8 files changed, 84 insertions, 0 deletions
diff --git a/app/scripts/controllers/blacklist.js b/app/scripts/controllers/blacklist.js
index df41c90c0..d965f80b8 100644
--- a/app/scripts/controllers/blacklist.js
+++ b/app/scripts/controllers/blacklist.js
@@ -1,6 +1,7 @@
 const ObservableStore = require('obs-store')
 const extend = require('xtend')
 const PhishingDetector = require('eth-phishing-detect/src/detector')
+const log = require('loglevel')
 
 // compute phishing lists
 const PHISHING_DETECTION_CONFIG = require('eth-phishing-detect/src/config.json')
diff --git a/app/scripts/controllers/currency.js b/app/scripts/controllers/currency.js
index 37a19ff0d..480c08b1c 100644
--- a/app/scripts/controllers/currency.js
+++ b/app/scripts/controllers/currency.js
@@ -1,5 +1,6 @@
   const ObservableStore = require('obs-store')
 const extend = require('xtend')
+const log = require('loglevel')
 
 // every ten minutes
 const POLLING_INTERVAL = 600000
diff --git a/app/scripts/controllers/infura.js b/app/scripts/controllers/infura.js
index c6b4c9de2..8f6dd837e 100644
--- a/app/scripts/controllers/infura.js
+++ b/app/scripts/controllers/infura.js
@@ -1,5 +1,6 @@
 const ObservableStore = require('obs-store')
 const extend = require('xtend')
+const log = require('loglevel')
 
 // every ten minutes
 const POLLING_INTERVAL = 10 * 60 * 1000
diff --git a/app/scripts/controllers/network.js b/app/scripts/controllers/network.js
index 617456cd7..45574e673 100644
--- a/app/scripts/controllers/network.js
+++ b/app/scripts/controllers/network.js
@@ -9,6 +9,7 @@ const extend = require('xtend')
 const EthQuery = require('eth-query')
 const createEventEmitterProxy = require('../lib/events-proxy.js')
 const networkConfig = require('../config.js')
+const log = require('loglevel')
 const { OLD_UI_NETWORK_TYPE, DEFAULT_RPC } = networkConfig.enums
 const INFURA_PROVIDER_TYPES = ['ropsten', 'rinkeby', 'kovan', 'mainnet']
 
diff --git a/app/scripts/controllers/recent-blocks.js b/app/scripts/controllers/recent-blocks.js
index 4ae3810eb..0c1ee4e38 100644
--- a/app/scripts/controllers/recent-blocks.js
+++ b/app/scripts/controllers/recent-blocks.js
@@ -2,6 +2,7 @@ const ObservableStore = require('obs-store')
 const extend = require('xtend')
 const BN = require('ethereumjs-util').BN
 const EthQuery = require('eth-query')
+const log = require('loglevel')
 
 class RecentBlocksController {
 
diff --git a/app/scripts/controllers/shapeshift.js b/app/scripts/controllers/shapeshift.js
index 203dd99bd..b2a1462c2 100644
--- a/app/scripts/controllers/shapeshift.js
+++ b/app/scripts/controllers/shapeshift.js
@@ -1,5 +1,6 @@
 const ObservableStore = require('obs-store')
 const extend = require('xtend')
+const log = require('loglevel')
 
 // every three seconds when an incomplete tx is waiting
 const POLLING_INTERVAL = 3000
diff --git a/app/scripts/controllers/token-rates.js b/app/scripts/controllers/token-rates.js
new file mode 100644
index 000000000..22e3e8154
--- /dev/null
+++ b/app/scripts/controllers/token-rates.js
@@ -0,0 +1,77 @@
+const ObservableStore = require('obs-store')
+
+// By default, poll every 3 minutes
+const DEFAULT_INTERVAL = 180 * 1000
+
+/**
+ * A controller that polls for token exchange
+ * rates based on a user's current token list
+ */
+class TokenRatesController {
+  /**
+   * Creates a TokenRatesController
+   *
+   * @param {Object} [config] - Options to configure controller
+   */
+  constructor ({ interval = DEFAULT_INTERVAL, preferences } = {}) {
+    this.store = new ObservableStore()
+    this.preferences = preferences
+    this.interval = interval
+  }
+
+  /**
+   * Updates exchange rates for all tokens
+   */
+  async updateExchangeRates () {
+    if (!this.isActive) { return }
+    const contractExchangeRates = {}
+    for (const i in this._tokens) {
+      const address = this._tokens[i].address
+      contractExchangeRates[address] = await this.fetchExchangeRate(address)
+    }
+    this.store.putState({ contractExchangeRates })
+  }
+
+  /**
+   * Fetches a token exchange rate by address
+   *
+   * @param {String} address - Token contract address
+   */
+  async fetchExchangeRate (address) {
+    try {
+      const response = await fetch(`https://exchanges.balanc3.net/prices?from=${address}&to=ETH&autoConversion=false&summaryOnly=true`)
+      const json = await response.json()
+      return json && json.length ? json[0].averagePrice : 0
+    } catch (error) { }
+  }
+
+  /**
+   * @type {Number} - Interval used to poll for exchange rates
+   */
+  set interval (interval) {
+    this._handle && clearInterval(this._handle)
+    if (!interval) { return }
+    this._handle = setInterval(() => { this.updateExchangeRates() }, interval)
+  }
+
+  /**
+   * @type {Object} - Preferences controller instance
+   */
+  set preferences (preferences) {
+    this._preferences && this._preferences.unsubscribe()
+    if (!preferences) { return }
+    this._preferences = preferences
+    this.tokens = preferences.getState().tokens
+    preferences.subscribe(({ tokens = [] }) => { this.tokens = tokens })
+  }
+
+  /**
+   * @type {Array} - Array of token objects with contract addresses
+   */
+  set tokens (tokens) {
+    this._tokens = tokens
+    this.updateExchangeRates()
+  }
+}
+
+module.exports = TokenRatesController
diff --git a/app/scripts/controllers/transactions.js b/app/scripts/controllers/transactions.js
index 336b0d8f7..c8211ebd7 100644
--- a/app/scripts/controllers/transactions.js
+++ b/app/scripts/controllers/transactions.js
@@ -7,6 +7,7 @@ const TransactionStateManager = require('../lib/tx-state-manager')
 const TxGasUtil = require('../lib/tx-gas-utils')
 const PendingTransactionTracker = require('../lib/pending-tx-tracker')
 const NonceTracker = require('../lib/nonce-tracker')
+const log = require('loglevel')
 
 /*
   Transaction Controller is an aggregate of sub-controllers and trackers