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Developing cacheable
PHP applications
Thijs Feryn
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Slow websites suck
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Hi, I’m Thijs
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I’m
@ThijsFeryn
on Twitter
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I’m an
Evangelist
At
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I’m an
Evangelist
At
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No content
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Cache
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Don’t
recompute
if the data
hasn’t
changed
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No content
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No content
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Reverse
caching
proxy
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Normally
User Server
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With ReCaPro *
User ReCaPro Server
* Reverse Caching Proxy
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Content Delivery Network
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No content
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No content
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HTTP caching mechanisms
Expires: Sat, 09 Sep 2017 14:30:00 GMT
Cache-control: public, max-age=3600,
s-maxage=86400
Cache-control: private, no-cache, no-store
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In an ideal world
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✓Stateless
✓Well-defined TTL
✓Cache / no-cache per resource
✓Cache variations
✓Conditional requests
✓HTTP fragments for non-
cacheable content
In an ideal world
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Reality
sucks
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Common
problems
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No content
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No content
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Time To Live
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Cache variations
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Authentication
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Legacy
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What if we
could design
our software
with HTTP
caching in
mind?
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✓Portability
✓Developer empowerment
✓Control
✓Consistent caching behavior
Caching state of mind
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No content
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Twig templates
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No content
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composer require symfony/flex
composer require annotations twig translation
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render('index.twig');
}
}
src/Controller/DefaultController.php
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{% extends "base.twig" %}
{% block title %}Home{% endblock %}
{% block content %}
{{ 'example' | trans }}
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Mauris consequat orci eget libero sollicitudin, non ultrices turpis mollis. Aliquam sit amet tempus elit. Ut viverra risus enim, ut venenatis justo accumsan nec. Praesent a dolor tellus. Maecenas non mauris leo. Pellentesque lobortis turpis at dapibus laoreet. Mauris rhoncus nulla et urna mollis, et lobortis magna ornare. Etiam et sapien consequat, egestas felis sit amet, dignissim enim.
Quisque quis mollis justo, imperdiet fermentum velit. Aliquam nulla justo, consectetur et diam non, luctus commodo metus. Vestibulum fermentum efficitur nulla non luctus. Nunc lorem nunc, mollis id efficitur et, aliquet sit amet ante. Sed ipsum turpis, vehicula eu semper eu, malesuada eget leo. Vestibulum venenatis dui id pulvinar suscipit. Etiam nec massa pharetra justo pharetra dignissim quis non magna. Integer id convallis lectus. Nam non ullamcorper metus. Ut vestibulum ex ut massa posuere tincidunt. Vestibulum hendrerit neque id lorem rhoncus aliquam. Duis a facilisis metus, a faucibus nulla.
{% endblock %} templates/index.twigSlide 37
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{% block title %}{% endblock %}
{{ include('header.twig') }}
{{ include('footer.twig') }}
templates/base.twig
{{ include('nav.twig') }}
{% block content %}{% endblock %}
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Footer templates/footer.twig
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home: Home
welcome : Welcome to the site
rendered : Rendered at %date%
example : An example page
log_in : Log in
login : Login
log_out : Log out
username : Username
password : Password
private : Private
privatetext : Looks like some very private data
translations/messages.en.yml
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home: Start
welcome : Welkom op de site
rendered : Samengesteld op %date%
example : Een voorbeeldpagina
log_in : Inloggen
login : Login
log_out : Uitloggen
username : Gebruikersnaam
password : Wachtwoord
private : Privé
privatetext : Deze tekst ziet er vrij privé uit
translations/messages.nl.yml
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getRequest();
