Developing cacheable PHP applications

This talk was delivered at the Drupal NYC meetup on July 22nd.

See https://feryn.eu/speaking/developing-cacheable-php-applications-2/ for more details

Transcript

1. DEVELOPING CACHEABLE
   PHP APPLICATIONS
   Thijs Feryn
   

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2. Slow websites
   SUCK
   

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3. WEB PERFORMANCE IS AN
   ESSENTIAL PART OF THE
   USER EXPERIENCE
   

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4. SLOW ~ DOWN
   

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8. THROWING
   SERVERS
   AT THE PROBLEM
   

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9. MO' MONEY
   MO' SERVERS
   MO' PROBLEMS
   

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10. IDENTIFY SLOWEST PARTS
    

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11. OPTIMIZE
    

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12. AFTER A WHILE YOU HIT THE LIMITS
    

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13. CACHE
    

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14. HI, I'M THIJS
    

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15. I'M AN
    EVANGELIST
    AT
    

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18. I'M @THIJSFERYN
    

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20. WE'RE HOSTING A MEETUP
    ✓ THURSDAY JULY 25TH
    ✓ 6PM - 9PM
    ✓ BARCADE, CHELSEA, NYC
    ✓ RSVP !
    https://info.varnish-software.com/varnish-nyc-meetup-2019
    

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22. DON’T RECOMPUTE
    IF THE DATA
    HASN’T CHANGED
    

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25. REVERSE CACHING PROXY
    

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26. NORMALLY
    USER SERVER
    

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27. WITH REVERSE CACHING PROXY
    USER PROXY SERVER
    

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31. HTTP CACHING MECHANISMS
    Expires: Sat, 23 July 2019 00:30:00 GMT
    Cache-control: public, max-age=3600,
    s-maxage=86400
    Cache-control: private, no-cache, no-store
    

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32. IN AN IDEAL WORLD
    

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33. ✓STATELESS
    ✓WELL-DEFINED TTL
    ✓CACHE / NO-CACHE PER RESOURCE
    ✓CACHE VARIATIONS
    ✓CONDITIONAL REQUESTS
    ✓PLACEHOLDERS FOR NON-CACHEABLE CONTENT
    ✓EDGE-SIDE LOGIC FOR PERSONALIZED CACHING
    IN AN IDEAL WORLD
    

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34. REALITY
    SUCKS
    

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37. TIME TO LIVE
    

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38. CACHE VARIATIONS
    

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39. LEGACY
    

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40. WHAT IF WE COULD
    DESIGN OUR
    SOFTWARE WITH
    HTTP CACHING IN
    MIND?
    

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41. CACHING STATE OF MIND
    ✓ PORTABILITY
    ✓ DEVELOPER EMPOWERMENT
    ✓ CONTROL
    ✓ CONSISTENT CACHING BEHAVIOR
    

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43. CACHE-CONTROL
    

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44. Cache-Control: public, s-maxage=500
    

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45. namespace App\Controller;
    use Symfony\Component\HttpFoundation\Request;
    use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;
    use Symfony\Bundle\FrameworkBundle\Controller\Controller;
    class DefaultController extends Controller
    {
    /**
    * @Route("/", name="home")
    */
    public function index()
    {
    return $this
    ->render('index.twig')
    ->setSharedMaxAge(500)
    ->setPublic();
    }
    }
    

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46. Cache-Control: private, no-store
    

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47. /**
    * @Route("/private", name="private")
    */
    public function private()
    {
    $response = $this
    ->render('private.twig')
    ->setPrivate();
    $response->headers->addCacheControlDirective('no-store');
    return $response;
    }
    

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48. CONDITIONAL
    REQUESTS
    

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49. ONLY FETCH PAYLOAD THAT HAS CHANGED
    

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50. HTTP/1.1 200 OK
    

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51. OTHERWISE:
    HTTP/1.1 304 NOT MODIFIED
    

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52. CONDITIONAL REQUESTS
    HTTP/1.1 200 OK
    Host: localhost
    Etag: 7c9d70604c6061da9bb9377d3f00eb27
    Content-type: text/html; charset=UTF-8
    Hello world output
    GET / HTTP/1.1
    Host: localhost
    

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53. CONDITIONAL REQUESTS
    HTTP/1.1 304 Not Modified
    Host: localhost
    Etag: 7c9d70604c6061da9bb9377d3f00eb27
    GET / HTTP/1.1
    Host: localhost
    If-None-Match: 7c9d70604c6061da9bb9377d3f00eb27
    

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54. CONDITIONAL REQUESTS
    HTTP/1.1 200 OK
    Host: localhost
    Last-Modified: Fri, 22 Jul 2016 10:11:16 GMT
    Content-type: text/html; charset=UTF-8
    Hello world output
    GET / HTTP/1.1
    Host: localhost
    

