curl -X POST --data '{"jsonrpc":"2.0","method":"eth_chainId","params":[],"id":1}'

// Result
{
  "id":83,
  "jsonrpc": "2.0",
  "result": "0x3d" // 61
}

Rationale

An ETH/ETC client can accidentally connect to an ETC/ETH RPC endpoint without knowing it unless it tries to sign a transaction or it fetch a transaction that is known to have signed with a chain ID. This has since caused trouble for application developers, such as MetaMask, to add multi-chain support.

Please note related links:

Backwards Compatibility

Not relevant.

Test Cases

Not currently implemented.

Implementation

Would be good to have a test to confirm that expected==got.

Reference

Return value QUANTITY adheres to standard JSON RPC hex value encoding, as documented here: https://github.com/ethereum/wiki/wiki/JSON-RPC#hex-value-encoding.

EIP 695: Create `eth_chainId` method for JSON-RPC Source