kernel.rst

.. index::
    single: Configuration reference; Kernel class

Configuring in the Kernel (e.g. AppKernel)

Some configuration can be done on the kernel class itself (usually called app/AppKernel.php). You can do this by overriding specific methods in the parent :class:`Symfony\\Component\\HttpKernel\\Kernel` class.

Configuration

• Charset
• Kernel Name
• Root Directory
• Cache Directory
• Log Directory

Charset

type: string default: UTF-8

This returns the charset that is used in the application. To change it, override the :method:`Symfony\\Component\\HttpKernel\\Kernel::getCharset` method and return another charset, for instance:

// app/AppKernel.php

// ...
class AppKernel extends Kernel
{
    public function getCharset()
    {
        return 'ISO-8859-1';
    }
}

Kernel Name

type: string default: app (i.e. the directory name holding the kernel class)

To change this setting, override the :method:`Symfony\\Component\\HttpKernel\\Kernel::getName` method. Alternatively, move your kernel into a different directory. For example, if you moved the kernel into a foo directory (instead of app), the kernel name will be foo.

The name of the kernel isn't usually directly important - it's used in the generation of cache files. If you have an application with multiple kernels, the easiest way to make each have a unique name is to duplicate the app directory and rename it to something else (e.g. foo).

Root Directory

.. versionadded:: 3.3
    The ``getRootDir()`` method is deprecated since Symfony 3.3. Use the new
    ``getProjectDir()`` method instead.

type: string default: the directory of AppKernel

This returns the root directory of your kernel. If you use the Symfony Standard edition, the root directory refers to the app directory.

To change this setting, override the :method:`Symfony\\Component\\HttpKernel\\Kernel::getRootDir` method:

// app/AppKernel.php

// ...
class AppKernel extends Kernel
{
    // ...

    public function getRootDir()
    {
        return realpath(parent::getRootDir().'/../');
    }
}

Project Directory

.. versionadded:: 3.3
    The ``getProjectDir()`` method was introduced in Symfony 3.3.

type: string default: the directory of the project composer.json

This returns the root directory of your Symfony project. It's calculated as the directory where the main composer.json file is stored.

If for some reason the composer.json file is not stored at the root of your project, you can override the :method:`Symfony\\Component\\HttpKernel\\Kernel::getProjectDir` method to return the right project directory:

// app/AppKernel.php

// ...
class AppKernel extends Kernel
{
    // ...

    public function getProjectDir()
    {
        return realpath(__DIR__.'/../');
    }
}

Cache Directory

type: string default: $this->rootDir/cache/$this->environment

This returns the path to the cache directory. To change it, override the :method:`Symfony\\Component\\HttpKernel\\Kernel::getCacheDir` method. Read ":ref:`override-cache-dir`" for more information.

Log Directory

type: string default: $this->rootDir/logs

This returns the path to the log directory. To change it, override the :method:`Symfony\\Component\\HttpKernel\\Kernel::getLogDir` method. Read ":ref:`override-logs-dir`" for more information.