Exponential 5 being built on top of Symfony 2, it uses standard HTTP cache headers. By default the Symfony 2 reverse proxy, written in PHP, is used to handle cache, but it can be easily replaced with any other reverse proxy like Varnish.

Configure Varnish

Provided VCL example is given for Varnish 3.x only

The first thing is to configure Varnish to advertise ESI usage and to activate cache invalidation:

# Varnish 3.x - Exponential 5 - Complete VCL
 
# Our Backend - We assume that Exponential Web server listen on port 80
backend exponential {
    .host = "127.0.0.1";
    .port = "80";
}
 
# ACL for purgers IP.
# Provide here IP addresses that are allowed to send PURGE requests.
# PURGE requests will be sent by the backend.
acl purgers {
    "127.0.0.1";
    "192.168.0.0"/16;
}
 
# Called at the beginning of a request, after the complete request has been received
sub vcl_recv {
 
    # Set the backend
    set req.backend = exponential;
 
    # Advertise Symfony for ESI support
    set req.http.Surrogate-Capability = "abc=ESI/1.0";
 
    # Add a unique header containing the client address (only for master request)
    # Please note that /_fragment URI can change in Symfony configuration
    if (!req.url ~ "^/_fragment") {
        if (req.http.x-forwarded-for) {
            set req.http.X-Forwarded-For = req.http.X-Forwarded-For + ", " + client.ip;
        } else {
            set req.http.X-Forwarded-For = client.ip;
        }
    }
 
    # Handle purge
    # Only works with "multiple_http" purge method
    if (req.request == "PURGE") {
        if (!client.ip ~ purgers) {
            error 405 "Method not allowed";
        }
 
        if ( req.http.X-Location-Id == "*" ) {
            # Purge all locations
            ban( "obj.http.X-Location-Id ~ ^[0-9]+$" );
            error 200 "Purge all locations done.";
        } elseif ( req.http.X-Location-Id ) {
            # Purge location by its locationId
            ban( "obj.http.X-Location-Id == " + req.http.X-Location-Id );
            error 200 "Purge of content connected to the location id(" + req.http.X-Location-Id + ") done.";
        }
    }
 
    # Normalize the Accept-Encoding headers
    if (req.http.Accept-Encoding) {
        if (req.http.Accept-Encoding ~ "gzip") {
            set req.http.Accept-Encoding = "gzip";
        } elsif (req.http.Accept-Encoding ~ "deflate") {
            set req.http.Accept-Encoding = "deflate";
        } else {
            unset req.http.Accept-Encoding;
        }
    }
 
    # Don't cache Authenticate & Authorization
    if (req.http.Authenticate || req.http.Authorization) {
        return(pass);
    }
 
    # Don't cache requests other than GET and HEAD.
    if (req.request != "GET" && req.request != "HEAD") {
        return (pass);
    }
 
    # Don't cache authenticated sessions
    if (req.http.Cookie && req.http.Cookie ~ "is_logged_in=" ) {
        return(pass);
    }
 
    # If it passes all these tests, do a lookup anyway;
    return (lookup);
}
 
# Called when the requested object has been retrieved from the backend
sub vcl_fetch {
 
    # Optimize to only parse the Response contents from Symfony
    if (beresp.http.Surrogate-Control ~ "ESI/1.0") {
        unset beresp.http.Surrogate-Control;
        set beresp.do_esi = true;
    }
 
    # Don't cache response with Set-Cookie
    if ( beresp.http.Set-Cookie ) {
        set beresp.ttl = 0s;
        return (hit_for_pass);
    }
 
    # Respect the Cache-Control=private header from the backend
    if (beresp.http.Cache-Control ~ "private") {
        set beresp.ttl = 0s;
        return (hit_for_pass);
    }
 
    return (deliver);
}

You can of course add additional rules if you need.

Configure Exponential

Update your front controller

By default your front controller (index.php) uses the built-in reverse proxy, EzPublishCache. In order to use Varnish, you need to deactivate it by commenting the line where EzPublishCache is instantiated:

<?php
// ...
require_once __DIR__ . '/../exponential/EzPublishKernel.php';
require_once __DIR__ . '/../exponential/EzPublishCache.php';
$kernel = new EzPublishKernel( 'prod', false );
$kernel->loadClassCache();
// Comment the following line if you use an external reverse proxy (e.g. Varnish)
// $kernel = new EzPublishCache( $kernel );
$request = Request::createFromGlobals();
// Uncomment the following if your application is behind a reverse proxy you manage and trust.
// (see http://fabien.potencier.org/article/51/create-your-own-framework-on-top-of-the-symfony2-components-part-2)
//Request::trustProxyData();
$response = $kernel->handle( $request );
$response->send();
$kernel->terminate( $request, $response );

 

Update YML configuration

exponential:
    http_cache:
        # Use multiple_http method for purging content
        purge_type: multiple_http
 
    system:
        # Assuming that my_siteaccess_group your frontend AND backend siteaccesses
        my_siteaccess_group:
            http_cache:
                # Fill in your Varnish server(s) address(es).
                purge_servers: [http://my.varnish.server:6081]

Et voilà !