danfinlay

MetaMask Snaps JSON-RPC UI API Documentation

This documentation covers the JSON-RPC methods provided by the SnapInterfaceController for generating user interfaces in MetaMask Snaps.

Overview

The MetaMask Snaps platform provides a JSON-RPC API for Snaps (third-party extensions) to create and interact with user interfaces within the MetaMask environment. These interfaces allow Snaps to display information, collect user input, and provide interactive experiences without requiring direct DOM access.

Available Methods

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Bio

danfinlay

• 
• Goal:
  • An [[Ethereum]] smart account architecture composed from a very small and simple pattern of flexible delegation with maximally off-chain, low-state contracts.
• Axioms / Dependencies / Prior Art / Prerequisites & Tools
  • [[gnosis-safe style module]]s
    • Each module can call any function on the parent contract.
  • [[create2]] deterministic addressing
    • Account can delegate to unpublished contracts.
  • [[Will-o-wisps]]
• Stateless delegations can clean themselves up, leaving no state-bloat on-chain.

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• low-level signing method
  • Things that need to be done
    • Consider this kind of raw signing from security. Ask [[Christian Lundkvist]]
    • Consider drafting an EIP for this, so it can get broader security consideration.
  • Code that would need to be changed
    • eth-json-rpc-middleware is a nice-to-change, although we could make a middleware just for this method.
    • It looks like eth-simple-keyring already signs arbitrary data, so the validation is not done at this level.
    • eth-keyring-controller also just passes through to the keyring, no validation.
• MetaMask Controller

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const funcString = '() => "foo"';
const funcA = new Function(funcString);
const funcB = new Function(funcString);

const map = new Map();
map.set(funcA, 'a');
map.set(funcB, 'b');
const aVal = map.get(funcA);
console.log(aVal === 'a');

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did:muport:QmRirsVfbq9KhAYjrTeWKBcEyTaJ6LLtjLBQkJX2cGwjQo

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signTypedData Test Cases

signTypedData_v1 (aka signTypedData in the MetaMask provider)

• privKey: 4af1bceebf7f3634ec3cff8a2c38e51178d5d4ce585c52d6043e5e2cc3418bb0
• param: [ { type: 'string', name: 'message', value: 'Hi, Alice!' } ]
• signature: 0x49e75d475d767de7fcc67f521e0d86590723d872e6111e51c393e8c1e2f21d032dfaf5833af158915f035db6af4f37bf2d5d29781cd81f28a44c5cb4b9d241531b

signTypedData_v3 (aka EIP 712 spec, aka ethSigUtil.signTypedData for bad reasons)

danfinlay

const requestedPermissions = {
  eth_accounts: {},
  eth_sendTransaction: {},
  eth_decrypt: {},
};

async function main () {
  const provider = window.ethereum
  await provider.enable({ requestedPermissions });
  await provider.send({ method: 'eth_sendTransaction', parameters:[{ to: me, value: aModestSum }] });

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