Intro to the WordPress JSON REST API

Last night I attended my local WordPress Meetup with the topic of the WordPress JSON REST API. I was really excited to attend because the whole idea of a REST API is something I know about, I just don’t really know what it does and what the purpose of it is. All that has changed.

Getting Some Closure

The discussion was led by Vasken Hauri of 10up. The subtitle for his talk was “Using the WP JSON API & Best Practices for Javascript and jQuery in WordPress.” He gave a great overview of how the API can be used and then launched into some code for best practices. There were a few moments I was very puzzled, then I realized that I knew what he was talking about, I was just used to seeing it in a different way.

My main experience in using a JSON API was my recent work on the Steam Achievements plugin I’ve been working on. Now I see that with the API plugin installed in your WordPress you can connect to the site to perform CRUD operations. JSON is great to work with because its a lot of data in a small package, and it’s a standard for giving and getting data across the internet. Using JSON to communicate to your WordPress site gives you a way to separate the data from the presentation.

This is best understood by a couple examples that were presented. This JSON REST API plugin was developed by the MOMA blog Inside / Out. Their site is presented as a Ruby on Rails front end, but use WordPress as their publishing platform. The use the JSON API in their Ruby Templates that pull the data from the WordPress Database.

Another great point that Vasken mentioned is the JSON end points will still work with cached pages. It will also be backwards compatible when WordPress adds the JSON API to WP Core, which will be happening in the next couple of updates.

There is a Chrome extension called Postman that lets you play around with all of the JSON REST API your site is outputting. You can even do it while running a site on a local server. I just installed it in Chrome and looking forward to seeing what I it can do.

Best Practices Going Forward

With the addition of the JSON REST API to Core its going to mean a lot more people are writing Javascript and Vasken wanted to give an overview of why its important to code in a way that wont screw things up in the future.

He began with some good examples of performance. Reminding us that it in PHP you want to avoid multiple calls to your database. Similarly in JS you want to avoid multiple calls to your DOM. Instead you should save the object that you call into a variable. However with all of these variables being made it can be a problem if you don’t plan your naming and run into name collision.

Prefixing your function names is a good option, but you can do one better in both PHP and in JS. Object Oriented PHP lets us avoid function name collisions with creating a class and instantiating it.

Whenever you have to globalize a variable make sure that it is unique. Don’t get lazy and give yourself problems in the future.

Javascript has a similar concept called Closures. Everything you can get with a PHP class you get with a Javascript closure.

With more Javascript being written to work with the JSON REST API we should be working within closures so we create functions that act on an instance but don’t go anywhere and muck things up.

Key Concepts

In closing Vasken gave us a few concepts to make sure we left with.

  • Write performant Javascript – Think about the limitations of your users and their devices. He recommended to test your Javascript and compare in different browsers/computers.
  • Consider the WordPress Ecosystem
  • Use Closures for your plugins whenever possible

I still have a lot to learn when it comes to Javascript. I’ve been reading David Flanagan’s Javascript: The Definitive Guide. It’s slow progress since I have so much else going on but I want to continue to expand to better jQuery and to a framework like Backbone or Angular as well.

There’s a lot on the horizon, but I’m ready to take it on.

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