extension/README.md

@polkadot/extension

A very simple scaffolding browser extension that injects a @polkadot/api Signer into a page, along with any associated accounts, allowing for use by the application. This is an extensible POC implementation of a Polkadot/Substrate browser signer.

As it stands, it does one thing: it only manages accounts and allows the signing of transactions with those accounts. (It does not inject providers for use by dapps, not does it perform the function of a wallet where it submits txs to the network).

Running

Currently is not packaged since it is under heavy development. To use -

1. Build via yarn build or yarn watch
2. Add the extension under chrome://extensions/ (ensure you have the Development flag set) and "Load unpacked"
3. When visiting http://localhost:3000 or https://polkadot.js.org/apps/ it will inject (the menifest currently only lists these 2 endpoints)

Once added, you can create an account (via a generated seed) or import via an existing seed.

Overview

It injects injectedWeb3 into the global window object, exposing the following:

// a version that identifies the actual injection version (future-use)
type Version = 0;

// an interface describing an account
interface Account {
  readonly address: string; // ss-58 encoded address
  readonly name?: string; // optional name for display
}

// exposes accounts
interface Accounts {
  readonly all: Array<Account>;
}

// a signer that communicates with the extension via sendMessage
interface Signer extends SignerInterface {
  // no specific signer extensions
}

interface Injected {
  readonly accounts: Accounts;
  readonly signer: Signer;
  readonly version: Version;
}

The app can use all or any of these, depending on needs. To instantiate the @polkadot/api with the provider (app does not have it's own) and the signer (allowing the extension to sign messages) can be done via -

import { ApiPromise } from '@polkadot/api';

const { signer } = window.injectedWeb3;
const api = await Api.create({ signer });