Caching on the Edge
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This document discusses caching in HTTP and provides examples of using HTTP caching headers like Cache-Control, Expires, ETag, and Last-Modified to improve performance. It explains how browsers, proxies, and other intermediaries can cache responses to reduce server load. Expiration headers indicate how long a response can be cached, while validation headers allow checking if content has changed to return 304 responses instead of full 200 responses when a cached response is still fresh.
![$ telnet localhost 80
Trying ::1...
Connected to localhost.
Escape character is '^]'.
GET / HTTP/1.1
Host: http.trainings.sensiolabs.com
HTTP/1.1 200 OK
Date: Wed, 15 Oct 2005 07:07:07 GMT
Server: Apache
Content-Length: 14
Content-Type: text/html
Hello World!
Connection closed by foreign host.](https://image.slidesharecdn.com/caching-on-the-edge-101102074015-phpapp02/85/Caching-on-the-Edge-16-320.jpg)
![// compute ETag value
$etag = '...';
if (
isset($_SERVER['HTTP_IF_NONE_MATCH'])
&& $_SERVER['HTTP_IF_NONE_MATCH'] == $etag
) {
header('HTTP/1.1 304 Not Modified');
} else {
header('ETag: '.$etag);
echo 'Hello';
}](https://image.slidesharecdn.com/caching-on-the-edge-101102074015-phpapp02/85/Caching-on-the-Edge-49-320.jpg)
![session_start();
$_SESSION['foo'] = 'bar';
echo 'Hello';](https://image.slidesharecdn.com/caching-on-the-edge-101102074015-phpapp02/85/Caching-on-the-Edge-63-320.jpg)
![RewriteEngine On
RewriteRule ^(.*)$ index.php [QSA,L]](https://image.slidesharecdn.com/caching-on-the-edge-101102074015-phpapp02/85/Caching-on-the-Edge-121-320.jpg)
![function has_surrogate_ESI_capability()
{
return isset($_SERVER['HTTP_SURROGATE_CAPABILITY'])
&& preg_match('#ESI/1.0#',
$_SERVER['HTTP_SURROGATE_CAPABILITY']);
}](https://image.slidesharecdn.com/caching-on-the-edge-101102074015-phpapp02/85/Caching-on-the-Edge-123-320.jpg)
![$_SERVER['HTTP_SURROGATE_CAPABILITY'] = 'symfony2="ESI/1.0"';
// quick hack... not secure at all!
$base = str_replace('index.php', '', $request->getScriptName());
$script = str_replace($base, '', $request->getRequestUri());
ob_start();
include __DIR__.'/'.$script;
$content = ob_get_clean();
$headers = array();
foreach (headers_list() as $header) {
$elements = explode(':', $header, 2);
$headers[$elements[0]] = trim($elements[1]);
}
// do not deal with response others than 200
// implementation depends on your code
return new Response($content, 200, $headers);](https://image.slidesharecdn.com/caching-on-the-edge-101102074015-phpapp02/85/Caching-on-the-Edge-131-320.jpg)
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Caching on the Edge
- 1. Speaker | Company Title // Presentation Name Caching on the Edge Fabien Potencier
- 2. Who are you?
- 3. May 1996 RFC1945 – HTTP/1.0
- 4. March 1999 RFC2616 – HTTP/1.1 http://www.ietf.org/rfc/rfc2616.txt
- 5. HTTP Bis –Work in progress http://tools.ietf.org/wg/httpbis/ http://www.flickr.com/photos/visualpanic/233508614
- 6. p1: Messaging: Low-level message parsing and connection management p2: Semantics: Methods, status codes and headers p3: Payload: Dealing with content, message-specific headers p4: Conditional Requests: e.g., If-Modified-Since p5: Range Requests: Getting partial content p6: Caching: Browser and intermediary caches p7: Authentication: HTTP authentication framework
- 7. HTTP
- 8. The Client sends a Request to the Server The Server sends back a Response to the Client A Client (browser, bot,WS, curl, …) A Server (Apache, nginx, …) The Request and the Response are HTTP messages
- 9. Let’s play with HTTP and HTTP headers
- 10. GET / HTTP/1.1 Host: http.trainings.sensiolabs.com
- 11. « The request-header fields allow the client to pass additional information about the request, and about the client itself, to the server.These fields act as request modifiers, with semantics equivalent to the parameters on a programming language method invocation. »
- 12. « Each HTTP header field consists of a case-insensitive field name followed by a colon (":"), optional whitespace, and the field value »
- 13. HTTP/1.1 200 OK Date: Wed, 15 Oct 2005 07:07:07 GMT Server: Apache Content-Length: 14 Content-Type: text/html Hello World!
