const Web3 = require('web3') const contracts = require('eth-contract-metadata') const { warn } = require('loglevel') const { MAINNET } = require('./network/enums') // By default, poll every 3 minutes const DEFAULT_INTERVAL = 180 * 1000 const ERC20_ABI = [{'constant': true, 'inputs': [{'name': '_owner', 'type': 'address'}], 'name': 'balanceOf', 'outputs': [{'name': 'balance', 'type': 'uint256'}], 'payable': false, 'type': 'function'}] /** * A controller that polls for token exchange * rates based on a user's current token list */ class DetectTokensController { /** * Creates a DetectTokensController * * @param {Object} [config] - Options to configure controller */ constructor ({ interval = DEFAULT_INTERVAL, preferences, network, keyringMemStore } = {}) { this.preferences = preferences this.interval = interval this.network = network this.keyringMemStore = keyringMemStore } /** * For each token in eth-contract-metada, find check selectedAddress balance. * */ async detectNewTokens () { if (!this.isActive) { return } if (this._network.store.getState().provider.type !== MAINNET) { return } this.web3.setProvider(this._network._provider) for (const contractAddress in contracts) { if (contracts[contractAddress].erc20 && !(this.tokenAddresses.includes(contractAddress.toLowerCase()))) { this.detectTokenBalance(contractAddress) } } } /** * Find if selectedAddress has tokens with contract in contractAddress. * * @param {string} contractAddress Hex address of the token contract to explore. * @returns {boolean} If balance is detected, token is added. * */ async detectTokenBalance (contractAddress) { const ethContract = this.web3.eth.contract(ERC20_ABI).at(contractAddress) ethContract.balanceOf(this.selectedAddress, (error, result) => { if (!error) { if (!result.isZero()) { this._preferences.addToken(contractAddress, contracts[contractAddress].symbol, contracts[contractAddress].decimals) } } else { warn(`MetaMask - DetectTokensController balance fetch failed for ${contractAddress}.`, error) } }) } /** * Restart token detection polling period and call detectNewTokens * in case of address change or user session initialization. * */ restartTokenDetection () { if (!(this.isActive && this.selectedAddress)) { return } this.detectNewTokens() this.interval = DEFAULT_INTERVAL } /** * @type {Number} */ set interval (interval) { this._handle && clearInterval(this._handle) if (!interval) { return } this._handle = setInterval(() => { this.detectNewTokens() }, interval) } /** * In setter when selectedAddress is changed, detectNewTokens and restart polling * @type {Object} */ set preferences (preferences) { if (!preferences) { return } this._preferences = preferences preferences.store.subscribe(({ tokens }) => { this.tokenAddresses = tokens.map((obj) => { return obj.address }) }) preferences.store.subscribe(({ selectedAddress }) => { if (this.selectedAddress !== selectedAddress) { this.selectedAddress = selectedAddress this.restartTokenDetection() } }) } /** * @type {Object} */ set network (network) { if (!network) { return } this._network = network this.web3 = new Web3(network._provider) } /** * In setter when isUnlocked is updated to true, detectNewTokens and restart polling * @type {Object} */ set keyringMemStore (keyringMemStore) { if (!keyringMemStore) { return } this._keyringMemStore = keyringMemStore this._keyringMemStore.subscribe(({ isUnlocked }) => { if (this.isUnlocked !== isUnlocked) { this.isUnlocked = isUnlocked if (isUnlocked) { this.restartTokenDetection() } } }) } /** * Internal isActive state * @type {Object} */ get isActive () { return this.isOpen && this.isUnlocked } } module.exports = DetectTokensController