Symfony2 - checking if file exists

If you want want to check the existence of a file which is not a twig template (so defined can't work), create a TwigExtension service and add file_exists() function to twig:

src/AppBundle/Twig/Extension/TwigExtension.php

<?php

namespace AppBundle\Twig\Extension;

class FileExtension extends \Twig_Extension
{

    /**
     * Return the functions registered as twig extensions
     * 
     * @return array
     */
    public function getFunctions()
    {
        return array(
            new Twig_SimpleFunction('file_exists', 'file_exists'),
        );
    }

    public function getName()
    {
        return 'app_file';
    }
}
?>

Register your service:

src/AppBundle/Resources/config/services.yml

# ...

parameters:

    app.file.twig.extension.class: AppBundle\Twig\Extension\FileExtension

services:

    app.file.twig.extension:
        class: %app.file.twig.extension.class%
        tags:
            - { name: twig.extension }

That's it, now you are able to use file_exists() inside a twig template ;)

Some template.twig:

{% if file_exists('/home/sybio/www/website/picture.jpg') %}
    The picture exists !
{% else %}
    Nope, Chuck testa !
{% endif %}

EDIT to answer your comment:

To use file_exists(), you need to specify the absolute path of the file, so you need the web directory absolute path, to do this give access to the webpath in your twig templates app/config/config.yml:

# ...

twig:
    globals:
        web_path: %web_path%

parameters:
    web_path: %kernel.root_dir%/../web

Now you can get the full physical path to the file inside a twig template:

{# Display: /home/sybio/www/website/web/img/games/3.jpg #}
{{ web_path~asset('img/games/'~item.getGame.id~'.jpg') }}

So you'll be able to check if the file exists:

{% if file_exists(web_path~asset('img/games/'~item.getGame.id~'.jpg')) %}

I've created a Twig function which is an extension of the answers I have found on this topic. My asset_if function takes two parameters: the first one is the path for the asset to display. The second parameter is the fallback asset, if the first asset does not exist.

Create your extension file:

src/Showdates/FrontendBundle/Twig/Extension/ConditionalAssetExtension.php:

<?php

namespace Showdates\FrontendBundle\Twig\Extension;

use Symfony\Component\DependencyInjection\ContainerInterface;

class ConditionalAssetExtension extends \Twig_Extension
{
    private $container;

    public function __construct(ContainerInterface $container)
    {
        $this->container = $container;
    }

    /**
     * Returns a list of functions to add to the existing list.
     *
     * @return array An array of functions
     */
    public function getFunctions()
    {
        return array(
            'asset_if' => new \Twig_Function_Method($this, 'asset_if'),
        );
    }

    /**
     * Get the path to an asset. If it does not exist, return the path to the
     * fallback path.
     * 
     * @param string $path the path to the asset to display
     * @param string $fallbackPath the path to the asset to return in case asset $path does not exist
     * @return string path
     */
    public function asset_if($path, $fallbackPath)
    {
        // Define the path to look for
        $pathToCheck = realpath($this->container->get('kernel')->getRootDir() . '/../web/') . '/' . $path;

        // If the path does not exist, return the fallback image
        if (!file_exists($pathToCheck))
        {
            return $this->container->get('templating.helper.assets')->getUrl($fallbackPath);
        }

        // Return the real image
        return $this->container->get('templating.helper.assets')->getUrl($path);
    }

    /**
     * Returns the name of the extension.
     *
     * @return string The extension name
     */
    public function getName()
    {
       return 'asset_if';
    }
}

Register your service (app/config/config.yml or src/App/YourBundle/Resources/services.yml):

services:
    showdates.twig.asset_if_extension:
        class: Showdates\FrontendBundle\Twig\Extension\ConditionalAssetExtension
        arguments: ['@service_container']
        tags:
          - { name: twig.extension }

Now use it in your templates like this:

<img src="{{ asset_if('some/path/avatar_' ~ app.user.id, 'assets/default_avatar.png') }}" />

Tags:

Twig

Symfony

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