- 14. Live HTTP headers Firefox extension http://livehttpheaders.mozdev.org/
- 15. $ curl -i http://http.trainings.sensiolabs.com/ HTTP/1.1 200 OK Date: Wed, 15 Oct 2005 07:07:07 GMT Server: Apache Content-Length: 14 Content-Type: text/html Hello World!
- 16. $ telnet localhost 80 Trying ::1... Connected to localhost. Escape character is '^]'. GET / HTTP/1.1 Host: http.trainings.sensiolabs.com HTTP/1.1 200 OK Date: Wed, 15 Oct 2005 07:07:07 GMT Server: Apache Content-Length: 14 Content-Type: text/html Hello World! Connection closed by foreign host.
- 17. HTTP Headers with PHP
- 19. Caching in the HTTP Specification
- 20. p1: Messaging: Low-level message parsing and connection management p2: Semantics: Methods, status codes and headers p3: Payload: Dealing with content, message-specific headers p4: Conditional Requests: e.g., If-Modified-Since p5: Range Requests: Getting partial content p6: Caching: Browser and intermediary caches p7: Authentication: HTTP authentication framework
- 21. HTTP Expiration HTTPValidation Fresh vs Stale
- 22. HTTP Headers for Expiration Cache-Control Expires
- 23. HTTP Headers forValidation Last-Modified / If-Modified-Since ETag / If-None-Match
- 24. HTTP Cache headers only work with“safe”HTTP methods (like GET & HEAD)
- 25. Never change the state of the server when serving a GET request (we are talking about the application’s state of course, you can log, cache, …)
- 26. HTTP Expiration
- 27. Expires « The "Expires" header field gives the date/time after which the response is considered stale. »
- 28. Browser YourPHPapplication SomeCache GET /foo HTTP/1.1 Host: foo.org GET /foo HTTP/1.1 Host: foo.org HTTP/1.1 200 OK Expires: Thu, 01 Dec … Hello GET /foo HTTP/1.1 200 OK Expires: Thu, 01 Dec … Hello HTTP/1.1 200 OK Expires: Thu, 01 Dec … Hello
- 29. Browser YourPHPapplication SomeCache GET /foo HTTP/1.1 Host: foo.org GET /foo HTTP/1.1 200 OK Expires: Thu, 01 Dec … Hello HTTP/1.1 200 OK Expires: Thu, 01 Dec … Hello Before expira4on Your applica4on is not called
- 30. Browser YourPHPapplication SomeCache GET /foo HTTP/1.1 Host: foo.org GET /foo HTTP/1.1 Host: foo.org HTTP/1.1 200 OK Expires: Thu, 01 Dec … Hello GET /foo HTTP/1.1 200 OK Expires: Thu, 01 Dec … Hello HTTP/1.1 200 OK Expires: Thu, 01 Dec … Hello A<er expira4on Not fresh
- 31. Expires: Thu, 01 Dec 2010 16:00:00 GMT Date in RFC1123 format, not RFC2822 (timezone always GMT, which is ~ UTC)
- 32. $expires = gmdate('D, j M Y H:i:s T', time() + 5); header('Expires: '.$expires);
- 33. $date = new DateTime(null, new DateTimeZone('UTC')); $date->modify('+5 seconds'); $expires = $date->format('D, d M Y H:i:s').' GMT'; $date = gmdate('D, j M Y H:i:s T', time() + 5); header('Expires: '.$expires);
- 36. WARNING The clocks on theWeb server AND the cache (aka browser) MUST be synchronised
- 37. WARNING « HTTP/1.1 servers SHOULD NOT send Expires dates more than one year in the future. »
- 38. Mostly useful to make static assets (images, css, js, …) cacheable with an extremely long expiry time But there is a better way!
