extension/packages/extension-dapp/src/index.ts

// Copyright 2019-2021 @polkadot/extension-dapp authors & contributors
// SPDX-License-Identifier: Apache-2.0

import type { Injected, InjectedAccount, InjectedAccountWithMeta, InjectedExtension, InjectedExtensionInfo, InjectedProviderWithMeta, InjectedWindow, ProviderList, Unsubcall, Web3AccountsOptions } from '@polkadot/extension-inject/types';

import { u8aEq } from '@polkadot/util';
import { decodeAddress, encodeAddress } from '@polkadot/util-crypto';

import initCompat from './compat';
import { documentReadyPromise } from './util';

// expose utility functions
export { unwrapBytes, wrapBytes } from './wrapBytes';

// just a helper (otherwise we cast all-over, so shorter and more readable)
const win = window as Window & InjectedWindow;

// don't clobber the existing object, but ensure non-undefined
win.injectedWeb3 = win.injectedWeb3 || {};

// true when anything has been injected and is available
function web3IsInjected (): boolean {
  return Object.keys(win.injectedWeb3).length !== 0;
}

// helper to throw a consistent error when not enabled
function throwError (method: string): never {
  throw new Error(`${method}: web3Enable(originName) needs to be called before ${method}`);
}

// internal helper to map from Array<InjectedAccount> -> Array<InjectedAccountWithMeta>
function mapAccounts (source: string, list: InjectedAccount[], ss58Format?: number): InjectedAccountWithMeta[] {
  return list.map(({ address, genesisHash, name, type }): InjectedAccountWithMeta => {
    const encodedAddress = address.length === 42 ? address : encodeAddress(decodeAddress(address), ss58Format);

    return ({
      address: encodedAddress,
      meta: { genesisHash, name, source },
      type
    });
  });
}

// have we found a properly constructed window.injectedWeb3
let isWeb3Injected = web3IsInjected();

// we keep the last promise created around (for queries)
let web3EnablePromise: Promise<InjectedExtension[]> | null = null;

export { isWeb3Injected, web3EnablePromise };

function getWindowExtensions (originName: string): Promise<[InjectedExtensionInfo, Injected | void][]> {
  return Promise.all(
    Object.entries(win.injectedWeb3).map(
      ([name, { enable, version }]): Promise<[InjectedExtensionInfo, Injected | void]> =>
        Promise.all([
          Promise.resolve({ name, version }),
          enable(originName).catch((error: Error): void => {
            console.error(`Error initializing ${name}: ${error.message}`);
          })
        ])
    )
  );
}

// enables all the providers found on the injected window interface
export function web3Enable (originName: string): Promise<InjectedExtension[]> {
  if (!originName) {
    throw new Error('You must pass a name for your app to the web3Enable function');
  }

  web3EnablePromise = documentReadyPromise(
    (): Promise<InjectedExtension[]> =>
      initCompat().then(() =>
        getWindowExtensions(originName)
          .then((values): InjectedExtension[] =>
            values
              .filter((value): value is [InjectedExtensionInfo, Injected] => !!value[1])
              .map(([info, ext]): InjectedExtension => {
                // if we don't have an accounts subscriber, add a single-shot version
                if (!ext.accounts.subscribe) {
                  ext.accounts.subscribe = (cb: (accounts: InjectedAccount[]) => void | Promise<void>): Unsubcall => {
                    ext.accounts.get().then(cb).catch(console.error);

                    return (): void => {
                      // no ubsubscribe needed, this is a single-shot
                    };
                  };
                }

                return { ...info, ...ext };
              })
          )
          .catch((): InjectedExtension[] => [])
          .then((values): InjectedExtension[] => {
            const names = values.map(({ name, version }): string => `${name}/${version}`);

            isWeb3Injected = web3IsInjected();
            console.log(`web3Enable: Enabled ${values.length} extension${values.length !== 1 ? 's' : ''}: ${names.join(', ')}`);

