Merge pull request #136 from liquality/is-wallet-available

WalletProvider: implement isWalletAvailable for ledger and metamask

Author: monokh

src/Client.js

@@ -538,6 +538,10 @@ export default class Client {
     return this.getMethod('refundSwap')(initiationTxHash, recipientAddress, refundAddress, secretHash, expiration)
   }
 
+  async isWalletAvailable () {
+    return this.getMethod('isWalletAvailable')()
+  }
+
   async getWalletNetworkId () {
     return this.getMethod('getWalletNetworkId')()
   }

src/providers/LedgerProvider.js

@@ -7,12 +7,15 @@ export default class LedgerProvider extends WalletProvider {
     return Transport.isSupported()
   }
 
-  constructor (App, baseDerivationPath, network) {
+  constructor (App, baseDerivationPath, network, ledgerScrambleKey) {
     super(network)
 
     this._App = App
     this._baseDerivationPath = baseDerivationPath
     this._network = network
+    // The ledger scramble key is required to be set on the ledger transport
+    // if communicating with the device using `transport.send` for the first time
+    this._ledgerScrambleKey = ledgerScrambleKey
     this._addressCache = {}
   }
 
@@ -58,6 +61,24 @@ export default class LedgerProvider extends WalletProvider {
     return this._appInstance
   }
 
+  async isWalletAvailable () {
+    const app = await this.getApp()
+    if (!app.transport.scrambleKey) { // scramble key required before calls
+      app.transport.setScrambleKey(this._ledgerScrambleKey)
+    }
+    const exchangeTimeout = app.transport.exchangeTimeout
+    app.transport.setExchangeTimeout(2000)
+    try {
+      // https://ledgerhq.github.io/btchip-doc/bitcoin-technical-beta.html#_get_random
+      await LedgerProvider.transport.send(0xe0, 0xc0, 0x00, 0x00)
+    } catch (e) {
+      return false
+    } finally {
+      app.transport.setExchangeTimeout(exchangeTimeout)
+    }
+    return true
+  }
+
   async getConnectedNetwork () {
     // Ledger apps do not provide connected network. It is separated in firmware.
     return this._network

src/providers/WalletProvider.js

@@ -11,7 +11,8 @@ export default class WalletProvider extends Provider {
         'constructor',
         '_networkMatchProxy',
         'getConnectedNetwork',
-        'assertNetworkMatch'
+        'assertNetworkMatch',
+        'isWalletAvailable'
       ].includes(method))
     return network ? new Proxy(this, { get: this._networkMatchProxy.bind(this) }) : this
   }
@@ -35,6 +36,10 @@ export default class WalletProvider extends Provider {
     }
   }
 
+  isWalletAvailable () {
+    throw new Error('isWalletAvailable not implemented.')
+  }
+
   getAddresses () {
     throw new Error('getAddresses not implemented.')
   }

src/providers/bitcoin/BitcoinLedgerProvider.js

@@ -10,7 +10,7 @@ import bip32 from 'bip32'
 
 export default class BitcoinLedgerProvider extends LedgerProvider {
   constructor (chain = { network: networks.bitcoin, segwit: false }, numberOfBlockConfirmation = 1) {
-    super(Bitcoin, `${chain.segwit ? '49' : '44'}'/${chain.network.coinType}'/0'/`, chain.network)
+    super(Bitcoin, `${chain.segwit ? '49' : '44'}'/${chain.network.coinType}'/0'/`, chain.network, 'BTC')
     this._derivationPath = `${chain.segwit ? '49' : '44'}'/${chain.network.coinType}'/0'/`
     this._network = chain.network
     this._bjsnetwork = chain.network.name.replace('bitcoin_', '') // for bitcoin js

src/providers/ethereum/EthereumLedgerProvider.js

@@ -6,7 +6,7 @@ import Address from '../../Address'
 
 export default class EthereumLedgerProvider extends LedgerProvider {
   constructor (chain = { network: networks.mainnet }) {
-    super(Ethereum, `44'/${chain.network.coinType}'/0'/`)
+    super(Ethereum, `44'/${chain.network.coinType}'/0'/`, chain.network, 'w0w') // srs!
   }
 
   async getAddressFromDerivationPath (path) {

src/providers/ethereum/EthereumMetaMaskProvider.js

@@ -16,6 +16,11 @@ export default class EthereumMetaMaskProvider extends WalletProvider {
     this._network = network
   }
 
+  async isWalletAvailable () {
+    const addresses = await this._toMM('eth_accounts')
+    return addresses.length > 0
+  }
+
   _toMM (method, ...params) {
     return new Promise((resolve, reject) => {
       this