From def036b79f27aba66d6fc2517b181cc3bb3ab481 Mon Sep 17 00:00:00 2001
From: Gordon Hall <gordon@gordonwritescode.com>
Date: Sun, 20 Apr 2014 14:04:52 -0400
Subject: [PATCH] setup connection pool and auto handling of bad seeds

---
 examples/PeerDiscovery.js |  9 +------
 lib/PeerManager.js        | 52 ++++++++++++++++++++++++++++-----------
 2 files changed, 39 insertions(+), 22 deletions(-)

diff --git a/examples/PeerDiscovery.js b/examples/PeerDiscovery.js
index 2662698..dfbec65 100644
--- a/examples/PeerDiscovery.js
+++ b/examples/PeerDiscovery.js
@@ -1,11 +1,4 @@
 var PeerManager = require('../lib/PeerManager');
 var peerman     = new PeerManager();
 
-peerman.discoverPeers(function(err, peers) {
-  // we can use this array of peers to add to the manager
-  // but let's limit it to 6 connections for this example
-  var p = 0;
-  do { peerman.addPeer(peers[p]); p++; } while (p < 6);
-  // then we can start the manager
-  peerman.start();
-});
+peerman.discover({ limit: 6 }).start();
diff --git a/lib/PeerManager.js b/lib/PeerManager.js
index d18bd98..85cbb22 100644
--- a/lib/PeerManager.js
+++ b/lib/PeerManager.js
@@ -3,7 +3,6 @@ var extend          = imports.extend || require('extend');
 var log             = imports.log || require('../util/log');
 var bitcoreDefaults = imports.config || require('../config');
 var Connection      = imports.Connection || require ('./Connection');
-
 var Peer            = imports.Peer || require('./Peer');
 
 GetAdjustedTime = imports.GetAdjustedTime || function () {
@@ -18,6 +17,7 @@ function PeerManager(config) {
   this.timer = null;
 
   this.peers = [];
+  this.pool = [];
   this.connections = [];
   this.isConnected = false;
   this.peerDiscovery = false;
@@ -30,8 +30,7 @@ function PeerManager(config) {
   // keep track of tried seeds and results
   this.seeds = {
     resolved: [],
-    failed: [],
-    results: {}
+    failed: []
   };
 }
 
@@ -68,6 +67,13 @@ PeerManager.prototype.addPeer = function(peer, port) {
   }
 };
 
+PeerManager.prototype.removePeer = function(peer) {
+  var index  = this.peers.indexOf(peer);
+  var exists = !!~index;
+  if (exists) this.peers.splice(index, 1);
+  return exists;
+};
+
 PeerManager.prototype.checkStatus = function checkStatus() {
   // Make sure we are connected to all forcePeers
   if(this.peers.length) {
@@ -91,7 +97,7 @@ PeerManager.prototype.checkStatus = function checkStatus() {
 };
 
 PeerManager.prototype.connectTo = function(peer) {
-  log.info('connecting to '+peer);
+  log.info('connecting to ' + peer);
   try {
     return this.addConnection(peer.createConnection(), peer);
   } catch (e) {
@@ -181,10 +187,16 @@ PeerManager.prototype.handleError = function(e) {
 };
 
 PeerManager.prototype.handleDisconnect = function(e) {
-  log.info('disconnected from peer '+e.peer);
+  log.info('disconnected from peer ' + e.peer);
   var i = this.connections.indexOf(e.conn);
   if(i != -1) this.connections.splice(i, 1);
 
+  this.removePeer(e.peer);
+  log.info('replacing peer with one from the pool of: ' + this.pool.length);
+  if (this.pool.length) {
+    this.addPeer(this.pool.pop());
+  }
+
   if(!this.connections.length) {
     this.emit('netDisconnected');
     this.isConnected = false;
@@ -219,13 +231,15 @@ PeerManager.prototype.getActiveConnections = function () {
   return this.connections.slice(0);
 };
 
-PeerManager.prototype.discoverPeers = function(callback) {
+PeerManager.prototype.discover = function(options, callback) {
   var self     = this;
   var async    = imports.async || require('async');
   var dns      = imports.dns || require('dns');
   var networks = imports.networks || require('../networks');
   var seeds    = networks[self.config.network].dnsSeeds;
 
+  self.limit = options.limit || 12;
+
   var dnsExecutor = seeds.map(function(seed) {
     return function(done) {
       // have we already resolved this seed?
@@ -240,17 +254,30 @@ PeerManager.prototype.discoverPeers = function(callback) {
         return done(null, []);
       }
 
-      // otherwise resolve the dns seed to get some peers
       log.info('resolving dns seed '+ seed);
+
       dns.resolve(seed, function(err, peers) {
         if (err) {
           log.err('failed to resolve dns seed '+ seed, err);
           self.seeds.failed.push(seed);
           return done(null, []);
         }
+
         log.info('found '+ peers.length + ' peers from ' + seed);
         self.seeds.resolved.push(seed);
-        self.seeds.results[seed] = peers;
+
+        // transform that list into a list of Peer instances
+        peers = peers.map(function(ip) {
+          return new Peer(ip, networks.defaultClientPort);
+        });
+
+        peers.forEach(function(p) {
+          if (self.peers.length < self.limit) self.addPeer(p);
+          else self.pool.push(p);
+        });
+
+        self.emit('peers', peers);
+
         return done(null, peers);
       });
 
@@ -266,13 +293,10 @@ PeerManager.prototype.discoverPeers = function(callback) {
       peers = peers.concat(peerlist);
     });
 
-    // transform that list into a list of Peer instances
-    peers = peers.map(function(ip) {
-      return new Peer(ip, networks.defaultClientPort);
-    });
-
-    callback(null, peers);
+    if (typeof callback === 'function') callback(null, peers);
   });
+
+  return self;
 };
 
 module.exports = require('soop')(PeerManager);