farcasterxyz/hub-monorepo @farcaster/core@0.20.0

on GitHub

Minor Changes

• 9c0d7c2: feat: builders and EIP-712 helpers for gasless signers (FIP-272)

  The V16 protos for KEY_ADD / KEY_REMOVE shipped in 0.18.11, but nothing above the wire
  format did — callers had to hand-roll the EIP-712 signatures and ABI encoding. This adds the
  missing layer.

  BREAKING for custom Eip712Signer subclasses. Four abstract methods are added to
  Eip712Signer; any class extending it outside this repo must implement them to compile. All
  four bundled signers (ViemLocalEip712Signer, ViemWalletEip712Signer, EthersEip712Signer,
  EthersV5Eip712Signer) are updated. Callers that only use signers are unaffected.

  • New gaslessKeys module: the Farcaster KeyAdd EIP-712 domain and its KeyAdd,
    KeyRemove and SignedKeyRequest types, verifyKeyAdd / verifyKeyRemove /
    verifyGaslessKeyRequest, metadata encode/decode, and the protocol constants
    (MAX_KEY_TTL_SECONDS, MAX_KEY_ADD_SCOPES, MAX_GASLESS_KEYS_PER_FID,
    ADMISSIBLE_KEY_ADD_SCOPES, key and signature type discriminants).
  • New Eip712Signer methods: signKeyAdd, signKeyRemove, signGaslessKeyRequest and
    getGaslessSignedKeyRequestMetadata.
  • New builders: makeKeyAddBody, makeKeyRemoveBody, makeKeyRemoveBodySelfRevoke,
    makeKeyAdd, makeKeyAddData, makeKeyRemove, makeKeyRemoveData.
  • validations.validateKeyAddBody and validateKeyRemoveBody, wired into
    validateMessageData so KEY_ADD / KEY_REMOVE are no longer rejected as
    bodyType is invalid. validateKeyAddBody also decodes the SignedKeyRequest
    metadata blob and, given the enclosing MessageData.timestamp, rejects an expired
    one — matching verify_signed_key_request_metadata so an authorization that the
    node would reject fails before submit rather than at merge time. It compares
    against the message's own timestamp, not wall-clock, so replaying a valid old
    message stays deterministic.

  Note that snapchain's SignedKeyRequest shares a struct name with the onchain
  SignedKeyRequestValidator flow but uses a different EIP-712 domain — Farcaster KeyAdd,
  chainId 1, no verifyingContract. The existing signKeyRequest and
  getSignedKeyRequestMetadata remain the onchain versions and produce signatures snapchain
  rejects; the Gasless-prefixed methods are their off-chain counterparts. The two are not
  interchangeable.