(Beyond)
WordPress 4.4
WordCamp NYC, 2015

Scott Taylor
• WordPress 4.4 Release Lead
• Core Committer
• Sr. Software Engineer, The
New York Times
• @wonderboymusic on Trac/
Twitter/Swarm/Instagram

Pre-4.4

My goals for 4.4
• Close as many tickets as possible
• Front-load development, no lull in activity
• Work on as many things as possible
• Find out what can be accomplished - try things, revert doesn’t
matter
• Find out what really needs to be fixed
• Rely on no one else to make progress
• Set goals for Trac

What’s in 4.4?
• REST API: Phase 1
• Term Meta + WP_Term
• Responsive Images
• Embeds beyond Embeds
• Twenty Sixteen
• Comments overhaul + WP_Comment

Things I learned
• Committers have a responsibility to the community
to move the project forward. Those who patch
tickets have no ability to commit their own code.
• Volunteers are not beholden to a project schedule.
• The burn out rate on components and features is
high.
• WordPress has frightening amounts of technical
debt.

Case Studies from 4.4

“PHP Manifests”
• a file like post.php contained PHP classes, dozens
of functions, and sometimes “top-level code”
• without a plan for these domains of the code, the
future will just be more bloat
• PSR-1 tells us to not mix symbols and side-effects
• Hack disallows top-level code

File Structure
• Classes should live in their own files
• Important for code organization
• Important for developer experience (DX™)
• Essential for Autoloading
• Moved functions out of admin handlers

Comments
• Comments were being queried in a ludicrous way
• Comment “permalinks” were designed poorly
• Extreme scale was not considered

“The Worst Case Scenario
should be your Default
Use Case” - Scott Taylor

Changes were made to
WP_Query that never made it
to WP_Comment_Query and
WP_User_Query

AJAX Unit Tests
• Have been running slow forever
• Everyone thought it was because of the @runInSeparateProcess
annotation
• Every test method was internally triggering ‘admin_init’
• ‘admin_init’ has the following callbacks hooked to it:
• _maybe_update_core
• _maybe_update_plugins
• _maybe_update_themes

Moden Application
Structure

Modern Structure

• Composer
• Node modules
• Gulp
• Git modules
• WordPress as a piece of a larger system

Ticking
Time
Bombs

“Globals will destroy
WordPress, Globals are
destroying WordPress”
- Scott Taylor

Backwards Compatibility
• Once a global is added, it can almost never be
replaced
• Globals are not immutable, every global import
requires type-checking or re-instantiation
• Top-level variables arbitrarily get hoisted into global
scope
• Functions are an anti-pattern in modern PHP
• Functions exist mainly for Themes to use

PHP is NOT a
template language

Template Language
• PHP is not a template language
• WordPress Themes are not portable
• inline PHP logic in markup is dangerous
• Engines like Mustache can be shared between
PHP and JS

HTTP
• WordPress does not support parallel HTTP
• HTTP does not scale when requests are made
serially

WordPress:
Good Intentions

REST API
• It’s great that we added this
• The main thing this does is replace XML-RPC
• REST is not new
• WordPress is not unique for having REST
• Many other languages/frameworks do it

Browserify
• write code that looks like Node for the browser
• break code into modules
• Media has to use a modified version of it
• Media exposed everything to global scope, so
plugin devs had the ability to wipe out entire
objects with their own version

Meta Query
• the Metadata API is great
• it is great for READING data
• it is awful for searching by value

Where we can
draw inspiration

PSR
• PSR-1 and PSR-2 describe Coding Standards
• PSR-3 describes Application Logging
• PSR-0 PSR-4 describes Autoloading
• Autoloading simplifies large codebases
• Autoloading encourages OO
• PSR-7 describes HTTP Request/Response interfaces

{
"repositories":[
{
"type":"composer",
"url":"http://wpackagist.org"
},
{
"type": "vcs",
"url": "https://github.com/newsdev/nyt-wp-media.git"
},
{
"type": "vcs",
"url": "https://github.com/newsdev/nyt-wp-bylines.git"
}
],
"require": {
"guzzlehttp/guzzle": "~6.0",
"mustache/mustache": "~2.5",
"symfony/http-foundation": "~2.7",
"monolog/monolog": "~1.14",
"wpackagist-plugin/akismet": "~3.1",
"wpackagist-plugin/amazon-s3-and-cloudfront": "~0.9",
"wpackagist-plugin/amazon-web-services": "~0.3",
"wpackagist-plugin/rewrite-rules-inspector": "~1.2",
"wpackagist-plugin/debug-bar": "0.8.*",
"wpackagist-plugin/debug-bar-console": "0.3.*",
"newsdev/nyt-wp-media": "dev-master",
"newsdev/nyt-wp-bylines": "dev-master"
},
"prefer-stable": true,
"autoload": {
"psr-4": {
"NYT" : "lib/php",
"NYTShell": "wp-content/themes/shell/php"
}
}
}

Node / Gulp / Express
• JavaScript is extremely popular
• Node is the back end and the front end
• Node is easy compared to many other low-level
languages
• Express is way easier than learning Apache/nginx
• Express routing is dead simple
• Share code on the back-end / front-end

Mustache
• Mustache is my current favorite template language
• Mustache is almost completely devoid of logic
• Mustache requires you to query your data ahead of
time
• Mustache is portable
• tools like Hogan allow you to compile your backend
templates for the front end

<span class="byline" itemprop="author creator" itemscope itemtype=“http://schema.org/Person"
itemid="{{ meta.website }}">
{{# meta.website }}
<a href="{{ meta.website }}" rel="author" title="{{ l10.more_articles_by }}{{# upper }}
{{ display_name }}{{/ upper }}">
{{/ meta.website }}
<span class="byline-author" data-byline-name="{{# upper }}{{ display_name }}{{/ upper }}"
itemprop="name" data-twitter-handle="{{ meta.twitter }}">{{ display_name }}</span>
{{# meta.website }}</a>{{/ meta.website }}
</span>

Guzzle
• written by Michael Dowling from AWS
• allows asynchronous requests
• implements Promises/A+ in PHP
• implements PSR-7

<?php
namespace NYTHttp;
use GuzzleHttpPromise;
trait Client {
protected $client;
protected $promises = [];
public function setConfig( $config = [] ) {
$this->client = new GuzzleHttpClient( $config );
}
public function add( $key, $request ) {
$this->promises[ $key ] = $request;
}
public function send() {
$results = Promiseunwrap( $this->promises );
$responses = [];
foreach ( $results as $key => $response ) {
$responses[ $key ] = [
'status' => $response->getStatusCode(),
'headers' => $response->getHeaders(),
// convert PsrHttpMessageStreamInterface to string
'body' => (string) $response->getBody(),
];
if ( in_array( 'application/json', $response->getHeader( 'Content-Type' ) ) )
{
$responses[ $key ]['body'] = json_decode( $responses[ $key ]['body'],
true );
}
}
// clear the queue
$this->promises = [];
return $responses;
}
}

Questions?