- 42. Don’t use Expires Use Cache-Control …except if you want to set a date, which should be pretty rare
- 43. HTTPValidation
- 44. “304 Not Modified”is your friend
- 45. HTTP Headers forValidation Etag / If-None-Match
- 46. Browser YourPHPapplication SomeCache GET /foo HTTP/1.1 Host: foo.org GET /foo HTTP/1.1 Host: foo.org GET /foo HTTP/1.1 200 OK ETag: abcdef … Hello HTTP/1.1 200 OK ETag: abcdef Hello HTTP/1.1 200 OK ETag: abcdef Hello
- 47. Browser YourPHPapplication SomeCache GET /foo HTTP/1.1 Host: foo.org GET /foo HTTP/1.1 Host: foo.org If-None-Match: abcdef HTTP/1.1 304 Not Modified GET /foo HTTP/1.1 200 OK ETag: abcdef … Hello HTTP/1.1 200 OK ETag: abcdef Hello If the resource has not changed
- 48. SomeCache GET /foo HTTP/1.1 200 OK ETag: abcdef … Hello Browser YourPHPapplication GET /foo HTTP/1.1 Host: foo.org GET /foo HTTP/1.1 Host: foo.org If-None-Match: abcdef If the resource has changed GET /foo HTTP/1.1 200 OK ETag: 123456 … Hello HTTP/1.1 200 OK ETag: 123456 Hello HTTP/1.1 200 OK ETag: 123456 Hello
- 49. // compute ETag value $etag = '...'; if ( isset($_SERVER['HTTP_IF_NONE_MATCH']) && $_SERVER['HTTP_IF_NONE_MATCH'] == $etag ) { header('HTTP/1.1 304 Not Modified'); } else { header('ETag: '.$etag); echo 'Hello'; }
- 50. This is a simple but naïve implementation…
- 51. HTTP Headers forValidation Last-Modified / If-Modified-Since
- 52. Browser YourPHPapplication SomeCache GET /foo HTTP/1.1 Host: foo.org GET /foo HTTP/1.1 Host: foo.org GET /foo HTTP/1.1 200 OK Last-Modified: Thu, … Hello HTTP/1.1 200 OK Last-Modified: Thu, … Hello HTTP/1.1 200 OK Last-Modified: Thu, … Hello
- 53. Browser YourPHPapplication SomeCache GET /foo HTTP/1.1 Host: foo.org GET /foo HTTP/1.1 Host: foo.org If-Modified-Since: Thu, HTTP/1.1 304 Not Modified GET /foo HTTP/1.1 200 OK Last-Modified: Thu, … Hello HTTP/1.1 200 OK Last-Modified: Thu, … Hello If the resource has not changed
- 54. SomeCache GET /foo HTTP/1.1 200 OK Last-Modified: Thu, … Hello GET /foo HTTP/1.1 200 OK Last-Modified: Sun, … Hello Browser YourPHPapplication GET /foo HTTP/1.1 Host: foo.org GET /foo HTTP/1.1 Host: foo.org If-Modified-Since: Thu, If the resource has changed HTTP/1.1 200 OK Last-Modified: Sun, … Hello HTTP/1.1 200 OK Last-Modified: Sun, … Hello
- 56. Browser YourPHPapplication SomeCache GET /foo HTTP/1.1 Host: foo.org GET /foo HTTP/1.1 Host: foo.org GET /foo HTTP/1.1 200 OK Etag: abcdef Cache-‐Control: max-‐ age=10 … Hello HTTP/1.1 200 OK ETag: abcdef Cache-‐Control: max-‐age=10 Hello HTTP/1.1 200 OK ETag: abcdef Cache-‐Control: max-‐age=10 Hello
- 57. Browser YourPHPapplication SomeCache GET /foo HTTP/1.1 Host: foo.org Before expira4on Your applica4on is not called GET /foo HTTP/1.1 200 OK Etag: abcdef Cache-‐Control: max-‐ age=10 … Hello HTTP/1.1 200 OK ETag: abcdef Cache-‐Control: max-‐age=10 Hello
- 58. Browser YourPHPapplication SomeCache GET /foo HTTP/1.1 Host: foo.org GET /foo HTTP/1.1 Host: foo.org If-None-Match: abcdef HTTP/1.1 304 Not Modified Cache-‐Control: max-‐age=10 A<er expira4on but resource s4ll valid GET /foo HTTP/1.1 200 OK Etag: abcdef Cache-‐Control: max-‐ age=10 … Hello HTTP/1.1 200 OK ETag: abcdef Cache-‐Control: max-‐age=10 Hello
