What is Node.js (and why should an IBM i programmer care)?

Section 1: Overview of Node.js on IBM i

Every RPG Programmer should understand Node.js

Grab a cup of tea (or something stronger, I won't judge) because we are about to do something that would have made my 1990s green-screen self spit out his coffee: we are going to run JavaScript on the IBM i.

Yes. JavaScript. On the AS400. iSeries. System i. IBM i. Whatever you call it in your shop - I still say AS400 when nobody is looking.

So what is Node.js?

Node.js is a JavaScript runtime built on Google's V8 engine - the same engine inside Chrome. Somebody clever (Ryan Dahl, back in 2009) ripped the engine out of the browser and let it run on a server. That means:

• JavaScript can read files, open sockets, talk to databases and serve web pages.
• It ships with npm, the largest package library on the planet. Need to send email, parse a CSV, generate a PDF? There is a package for that. Probably twelve.
• It runs on Linux, Windows, macOS... and, thanks to IBM's open source team, IBM i (in the PASE environment).

Where does it live on IBM i?

Node.js runs in PASE (Portable Application Solutions Environment) - the AIX-compatible runtime that sits alongside ILE on your box. You install it with the open source package manager (yum) and it lands under /QOpenSys/pkgs/. We will do all of that, step by step, in Section 3.

Crucially, it isn't a "foreign" box bolted on the side. Node.js on IBM i can:

• Run SQL directly against Db2 for i (via the odbc or idb-connector packages).
• Call RPG/CL programs, commands and service programs (via itoolkit and XMLSERVICE).
• Read and write the IFS like any other file system.

What we'll build in this course

By the end of the course you'll have a working web application - a food ingredients database with Create, Read, Update and Delete - running on your IBM i, written in Node.js, talking to a real Db2 for i table. Here is the roadmap:

1. Overview (you are here)
2. Advantages of Node.js compared with RPG, Java, Python and PHP
3. Installing Node.js, npm and the database drivers
4. Building web services with Express and the IBM i toolkit
5. The CRUD application, from SQL DDL to a browser front end

Right, enough waffle. Onwards!