silverstripe-framework/docs/en/topics/controller.md

Controller

Base controller class. You will extend this to take granular control over the actions and url handling of aspects of your SilverStripe site.

Usage

The following example is for a simple [api:Controller] class. If you're using the cms module and looking at Page_Controller instances you won't need to setup your own routes since the cms module handles these routes.

mysite/code/Controllers/FastFood.php

:::php
<?php

class FastFood_Controller extends Controller {
	public static $allowed_actions = array('order');
    public function order(SS_HTTPRequest $request) {
        print_r($arguments);
    }
}

Routing

mysite/_config/routes.yml

:::yaml
---
Name: myroutes
After: framework/routes#coreroutes
---
Director:
  rules:
    'fastfood/$Action/$ID/$Name': 'FastFood_Controller'

Request for /fastfood/order/24/cheesefries would result in the following to the $arguments above. If needed, use ?flush=1 on the end of request after making any code changes to your controller.

:::ss
Array
(
    [Action] => order
    [ID] => 24
    [Name] => cheesefries
)

SilverStripe automatically adds a URL routing entry based on the controller's class name, so a `MyController` class is accessible through `http://yourdomain.com/MyController`.

Access Control

Through $allowed_actions

All public methods on a controller are accessible by their name through the $Action part of the URL routing, so a MyController->mymethod() is accessible at http://yourdomain.com/MyController/mymethod. This is not always desireable, since methods can return internal information, or change state in a way that's not intended to be used through a URL endpoint.

SilverStripe strongly recommends securing your controllers through defining a $allowed_actions array on the class, which allows whitelisting of methods, as well as a concise way to perform checks against permission codes or custom logic.

:::php
class MyController extends Controller {
	public static $allowed_actions = array(
		// someaction can be accessed by anyone, any time
		'someaction', 
		// So can otheraction
		'otheraction' => true, 
		// restrictedaction can only be people with ADMIN privilege
		'restrictedaction' => 'ADMIN', 
		// complexaction can only be accessed if $this->canComplexAction() returns true
		'complexaction' '->canComplexAction' 
	);
}

There's a couple of rules guiding these checks:

• Each controller is only responsible for access control on the methods it defines
• If a method on a parent class is overwritten, access control for it has to be redefined as well
• An action named "index" is whitelisted by default
• A wildcard (*) can be used to define access control for all methods (incl. methods on parent classes)
• Specific method entries in $allowed_actions overrule any * settings
• Methods returning forms also count as actions which need to be defined
• Form action methods (targets of FormAction) should NOT be included in $allowed_actions, they're handled separately through the form routing (see the "forms" topic)
• $allowed_actions can be defined on Extension classes applying to the controller.

If the permission check fails, SilverStripe will return a "403 Forbidden" HTTP status.

Through the action

Each method responding to a URL can also implement custom permission checks, e.g. to handle responses conditionally on the passed request data.

:::php
class MyController extends Controller {
	public static $allowed_actions = array('myaction');
	public function myaction($request) {
		if(!$request->getVar('apikey')) {
			return $this->httpError(403, 'No API key provided');
		} 
			
		return 'valid';
	}
}

Unless you transform the response later in the request processing, it'll look pretty ugly to the user. Alternatively, you can use ErrorPage::response_for(<status-code>) to return a more specialized layout.

Note: This is recommended as an addition for $allowed_actions, in order to handle more complex checks, rather than a replacement.

Through the init() method

After checking for allowed_actions, each controller invokes its init() method, which is typically used to set up common state in the controller, and include JavaScript and CSS files in the output which are used for any action. If an init() method returns a SS_HTTPResponse with either a 3xx or 4xx HTTP status code, it'll abort execution. This behaviour can be used to implement permission checks.

:::php
class MyController extends Controller {
	public static $allowed_actions = array();
	public function init() {
		parent::init();
		if(!Permission::check('ADMIN')) return $this->httpError(403);
	}
}

URL Handling

In the above example the URLs were configured using the [api:Director] rules in the routes.yml file. Alternatively you can specify these in your Controller class via the $url_handlers static array (which gets processed by the [api:RequestHandler]).

This is useful when you want to subvert the fixed action mapping of fastfood/order/* to the function order. In the case below we also want any orders coming through /fastfood/drivethrough/ to use the same order function.

mysite/code/Controllers/FastFood.php

:::php
class FastFood_Controller extends Controller {
    static $allowed_actions = array('drivethrough');
    public static $url_handlers = array(
        'drivethrough/$Action/$ID/$Name' => 'order'
    );

URL Patterns

The [api:RequestHandler] class will parse all rules you specify against the following patterns.

A rule must always start with alphabetical ([A-Za-z]) characters or a $Variable declaration

Pattern	Description
$	Param Variable - Starts the name of a paramater variable, it is optional to match this unless ! is used
!	Require Variable - Placing this after a parameter variable requires data to be present for the rule to match
//	Shift Point - Declares that only variables denoted with a $ are parsed into the $params AFTER this point in the regex

Examples

See maetl's article in the Links below of a detailed explanation.

$Action/$ID/$OtherID - Standard URL handler for a Controller. Take whatever URLSegment it is set to, find the Action to match a function in the controller, and parse two optional $param variables that will be named ID and OtherID.

admin/help//$Action/$ID - Match an url starting with /admin/help/, but don't include /help/ as part of the action (the shift point is set to start parsing variables and the appropriate controller action AFTER the //)

tag/$Tag! - Match an URL starting with /tag/ after the controller's URLSegment and require it to have something after it. If the URLSegment is order then /order/tag/34 and /order/tag/asdf match but /order/tag/ will not

You can use the debug_request=1 switch from the urlvariabletools to see these in action.

Redirection

Controllers facilitate HTTP redirection.

Note: These methods have been formerly located on the [api:Director] class.

• redirect("action-name"): If there's no slash in the URL passed to redirect, then it is assumed that you want to go to a different action on the current controller.
• redirect("relative/url"): If there is a slash in the URL, it's taken to be a normal URL. Relative URLs will are assumed to be relative to the site-root.
• redirect("http://www.absoluteurl.com"): Of course, you can pass redirect() absolute URLs too.
• redirectBack(): This will return you to the previous page.

The redirect() method takes an optional HTTP status code, either 301 for permanent redirects, or 302 for temporary redirects (default).

API Documentation

[api:Controller]

Links

• [api:Director] class
• execution-pipeline
• URL Handling in Controllers by maetl