From 396bed8873c25c12888ae852d8bf7fbd1f6ac809 Mon Sep 17 00:00:00 2001
From: Matias Alejo Garcia <ematiu@gmail.com>
Date: Tue, 16 Feb 2016 17:09:53 -0300
Subject: [PATCH] add multiple insight server support

---
 config.js                               |   2 +
 lib/blockchainexplorers/insight.js      |  49 +++----
 lib/blockchainexplorers/request-pull.js |  57 ++++++++
 package.json                            |  26 ++--
 test/request-pull.js                    | 170 ++++++++++++++++++++++++
 5 files changed, 270 insertions(+), 34 deletions(-)
 create mode 100644 lib/blockchainexplorers/request-pull.js
 create mode 100644 test/request-pull.js

diff --git a/config.js b/config.js
index 9afe4eb..c0479c3 100644
--- a/config.js
+++ b/config.js
@@ -43,6 +43,8 @@ var config = {
     testnet: {
       provider: 'insight',
       url: 'https://test-insight.bitpay.com:443',
+      // Multiple servers (in priority order)
+      // url: ['http://a.b.c', 'https://test-insight.bitpay.com:443'],
     },
   },
   pushNotificationsOpts: {
diff --git a/lib/blockchainexplorers/insight.js b/lib/blockchainexplorers/insight.js
index 950930f..f3d5c43 100644
--- a/lib/blockchainexplorers/insight.js
+++ b/lib/blockchainexplorers/insight.js
@@ -4,8 +4,8 @@ var _ = require('lodash');
 var $ = require('preconditions').singleton();
 var log = require('npmlog');
 log.debug = log.verbose;
-var request = require('request');
 var io = require('socket.io-client');
+var prequest = require('./request-pull');
 
 function Insight(opts) {
   $.checkArgument(opts);
@@ -14,7 +14,7 @@ function Insight(opts) {
 
   this.apiPrefix = opts.apiPrefix || '/api';
   this.network = opts.network || 'livenet';
-  this.url = opts.url;
+  this.hosts = opts.url;
 };
 
 
@@ -28,23 +28,23 @@ var _parseErr = function(err, res) {
 };
 
 Insight.prototype.getConnectionInfo = function() {
-  return 'Insight (' + this.network + ') @ ' + this.url;
+  return 'Insight (' + this.network + ') @ ' + this.hosts;
 };
 
 /**
  * Retrieve a list of unspent outputs associated with an address or set of addresses
  */
 Insight.prototype.getUnspentUtxos = function(addresses, cb) {
-  var url = this.url + this.apiPrefix + '/addrs/utxo';
   var args = {
     method: 'POST',
-    url: url,
+    hosts: this.hosts,
+    path: this.apiPrefix + '/addrs/utxo',
     json: {
       addrs: [].concat(addresses).join(',')
     },
   };
 
-  request(args, function(err, res, unspent) {
+  prequest(args, function(err, res, unspent) {
     if (err || res.statusCode !== 200) return cb(_parseErr(err, res));
     return cb(null, unspent);
   });
@@ -54,30 +54,30 @@ Insight.prototype.getUnspentUtxos = function(addresses, cb) {
  * Broadcast a transaction to the bitcoin network
  */
 Insight.prototype.broadcast = function(rawTx, cb) {
-  var url = this.url + this.apiPrefix + '/tx/send';
   var args = {
     method: 'POST',
-    url: url,
+    hosts: this.hosts,
+    path: this.apiPrefix + '/tx/send',
     json: {
       rawtx: rawTx
     },
   };
 
-  request(args, function(err, res, body) {
+  prequest(args, function(err, res, body) {
     if (err || res.statusCode !== 200) return cb(_parseErr(err, res));
     return cb(null, body ? body.txid : null);
   });
 };
 
 Insight.prototype.getTransaction = function(txid, cb) {
-  var url = this.url + this.apiPrefix + '/tx/' + txid;
   var args = {
     method: 'GET',
-    url: url,
+    hosts: this.hosts,
+    path:  this.apiPrefix + '/tx/' + txid,
     json: true,
   };
 
-  request(args, function(err, res, tx) {
+  prequest(args, function(err, res, tx) {
     if (res && res.statusCode == 404) return cb();
     if (err || res.statusCode !== 200)
       return cb(_parseErr(err, res));
@@ -91,16 +91,16 @@ Insight.prototype.getTransactions = function(addresses, from, to, cb) {
   if (_.isNumber(from)) qs.push('from=' + from);
   if (_.isNumber(to)) qs.push('to=' + to);
 
-  var url = this.url + this.apiPrefix + '/addrs/txs' + (qs.length > 0 ? '?' + qs.join('&') : '');
   var args = {
     method: 'POST',
-    url: url,
+    hosts: this.hosts,
+    path: this.apiPrefix + '/addrs/txs' + (qs.length > 0 ? '?' + qs.join('&') : ''),
     json: {
       addrs: [].concat(addresses).join(',')
     },
   };
 