- 59. You can combine HTTP headers the way you want Expiration wins overValidation
- 60. Expiration allows you to scale as less requests hit your server (and client speed is better too) Validation saves bandwidth
- 61. The goal is to never generate the same response twice
- 62. PHP and Cache HTTP headers
- 63. session_start(); $_SESSION['foo'] = 'bar'; echo 'Hello';
- 65. Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0
- 66. Kinds of caches
- 67. Browser Cache
- 68. On the server side Browser YourPHPapplication BrowserCache
- 69. Within a Company On the server side Browser YourPHPapplication BrowserBrowser BrowserCacheBrowserCacheBrowserCache
- 70. Proxy Cache
- 71. On the server side Within a Company Browser YourPHPapplication BrowserBrowser BrowserCacheBrowserCacheBrowserCache ProxyCache
- 72. On the server side Within a Company Browser YourPHPapplication BrowserBrowser BrowserCacheBrowserCacheBrowserCache ProxyCache Within a Company BrowserBrowserBrowser BrowserCacheBrowserCacheBrowserCache ProxyCache
- 73. Gateway Cache
- 74. On the server side YourPHPapplication Browser BrowserCache GatewayCache
- 75. Within a Company On the server side Browser YourPHPapplication BrowserBrowser BrowserCacheBrowserCacheBrowserCache GatewayCache
- 76. On the server side Within a Company Browser YourPHPapplication BrowserBrowser BrowserCacheBrowserCacheBrowserCache ProxyCache BrowserBrowser BrowserCacheBrowserCache GatewayCache
- 77. Your PHP application Gateway Cache Reverse Proxy Cache Surrogate Cache HTTP Accelerator Browser Browser Cache Proxy Cache
- 78. Browser Cache Local cache for when you hit“back”or when images are reused throughout a website
- 79. Proxy Cache A shared cache Many people behind a single proxy Installed by large corporations and ISPs Reduce latency and network traffic
- 80. Gateway Cache A shared cache on the server side Installed by network administrators Make websites more scalable, reliable and performing better CDNs like Akaïma are gateway caches
- 81. Today, we will mainly talk about Gateway caches
- 82. Edge Caching
- 84. HTTP 1.1 allows caching anything by default unless explicit Cache-Control header
- 85. In practice, most caches avoid anything with Cache-Control Cookie / Set-Cookie WWW-Authenticate / Authorization POST / PUT 302 / 307 status codes
- 86. Cache-Control: private This is the default with PHP when you have a session Browser cache will still work fine here (public means shared caches, private means browser cache)
- 87. A gateway cache won't cache anything "private" or carrying a cookie In a real-world: tracking cookies (Google Analytics)
- 88. All proxies do caching based on the same HTTP headers
- 89. We need several clients to understand how it works and how the cached is shared
- 90. HTTP Expiration
- 91. GatewayCache Bob YourPHPapplication Bob’sCache GET /foo HTTP/1.1 Host: foo.org GET /foo HTTP/1.1 Host: foo.org GET /foo HTTP/1.1 Host: foo.org GET /foo HTTP/1.1 200 OK C-C: max-age=600 … Hello HTTP/1.1 200 OK C-C: max-age=600 Hello HTTP/1.1 200 OK C-C: max-age=600 Hello GET /foo HTTP/1.1 200 OK C-C: max-age=600 … Hello HTTP/1.1 200 OK C-C: max-age=600 Hello
