7. Custom calculators¶

Sylius ships with several default calculators, but you can easily register your own.

7.1. Simple calculators¶

All shipping cost calculators implement CalculatorInterface. In our example we’ll create a calculator which calls an external API to obtain the shipping cost.

<?php

// src/Acme/ShopBundle\Shipping/DHLCalculator.php

namespace Acme\ShopBundle\Shipping;

use Acme\ShopBundle\Shipping\DHLService;
use Sylius\Bundle\ShippingBundle\Calculator\Calculator;
use Sylius\Bundle\ShippingBundle\Model\ShippingSubjectInterface;

class DHLCalculator extends Calculator
{
    private $dhlService;

    public function __construct(DHLService $dhlService)
    {
        $this->dhlService = $dhlService;
    }

    public function calculate(ShippingSubjectInterface $subject, array $configuration)
    {
        return $this->dhlService->getShippingCostForWeight($subject->getShippingWeight());
    }
}

Now, you need to register your new service in container and tag it with sylius.shipping_calculator.

<?xml version="1.0" encoding="UTF-8"?>

<container xmlns="http://symfony.com/schema/dic/services"
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
           xsi:schemaLocation="http://symfony.com/schema/dic/services
                               http://symfony.com/schema/dic/services/services-1.0.xsd">

    <services>
        <service id="acme.shipping_calculator.dhl" class="Acme\ShopBundle\Shipping\DHLCalculator">
            <argument type="service" id="acme.dhl_service" />
            <tag name="sylius.shipping_calculator" calculator="dhl" label="DHL" />
        </service>
    </services>
</container>

That would be all. This new option (“DHL”) will appear on the ShippingMethod creation form, in the “calculator” field.

7.2. Configurable calculators¶

You can also create configurable calculators, meaning that you can have several ShippingMethod‘s using same type of calculator, with different settings.

Let’s modify the DHLCalculator, so that it charges 0 if shipping more than X items. First step is to define the configuration options, using the Symfony OptionsResolver component.

<?php

// src/Acme/ShopBundle\Shipping/DHLCalculator.php

namespace Acme\ShopBundle\Shipping;

use Acme\ShopBundle\Shipping\DHLService;
use Sylius\Bundle\ShippingBundle\Calculator\Calculator;
use Sylius\Bundle\ShippingBundle\Model\ShippingSubjectInterface;
use Symfony\Component\OptionsResolver\OptionsResolverInterface;

class DHLCalculator extends Calculator
{
    private $dhlService;

    public function __construct(DHLService $dhlService)
    {
        $this->dhlService = $dhlService;
    }

    public function calculate(ShippingSubjectInterface $subject, array $configuration)
    {
        return $this->dhlService->getShippingCostForWeight($subject->getShippingWeight());
    }

    /**
    * {@inheritdoc}
    */
    public function isConfigurable()
    {
        return true;
    }

    public function setConfiguration(OptionsResolverInterface $resolver)
    {
        $resolver
            ->setDefaults(array(
                'limit' => 10
            ))
            ->setAllowedTypes(array(
                'limit' => array('integer'),
            ))
        ;
    }
}

Done, we’ve set the default item limit to 10. Now we have to create a form type which will be displayed if our calculator is selected.

<?php

// src/Acme/ShopBundle/Form/Type/Shipping/DHLConfigurationType.php

namespace Acme\ShopBundle\Form\Type\Shipping;

use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\OptionsResolver\OptionsResolverInterface;
use Symfony\Component\Validator\Constraints\NotBlank;
use Symfony\Component\Validator\Constraints\Type;

class DHLConfigurationType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            ->add('limit', 'integer', array(
                'label' => 'Free shipping above total items',
                'constraints' => array(
                    new NotBlank(),
                    new Type(array('type' => 'integer')),
                )
            ))
        ;
    }

    public function setDefaultOptions(OptionsResolverInterface $resolver)
    {
        $resolver
            ->setDefaults(array(
                'data_class' => null
            ))
        ;
    }

    public function getName()
    {
        return 'acme_shipping_calculator_dhl';
    }
}

We also need to register the form type and the calculator in the container.

<?xml version="1.0" encoding="UTF-8"?>

<container xmlns="http://symfony.com/schema/dic/services"
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
           xsi:schemaLocation="http://symfony.com/schema/dic/services
                               http://symfony.com/schema/dic/services/services-1.0.xsd">

    <services>
        <service id="acme.shipping_calculator.dhl" class="Acme\ShopBundle\Shipping\DHLCalculator">
            <argument type="service" id="acme.dhl_service" />
            <tag name="sylius.shipping_calculator" calculator="dhl" label="DHL" />
        </service>
        <service id="acme.form.type.shipping_calculator.dhl" class="Acme\ShopBundle\Form\Type\Shipping\DHLConfigurationType">
            <tag name="form.type" alias="acme_shipping_calculator_dhl" />
        </service>
    </services>
</container>

Finally, configure the calculator to use the form, by implementing simple getConfigurationFormType method.

<?php

// src/Acme/ShopBundle\Shipping/DHLCalculator.php

namespace Acme\ShopBundle\Shipping;

use Acme\ShopBundle\Shipping\DHLService;
use Sylius\Bundle\ShippingBundle\Calculator\Calculator;
use Sylius\Bundle\ShippingBundle\Model\ShippingSubjectInterface;
use Symfony\Component\OptionsResolver\OptionsResolverInterface;

class DHLCalculator extends Calculator
{
    private $dhlService;

    public function __construct(DHLService $dhlService)
    {
        $this->dhlService = $dhlService;
    }

    public function calculate(ShippingSubjectInterface $subject, array $configuration)
    {
        return $this->dhlService->getShippingCostForWeight($subject->getShippingWeight());
    }

    /**
    * {@inheritdoc}
    */
    public function isConfigurable()
    {
        return true;
    }

    public function setConfiguration(OptionsResolverInterface $resolver)
    {
        $resolver
            ->setDefaults(array(
                'limit' => 10
            ))
            ->setAllowedTypes(array(
                'limit' => array('integer'),
            ))
        ;
    }

    public function getConfigurationFormType()
    {
        return 'acme_shipping_calculator_dhl';
    }
}

Perfect, now we’re able to use the configuration inside the calculate method.

<?php

// src/Acme/ShopBundle\Shipping/DHLCalculator.php

namespace Acme\ShopBundle\Shipping;

use Acme\ShopBundle\Shipping\DHLService;
use Sylius\Bundle\ShippingBundle\Calculator\Calculator;
use Sylius\Bundle\ShippingBundle\Model\ShippingSubjectInterface;
use Symfony\Component\OptionsResolver\OptionsResolverInterface;

class DHLCalculator extends Calculator
{
    private $dhlService;

    public function __construct(DHLService $dhlService)
    {
        $this->dhlService = $dhlService;
    }

    public function calculate(ShippingSubjectInterface $subject, array $configuration)
    {
        if ($subject->getShippingItemCount() > $configuration['limit']) {
            return 0;
        }

        return $this->dhlService->getShippingCostForWeight($subject->getShippingWeight());
    }

    /**
    * {@inheritdoc}
    */
    public function isConfigurable()
    {
        return true;
    }

    public function setConfiguration(OptionsResolverInterface $resolver)
    {
        $resolver
            ->setDefaults(array(
                'limit' => 10
            ))
            ->setAllowedTypes(array(
                'limit' => array('integer'),
            ))
        ;
    }

    public function getConfigurationFormType()
    {
        return 'acme_shipping_calculator_dhl';
    }
}

Your new configurable calculator is ready to use. When you select the “DHL” calculator in ShippingMethod form, configuration fields will appear automatically.