Composing a Better Phuture

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Composing a Better Phuture by Jeremy Lindblom @jeremeamia

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● Composer ● Packages ● SemVer ● Autoloading ● PSRs Composing a Better Phuture

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But first, a history lesson. (Don’t worry, we’ll only cover a few years)

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PHP is “mostly dead” 2008

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is “mostly dead” 2008 2009 PHP 5.3.0 is released

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♥ for Git/GitHub grow 2010

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PSR-0 & Composer 2011

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HaPHPy 20th Birthday 2015

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1. Dependency Manager 2. Autoloader Generator What is Composer?

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1. Dependency Manager 2. Autoloader Generator What is Composer?

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Dependency Management ● Declare, resolve, and install project-specific dependencies ● Use others’ code ○ Use open source packages ○ Focus on your biz features ○ Avoid “NIH syndrome” ● Create reusable packages in your own org

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Before Composer ● Compile PHP with extensions ● System-level package managers ● PEAR packages (system-system) ● Include 3rd-party code in source ● Git submodules Composer inspired by bundler and npm

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getcomposer.org packagist.org

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https://github.com/engrade/engrade-php-sdk/blob/master/composer.json Composer.json Example

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Specifying Versions MAJOR.MINOR.PATCH (SemVer.org) “{vendor}/{package}”: “{version constraints}” ● “>=3.1.4” – Use any version >= 3.1.4 ● “3.1.*” – Use any patch version of 3.1 ● “~3.2” – Use any 3.x version >= 3.2

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Installing Composer curl -sS https://getcomposer.org/installer | php mv composer.phar /usr/local/bin/composer

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Installing Your Dependencies For development: composer install and composer update For production: composer install --no-dev --optimize-autoloader

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SHOULD YOU COMMIT YOUR composer.lock FILE? THE ANSWER MAY SHOCK YOU!

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For Applications? ?

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For Applications? YES!

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For Applications? For Libraries? ? YES!

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For Applications? For Libraries? Sure. YES!

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How do you use your installed code? get(‘http://example.com’);

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1. Dependency Manager 2. Autoloader Generator What is Composer?

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— Includes —

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a.php CODE CODE include ‘b.php’; CODE Includes = Why I Started Using PHP b.php CODE CODE CODE CODE Executed code CODE CODE CODE CODE CODE CODE CODE

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Includes = Why I Started Using PHP header.php sidebar.php main.php

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include include_once require require_once Including vs. Requiring What’s the difference between all of these?

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Including Classes - Not Fun

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The Bottom Line Explicit includes/requires are: 1. Necessary and helpful for procedural code. 2. Cumbersome and harmful for object- oriented code.

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— Autoloaders —

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What is an Autoloader? 1. A callback triggered when a non-existent class is referenced.

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What is an Autoloader? 1. A callback triggered when a non-existent class is referenced. 2. A function that provides a definition for a specified class name.

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Autoloader Advantages ● Classes are loaded on demand ○ No need to write specific include statements ○ Class never loaded unless it’s needed ● Leads to better code maintainability ● Easy to write

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Simple Autoloader Implementation class Autoloader { public function __construct($root) {...} public function load($class) { $path = $path->root; $path .= str_replace(‘\\’, ‘/’, $class); if (file_exists($path)) require $path; } }

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Registering Autoloaders $loader = new Autoloader(__DIR__); spl_autoload_register([$loader, ‘load’]);

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Autoloader Implementation Tips ● You can have multiple autoloaders. ● Don’t throw errors/exceptions if a file doesn’t exist. Let the other autoloaders try. ● Don’t use the __autoload() function. ● Use Composer’s autoloader. ○ You don’t have to write your own ○ It already follows the PSR autoloading standards

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— PSRs & PHP-FIG —

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● FIG = Framework Interop Group ● PSR = PHP Standards Recommendation ○ Autoloading: PSR-0, PSR-4 ○ Others: ■ PSR-1, PSR-2 - Coding style ■ PSR-3 - Logging interface ■ PSR-7 - HTTP message interface PHP-FIG

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Autoloader Implementation Revisited class Autoloader { public function __construct($root) {...} public function load($class) { $path = $path->root; $path .= str_replace(‘\\’, ‘/’, $class); if (file_exists($path)) require $path; } }

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Class to load: Zend\Http\Client Include file: /Zend/Http/Client.php Autoloading PSRs (PSR-0)

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Source root base namespace: Zend\Http Class to load: Zend\Http\Client Include file: /Client.php Autoloading PSRs (PSR-4)

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Base Namespace in composer.json { ... "autoload": { "psr-4": { "Zend\\Http\\": "src/" } } }

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— Optimization —

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BAD GOOD There are many ways to implement autoloaders.

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All classes in one file; no autoloader BAD GOOD

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Many autoloaders; Each can only load 1 class BAD GOOD

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BAD GOOD 2 1

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BAD GOOD Composer autoloader (1 autoloader handles all classes)

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BAD GOOD Composer optimized autoloader (1 autoloader; fast lookup; no file_exists)

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Classmap Autoloading In your project root: composer install --no-dev --optimize-autoloader

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Classmap Autoloading $paths = [...]; // class => file mappings if (isset($paths[$class])) require $paths[$class]; // vs. $path = $root . str_replace(‘\\’, ‘/’, $class); if (file_exists($path)) require $path;