- 92. Bob’sCache GatewayCache Bob YourPHPapplication GET /foo HTTP/1.1 Host: foo.org GET /foo HTTP/1.1 200 OK C-C: max-age=600 … Hello HTTP/1.1 200 OK C-C: max-age=600 Hello GET /foo HTTP/1.1 200 OK C-C: max-age=600 … Hello
- 93. BrowserCache Alice YourPHPapplication GET /foo HTTP/1.1 Host: foo.org GET /foo HTTP/1.1 Host: foo.org HTTP/1.1 200 OK C-C: max-age=600 Hello HTTP/1.1 200 OK C-C: max-age=600 Hello GatewayCache GET /foo HTTP/1.1 200 OK C-C: max-age=600 … Hello GET /foo HTTP/1.1 200 OK C-C: max-age=600 … Hello
- 94. HTTPValidation
- 95. Bob’sCache GatewayCache Bob YourPHPapplication GET /foo HTTP/1.1 Host: foo.org GET /foo HTTP/1.1 Host: foo.org GET /foo HTTP/1.1 Host: foo.org GET /foo HTTP/1.1 200 OK Etag: abcde … Hello HTTP/1.1 200 OK Etag: abcde Hello HTTP/1.1 200 OK Etag: abcde Hello GET /foo HTTP/1.1 200 OK Etag: abcde … Hello HTTP/1.1 200 OK Etag: abcde Hello
- 96. Bob’sCache GatewayCache Bob YourPHPapplication GET /foo HTTP/1.1 Host: foo.org GET /foo HTTP/1.1 Host: foo.org If-None-Match: ab GET /foo HTTP/1.1 Host: foo.org If-None-Match: ab GET /foo HTTP/1.1 200 OK Etag: ab … Hello HTTP/1.1 200 OK Etag: ab Hello GET /foo HTTP/1.1 200 OK Etag: ab … Hello 304 Not Modified304 Not Modified
- 97. GatewayCache YourPHPapplication BrowserCache GET /foo HTTP/1.1 Host: foo.org GET /foo HTTP/1.1 Host: foo.org GET /foo HTTP/1.1 Host: foo.org If-None-Match: ab GET /foo HTTP/1.1 200 OK Etag: ab … Hello HTTP/1.1 200 OK Etag: ab Hello 304 Not Modified Alice HTTP/1.1 200 OK Etag: ab Hello GET /foo HTTP/1.1 200 OK Etag: ab … Hello
- 98. Gateway caches Varnish (only does that and tries to do it well) Squid (just one way to use it) mod_cache (Apache)
- 99. Gateway caches are a great way to make your website performs better
- 100. But what if you cannot cache whole pages? What if a page has "more" dynamic parts?
- 101. Lorem ipsum dolor sit amet, consectetur adipiscing elit. In vel nulla arcu, vitae cursus nunc. Integer semper turpis et enim porRtor iaculis. Nulla facilisi. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Mauris vehicula ves4bulum dictum. Aenean non velit tortor. Nullam adipiscing malesuada aliquam. Mauris dignissim, urna quis iaculis tempus, justo libero porRtor est, nec eleifend est elit vitae ante. Curabitur interdum luctus metus. Lorem ipsum dolor sit amet, consectetur adipiscing elit. In vel nulla arcu, vitae cursus nunc. Integer semper turpis et enim porRtor iaculis. Nulla facilisi. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Mauris vehicula ves4bulum dictum. Aenean non velit tortor. Nullam adipiscing malesuada aliquam. Mauris dignissim, urna quis iaculis tempus, justo libero porRtor est, nec eleifend est elit vitae ante. Curabitur interdum luctus metus, in pulvinar lectus rutrum sit amet. Duis gravida, metus in dictum eleifend, dolor risus 4ncidunt ligula, non volutpat nulla sapien in elit. Nulla rutrum erat id neque suscipit eu ultricies odio sollicitudin. Aliquam a mi vel eros placerat hendrerit. Phasellus porRtor, augue sit amet vulputate venena4s, dui leo commodo odio, a euismod turpis ligula in elit. cacheable for 10 seconds cacheable for 5 seconds
- 102. ESI… or Edge Side Includes http://www.w3.org/TR/esi-lang
