Composing a Better Phuture

Composer is both a dependency management and autoloader generation tool for PHP. This presentation highlights how and why we use Composer.

Transcript

1. Composing
   a Better
   Phuture
   by Jeremy Lindblom
   @jeremeamia
   

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

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

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4. PHP is “mostly dead”
   2008
   

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5. is “mostly dead”
   2008
   2009
   PHP 5.3.0 is released
   

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6. ♥ for Git/GitHub grow
   2010
   

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7. PSR-0 & Composer
   2011
   

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8. HaPHPy 20th Birthday
   2015
   

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

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

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13. 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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14. 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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15. getcomposer.org packagist.org
    

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

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

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

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20. your-project-root/
    |— src/
    |— tests/
    |— vendor/
    |— composer.json
    |— composer.lock
    What does that do?
    

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

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22. For Applications?
    ?
    

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23. For Applications?
    YES!
    

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24. For Applications? For Libraries?
    ?
    YES!
    

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25. For Applications? For Libraries?
    Sure.
    YES!
    

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26. How do you use your installed code?
    require ‘vendor/autoload.php’;
    $client = new GuzzleHttp\Client();
    $response = $client->get(‘http://example.com’);
    

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

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28. — Includes —
    

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

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

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33. Including Classes - Not Fun
    // NOTE: Assuming one class per file
    require_once(‘classes/user.class.php’);
    require_once(‘classes/page.class.php’);
    require_once(‘classes/role.class.php’);
    require_once(‘classes/db.class.php’);
    // ...
    

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34. 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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35. — Autoloaders —
    

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

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37. 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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38. 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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39. 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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40. Registering Autoloaders
    $loader = new Autoloader(__DIR__);
    spl_autoload_register([$loader, ‘load’]);
    

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41. 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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42. — PSRs & PHP-FIG —
    

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44. ● 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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45. 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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46. 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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47. Class to load: Zend\Http\Client
    Include file:
    /Zend/Http/Client.php
    Autoloading PSRs (PSR-0)
    

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

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

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50. — Optimization —
    

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51. BAD
    GOOD
    There are many ways to implement autoloaders.
    

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52. All classes in one file; no autoloader
    BAD
    GOOD
    

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53. Many autoloaders; Each can only load 1 class
    BAD
    GOOD
    

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54. BAD
    GOOD
    2 1
    

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55. BAD
    GOOD
    Composer autoloader
    (1 autoloader handles all classes)
    

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

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

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58. 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;
    

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59. One Autoloader to rule them all.
    

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60. Composing
    a Better
    Phuture
    by Jeremy Lindblom
    @jeremeamia
    

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