Parser: check stream readable before read()

lib/Parser.js

@@ -76,8 +76,10 @@ Parser.prototype.setStream = function(stream) {
 };
 
 Parser.prototype._tryread = function(n) {
-  var r = this._stream.read(n);
+  if (this._stream.readable) {
-  r && this._parse(r);
+    var r = this._stream.read(n);
+    r && this._parse(r);
+  }
 };
 
 Parser.prototype._parse = function(data) {