- 103. Lorem ipsum dolor sit amet, consectetur adipiscing elit. In vel nulla arcu, vitae cursus nunc. Integer semper turpis et enim porRtor iaculis. Nulla facilisi. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Mauris vehicula ves4bulum dictum. Aenean non velit tortor. Nullam adipiscing malesuada aliquam. Mauris dignissim, urna quis iaculis tempus, justo libero porRtor est, nec eleifend est elit vitae ante. Curabitur interdum luctus metus. Lorem ipsum dolor sit amet, consectetur adipiscing elit. In vel nulla arcu, vitae cursus nunc. Integer semper turpis et enim porRtor iaculis. Nulla facilisi. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Mauris vehicula ves4bulum dictum. Aenean non velit tortor. Nullam adipiscing malesuada aliquam. Mauris dignissim, urna quis iaculis tempus, justo libero porRtor est, nec eleifend est elit vitae ante. Curabitur interdum luctus metus, in pulvinar lectus rutrum sit amet. Duis gravida, metus in dictum eleifend, dolor risus 4ncidunt ligula, non volutpat nulla sapien in elit. Nulla rutrum erat id neque suscipit eu ultricies odio sollicitudin. Aliquam a mi vel eros placerat hendrerit. Phasellus porRtor, augue sit amet vulputate venena4s, dui leo commodo odio, a euismod turpis ligula in elit.
- 104. Lorem ipsum dolor sit amet, consectetur adipiscing elit. In vel nulla arcu, vitae cursus nunc. Integer semper turpis et enim porRtor iaculis. Nulla facilisi. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Mauris vehicula ves4bulum dictum. Aenean non velit tortor. Nullam adipiscing malesuada aliquam. Mauris dignissim, urna quis iaculis tempus, justo libero porRtor est, nec eleifend est elit vitae ante. Curabitur interdum luctus metus, in pulvinar lectus rutrum sit amet. Duis gravida, metus in dictum eleifend, dolor risus 4ncidunt ligula, non volutpat nulla sapien in elit. Nulla rutrum erat id neque suscipit eu ultricies odio sollicitudin. Aliquam a mi vel eros placerat hendrerit. Phasellus porRtor, augue sit amet vulputate venena4s, dui leo commodo odio, a euismod turpis ligula in elit. <esi:include src="..." />
- 106. BrowserCache GatewayCache Browser YourPHPapplication GET /foo HTTP/1.1 Host: foo.org GET /foo HTTP/1.1 Host: foo.org GET /foo HTTP/1.1 Host: foo.org GET /bar HTTP/1.1 Host: foo.org Lorem ipsum dolor <esi:include src="hYp.." /> HTTP/1.1 200 OK Lorem ipsum dolor HTTP/1.1 200 OK Lorem ipsum dolor sit amet, Lorem ipsum dolor HTTP/1.1 200 OK Lorem ipsum dolor sit amet, Lorem ipsum dolor HTTP/1.1 200 OK
- 107. BrowserCache GatewayCache Browser YourPHPapplication GET /foo HTTP/1.1 Host: foo.org GET /foo HTTP/1.1 Host: foo.org GET /foo HTTP/1.1 Host: foo.org GET /bar HTTP/1.1 Host: foo.org Lorem ipsum dolor <esi:include src="hYp.." /> HTTP/1.1 200 OK C-C: max-age=10 Lorem ipsum dolor HTTP/1.1 200 OK C-C: max-age=5 Lorem ipsum dolor sit amet, Lorem ipsum dolor HTTP/1.1 200 OK Lorem ipsum dolor sit amet, Lorem ipsum dolor HTTP/1.1 200 OK GET /foo C-C: max-age=10 Lor <esi:include /> GET /bar C-C: max-age=5 Lorem GET /foo C-C: max-age=10 Lor Lorem
- 108. BrowserCache GatewayCache Browser YourPHPapplication GET /foo HTTP/1.1 Host: foo.org Lorem ipsum dolor sit amet, Lorem ipsum dolor HTTP/1.1 200 OK GET /foo C-C: max-age=10 Lor <esi:include /> GET /bar C-C: max-age=5 Lorem GET /foo C-C: max-age=10 Lor Lorem 2 seconds later…
