[FEATURE] Add listener for address at RIPPLE_ADDRESS

Procfile

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+listener node listener.js

listener.js

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+var WebSocket = require('ws'),
+    Payment = require('./payment');
+var websocketUrl = 'wss://s1.ripple.com';
+var rippleAddress = process.env.RIPPLE_ADDRESS;
+
+function onOpen() {
+  console.log('connection opened');
+  this.send('{"command":"subscribe","id":0,"accounts":["'+rippleAddress+'"]}');
+  console.log('listening for activity for account: '+ rippleAddress);
+}
+
+function onMessage(data, flags) {
+  var response = JSON.parse(data);
+  if (response.type == 'transaction') {
+    try {
+      var payment = new Payment(data);
+      console.log(payment.toJSON());
+    } catch(e) {
+      console.log(e);
+    }
+  }
+}
+
+function onClose() {
+  console.log('connection closed')
+  delete this;
+  connectWebsocket(websocketUrl);
+}
+
+function connectWebsocket(url) {
+  console.log('connecting to '+url);
+  try {
+    var ws = new WebSocket(url);
+    ws.on('open', onOpen);
+    ws.on('message', onMessage);
+    ws.on('close', onClose);
+  } catch(e) {
+    console.log('error connecting', e);
+    console.log('trying again...');
+    connectWebsocket(url);
+  }
+}
+
+connectWebsocket(websocketUrl);

payment.js

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+var gatewayHotWalletAddress = process.env.RIPPLE_ADDRESS;
+
+function Ledger(hash, index) {
+  this.hash = hash;
+  this.index = index;
+  this.transactions = [];
+}
+
+function Payment(msg) {
+  var message = JSON.parse(msg);
+  this.result = message.engine_result;
+  this.validated = message.validated;
+
+  function parseXrpAmount(drops) {
+    return parseFloat(drops) / 100000;
+  }
+
+  if ((typeof message.transaction.Amount) == 'string') {
+    this.toAmount = parseXrpAmount(message.transaction.Amount);
+    this.toCurrency = 'XRP';
+  } else {
+    this.toAmount = message.transaction.Amount.value;
+    this.toCurrency = message.transaction.Amount.currency;
+  }
+
+  if (!!message.transaction.SendMax) {
+    this.fromAmount = message.transaction.SendMax.value;
+    this.fromCurrency = message.transaction.SendMax.currency;
+  } else {
+    this.fromAmount = parseXrpAmount(message.transaction.Amount);
+    this.fromCurrency = 'XRP';
+  }
+
+  this.toAddress = message.transaction.Destination;
+  this.fromAddress = message.transaction.Account;
+
+  this.txState = message.meta.TransactionResult;
+  this.txHash = message.transaction.hash;
+  this.destinationTag = message.transaction.DestinationTag;
+
+  if (this.result != 'tesSUCCESS') {
+    throw new Error("Result not tesSUCCESS");
+  }
+
+  if (!this.validated) {
+    throw new Error("Payment not validated");
+  }
+}
+
+Payment.prototype.toJSON = function() {
+  return {
+    validated: this.validated,
+    txState: this.txState,
+    txHash: this.txHash,
+    toCurrency: this.toCurrency,  
+    fromCurrency: this.fromCurrency,
+    toAmount: this.toAmount,
+    fromAmount: this.fromAmount,
+    toAddress: this.toAddress,
+    fromAddress: this.fromAddress,
+    destinationTag: this.destinationTag
+  }
+}
+
+Payment.parseFromMessage = function(message) {
+  if (!message.validated) { return false }
+  if (message.engine_result != 'tesSUCCESS') { return false }
+  if (message.transaction.PaymentType != 'Payment') { return false }
+  return new Payment(message);
+}
+
+module.exports = Payment;