Catch JSON.stringfy exceptions instead of silent failing

index.js

@@ -124,19 +124,31 @@ function Encoder() {}
  */
 
 Encoder.prototype.encode = function(obj, callback){
-  if ((obj.type === exports.EVENT || obj.type === exports.ACK) && hasBin(obj.data)) {
-    obj.type = obj.type === exports.EVENT ? exports.BINARY_EVENT : exports.BINARY_ACK;
-  }
 
-  debug('encoding packet %j', obj);
+  if (obj.type === exports.EVENT || obj.type === exports.ACK) {
+    /**
+     * For object data with circular references, hasBin will throw
+     * exceptions, which must be handled or it could hang the channel.
+     * And the circular references only happen to non-Binary data, 
+     * so we will invoke callback with an array.
+     */
+    try {
+      if (hasBin(obj.data)) {
+        obj.type = obj.type === exports.EVENT ? exports.BINARY_EVENT : exports.BINARY_ACK;
+      }
+    } catch (e) {
+      callback([encodeError()]);
+    }
+  }    
 
+  debug('encoding packet %j', obj);
+
   if (exports.BINARY_EVENT === obj.type || exports.BINARY_ACK === obj.type) {
     encodeAsBinary(obj, callback);
-  }
-  else {
+  } else {
     var encoding = encodeAsString(obj);
     callback([encoding]);
-  }
+  }    
 };
 
 /**
@@ -170,7 +182,11 @@ function encodeAsString(obj) {
 
   // json data
   if (null != obj.data) {
-    str += JSON.stringify(obj.data);
+    try {
+      str += JSON.stringify(obj.data);
+    } catch (e) {
+      return encodeError();
+    }
   }
 
   debug('encoded %j as %s', obj, str);
@@ -398,3 +414,7 @@ function error() {
     data: 'parser error'
   };
 }
+
+function encodeError() {
+  return exports.ERROR + JSON.stringify('encode error');
+}

test/parser.js

@@ -1,8 +1,6 @@
 var parser = require('../index.js');
 var expect = require('expect.js');
 var helpers = require('./helpers.js');
-var encode = parser.encode;
-var decode = parser.decode;
 
 describe('parser', function(){
 
@@ -51,6 +49,28 @@ describe('parser', function(){
     });
   });
 
+  it('encodes a circular object (return error)', function() {
+    var john = new Object();  
+    var mary = new Object();  
+
+    john.sister = mary;  
+    mary.brother = john;  
+
+    var data = {
+      type: parser.EVENT,
+      data: john,
+      id: 1,
+      nsp: '/'
+    }
+
+    var error = parser.ERROR + JSON.stringify('encode error');
+    var encoder = new parser.Encoder();
+
+    encoder.encode(data, function(encodedPackets) {
+      expect(encodedPackets[0]).to.be(error);
+    });
+  });
+
   it('decodes a bad binary packet', function(){
     try {
       var decoder = new parser.Decoder();