$preferredLanguage = $request->getPreferredLanguage();
if(null !== $preferredLanguage) {
$request->setLocale($preferredLanguage);
}
}
}
src/EventListener/LocaleListener.php
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services:
_defaults:
autowire: true
autoconfigure: true
public: false
App\:
resource: '../src/*'
exclude: '../src/{Entity,Migrations,Tests,Kernel.php}'
App\Controller\:
resource: '../src/Controller'
tags: ['controller.service_arguments']
App\EventListener\LocaleListener:
tags:
- { name: kernel.event_listener, event: kernel.request, priority: 100}
config/services.yml
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Accept-Language: en
Accept-Language: nl
VS
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No content
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No content
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The mission
Maximum
Cacheability
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Cache-control
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Cache-Control: public, s-maxage=500
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render('index.twig')
->setSharedMaxAge(500)
->setPublic();
}
}
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Conditional
requests
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Only fetch
payload that has
changed
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HTTP/1.1 200 OK
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Otherwise:
HTTP/1.1 304 Not Modified
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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
User-Agent: curl/7.48.0
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Conditional requests
HTTP/1.0 304 Not Modified
Host: localhost
Etag: 7c9d70604c6061da9bb9377d3f00eb27
GET / HTTP/1.1
Host: localhost
User-Agent: curl/7.48.0
If-None-Match:
7c9d70604c6061da9bb9377d3f00eb27
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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
User-Agent: curl/7.48.0
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Conditional requests
HTTP/1.0 304 Not Modified
Host: localhost
Last-Modified: Fri, 22 Jul 2016 10:11:16 GMT
GET / HTTP/1.1
Host: localhost
User-Agent: curl/7.48.0
If-Last-Modified: Fri, 22 Jul 2016 10:11:16
GMT
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composer require symfony-bundles/redis-bundle
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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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{
$this->redis = $redis;
$this->logger = $logger;
}
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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Do not cache
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Cache-Control: private, no-store
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/**
* @Route("/private", name="private")
*/
public function private()
{
$response = $this
->render('private.twig')
->setPrivate();
$response->headers->addCacheControlDirective('no-store');
return $response;
}
Dot not
cache private
page
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session
cookie
No cache
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No content
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Code
renders
single HTTP
response
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Lowest
common
denominator:
no cache
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Block caching
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Edge Side Includes
✓Placeholder
✓Parsed by Varnish
✓Output is a composition of blocks
✓State per block
✓TTL per block
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Surrogate-Capability: key="ESI/1.0"
Surrogate-Control: content="ESI/1.0"
Varnish
Backend
Parse ESI placeholders
Varnish
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ESI
vs
AJAX
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✓ Server-side
✓ Standardized
✓ Processed on the
“edge”, no in the
browser
✓ Generally faster
Edge-Side Includes
- Sequential
- One fails, all fail
- Limited
implementation in
Varnish
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✓ Client-side
✓ Common knowledge
✓ Parallel processing
✓ Graceful
degradation
AJAX
- Processed by the
browser
- Extra roundtrips
- Somewhat slower
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Subrequests
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{{ include('header.twig') }}
{{ include('footer.twig') }}
{{ include('nav.twig') }}
{% block content %}{% endblock %}
{{ render_esi(url('header')) }}
{{ render_esi(url('footer')) }}
{{ render_esi(url('nav')) }}
{% block content %}{% endblock %}
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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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/**
* @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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Problem:
no language
cache
variation
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Vary: Accept-Language
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getResponse();
$response->setVary('Accept-Language',false);
}
}
src/EventListener/VaryListener.php
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What if you can't
leverage HTTP?
