PSRs: what, why and how?

While increasingly important in our ecosystem, the PHP Standards Recommendations remain too little known and somewhat mystical for many of us. In this talk, I propose to understand what is a PSR and then to briefly review all the existing recommendations, whether validated, accepted or draft. We will also come back to the importance and purpose of these standards as well as their development process.

Transcript

1. PSRs: what,
   why and how?
   ___
   Julien Janvier
   @jujanvier
   https://joind.in/talk/ebe72
   

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2. PHP
   Standard
   Recommendation
   

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3. What is a PSR?
   

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4. accepted
   PSR-1: Basic Coding Standard
   

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5. accepted
   PSR-2: Coding Style Guide
   

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6. draft
   PSR-12: Extended Coding Style Guide
   

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7. draft
   PSR-5: PHPDoc Standard
   /**
   * @method int MyMagicMethod(string $argument1) {
   * This is the summary for MyMagicMethod.
   *
   * @param string $argument1 Description for argument 1.
   *
   * @return int
   * }
   */
   class MyMagicClass
   {
   // ...
   }
   

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8. Who is behind these standards?
   

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9. Framework Interoperability Group
   www.php-fig.org
   www.github.com/php-fig/fig-standards
   @phpfig
   

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10. ...and many more...
    ...and many more...
    

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11. How these standards are written?
    

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12. Member Project
    Project Representative
    Core Committee
    

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13. Working Group =
    Editor + Sponsor +
    Contributors
    

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14. Pre draft >> Draft >>
    Review >> Accepted >>
    Dreprecate
    

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15. Let’s go!
    

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16. Autoloading
    

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17. PSR-0: Autoloading Standard
    Nelmio\Alice\ => src/
    class Nelmio\Alice\Loader\Yaml
    src/Nelmio/Alice/Loader/Yaml.php
    class Nelmio_Alice_Loader_Yaml
    deprecated
    

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18. PSR-0: Autoloading Standard
    Nelmio\Alice\ => src/
    class Nelmio\Alice\Loader\Yaml
    src/Nelmio/Alice/Loader/Yaml.php
    accepted
    src/Loader/Yaml.php
    class Nelmio_Alice_Loader_Yaml
    PSR-4: Autoloader
    deprecated
    

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19. What prompted the
    FIG to write the first
    standards back in
    2009?
    

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20. What prompted the
    FIG to write the first
    standards back in
    2009?
    Almost impossible to
    reuse others’ code.
    

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21. Security issues
    

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22. draft
    PSR-9: Security Reporting Process
    
    security@example.org
    

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23. draft
    PSR-10: Security Disclosure Publication
    
    

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24. Why knowing
    existing standards
    is useful?
    

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25. Why knowing
    existing standards
    is useful?
    Let us take
    advantage of others’
    researches.
    

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26. Day-to-day tools
    

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27. accepted
    PSR-3: Logger Interface
    

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28. accepted
    PSR-3: Logger Interface
    namespace Psr\Log;
    interface LoggerInterface
    {
    /**
    * Action must be taken immediately.
    * Example: Entire website down, database unavailable, etc.
    * This should trigger the SMS alerts and wake you up.
    *
    * @param string $message
    * @param array $context
    *
    * @return void
    */
    public function alert($message, array $context = array());
    

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29. Why a standard
    when there
    is already “one”?
    

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30. Why a standard
    when there
    is already “one”?
    Our needs evolve.
    

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31. accepted
    PSR-11: Container Interface
    namespace Psr\Container;
    interface ContainerInterface
    {
    /**
    * Finds an entry of the container by its identifier and returns it.
    *
    * @param string $id Identifier of the entry to look for.
    *
    * @throws NotFoundExceptionInterface No entry was found for this id.
    * @throws ContainerExceptionInterface Error while retrieving the entry.
    *
    * @return mixed Entry.
    */
    public function get($id);
    

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32. accepted
    PSR-11: Container Interface
    

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33. Why a standard
    when there are
    already so many
    libraries?
    

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34. Why a standard
    when there are
    already so many
    libraries?
    Offer us a world of
    new possibilities.
    

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35. accepted
    PSR-6: Caching Interface
    // $pool is an instance of Psr\Cache\CacheItemPoolInterface
    // $item is an instance of Psr\Cache\CacheItemInterface
    $item = $pool->getItem('foo');
    if (!$item->isHit()) {
    $item->set('bar');
    $item->expiresAfter(3600);
    $pool->save($item);
    }
    $value = $item->get();
    

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36. accepted
    PSR-16: Simple Cache
    // $cache is an instance of Psr\SimpleCache\CacheInterface
    if (null === $cache->get('foo')) {
    $cache->set('foo', 'bar', 3600);
    }
    $value = $cache->get('foo');
    

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37. draft
    PSR-14: Event Manager
    namespace Psr\EventManager;
    interface EventManagerInterface
    {
    public function attach($event, $callback, $priority = 0);
    public function detach($event, $callback);
    public function clearListeners($event);
    public function trigger($event, $target = null, $argv =
    array());
    }
    interface EventInterface
    {
    // ...
    }
    

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38. Why a standard for
    “problems” that
    already have been
    resolved by our
    framework?
    

