Be lazy, be ESI: HTTP caching and Symfony2 @ PHPDay 2011 05-13-2011

HTTP caching and Symfony2Be lazy, be ESI Alessandro Nadalin May, 13 2011

Symfony2 sucks at caching

because it doesnt have an application caching layer

high five, thats great

Sf2 embraces the HTTP caching specification and thats not because

Fabien is lazy

thats because

Fabien kicks asses

HTTP cache is a King in Symfony2

Caching in Symfony2

Caching is, obviously, a matter of the response

since the response is an object, we have some basic OO stuff to handle HTTP cache

Creating a responsepublic function indexAction(){ $res = $this->render(MyBundle:Default:home.html.twig, array( title => My blog, )); return $res;}

Expiration

Expirationpublic function indexAction(){ $res = $this->render(MyBundle:Default:home.html.twig, array( title => My blog, )); $date = new DateTime(); $date->modify(+600 seconds); $res->setExpires($date); return $res;}

Expiration through Cache-Controlpublic function indexAction(){ $res = $this->render(MyBundle:Default:home.html.twig, array( title => My blog, )); $res->setMaxAge(600); $res->setSharedMaxAge(600); return $res;}

Expiration through Cache-Controlpublic function indexAction(){ $res = $this->render(MyBundle:Default:home.html.twig, array( title => My blog, )); $res->setMaxAge(600); $res->setSharedMaxAge(600); return $res;} Shared caches, like Symfony2 reverse proxy

Validation

Validationpublic function articleAction($id){ $article = $this->get(entity_manager)->query($id)... $res = $this->render(MyBundle:Default:article.html.twig, array( article => $article, )); $etag = "article:{$article->getId()}:{$article->getVersion()}"; $res->setETag($etag); $res->setLastModified($article->getModifiedAt()); return $res;

Validationpublic function articleAction($id){ $article = $this->get(entity_manager)->query($id)... $res = $this->render(MyBundle:Default:article.html.twig, array( article => $article, )); $etag = "article:{$article->getId()}:{$article->getVersion()}"; Datetime object $res->setETag($etag); $res->setLastModified($article->getModifiedAt()); return $res;

Automagically get a Datetime from Doctrine2namespace AcmeBlogBundleEntity;/** * @orm:Entity * @orm:Table(name="article") */class Article{ /** * @orm:Column(type="datetime", name="modified_at") */ protected $modifiedAt;

but hey, you say

whats the advatage of using validation if we always hit the DB and create a new Response?

Validation, the right waypublic function articleAction($id){ $res = new Response() $etag = Memcache::get("Article:{$id}:etag"); $lastModified = Memcache::get("Article:{$id}:last_modified"); $res->setETag($etag); $res->setLastModified($lastModified); if ($res->isNotModified($this->get(request))) { return $res; } $article = $this->get(entity_manager)->query($id)... ...

Calculating an Etag, or a date, is cheaper than generating a full MVC response

Control your power

Additional managementpublic function articleAction($id){ $res = new Response() $res->setVary(array( Accept-Encoding, )); $res->setPublic(); $res->setNotModified(); ...

Varying the responsepublic function articleAction($id){ $res = new Response() $res->setVary(array( Accept-Encoding, )); $res->setPublic(); $res->setNotModified(); ...

Cacheable by all cachespublic function articleAction($id){ $res = new Response() $res->setVary(array( Accept-Encoding, )); $res->setPublic(); $res->setNotModified(); ...

or by local onlypublic function articleAction($id){ $res = new Response() $res->setVary(array( Accept-Encoding, )); $res->setPrivate(); $res->setNotModified(); ...

Good old 304public function articleAction($id){ $res = new Response() $res->setVary(array( Accept-Encoding, )); $res->setPrivate(); $res->setNotModified(); ...

Stalepublic function articleAction($id){ $res = new Response() $res->setVary(array( Accept-Encoding, )); $res->setPrivate(); $res->expire(); ...

but hey, you say

HTTPs cache fails when dealing with really dynamic pages,because consumers will always have to hit the origin server,although a part of the page would be cacheable ( header and footer, for example )

no bueno, you say

ESI was built for that http://www.w3.org/TR/esi-lang<esi:include src="http://mysite.com/twitterfeeds.html" />

ESI and Symfony2# controller$response->setSharedMaxAge(3600);# app/config/config.ymlframework: esi: { enabled: true }# template{% render ...:twitterFeeds with {}, {standalone: true} %}# fragment controller$response->setSharedMaxAge(15);

Use Symfony2 reverse proxy

Use Symfony2 reverse proxy (slower)

or Varnishhttp://www.varnish-cache.org/

Varnish configurationbackend apache { .host = "127.0.0.1"; .port = "8080";}sub vcl_recv { unset req.http.Accept-Encoding; unset req.http.Vary; set req.http.Surrogate-Capability = "abc=ESI/1.0";}sub vcl_fetch { esi; ...

Varnish configurationbackend apache { .host = "127.0.0.1"; tell Symfony2 .port = "8080"; youre behind a reverse proxy} able to handle the ESI specificationsub vcl_recv { unset req.http.Accept-Encoding; unset req.http.Vary; set req.http.Surrogate-Capability = "abc=ESI/1.0";}sub vcl_fetch { esi; ...}

Why HTTP caching is so important?

Ask yourself:as a developer, what do I want on my application?

