|
| 1 | +..index:: |
| 2 | + single: Cache; SSI |
| 3 | + single: SSI |
| 4 | + |
| 5 | +.. _server-side-includes: |
| 6 | + |
| 7 | +Working with Server Side Includes |
| 8 | +================================= |
| 9 | + |
| 10 | +In a similar way as:doc:`ESI (Edge Side Includes)<esi>`, SSI can be used to |
| 11 | +control HTTP caching on fragments of a response. The most important |
| 12 | +difference that is SSI is known directly by most web servers like |
| 13 | +`Apache<https://httpd.apache.org/docs/current/en/howto/ssi.html>`_, |
| 14 | +`Nginx<https://nginx.org/en/docs/http/ngx_http_ssi_module.html>`_ etc. |
| 15 | + |
| 16 | +The SSI instructions are done in HTML comments: |
| 17 | + |
| 18 | +..code-block::html |
| 19 | + |
| 20 | + <!DOCTYPE html> |
| 21 | + <html> |
| 22 | + <body> |
| 23 | +<!-- ... some content--> |
| 24 | + |
| 25 | +<!-- Embed the content of another page here--> |
| 26 | +<!--#include virtual="http://..."--> |
| 27 | + |
| 28 | +<!-- ... more content--> |
| 29 | + </body> |
| 30 | + </html> |
| 31 | + |
| 32 | +There is some other `available directives |
| 33 | +<https://en.wikipedia.org/wiki/Server_Side_Includes#Directives>`_ but |
| 34 | +Symfony manages only the ``#include virtual`` one. |
| 35 | + |
| 36 | +..caution:: |
| 37 | + |
| 38 | + Be careful with SSI, your website may be victim of injections. |
| 39 | + Please read this OWASP article first: |
| 40 | + https://www.owasp.org/index.php/Server-Side_Includes_(SSI)_Injection. |
| 41 | + |
| 42 | +When the web server reads an SSI directive, it requests the given URI or gives |
| 43 | +directly from its cache. It repeats this process until there is no more |
| 44 | +SSI directives to handle. Then, it merges all responses into one and sends |
| 45 | +it to the client. |
| 46 | + |
| 47 | +.. _using-ssi-in-symfony: |
| 48 | + |
| 49 | +Using SSI in Symfony |
| 50 | +~~~~~~~~~~~~~~~~~~~~ |
| 51 | + |
| 52 | +First, to use SSI, be sure to enable it in your application configuration: |
| 53 | + |
| 54 | +..configuration-block:: |
| 55 | + |
| 56 | + ..code-block::yaml |
| 57 | +
|
| 58 | +# config/packages/framework.yaml |
| 59 | +framework: |
| 60 | +# ... |
| 61 | +ssi:{ enabled: true } |
| 62 | +
|
| 63 | + ..code-block::xml |
| 64 | +
|
| 65 | +<!-- config/packages/framework.xml--> |
| 66 | + <?xml version="1.0" encoding="UTF-8" ?> |
| 67 | + <containerxmlns="http://symfony.com/schema/dic/symfony" |
| 68 | +xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" |
| 69 | +xmlns:framework="http://symfony.com/schema/dic/symfony" |
| 70 | +xsi:schemaLocation="http://symfony.com/schema/dic/services |
| 71 | + http://symfony.com/schema/dic/services/services-1.0.xsd |
| 72 | + http://symfony.com/schema/dic/symfony |
| 73 | + http://symfony.com/schema/dic/symfony/symfony-1.0.xsd"> |
| 74 | +
|
| 75 | + <framework:config> |
| 76 | +<!-- ...--> |
| 77 | + <framework:ssienabled="true" /> |
| 78 | + </framework:config> |
| 79 | + </container> |
| 80 | +
|
| 81 | + ..code-block::php |
| 82 | +
|
| 83 | + // config/packages/framework.php |
| 84 | + $container->loadFromExtension('framework', array( |
| 85 | + // ... |
| 86 | + 'ssi' => array('enabled' => true), |
| 87 | + )); |
| 88 | +
|
| 89 | +Suppose you have a page with private content like a Profile page and you want |
| 90 | +to cache a static GDPR content block. With SSI, you can add some expiration |
| 91 | +on this block and keep the page private:: |
| 92 | + |
| 93 | + // src/Controller/ProfileController.php |
| 94 | + |
| 95 | + // ... |
| 96 | + class ProfileController extends AbstractController |
| 97 | + { |
| 98 | + public function index(): Response |
| 99 | + { |
| 100 | + // by default, responses are private |
| 101 | + return $this->render('profile/index.html.twig'); |
| 102 | + } |
| 103 | + |
| 104 | + public function gdpr(): Response |
| 105 | + { |
| 106 | + $response = $this->render('profile/gdpr.html.twig'); |
| 107 | + |
| 108 | + // sets to public and adds some expiration |
| 109 | + $response->setSharedMaxAge(600); |
| 110 | + |
| 111 | + return $response; |
| 112 | + } |
| 113 | + } |
| 114 | + |
| 115 | +The profile index page has not public caching, but the GDPR block has |
| 116 | +10 minutes of expiration. Let's include this block into the main one: |
| 117 | + |
| 118 | +..code-block::twig |
| 119 | +
|
| 120 | + {# templates/profile/index.html.twig #} |
| 121 | +
|
| 122 | + {# you can use a controller reference #} |
| 123 | + {{ render_ssi(controller('App\Controller\ProfileController::gdpr')) }} |
| 124 | +
|
| 125 | + {# ... or a URL #} |
| 126 | + {{ render_ssi(url('profile_gdpr')) }} |
| 127 | +
|
| 128 | +The ``render_ssi`` twig helper will generate something like: |
| 129 | + |
| 130 | +..code-block::html |
| 131 | + |
| 132 | +<!--#include virtual="/_fragment?_hash=abcdef1234&_path=_controller=App\Controller\ProfileController::gdpr"--> |
| 133 | + |
| 134 | +``render_esi`` ensures that SSI directive are generated only if the request |
| 135 | +has the header requirement like ``Surrogate-Capability: device="SSI/1.0"`` |
| 136 | +(normally given by the web server). |
| 137 | +Otherwise it will embed directly the sub-response. |
| 138 | + |
| 139 | +..note:: |
| 140 | + |
| 141 | + For more information about Symfony cache fragments, take a tour on |
| 142 | + the:ref:`ESI documentation<http_cache-fragments>`. |