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39. Why a standard for
    “problems” that
    already have been
    resolved by our
    framework?
    Avoid to couple our
    business code to a
    vendor library.
    

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40. Web
    

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41. accepted
    PSR-7: HTTP Message Interface
    POST /path HTTP/1.1
    Host: example.com
    foo=bar&baz=bat
    HTTP/1.1 200 OK
    Content-Type: text/plain
    This is the response body
    

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42. accepted
    PSR-7: HTTP Message Interface
    Request Response
    Message
    ServerRequest
    Stream
    Uri
    UploadedFile
    getBody()
    getUploadedFiles()
    

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43. PSR-17: HTTP Factories
    namespace Psr\Http\Message;
    use Psr\Http\Message\StreamInterface;
    interface StreamFactoryInterface
    {
    public function createStream($content = '');
    public function createStreamFromFile($filename, $mode = 'r');
    public function createStreamFromResource($resource);
    }
    review
    

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44. accepted
    PSR-13: Hypermedia Links
    namespace Psr\Link;
    interface LinkInterface
    {
    public function getHref();
    public function isTemplated();
    public function getRels();
    public function getAttributes();
    }
    

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45. What standards
    about so low levels
    topics can bring?
    

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46. What standards
    about so low levels
    topics can bring?
    Maybe it opens the
    gates of PHP native
    implementations.
    

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47. PSR-15: HTTP Middlewares
    Working with Slim Middleware, by Timothy Boronczyk
    vote
    

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48. PSR-15: HTTP Middlewares
    use Psr\Http\ServerMiddleware\DelegateInterface;
    use Psr\Http\ServerMiddleware\MiddlewareInterface;
    use Psr\Http\Message\ServerRequestInterface;
    class CacheMiddleware implements MiddlewareInterface
    {
    public function process(
    ServerRequestInterface $request, DelegateInterface $delegate
    ) {
    if (null === $response = $this->cache->get(/**a key**/)) {
    $response = $delegate->process($request);
    $this->cache->set(/**a key**/, $response);
    }
    return $response;
    }
    vote
    

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49. Why those
    standards?
    

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50. Why those
    standards?
    Promote
    interoperability.
    

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51. PSR-8: Huggable Interface
    draft
    

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52. Only members can vote...
    

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53. ...but everybody can participate :)
    

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54. www.php-fig.org/get-involved/
    

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55. Thanks :)
    ___
    Julien Janvier
    @jujanvier
    https://joind.in/talk/ebe72
    

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56. Webography
    ● FIG / FIG 3.0
    ○ The PHP-FIG: Past, Present & Future - podcast with a few FIG members
    ○ Why PHP-FIG matters - by Evert Pot
    ○ FIG 3.0 Proposal - by Larry Garfield
    ○ The TL;DR of FIG 3.0 - by Michael Cullum
    ○ Michael Cullum Talks About PHP FIG, PSR & Symfony - with Michael Cullum
    ○ Phil Sturgeon Talks About API Development, PHP-FIG, PHP Books And The Future Of PHP -
    with Phil Sturgeon
    ○ PHP FIG: Breaking down the Boundaries - by Michael Cullum (video here)
    ● PSR-0
    ○ Is PSR-0 Shortsighted, or are you? - by Phil Sturgeon
    ○ Composer and PSR-0: Friends, Not Relatives - by Phil Sturgeon
    

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57. Webography
    ● PSR 6
    ○ An Open Letter To PHP-FIG - by Anthony Ferrara
    ○ PSR-6 Has Serious Problems - by Andrew Carter
    ○ PSR-6 Is About To Pass And Still Has Serious Problems - by Andrew Carter
    ○ [VOTE][Accept] PSR-6 Caching Interfaces - by Paul Dragoonis
    ● PSR 9 / PSR 10
    ○ Call for volunteers - by Michael Hess
    ● PSR-11
    ○ [PSR-11+] An overview of interoperable PHP modules - by David Négrier
    ○ [PSR-11+] An update on standard service providers - by David Négrier
    

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58. Webography
    ● PSR-7 / Middlewares
    ○ Two things to know about PSR-7 - by Rob Allen
    ○ Middleware concept - by Slim framework
    ○ Writing PSR-7 middleware - by Rob Allen
    ○ HTTP, PSR-7 and Middleware - by Rob Allen
    ○ PSR-7 And Middleware, The Future Of PHP - by Matthew Weier O'Phinney
    ○ All About Middleware - problems about PRS-7 by Anthony Ferrara
    ○ All About PSR-7 Middleware - answer about Anthony Ferrara’s post by Woody Gilk
    ○ Dependency Inversion and PSR-7 Bodies - by Woody Gilk
    ○ PSR-7 Objects Are Not Immutable - by Andrew Carter
    ○ Working with Slim Middleware - by Timothy Boronczyk
    ● PSR-15 / Middlewares
    ○ Using Anonymous Classes to Write Middleware - by Matthew Weier O'Phinney
    ○ Stack middlewares - by Igor Wiedler
    

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