silverstripe-framework/docs/en/reference/execution-pipeline.md

Execution Pipeline

Introduction

This page documents all the steps from an URL request to the delivered page.

.htaccess and RewriteRule

Silverstripe uses mod_rewrite to deal with page requests. So instead of having your normal everyday index.php file which tells all, you need to look elsewhere.

The basic .htaccess file after installing SilverStripe looks like this:

<file>
### SILVERSTRIPE START ###

<Files *.ss>
Order deny,allow
Deny from all
Allow from 127.0.0.1
</Files>

<IfModule mod_rewrite.c>
RewriteEngine On

RewriteRule ^vendor(/|$) - [F,L,NC]
RewriteRule silverstripe-cache(/|$) - [F,L,NC]
RewriteRule composer\.(json|lock) - [F,L,NC]

RewriteCond %{REQUEST_URI} ^(.*)$
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule .* framework/main.php?url=%1 [QSA]
</IfModule>
### SILVERSTRIPE END ###
</file>

The <Files> section denies direct access to the template files from anywhere but the server itself.

The <IfModule> section enables the rewriting engine. Requests will be rewritten if they meet the following criteria:

• URI doesn't end in .gif, .jpg, .png, .css, or .js
• The requested file doesn't exist on the filesystem

The rewriting engine then calls framework/main.php with the REQUEST_FILENAME (%1) as the url parameter and also appends the original QUERY_STRING. Example: "myblog/cakes?page=2" is rewritten as "framework/main.php?url=myblog/cakes&page=2".

See the mod_rewrite documentation for more information on how mod_rewrite works.

main.php

All requests go through main.php, which sets up the environment and then hands control over to Director.

Director and URL patterns

main.php relies on [api:Director] to work out which controller should handle this request. [api:Director] will instantiate that controller object and then call [api:Controller::run()].

In general, the URL is build up as follows: page/action/ID/otherID - e.g. http://localhost/mypage/addToCart/12. This will add an object with ID 12 to the cart.

When you create a function, you can access the ID like this:

:::php
public function addToCart ($request) {
	$param = $request->allParams();
	echo "my ID = " . $param["ID"];
	$obj = MyProduct::get()->byID($param["ID"]);
	$obj->addNow();
}

Controllers and actions

[api:Controller]s are the building blocks of your application.

See: The API documentation for [api:Controller]

You can access the following controller-method with /team/signup

:::php
class Team extends DataObject {}

class Team_Controller extends Controller {

	private static $allowed_actions = array('signup');
	
	public function signup($id, $otherId) {
		return $this->renderWith('MyTemplate');
	}
	
}

SSViewer template rendering

See templates for information on the SSViewer template system.

Flush requests

If ?flush=1 is requested in the URL, e.g. http://mysite.com?flush=1, this will trigger a call to flush() on any classes that implement the Flushable interface.

See reference documentation on Flushable for more details.