- 109. BrowserCache GatewayCache Browser YourPHPapplication GET /foo HTTP/1.1 Host: foo.org Lorem ipsum dolor sit amet, Lorem ipsum dolor HTTP/1.1 200 OK GET /foo C-C: max-age=10 Lor <esi:include /> GET /bar C-C: max-age=5 Lorem GET /foo C-C: max-age=10 Lor Lorem 7 seconds later… WRONG
- 111. BrowserCache GatewayCache Browser YourPHPapplication GET /foo HTTP/1.1 Host: foo.org GET /foo HTTP/1.1 Host: foo.org GET /foo HTTP/1.1 Host: foo.org GET /bar HTTP/1.1 Host: foo.org Lorem ipsum dolor <esi:include src="hYp.." /> HTTP/1.1 200 OK C-C: s-maxage=10 Lorem ipsum dolor HTTP/1.1 200 OK C-C: s-maxage=5 Lorem ipsum dolor sit amet, Lorem ipsum dolor HTTP/1.1 200 OK Lorem ipsum dolor sit amet, Lorem ipsum dolor HTTP/1.1 200 OK GET /foo C-C: s-maxage=10 Lor <esi:include /> GET /bar C-C: s-maxage=5 Lorem
- 112. BrowserCache GatewayCache Browser YourPHPapplication GET /foo HTTP/1.1 Host: foo.org GET /foo HTTP/1.1 Host: foo.org Lorem ipsum dolor sit amet, Lorem ipsum dolor HTTP/1.1 200 OK Lorem ipsum dolor sit amet, Lorem ipsum dolor HTTP/1.1 200 OK GET /foo C-C: s-maxage=10 Lor <esi:include /> GET /bar C-C: s-maxage=5 Lorem 2 seconds later…
- 113. BrowserCache GatewayCache Browser YourPHPapplication GET /foo HTTP/1.1 Host: foo.org GET /foo HTTP/1.1 Host: foo.org GET /bar HTTP/1.1 Host: foo.org Lorem ipsum dolor HTTP/1.1 200 OK C-C: s-maxage=5 Lorem ipsum dolor sit amet, Lorem ipsum dolor HTTP/1.1 200 OK Lorem ipsum dolor sit amet, Lorem ipsum dolor HTTP/1.1 200 OK GET /foo C-C: s-maxage=10 Lor <esi:include /> GET /bar C-C: s-maxage=5 Lorem 7 seconds later…
- 114. Lorem ipsum dolor sit amet, consectetur adipiscing elit. In vel nulla arcu, vitae cursus nunc. Integer semper turpis et enim porRtor iaculis. Nulla facilisi. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Mauris vehicula ves4bulum dictum. Aenean non velit tortor. Nullam adipiscing malesuada aliquam. Mauris dignissim, urna quis iaculis tempus, justo libero porRtor est, nec eleifend est elit vitae ante. Curabitur interdum luctus metus. Lorem ipsum dolor sit amet, consectetur adipiscing elit. In vel nulla arcu, vitae cursus nunc. Integer semper turpis et enim porRtor iaculis. Nulla facilisi. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Mauris vehicula ves4bulum dictum. Aenean non velit tortor. Nullam adipiscing malesuada aliquam. Mauris dignissim, urna quis iaculis tempus, justo libero porRtor est, nec eleifend est elit vitae ante. Curabitur interdum luctus metus, in pulvinar lectus rutrum sit amet. Duis gravida, metus in dictum eleifend, dolor risus 4ncidunt ligula, non volutpat nulla sapien in elit. Nulla rutrum erat id neque suscipit eu ultricies odio sollicitudin. Aliquam a mi vel eros placerat hendrerit. Phasellus porRtor, augue sit amet vulputate venena4s, dui leo commodo odio, a euismod turpis ligula in elit. Lorem ipsum dolor sit amet, consectetur adipiscing elit. In vel nulla arcu, vitae cursus nunc. Integer semper turpis et enim porRtor iaculis. Nulla facilisi. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Mauris vehicula ves4bulum dictum. Aenean non velit tortor. Nullam adipiscing malesuada aliquam. Lorem ipsum dolor sit amet, consectetur adipiscing elit. In vel nulla arcu, vitae cursus nunc. main template layout base layout included page included page included page