-  request(args, function(err, res, txs) {
+  prequest(args, function(err, res, txs) {
     if (err || res.statusCode !== 200) return cb(_parseErr(err, res));
 
     if (_.isObject(txs) && txs.items)
@@ -116,14 +116,14 @@ Insight.prototype.getTransactions = function(addresses, from, to, cb) {
 Insight.prototype.getAddressActivity = function(address, cb) {
   var self = this;
 
-  var url = self.url + self.apiPrefix + '/addr/' + address;
   var args = {
     method: 'GET',
-    url: url,
+    hosts: this.hosts,
+    path: self.apiPrefix + '/addr/' + address,
     json: true,
   };
 
-  request(args, function(err, res, result) {
+  prequest(args, function(err, res, result) {
     if (res && res.statusCode == 404) return cb();
     if (err || res.statusCode !== 200)
       return cb(_parseErr(err, res));
@@ -134,24 +134,27 @@ Insight.prototype.getAddressActivity = function(address, cb) {
 };
 
 Insight.prototype.estimateFee = function(nbBlocks, cb) {
-  var url = this.url + this.apiPrefix + '/utils/estimatefee';
+  var path = this.apiPrefix + '/utils/estimatefee';
   if (nbBlocks) {
-    url += '?nbBlocks=' + [].concat(nbBlocks).join(',');
+    path += '?nbBlocks=' + [].concat(nbBlocks).join(',');
   }
 
   var args = {
     method: 'GET',
-    url: url,
+    hosts: this.hosts,
+    path: path,
     json: true,
   };
-  request(args, function(err, res, body) {
+  prequest(args, function(err, res, body) {
     if (err || res.statusCode !== 200) return cb(_parseErr(err, res));
     return cb(null, body);
   });
 };
 