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Write VCL
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sub vcl_recv {
if (req.url ~ "^/status\.php$" ||
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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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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No content
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Transfer-Encoding: chunked
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Auto-placeholdering
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BigPipe
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[{"command":"insert","method":"replaceWith","selector":"[data-big-
pipe-placeholder-
id=\u0022callback=Drupal%5CCore%5CRender%5CElement%5CStatusMessages%
3A%3ArenderMessages\u0026args%5B0%5D\u0026token=_HAdUpwWmet0TOTe2PSi
JuMntExoshbm1kh2wQzzzAA\u0022]","data":"","settings":null}]
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No content
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✓Navigation page
✓Private page
Weak spots
Not cached
because of
stateful content
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Move state client-side
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Replace PHP session with
JSON Web Tokens
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JWT
eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiJhZG1pb
iIsImV4cCI6MTQ5NTUyODc1NiwibG9naW4iOnRydWV9.u4Idy-
SYnrFdnH1h9_sNc4OasORBJcrh2fPo1EOTre8
✓3 parts
✓Dot separated
✓Base64 encoded JSON
✓Header
✓Payload
✓Signature (HMAC with secret)
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eyJzdWIiOiJhZG1pbiIsIm
V4cCI6MTQ5NTUyODc1Niwi
bG9naW4iOnRydWV9
{
"alg": "HS256",
"typ": "JWT"
}
{
"sub": "admin",
"exp": 1495528756,
"login": true
}
HMACSHA256(
base64UrlEncode(header) + "." +
base64UrlEncode(payload),
secret
)
eyJhbGciOiJIUzI1NiIsI
nR5cCI6IkpXVCJ9
u4Idy-
SYnrFdnH1h9_sNc4OasOR
BJcrh2fPo1EOTre8
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JWT
Cookie:token=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJz
dWIiOiJhZG1pbiIsImV4cCI6MTQ5NTUyODc1NiwibG9naW4iOnRydW
V9.u4Idy-SYnrFdnH1h9_sNc4OasORBJcrh2fPo1EOTre8
✓Stored in a cookie
✓Can be validated by Varnish
✓Payload can be processed by any
language (e.g. Javascript)
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sub jwt {
std.log("Ready to perform some JWT magic");
if(cookie.isset("jwt_cookie")) {
#Extract header data from JWT
var.set("token", cookie.get("jwt_cookie"));
var.set("header", regsub(var.get("token"),"([^\.]+)\.[^\.]+\.[^\.]+","\1"));
var.set("type", regsub(digest.base64url_decode(var.get("header")),{"^.*?"typ"\s*:\s*"(\w+)".*?$"},"\1"));
var.set("algorithm", regsub(digest.base64url_decode(var.get("header")),{"^.*?"alg"\s*:\s*"(\w+)".*?$"},"\1"));
#Don't allow invalid JWT header
if(var.get("type") == "JWT" && var.get("algorithm") == "HS256") {
#Extract signature & payload data from JWT
var.set("rawPayload",regsub(var.get("token"),"[^\.]+\.([^\.]+)\.[^\.]+$","\1"));
var.set("signature",regsub(var.get("token"),"^[^\.]+\.[^\.]+\.([^\.]+)$","\1"));
var.set("currentSignature",digest.base64url_nopad_hex(digest.hmac_sha256(var.get("key"),var.get("header") + "." + var.get("rawPayload"))));
var.set("payload", digest.base64url_decode(var.get("rawPayload")));
var.set("exp",regsub(var.get("payload"),{"^.*?"exp"\s*:\s*([0-9]+).*?$"},"\1"));
var.set("jti",regsub(var.get("payload"),{"^.*?"jti"\s*:\s*"([a-z0-9A-Z_\-]+)".*?$"},"\1"));
var.set("userId",regsub(var.get("payload"),{"^.*?"uid"\s*:\s*"([0-9]+)".*?$"},"\1"));
var.set("roles",regsub(var.get("payload"),{"^.*?"roles"\s*:\s*"([a-z0-9A-Z_\-, ]+)".*?$"},"\1"));
#Only allow valid userId
if(var.get("userId") ~ "^\d+$") {
#Don't allow expired JWT
if(std.time(var.get("exp"),now) >= now) {
#SessionId should match JTI value from JWT
if(cookie.get(var.get("sessionCookie")) == var.get("jti")) {
#Don't allow invalid JWT signature
if(var.get("signature") == var.get("currentSignature")) {
#The sweet spot
set req.http.X-login="true";
} else {
std.log("JWT: signature doesn't match. Received: " + var.get("signature") + ", expected: " + var.get("currentSignature"));
}
} else {
std.log("JWT: session cookie doesn't match JTI." + var.get("sessionCookie") + ": " + cookie.get(var.get("sessionCookie")) + ", JTI:" + var.get("jti"));
}
} else {
std.log("JWT: token has expired");
}
} else {
std.log("UserId '"+ var.get("userId") +"', is not numeric");
}
} else {
std.log("JWT: type is not JWT or algorithm is not HS256");
}
std.log("JWT processing finished. UserId: " + var.get("userId") + ". X-Login: " + req.http.X-login);
}
#Look for full private content
if(req.url ~ "/node/2" && req.url !~ "^/user/login") {
if(req.http.X-login != "true") {
return(synth(302,"/user/login?destination=" + req.url));
}
}
}
Insert incomprehensible
Varnish VCL code here …
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X-Login: true
End result:
X-Login: false
Custom request
header set by
Varnish
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Extra cache
variation
required
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Vary: Accept-Language, X-Login
Content for logged-in
& anonymous differs
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function getCookie(name) {
var value = "; " + document.cookie;
