composer.json

{
    "autoload": {
        "psr-0": {
            "": "lib/"
        }
    }
}

twigfilter.info

name = Twig Filter
core = 7.x
dependencies[] = pimple

twigfilter.module

<?php

/**
 * Implements hook_filter_info().
 */
function twigfilter_filter_info() {
  $filters['twig'] = array(
    'title' => t('Twig'),
    'process callback' => 'twig_filter_process',
  );
  return $filters;
}

/**
 * Implements hook_filter_process().
 */
function twig_filter_process($text, $filter, $format, $langcode, $cache, $cache_id) {
  try {
    return twig_render($text);
  } catch (\Twig_Error_Syntax $e) {
    drupal_set_message($e->getMessage(), 'error');
    return $text;
  }
}

/**
 * Helper function to actually render templates.
 */
function twig_render($template, array $context = array()) {
  $c = pimple_get_container();

  /** @var \Twig_Environment $twig */
  $twig = $c['twig_filter'];

  /** @var \Twig_Extension_Sandbox $sandbox */
  if ($twig->hasExtension('sandbox')) {
    $sandbox = $twig->getExtension('sandbox');
    if (!$alreadySandboxed = $sandbox->isSandboxed()) {
      $sandbox->enableSandbox();
    }

    $output = $twig->render($template, $context);

    if (!$alreadySandboxed) {
      $sandbox->disableSandbox();
    }

    return $output;
  }

  return $twig->render($template, $context);
}

twigfilter.pimple.inc

<?php

/**
 * Implements hook_pimple_info_alter().
 *
 * @return array
 */
function twigfilter_pimple_info_alter(&$info) {
  foreach ($info as &$definition) {
    $definition['providers'][] = array(
      'class' => 'TwigFormatServiceProvider',
      'values' => array(
        'twig.sandbox.allowed_tags' => array('entity_view'),
        'twig.sandbox.allowed_functions' => array('entity_load','entity_view','drupal_render'),
      ),
    );
  }
}

TwigFormatServiceProvider.php

<?php

class TwigFormatServiceProvider implements \Pimple\ServiceProviderInterface
{
    public function register(\Pimple\Container $pimple)
    {
        $pimple['twig.sandbox.allowed_tags'] = array();
        $pimple['twig.sandbox.allowed_filters'] = array();
        $pimple['twig.sandbox.allowed_methods'] = array();
        $pimple['twig.sandbox.allowed_properties'] = array();
        $pimple['twig.sandbox.allowed_functions'] = array();

        $pimple['twig_filter'] = function (\Pimple\Container $c) {
            /** @var \Twig_Environment $twig */
            $twig = new \Twig_Environment($c['twig.loader.string'], array_merge($c['twig.options'], array(
              'optimizations' => 0,
              'cache' => false,
            )));

            $twig->addExtension($c['twig.extension.sandbox']);

            $twig->addTokenParser($c['twig.token_parser.entity_view']);

            $twig->registerUndefinedFunctionCallback(function ($name) {
                if (in_array($name, array('entity_load', 'entity_view', 'drupal_render')) && function_exists($name)) {
                    return new Twig_SimpleFunction($name, $name);
                }

                return false;
            });

            return $twig;
        };

        $pimple['twig.token_parser.entity_view'] = function () {
            return new \Drufony\Bridge\Twig\TokenParser\EntityViewTokenParser();
        };

        $pimple['twig.extension.sandbox'] = function (\Pimple\Container $c) {
            return new Twig_Extension_Sandbox($c['twig.sandbox.security_policy']);
        };

        $pimple['twig.sandbox.security_policy'] = function (\Pimple\Container $c) {
            return new Twig_Sandbox_SecurityPolicy(
              $c['twig.sandbox.allowed_tags'],
              $c['twig.sandbox.allowed_filters'],
              $c['twig.sandbox.allowed_methods'],
              $c['twig.sandbox.allowed_properties'],
              $c['twig.sandbox.allowed_functions']
            );
        };
    }
}