Wednesday, August 17, 2016

Node.js and Oracle NoSQL Database

Oracle NoSQL Database is an interesting option to consider when you want a schemaless, fast, scale-able database which can provide relaxed (eventual) consistency. Oracle provides a Node.js driver for this database. In this blog I'll describe how to install Oracle NoSQL database and how to connect to it from a Node.js application.

The Node.js driver provided by Oracle is currently in preview version 3.3.7. It uses NoSQL client version which does not work with 4.x versions of NoSQL database, so I downloaded Oracle NoSQL Database, Enterprise Edition 12cR1 ( from here (the version number was closest to the version number of the client software).

Saturday, August 13, 2016

Application Container Cloud: Node.js hosting with enterprise-grade features

Oracle's Application Container Cloud allows you to run Java SE, Node.js and PHP applications (and more is coming) in a Docker container hosted in the Oracle Public Cloud (OPC). Node.js can crash when applications do strange things. You can think of incorrect error handling, blocking calls or strange memory usage. In order to host Node.js in a manageable, stable and robust way in an enterprise application landscape, certain measures need to be taken. Application Container Cloud provides many of those measures and makes hosting Node.js applications easy. In this blog article I'll describe why you would want to use Oracle Application Container Cloud. I'll illustrate this with examples of my experience with the product.

Thursday, August 11, 2016

Node.js: My first SOAP service

I created a simple HelloWorld SOAP service running on Node.js. Why did I do that? I wanted to try if Node.js was a viable solution to use as middleware layer in an application landscape. Not all clients can call JSON services. SOAP is still very common. If Node.js is to be considered for such a role, it should be possible to host SOAP services on it. My preliminary conclusion is that it is possible to host SOAP services on Node.js but you should carefully consider how you want to do this.

I tried to create the SOAP service in two distinct ways.
  • xml2js. This Node.js module allows transforming XML to JSON and back. The JSON which is created can be used to easily access content with JavaScript. This module is fast and lightweight, but does not provide specific SOAP functionality.
  • soap. This Node.js module provides some abstractions and features which make working with SOAP easier. The module is specifically useful when calling SOAP services (when Node.js is the client). When hosting SOAP services, the means to control the specific response to a call are limited (or undocumented)
Using both modules, I encountered some challenges which I will describe and how (and if) I solved them. You can find my sample code here.

Tuesday, August 9, 2016

Node.js: A simple pattern to increase perceived performance

The asynchronous nature of code running on Node.js provides many interesting options for service orchestration. In this example I will call two translation services (Google and SYSTRAN). I will call both of them quickly after each other (milliseconds). The first answer to be returned, will be the answer returned to the caller. The second answer will be ignored. I've used a minimal set of Node modules for this; http, url, request. Also I wrapped the translation API's to provide a similar interface which allows me to call them with the same request objects. You can download the code here. In the below picture this simple scenario is illustrated. I'm not going to talk about the event loop and the call stack. Watch this presentation for a nice elaboration on those.