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55. CONDITIONAL REQUESTS
    HTTP/1.1 304 Not Modified
    Host: localhost
    Last-Modified: Fri, 22 Jul 2016 10:11:16 GMT
    GET / HTTP/1.1
    Host: localhost
    If-Last-Modified: Fri, 22 Jul 2016 10:11:16 GMT
    

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56. Cache-Control: public, max-age=100,
    s-maxage=500, stale-while-revalidate=20
    

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57. QUICKLY
    

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58. EARLY
    

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59. Store &
    retrieve
    Etag
    

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60. namespace App\EventListener;
    use Symfony\Component\HttpFoundation\Response;
    use Symfony\Component\HttpFoundation\Request;
    use Symfony\Component\HttpKernel\Event\GetResponseEvent;
    use Symfony\Component\HttpKernel\Event\FilterResponseEvent;
    use SymfonyBundles\RedisBundle\Redis\Client as RedisClient;
    class ConditionalRequestListener
    {
    protected $redis;
    public function __construct(RedisClient $redis)
    {
    $this->redis = $redis;
    }
    protected function isModified(Request $request, $etag)
    {
    if ($etags = $request->getETags()) {
    return in_array($etag, $etags) || in_array('*', $etags);
    }
    return true;
    }
    ...
    src/EventListener/ConditionalRequestListener.php
    

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61. {
    $this->redis = $redis;
    }
    protected function isModified(Request $request, $etag)
    {
    if ($etags = $request->getETags()) {
    return in_array($etag, $etags) || in_array('*', $etags);
    }
    return true;
    }
    public function onKernelRequest(GetResponseEvent $event)
    {
    $request = $event->getRequest();
    $etag = $this->redis->get('etag:'.md5($request->getUri()));
    if(!$this->isModified($request,$etag)) {
    $event->setResponse(Response::create('Not Modified',Response::HTTP_NOT_MODIFIED));
    }
    }
    public function onKernelResponse(FilterResponseEvent $event)
    {
    $response = $event->getResponse();
    $request = $event->getRequest();
    $etag = md5($response->getContent());
    $response->setEtag($etag);
    if($this->isModified($request,$etag)) {
    $this->redis->set('etag:'.md5($request->getUri()),$etag);
    }
    }
    }
    src/EventListener/ConditionalRequestListener.php
    

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62. CONTENT COMPOSITION
    & PLACEHOLDERS
    

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64. Shopping
    cart or account
    information
    

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65. SESSION
    COOKIE
    NO CACHE
    

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66. CODE
    RENDERS
    SINGLE
    HTTP
    RESPONSE
    

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67. LOWEST
    COMMON
    DENOMINATOR:
    NO CACHE
    

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68. PLACEHOLDERS
    

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69. AJAX
    

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70. Non-cached
    AJAX call
    

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71. EDGE SIDE INCLUDES
    

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72. EDGE SIDE INCLUDES
    ✓ PLACEHOLDER
    ✓ W3C STANDARD
    ✓ PROCESSED "ON THE EDGE" (E.G. VARNISH)
    ✓ OUTPUT IS A COMPOSITION OF BLOCKS
    ✓ STATE PER BLOCK
    ✓ TTL PER BLOCK
    
    

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73. VARNISH Surrogate-Capability: key="ESI/1.0"
    Surrogate-Control: content="ESI/1.0"
    
    BACKEND
    Parse ESI placeholders
    VARNISH
    

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74. Non-cached ESI
    placeholder
    

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75. ESI VS AJAX
    

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76. EDGE SIDE INCLUDES
    ✓ SERVER-SIDE
    ✓ STANDARDIZED
    ✓ PROCESSED ON THE
    “EDGE”, NOT IN THE
    BROWSER
    ✓ GENERALLY FASTER
    - SEQUENTIAL 

    (ONLY PARALLEL IN ENTERPRISE VERSION)
    - ONE FAILS, ALL FAIL
    - LIMITED IMPLEMENTATION
    IN VARNISH
    

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77. AJAX
    ✓ CLIENT-SIDE
    ✓ COMMON KNOWLEDGE
    ✓ PARALLEL PROCESSING
    ✓ GRACEFUL DEGRADATION
    - PROCESSED BY THE
    BROWSER
    - EXTRA ROUNDTRIPS
    - SOMEWHAT SLOWER
    

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78. COMPOSITION AT THE VIEW LAYER
    

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79. /**
    * @Route("/", name="home")
    */
    public function index()
    {
    return $this
    ->render('index.twig')
    ->setPublic()
    ->setSharedMaxAge(500);
    }
    /**
    * @Route("/header", name="header")
    */
    public function header()
    {
    $response = $this
    ->render('header.twig')
    ->setPrivate();
    $response->headers->addCacheControlDirective('no-store');
    return $response;
    }
    /**
    * @Route("/footer", name="footer")
    */
    public function footer()
    {
    $response = $this->render('footer.twig');
    $response
    ->setSharedMaxAge(500)
    ->setPublic();
    return $response;
    }
    /**
    * @Route("/nav", name="nav")
    */
    public function nav()
    {
    $response = $this->render('nav.twig');
    $response
    ->setVary('X-Login',false)
    ->setSharedMaxAge(500)
    ->setPublic();
    return $response;
    }
    Controller
    action per
    fragment
    

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80. 

