forked from DecentralizedClimateFoundation/DCIPs
98 lines
3.0 KiB
Markdown
98 lines
3.0 KiB
Markdown
---
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eip: 695
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title: Create `eth_chainId` method for JSON-RPC
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author: Isaac Ardis <isaac.ardis@gmail.com>, Wei Tang (@sorpaas), Fan Torchz (@tcz001), Erik Marks (@rekmarks)
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discussions-to: https://ethereum-magicians.org/t/eip-695-create-eth-chainid-method-for-json-rpc/1845
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type: Standards Track
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category: Interface
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status: Final
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created: 2017-08-21
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requires: 155
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---
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## Simple Summary
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Include `eth_chainId` method in `eth_`-namespaced JSON-RPC methods.
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## Abstract
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The `eth_chainId` method should return a single STRING result
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for an integer value in hexadecimal format, describing the
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currently configured `CHAIN_ID` value used for signing replay-protected transactions,
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introduced by [EIP-155](./eip-155.md).
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## Motivation
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Currently although we can use `net_version` RPC call to get the
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current network ID, there's no RPC for querying the chain ID. This
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makes it impossible to determine the current actual blockchain using
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the RPC.
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## Specification
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### `eth_chainId`
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Returns the currently configured chain ID, a value used in replay-protected transaction
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signing as introduced by [EIP-155](./eip-155.md).
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The chain ID returned should always correspond to the information in the current known
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head block. This ensures that caller of this RPC method can always use the retrieved
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information to sign transactions built on top of the head.
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If the current known head block does not specify a chain ID, the client should treat any
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calls to `eth_chainId` as though the method were not supported, and return a suitable
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error.
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#### Parameters
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None.
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#### Returns
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`QUANTITY` - integer of the current chain ID.
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#### Example
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```js
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curl -X POST --data '{"jsonrpc":"2.0","method":"eth_chainId","params":[],"id":83}'
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// Result
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{
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"id": 83,
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"jsonrpc": "2.0",
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"result": "0x3d" // 61
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}
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```
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## Rationale
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An ETH/ETC client can accidentally connect to an ETC/ETH RPC
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endpoint without knowing it unless it tries to sign a transaction or
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it fetch a transaction that is known to have signed with a chain
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ID. This has since caused trouble for application developers, such as
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MetaMask, to add multi-chain support.
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## Backwards Compatibility
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Not relevant.
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## Security Considerations
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Consumers should prefer `eth_chainId` over `net_version`, so that they can reliably identify chain they are communicating with.
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Implementers should take care to implement `eth_chainId` correctly and promote its use, since the chain ID is critical in replay attack prevention as described in [EIP-155](./eip-155.md), and consumers will rely on it to identify the chain they are communicating with.
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## Implementation
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- [Parity PR](https://github.com/paritytech/parity/pull/6329)
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- [Geth PR](https://github.com/ethereum/go-ethereum/pull/17617)
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- [Geth Classic PR](https://github.com/ethereumproject/go-ethereum/pull/336)
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## Reference
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Return value `QUANTITY` adheres to standard JSON RPC hex value encoding, as documented in the [Ethereum Wiki](https://github.com/ethereum/wiki/wiki/JSON-RPC#hex-value-encoding).
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## Copyright
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Copyright and related rights waived via [CC0](../LICENSE.md).
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