EvolveLoose coupling Work less

EvolveBecause you want your platform to extensible Loose coupling Work less

EvolveBecause you want your platform to extensible Loose couplingBecause you want it to be easy to integrate with, evolve, plugand mantain Work less

EvolveBecause you want your platform to extensible Loose couplingBecause you want it to be easy to integrate with, evolve, plugand mantain Work lessBecause every LoC is bug-prone and our man-day is a hard-to-scale cost

enters our Hero #1

enters our Hero #2

http://www.lullabot.com/articles/a-beginners-guide-to-caching-data

it supportsHTTP caching! http://drupal.org/node/147310

it supportsHTTP caching! http://drupal.org/node/147310 ( people is supposed to clap their hands here )

wait.... how?

Default headersExpires = Sun, 19 Nov 1978 05:00:00 GMT,Cache-Control = no-cache, must-revalidate,ETag = $_SERVER[REQUEST_TIME],

is that even legal?

"but you can redefine them!"

drupal_add_http_header()

function drupal_add_http_header(){ ... ... drupal_send_headers($headers);}

so, whatdrupal_send_headers() can do so evil?

header() , of course

which means

drupal_add_http_header(Dumb-Header, Im batman!);...// other logic...drupal_add_http_header(Dumb-Header, Im not);var_dump(headers_list());

drupal_add_http_header(Dumb-Header, Im batman!);...// other logic...drupal_add_http_header(Dumb-Header, Im not);var_dump(headers_list());array 0 => string X-Powered-By: PHP/5.3.2-1ubuntu4.7 1 => string Cache: Im not

drupal_add_http_header(Dumb-Header, I-m batman!);...// other logic...drupal_add_http_header(Dumb-Header, false);var_dump(headers_list());

drupal_add_http_header(Dumb-Header, I-m batman!);...// other logic...drupal_add_http_header(Dumb-Header, false);var_dump(headers_list());array 0 => string X-Powered-By: PHP/5.3.2-1ubuntu4.7 1 => string Cache: Im batman

drupal_add_http_header(Dumb-Header, I-m batman!);...// other logic...drupal_add_http_header(Dumb-Header, );var_dump(headers_list());

drupal_add_http_header(Dumb-Header, I-m batman!);...// other logic...drupal_add_http_header(Dumb-Header, );var_dump(headers_list());array 0 => string X-Powered-By: PHP/5.3.2-1ubuntu4.7 1 => string Cache:

you can use header_remove() ( PHP 5.3 )

and create a new class to manage/keep track ofheaders and caching directives

but were lazy andwe dont want to reinvent the wheel

GoalsWork less evolve loose coupling

everything is done for us! :) but....

tmp files, cache tables, procedural code... mmmmh.... gotta be something better

Frameworks

symfony ONE

Cache is used for compiling routes, autoloading, ...

Cache is used for compiling routes, autoloading, ... ...but also for storing the view

at least because we use a framework

Less work

because the hard work is delegated to the browser/proxy

Evolve

because cache is abstracted from the application

Loose coupling

because caching is bound to the protocol, HTTP, notto your implementation ( Sf, RoR, Django )

Alessandro Nadalin

Alessandro Nadalin odino.org

Alessandro Nadalin odino.org @_odino_

Alessandro Nadalin odino.org @_odino_ http://joind.in/talk/view/2988

Alessandro Nadalin odino.org @_odino_ http://joind.in/talk/view/2988 Thanks!

Creditshttp://www.flickr.com/photos/snakphotography/5004775320/sizes/o/in/photostream/ http://www.flickr.com/photos/ashatenbroeke/4367373081/sizes/z/in/photostream/ http://www.flickr.com/photos/juanpg/3333385784/sizes/z/in/photostream/ http://www.flickr.com/photos/congvo/301678287/sizes/l/in/photostream/ http://www.flickr.com/photos/adamrice/280300202/sizes/l/in/photostream/ http://www.flickr.com/photos/tomer_a/541411897/sizes/o/in/photostream/ http://www.flickr.com/photos/subpra/4514008262/sizes/l/in/photostream/ http://www.flickr.com/photos/lippincott/2539720043/sizes/l/in/photostream/ http://www.flickr.com/photos/rawryder/5086090931/sizes/l/in/photostream/ http://www.flickr.com/photos/robboudon/5312731161/sizes/l/in/photostream/ http://www.flickr.com/photos/bc-burnslibrary/4158243488/sizes/o/in/photostream/http://www.flickr.com/photos/13606325@N08/2416993706/sizes/o/in/photostream/ http://www.flickr.com/photos/neothezion/5135841069/sizes/l/in/photostream/ http://www.flickr.com/photos/planetschwa/2494067809/ http://www.flickr.com/photos/thomasthomas/258931782/ http://www.flickr.com/photos/jungle_boy/220181177/sizes/l/in/photostream/ http://www.flickr.com/photos/ramduk/3708039504/sizes/z/in/photostream/ http://www.flickr.com/photos/sashawolff/3228711025/sizes/l/in/photostream/

http://www.symfony.es	930
http://odino.org	314
http://www.odino.org	164
http://paper.li	10
http://www.sfexception.com	8
http://127.0.0.1:4000	7
http://a0.twimg.com	4
http://webcache.googleusercontent.com	1
http://twitter.com	1
https://twitter.com	1
http://odino.github.com	1
http://www.old.odino.org	1

Be lazy, be ESI: HTTP caching and Symfony2 @ PHPDay 2011 05-13-2011

by Alessandro Nadalin

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