var parts = value.split("; " + name + "=");
if (parts.length == 2) return parts.pop().split(";").shift();
}
function parseJwt (token) {
var base64Url = token.split('.')[1];
var base64 = base64Url.replace('-', '+').replace('_', '/');
return JSON.parse(window.atob(base64));
};
$(document).ready(function(){
if ($.cookie('token') != null ){
var token = parseJwt($.cookie("token"));
$("#usernameLabel").html(', ' + token.sub);
}
});
Parse JWT
in Javascript
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Does not require
backend access
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composer require firebase/php-jwt
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key = $key;
$this->username = $username;
$this->password = $password;
}
public function jwt($username)
{
return JWT::encode([
'sub'=>$username,
'exp'=>time() + (4 * 24 * 60 * 60),
'login'=>true,
],$this->key);
}
public function createCookie($username)
{
return new Cookie("token",$this->jwt($username), time() + (3600 * 48), '/', null,
false, false);
}
public function validate($token)
{
src/Service/JwtAuthentication.php
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$this->password = $password;
}
public function jwt($username)
{
return JWT::encode([
'sub'=>$username,
'exp'=>time() + (4 * 24 * 60 * 60),
//'exp'=>time() + 60,
'login'=>true,
],$this->key);
}
public function createCookie($username)
{
return new Cookie("token",$this->jwt($username), time() + (3600 * 48), '/', null,
false, false);
}
public function validate($token)
{
try {
$data = JWT::decode($token,$this->key,['HS256']);
$data = (array)$data;
if($data['sub'] !== $this->username) {
return false;
}
return true;
} catch(\UnexpectedValueException $e) {
return false;
}
}
}
src/Service/JwtAuthentication.php
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services:
App\Service\JwtAuthentication:
arguments:
$key: '%env(JWT_KEY)%'
$username: '%env(JWT_USERNAME)%'
$password: '%env(JWT_PASSWORD)%'
src/Service/JwtAuthentication.php
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###> JWT authentication ###
JWT_KEY=SlowWebSitesSuck
JWT_USERNAME=admin
JWT_PASSWORD=$2y$10$431rvq1qS9ewNFP0Gti/o.kBbuMK4zs8IDTLlxm5uzV7cbv8wKt0K
###< JWT authentication ###
.env
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/**
* @Route("/login", name="login", methods="GET")
*/
public function login(Request $request, JwtAuthentication $jwt)
{
if($jwt->validate($request->cookies->get('token'))) {
return new RedirectResponse($this->generateUrl('home'));
}
$response = $this->render('login.twig',['loginLogoutUrl'=>$this-
>generateUrl('login'),'loginLogoutLabel'=>'log_in']);
$response
->setSharedMaxAge(500)
->setVary('X-Login',false)
->setPublic();
return $response;
}
/**
* @Route("/login", name="loginpost", methods="POST")
*/
public function loginpost(Request $request, JwtAuthentication $jwt)
{
$username = $request->get('username');
$password = $request->get('password');
if(!$username || !$password || getenv('JWT_USERNAME') != $username || !
password_verify($password,getenv('JWT_PASSWORD'))) {
return new RedirectResponse($this->generateUrl('login'));
}
$response = new RedirectResponse($this->generateUrl('home'));
$response->headers->setCookie($jwt->createCookie($username));
return $response;
}
src/Controller/DefaultController.php
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/**
* @Route("/logout", name="logout")
*/
public function logout()
{
$response = new RedirectResponse($this->generateUrl('login'));
$response->headers->clearCookie('token');
return $response;
}
src/Controller/DefaultController.php
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/**
* @Route("/nav", name="nav")
*/
public function nav(Request $request, JwtAuthentication $jwt)
{
if($jwt->validate($request->cookies->get('token'))) {
$loginLogoutUrl = $loginLogoutUrl = $this->generateUrl('logout');
$loginLogoutLabel = 'log_out';
} else {
$loginLogoutUrl = $this->generateUrl('login');
$loginLogoutLabel = 'log_in';
}
$response = $this->render('nav.twig',
['loginLogoutUrl'=>$loginLogoutUrl,'loginLogoutLabel'=>$loginLogoutLabel]);
$response
->setVary('X-Login',false)
->setSharedMaxAge(500)
->setPublic();
return $response;
}
src/Controller/DefaultController.php
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{% extends "base.twig" %}
{% block title %}Login{% endblock %}
{% block content %}
{% endblock %}
templates/login.twig
{{ 'log_in' | trans }}
{{ 'username' | trans }}
{{ 'password' | trans }}
{{ 'log_in' | trans }}
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No content
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No content
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Cookie:
token=eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1Ni
J9.eyJzdWIiOiJhZG1pbiIsImV4cCI6MTUyMDk0M
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5d62O5aMdCotKvCqd7F8qFqZC2Y
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With the proper VCL, Varnish
can process the JWT and
make cache variations for
authenticated & anonymous
content
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https://github.com/ThijsFeryn/
cacheable-sites-symfony4
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https://feryn.eu
https://twitter.com/ThijsFeryn
https://instagram.com/ThijsFeryn
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