Creating Menus as Services

Creating Menus as Services

Note

Registering a menu as service comes with several limitations:

  • it does not allow to use builder options
  • it reuses the same instance several times in case you render the same menu several times, which can have weird side-effects.

It is recommended to register only menu builders as services instead.

This bundle gives you a really convenient way to create menus by following a convention and - if needed - injecting the entire container.

However, if you want to, you can instead choose to create a service for your menu object. The advantage of this method is that you can inject the exact dependencies that your menu needs, instead of injecting the entire service container. This can lead to code that is more testable and also potentially more reusable. The disadvantage is that it needs just a little more setup.

Start by creating a builder for your menu. You can stick as many menus into a builder as you want, so you may only have one (or just a few) of these builder classes in your application:

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// src/AppBundle/Menu/MenuBuilder.php

namespace AppBundle\Menu;

use Knp\Menu\FactoryInterface;
use Symfony\Component\HttpFoundation\RequestStack;

class MenuBuilder
{
    private $factory;

    /**
     * @param FactoryInterface $factory
     */
    public function __construct(FactoryInterface $factory)
    {
        $this->factory = $factory;
    }

    public function createMainMenu(RequestStack $requestStack)
    {
        $menu = $this->factory->createItem('root');

        $menu->addChild('Home', ['route' => 'homepage']);
        // ... add more children

        return $menu;
    }
}

Next, register two services: one for your menu builder, and one for the menu object created by the createMainMenu method:

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# app/config/services.yml
services:
    app.menu_builder:
        class: AppBundle\Menu\MenuBuilder
        arguments: ["@knp_menu.factory"]

    app.main_menu:
        class: Knp\Menu\MenuItem # the service definition requires setting the class
        factory: ["@app.menu_builder", createMainMenu]
        arguments: ["@request_stack"]
        tags:
            - { name: knp_menu.menu, alias: main } # The alias is what is used to retrieve the menu

    # ...

Note

The menu service must be public as it will be retrieved at runtime to keep it lazy-loaded.

Note

If you are using Symfony 2.5 or older version please check the Using a Factory to Create Services article for correct factories syntax corresponding to your version.

You can now render the menu directly in a template via the name given in the alias key above:

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{{ knp_menu_render('main') }}

Suppose now we need to create a second menu for the sidebar. The process is simple! Start by adding a new method to your builder:

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// src/AppBundle/Menu/MenuBuilder.php

// ...

class MenuBuilder
{
    // ...

    public function createSidebarMenu(RequestStack $requestStack)
    {
        $menu = $this->factory->createItem('sidebar');

        $menu->addChild('Home', ['route' => 'homepage']);
        // ... add more children

        return $menu;
    }
}

Now, create a service for just your new menu, giving it a new name, like sidebar:

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# app/config/services.yml
services:
    app.sidebar_menu:
        class: Knp\Menu\MenuItem
        factory: ["@app.menu_builder", createSidebarMenu]
        arguments: ["@request_stack"]
        tags:
            - { name: knp_menu.menu, alias: sidebar } # Named "sidebar" this time

    # ...

It can now be rendered, just like the other menu:

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{{ knp_menu_render('sidebar') }}

This work, including the code samples, is licensed under a Creative Commons BY-SA 3.0 license.