    {{ include('header.twig') }}

    

    

    {{ include('nav.twig') }}

    

    

    {% block content %}{% endblock %}

    

    

    {{ include('footer.twig') }}

    
    

    {{ render_esi(url('header')) }}

    

    

    {{ render_esi(url('nav')) }}

    

    

    {% block content %}{% endblock %}

    

    

    {{ render_esi(url('footer')) }}

    
    

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81. 
    
    
    
    
    
    
    
    An example page Rendered at 2017-05-17 16:57:14
    
    Lorem ipsum dolor sit amet, consectetur adipiscing elit. Mauris consequat orci eget libero
    sollicitudin,…
    
    
    
    
    

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82. CACHE VARIATIONS
    

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83. HOW DO YOU IDENTIFY AN
    OBJECT IN CACHE?
    

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84. THE URL IDENTIFIES
    THE OBJECT IN CACHE
    

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85. WHAT IF THE CONTENT
    OF A URL VARIES
    BASED ON THE VALUE
    OF A REQUEST
    HEADER?
    

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86. CACHE VARIATIONS
    HTTP/1.1 200 OK
    Host: localhost
    Content-Language: en
    Content-type: text/html; charset=UTF-8
    Hello world output
    GET / HTTP/1.1
    Host: localhost
    Accept-Language: en, nl, de
    

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87. Vary: Accept-Language
    Request
    header
    value
    Response
    header
    

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88. WHAT IF YOU CAN'T
    LEVERAGE HTTP?
    

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89. WRITE VCL CODE
    

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90. sub vcl_recv {
    if (req.url ~ "^/status\.php$" ||
    req.url ~ "^/update\.php$" ||
    req.url ~ "^/admin$" ||
    req.url ~ "^/admin/.*$" ||
    req.url ~ "^/flag/.*$" ||
    req.url ~ "^.*/ajax/.*$" ||
    req.url ~ "^.*/ahah/.*$") {
    return (pass);
    }
    }
    URL
    blacklist
    example
    

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91. vcl 4.0;
    sub vcl_recv {
    if (req.http.Cookie) {
    set req.http.Cookie = ";" + req.http.Cookie;
    set req.http.Cookie = regsuball(req.http.Cookie, "; +", ";");
    set req.http.Cookie = regsuball(req.http.Cookie,
    ";(SESS[a-z0-9]+|SSESS[a-z0-9]+|NO_CACHE)=", "; \1=");
    set req.http.Cookie = regsuball(req.http.Cookie, ";[^ ][^;]*", "");
    set req.http.Cookie = regsuball(req.http.Cookie, "^[; ]+|[; ]+$", "");
    if (req.http.Cookie == "") {
    unset req.http.Cookie;
    }
    else {
    return (pass);
    }
    }
    }
    Cookie
    example
    

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93. VARNISH ENTERPRISE
    ✓ CLIENT SSL TERMINATION
    ✓ BACKEND SSL CONNECTIONS
    ✓ PARALLEL ESI
    ✓ MASSIVE STORAGE ENGINE
    ✓ ENCRYPTION
    ✓ THROTTLING
    ✓ RATE LIMITING
    ✓ PREFETCHING
    ✓ GEOLOCATION
    ✓ AUTHENTICATION
    ✓ EDGESTASH
    ✓ CUSTOM STATISTICS
    ✓ ADMIN MODULE
    ✓ SUPPORT
    ✓ HIGH AVAILABILITY
    

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94. EDGE CONTENT
    TRANSFORMATION
    

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95. HTTP/1.1 200 OK
    Accept-Ranges: bytes
    Age: 11
    Cache-Control: max-age=30, public, s-maxage=100
    Content-Type: text/html; charset=UTF-8
    Date: Thu, 11 Jul 2019 13:47:57 GMT
    X-Varnish: 262420 262415
    Hello Thijs
    Hello {{username}}
    USER
    VARNISH
    ENTERPRISE
    ORIGIN
    GET /liked HTTP/1.1
    Cookie:PHPSESSID=21779b3a7a75fca1851954b9810faa26
    GET sf_s21779b3a7a75fca1851954b9810faa26
    

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96. HTTPS://AWS.AMAZON.COM/QUICKSTART/ARCHITECTURE/VARNISH/
    

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99. WE'RE HOSTING A MEETUP
    ✓ THURSDAY JULY 25TH
    ✓ 6PM - 9PM
    ✓ BARCADE, CHELSEA, NYC
    ✓ RSVP !
    https://info.varnish-software.com/varnish-nyc-meetup-2019
    

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101. HTTPS://FERYN.EU
     HTTPS://TWITTER.COM/THIJSFERYN
     HTTPS://INSTAGRAM.COM/THIJSFERYN
     

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