 Insight.prototype.initSocket = function() {
-  var socket = io.connect(this.url, {
+
+  // sockets always use the first server on the pull
+  var socket = io.connect(this.hosts[0], {
     'reconnection': true,
   });
   return socket;
diff --git a/lib/blockchainexplorers/request-pull.js b/lib/blockchainexplorers/request-pull.js
new file mode 100644
index 0000000..944b455
--- /dev/null
+++ b/lib/blockchainexplorers/request-pull.js
@@ -0,0 +1,57 @@
+var _ = require('lodash');
+var async = require('async');
+var $ = require('preconditions').singleton();
+
+var log = require('npmlog');
+log.debug = log.verbose;
+
+/**
+ * Query a server, using one of the given options
+ *
+ * @param {Object} opts
+ * @param {Array} opts.hosts Array of hosts to query. Until the first success one.
+ * @param {Array} opts.path Path to request in each server
+ */
+var requestPull = function(args, cb) {
+  $.checkArgument(args.hosts);
+  request = args.request || require('request');
+
+  if (!_.isArray(args.hosts))
+    args.hosts = [args.hosts];
+
+  var urls = _.map(args.hosts, function(x) {
+    return (x + args.path);
+  });
+  var nextUrl, result, success;
+
+  async.whilst(
+    function() {
+      nextUrl = urls.shift();
+      return nextUrl && !success;
+    },
+    function(a_cb) {
+      args.uri = nextUrl;
+      request(args, function(err, res, body) {
+        if (err) {
+          log.warn('REQUEST FAIL: ' + nextUrl + ' ERROR: ' + err);
+        }
+
+        if (res) {
+          success = !!res.statusCode.toString().match(/^[1234]../);
+          if (!success) {
+            log.warn('REQUEST FAIL: ' + nextUrl + ' STATUS CODE: ' + res.statusCode);
+          }
+        }
+
+        result = [err, res, body];
+        return a_cb();
+      });
+    },
+    function(err) {
+      if (err) return cb(err);
+      return cb(result[0], result[1], result[2]);
+    }
+  );
+};
+
+module.exports = requestPull;
diff --git a/package.json b/package.json
index 5fcad8a..fd20c7d 100644
--- a/package.json
+++ b/package.json
@@ -19,7 +19,7 @@
     "url": "https://github.com/bitpay/bitcore-wallet-service/issues"
   },
   "dependencies": {
-    "async": "^0.9.0",
+    "async": "^0.9.2",
     "bitcore-lib": "^0.13.7",
     "body-parser": "^1.11.0",
     "coveralls": "^2.11.2",
@@ -65,14 +65,18 @@
     "coveralls": "./node_modules/.bin/istanbul cover ./node_modules/mocha/bin/_mocha --report lcovonly -- -R spec && cat ./coverage/lcov.info | ./node_modules/coveralls/bin/coveralls.js && rm -rf ./coverage"
   },
   "bitcoreNode": "./bitcorenode",
-  "contributors": [{
-    "name": "Braydon Fuller",
-    "email": "braydon@bitpay.com"
-  }, {
-    "name": "Ivan Socolsky",
-    "email": "ivan@bitpay.com"
-  }, {
-    "name": "Matias Alejo Garcia",
-    "email": "ematiu@gmail.com"
-  }]
+  "contributors": [
+    {
+      "name": "Braydon Fuller",
+      "email": "braydon@bitpay.com"
+    },
+    {
+      "name": "Ivan Socolsky",
+      "email": "ivan@bitpay.com"
+    },
+    {
+      "name": "Matias Alejo Garcia",
+      "email": "ematiu@gmail.com"
+    }
+  ]
 }
diff --git a/test/request-pull.js b/test/request-pull.js
new file mode 100644
index 0000000..6163bd2
--- /dev/null
+++ b/test/request-pull.js
@@ -0,0 +1,170 @@
+'use strict';
+
+var _ = require('lodash');
+var chai = require('chai');
+var sinon = require('sinon');
+var should = chai.should();
+var prequest = require('../lib/blockchainexplorers/request-pull');
+
+describe('request-pull', function() {
+  var request;
+
+  beforeEach(function() {
+    request = sinon.stub();
+  });
+  it('should support url as string', function(done) {
+
+    request.yields(null, {
+      statusCode: 200
+    }, 'abc');
+
+    prequest({
+      hosts: 'url1',
+      request: request,
+    }, function(err, res, body) {
+      should.not.exist(err);
+      body.should.be.equal('abc');
+      res.statusCode.should.be.equal(200);
+      done();
+    });
+  });
+  it('should support url as string (500 response)', function(done) {
+    request.yields(null, {
+      statusCode: 500
+    });
+    prequest({
+      hosts: 'url1',
+      request: request,
+    }, function(err, res, body) {
+      should.not.exist(err);
+      res.statusCode.should.be.equal(500);
+      done();
+    });
+  });
+  it('should support url as array of strings', function(done) {
+    request.yields(null, {
+      statusCode: 200
+    }, 'abc');
+    prequest({
+      hosts: ['url1', 'url2'],
+      request: request,
+    }, function(err, res, body) {
+      should.not.exist(err);
+      body.should.be.equal('abc');
+      done();
+    });
+  });
+  it('should try 2nd url if first is unsuccessful (5xx)', function(done) {
+    request.onCall(0).yields(null, {
+      statusCode: 500
+    });
+    request.onCall(1).yields(null, {
+      statusCode: 550
+    });
+    prequest({
+      hosts: ['url1', 'url2'],
+      request: request,
+    }, function(err, res, body) {
+      should.not.exist(err);
+      res.statusCode.should.be.equal(550);
+      done();
+    });
+  });
+  it('should query 3th url if first 2 are unsuccessful (5xx)', function(done) {
+    request.onCall(0).yields(null, {
+      statusCode: 500
+    });
+    request.onCall(1).yields(null, {
+      statusCode: 550
+    });
+    request.onCall(2).yields(null, {
+      statusCode: 200,
+    }, 'abc');
+    prequest({
+      hosts: ['url1', 'url2', 'url3'],
+      request: request,
+    }, function(err, res, body) {
+      should.not.exist(err);
+      body.should.be.equal('abc');
+      done();
+    });
+  });
+  it('should query only the first url if response is 404', function(done) {
+    request.onCall(0).yields(null, {
+      statusCode: 404
+    });
+    request.onCall(1).yields(null, {
+      statusCode: 550
+    });
+    prequest({
+      hosts: ['url1', 'url2'],
+      request: request,
+    }, function(err, res, body) {
+      should.not.exist(err);
+      res.statusCode.should.be.equal(404);
+      done();
+    });
+  });
+  it('should query only the first 2 urls if the second is successfull (5xx)', function(done) {
+    request.onCall(0).yields(null, {
+      statusCode: 500
+    });
+    request.onCall(1).yields(null, {
+      statusCode: 200,
+    }, '2nd');
+    request.onCall(2).yields(null, {
+      statusCode: 200,
+    }, 'abc');
+    prequest({
+      hosts: ['url1', 'url2', 'url3'],
+      request: request,
+    }, function(err, res, body) {
+      should.not.exist(err);
+      body.should.be.equal('2nd');
+      res.statusCode.should.be.equal(200);
+      done();
+    });
+  });
+  it('should query only the first 2 urls if the second is successfull (timeout)', function(done) {
+    request.onCall(0).yields({
+      code: 'ETIMEDOUT',
+      connect: true
+    });
+    request.onCall(1).yields(null, {
+      statusCode: 200,
+    }, '2nd');
+    request.onCall(2).yields(null, {
+      statusCode: 200,
+    }, 'abc');
+    prequest({
+      hosts: ['url1', 'url2', 'url3'],
+      request: request,
+    }, function(err, res, body) {
+      should.not.exist(err);
+      body.should.be.equal('2nd');
+      res.statusCode.should.be.equal(200);
+      done();
+    });
+
+  });
+  it('should use the latest response if all requests are unsuccessfull', function(done) {
+    request.onCall(0).yields({
+      code: 'ETIMEDOUT',
+      connect: true
+    });
+    request.onCall(1).yields(null, {
+      statusCode: 505,
+    }, '2nd');
+    request.onCall(2).yields(null, {
+      statusCode: 510,
+    }, 'abc');
+    prequest({
+      hosts: ['url1', 'url2', 'url3'],
+      request: request,
+    }, function(err, res, body) {
+      should.not.exist(err);
+      res.statusCode.should.be.equal(510);
+      done();
+    });
+  });
+});