add preload option. better errors.

lib/bcoin/chain.js

@@ -96,12 +96,18 @@ Chain.prototype._init = function _init() {
 
   utils.debug('Chain is loading.');
 
-  this.preload(function(start) {
+  this.preload(function(err, start) {
+    if (err) {
+      utils.debug('Preloading chain failed.');
+      utils.debug('Reason: %s', err.message);
+    }
     utils.nextTick(function() {
       var count = self.db.count();
       var i = start || 1;
       var lastEntry;
 
+      utils.debug('Starting chain load at height: %s', i);
+
       function done(height) {
         if (height != null) {
           utils.debug(
@@ -142,9 +148,12 @@ Chain.prototype.preload = function preload(callback) {
   var url = 'https://headers.electrum.org/blockchain_headers';
   var chainHeight, buf, height, stream;
 
-  if (this.options.preload === false)
+  if (!this.options.preload)
     return callback();
 
+  if (network.type !== 'main')
+    return callback(new Error('Electrum.org only offers `main` headers.'));
+
   utils.debug('Loading %s', url);
 
   stream = request.get(url);
@@ -157,18 +166,15 @@ Chain.prototype.preload = function preload(callback) {
 
   stream.on('response', function(res) {
     if (res.statusCode >= 400) {
-      utils.debug('Could not load electrum headers');
-      utils.debug('Status: %d', res.statusCode);
       stream.destroy();
-      return callback();
+      return callback(new Error('Bad response code: ' + res.statusCode));
     }
   });
 
   stream.on('error', function(err) {
-    utils.debug('Could not load electrum headers');
+    var start = Math.max(0, height - 2);
-    utils.debug(err.stack + '');
+    self.resetHeight(start);
-    self.resetHeight(Math.max(0, height - 2));
+    return callback(err, start + 1);
-    return callback(Math.max(0, height - 2));
   });
 
   stream.on('data', function(data) {
@@ -196,13 +202,14 @@ Chain.prototype.preload = function preload(callback) {
 
     blocks.forEach(function(data) {
       var entry = bcoin.chainblock.fromRaw(self, height, data);
+      var start;
 
       // Do some paranoid checks.
       if (lastEntry && entry.prevBlock !== lastEntry.hash) {
-        utils.debug('Electrum headers are corrupt. Resetting.');
+        start = Math.max(0, height - 2);
         stream.destroy();
-        self.resetHeight(Math.max(0, height - 2));
+        self.resetHeight(start);
-        return callback(Math.max(0, height - 2));
+        return callback(new Error('Corrupt headers.'), start + 1);
       }
 
       lastEntry = entry;
@@ -226,7 +233,7 @@ Chain.prototype.preload = function preload(callback) {
   });
 
   stream.on('end', function() {
-    return callback(height + 1);
+    return callback(null, height + 1);
   });
 };
 

lib/bcoin/pool.js

@@ -85,7 +85,8 @@ function Pool(options) {
 
   this.chain = new bcoin.chain({
     fullNode: this.options.fullNode,
-    multiplePeers: this.options.multiplePeers
+    multiplePeers: this.options.multiplePeers,
+    preload: this.options.preload
   });
 
   this.watchMap = {};