CaseInsensitiveStringFilter.php

<?php

namespace Liip\AcmeBundle\Filter;

use Sonata\AdminBundle\Form\Type\Filter\ChoiceType;
use Sonata\AdminBundle\Datagrid\ProxyQueryInterface;
use Sonata\DoctrineORMAdminBundle\Filter\StringFilter;

class CaseInsensitiveStringFilter extends StringFilter
{
    /**
     * {@inheritdoc}
     */
    public function filter(ProxyQueryInterface $queryBuilder, $alias, $field, $data)
    {
        if (!$data || !is_array($data) || !array_key_exists('value', $data)) {
            return;
        }

        $data['value'] = trim($data['value']);

        if (strlen($data['value']) == 0) {
            return;
        }

        $data['type'] = !isset($data['type']) ?  ChoiceType::TYPE_CONTAINS : $data['type'];

        $operator = $this->getOperator((int) $data['type']);

        if (!$operator) {
            $operator = 'LIKE';
        }

        // c.name > '1' => c.name OPERATOR :FIELDNAME
        $parameterName = $this->getNewParameterName($queryBuilder);
        $this->applyWhere($queryBuilder, sprintf('LOWER(%s.%s) %s :%s', $alias, $field, $operator, $parameterName));

        if ($data['type'] != ChoiceType::TYPE_EQUAL) {
            $data['value'] = sprintf($this->getOption('format'), $data['value']);
        }
        
        $queryBuilder->setParameter($parameterName, strtolower($data['value']));
    }

    /**
     * exact copy-paste because private method
     */
    private function getOperator($type)
    {
        $choices = array(
            ChoiceType::TYPE_CONTAINS         => 'LIKE',
            ChoiceType::TYPE_NOT_CONTAINS     => 'NOT LIKE',
            ChoiceType::TYPE_EQUAL            => '=',
        );

        return isset($choices[$type]) ? $choices[$type] : false;
    }
}