- 116. varnishlog -i TxURL varnishlog –o VCL_call hit | grep RxURL
- 117. Make your application work when ESI is enabled and when it’s not And only parse for ESIs when it’s needed
- 121. RewriteEngine On RewriteRule ^(.*)$ index.php [QSA,L]
- 122. sub vcl_recv { set req.http.Surrogate-Capability = "abc=ESI/1.0"; } sub vcl_fetch { if (beresp.http.Surrogate-Control ~ "ESI/1.0") { unset beresp.http.Surrogate-Control; esi; } }
- 123. function has_surrogate_ESI_capability() { return isset($_SERVER['HTTP_SURROGATE_CAPABILITY']) && preg_match('#ESI/1.0#', $_SERVER['HTTP_SURROGATE_CAPABILITY']); }
- 125. function include($path) { if (has_surrogate_ESI_capability()) { $path = get_absolute_path($path); echo '<esi:include src="'.$path.'" />'; add_surrogate_control(); } else { include dirname(__FILE__).'/'.$path; } }
- 126. Imagine the power when you combine ESI, expiration, validation, max-age, s-maxage, …
- 127. Why would you want to reinvent the wheel? and implement your own caching system?
- 128. Because you cannot afford to useVarnish? Because you use a shared hosting company?
- 129. <?php // With the Symfony2 HTTP accelerator instead of Varnish // won't work if you use exit() for instance... // won't work if you have "global" state // This is just a skeleton to get you started // Of course, this is native with Symfony2 ;)
- 130. use SymfonyComponentHttpFoundationResponse; use SymfonyComponentHttpFoundationRequest; use SymfonyComponentHttpKernelHttpKernelInterface; use SymfonyComponentHttpKernelCacheCache; use SymfonyComponentHttpKernelCacheEsi; use SymfonyComponentHttpKernelCacheStore; class AppKernel implements HttpKernelInterface { public function handle(Request $request = null, $type = HttpKernelInterface::MASTER_REQUEST, $raw = false) { return new Response($content, 200, $headers); } public function getRequest() {} }
- 131. $_SERVER['HTTP_SURROGATE_CAPABILITY'] = 'symfony2="ESI/1.0"'; // quick hack... not secure at all! $base = str_replace('index.php', '', $request->getScriptName()); $script = str_replace($base, '', $request->getRequestUri()); ob_start(); include __DIR__.'/'.$script; $content = ob_get_clean(); $headers = array(); foreach (headers_list() as $header) { $elements = explode(':', $header, 2); $headers[$elements[0]] = trim($elements[1]); } // do not deal with response others than 200 // implementation depends on your code return new Response($content, 200, $headers);
- 132. $kernel = new AppKernel(); $store = new Store('/path/to/http_cache'); $esi = new Esi(); $cache = new Cache($kernel, $store, $esi); $cache->handle()->send(); error_log($cache->getLog());
- 133. Goal Be as dynamic as needed Hit the application as less as possible
- 134. The power is even bigger than what you think…
- 139. PURGE: varnishadm -T localhost:6082 purgeurl "^/images/ »
- 140. acl purge_acl { "localhost"; "1.2.3.4"; } sub vcl_recv { if (req.request == "PURGE") { if (!client.ip ~ purge_acl) { error 405 "Not allowed."; } purge_url(req.url); error 200 "Purged."; } return(lookup); } curl -X PURGE http://...
- 141. WARNING Don't use GZIP with ESI asVarnish won't be able to assemble the page