            return values;
          })
      )
  );

  return web3EnablePromise;
}

// retrieve all the accounts across all providers
export async function web3Accounts ({ accountType, ss58Format }: Web3AccountsOptions = {}): Promise<InjectedAccountWithMeta[]> {
  if (!web3EnablePromise) {
    return throwError('web3Accounts');
  }

  const accounts: InjectedAccountWithMeta[] = [];
  const injected = await web3EnablePromise;

  const retrieved = await Promise.all(
    injected.map(async ({ accounts, name: source }): Promise<InjectedAccountWithMeta[]> => {
      try {
        const list = await accounts.get();

        return mapAccounts(source, list.filter(({ type }) => type && accountType ? accountType.includes(type) : true), ss58Format);
      } catch (error) {
        // cannot handle this one
        return [];
      }
    })
  );

  retrieved.forEach((result): void => {
    accounts.push(...result);
  });

  const addresses = accounts.map(({ address }) => address);

  console.log(`web3Accounts: Found ${accounts.length} address${accounts.length !== 1 ? 'es' : ''}: ${addresses.join(', ')}`);

  return accounts;
}

export async function web3AccountsSubscribe (cb: (accounts: InjectedAccountWithMeta[]) => void | Promise<void>, { ss58Format }: Web3AccountsOptions = {}): Promise<Unsubcall> {
  if (!web3EnablePromise) {
    return throwError('web3AccountsSubscribe');
  }

  const accounts: Record<string, InjectedAccount[]> = {};

  const triggerUpdate = (): void | Promise<void> =>
    cb(
      Object.entries(accounts).reduce(
        (result: InjectedAccountWithMeta[], [source, list]): InjectedAccountWithMeta[] => {
          result.push(...mapAccounts(source, list, ss58Format));

          return result;
        },
        []
      )
    );

  const unsubs = (await web3EnablePromise).map(
    ({ accounts: { subscribe }, name: source }): Unsubcall =>
      subscribe((result): void => {
        accounts[source] = result;

        // eslint-disable-next-line @typescript-eslint/no-floating-promises
        triggerUpdate();
      })
  );

  return (): void => {
    unsubs.forEach((unsub): void => {
      unsub();
    });
  };
}

// find a specific provider based on the name
export async function web3FromSource (source: string): Promise<InjectedExtension> {
  if (!web3EnablePromise) {
    return throwError('web3FromSource');
  }

  const sources = await web3EnablePromise;
  const found = source && sources.find(({ name }): boolean => name === source);

  if (!found) {
    throw new Error(`web3FromSource: Unable to find an injected ${source}`);
  }

  return found;
}

// find a specific provider based on an address
export async function web3FromAddress (address: string): Promise<InjectedExtension> {
  if (!web3EnablePromise) {
    return throwError('web3FromAddress');
  }

  const accounts = await web3Accounts();
  let found: InjectedAccountWithMeta | undefined;

  if (address) {
    const accountU8a = decodeAddress(address);

    found = accounts.find((account): boolean => u8aEq(decodeAddress(account.address), accountU8a));
  }

  if (!found) {
    throw new Error(`web3FromAddress: Unable to find injected ${address}`);
  }

  return web3FromSource(found.meta.source);
}

// retrieve all providers exposed by one source
export async function web3ListRpcProviders (source: string): Promise<ProviderList | null> {
  const { provider } = await web3FromSource(source);

  if (!provider) {
    console.warn(`Extension ${source} does not expose any provider`);

    return null;
  }

  return provider.listProviders();
}

// retrieve all providers exposed by one source
export async function web3UseRpcProvider (source: string, key: string): Promise<InjectedProviderWithMeta> {
  const { provider } = await web3FromSource(source);

  if (!provider) {
    throw new Error(`Extension ${source} does not expose any provider`);
  }

  const meta = await provider.startProvider(key);

  return { meta, provider };
}