better error handling

app.js

@@ -82,6 +82,8 @@ api.on('connection', function(spark) {
             data.stats.latency = spark.latency;
 
             var stats = Nodes.update(data.id, data.stats);
+            if(stats !== false)
+            {
                 client.write({action: 'update', data: stats});
 
                 var blockPropagationChart = Nodes.blockPropagationChart();
@@ -90,6 +92,7 @@ api.on('connection', function(spark) {
                 var uncleCount = Nodes.getUncleCount();
                 client.write({action: 'uncleCount', data: uncleCount});
             }
+        }
     });
 
     spark.on('node-ping', function(data){

models/collection.js

@@ -27,6 +27,10 @@ Collection.prototype.update = function(id, stats)
 		return false;
 
 	var block = this._history.add(stats.block, id);
+
+	if(! block)
+		return false;
+
 	var propagationHistory = this._history.getNodePropagation(id);
 
 	stats.block.arrived = block.arrived;

models/history.js

@@ -33,6 +33,8 @@ var History = function History(data)
 
 History.prototype.add = function(block, id)
 {
+	if(typeof block !== 'undefined' && typeof block.number !== 'undefined' && typeof block.uncles !== 'undefined' && typeof block.transactions !== 'undefined')
+	{
 		var historyBlock = this.search(block.number);
 
 		var now = (new Date()).getTime();
@@ -74,6 +76,9 @@ History.prototype.add = function(block, id)
 		this.getNodePropagation(id);
 
 		return block;
+	}
+
+	return false;
 }
 
 History.prototype._save = function(block)