GraphQl implementation in magento2

What is GraphQl – GraphQL is a query language for Application Programming Interface (API) and a runtime for fulfilling those queries with your existing data.

GraphQL provides a complete and understandable description of the data in your API. Using GraphQL we create own schema which is organized in terms of types and fields.

GraphQL uses types to ensure channel only ask for what’s possible and provide clear and helpful errors. Also, you can check how to create REST API in Magento 2.

This blog assumes your familiarity with GraphQL concepts. If it is not the case – first learn about GraphQL on the official website or you can read our previous blog How to use GraphQL in php.

For implementing GraphQL in magento2 you have to create following files :-

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1 – create this file for register your module app/code/Test/TestGraphQl/registration.php

<?php
/**
 * Webkul Software.
 *
 * @category  Webkul
 * @package   Test_TestGraphQl
 * @author    Webkul
 * @license   https://store.webkul.com/license.html
 */
\Magento\Framework\Component\ComponentRegistrar::register(
    \Magento\Framework\Component\ComponentRegistrar::MODULE,
    'Test_TestGraphQl',
    __DIR__
);

2 – For define module name you have to create app/code/Test/TestGraphQl/etc/module.xml

<?xml version="1.0"?>
<!--
/**
* Webkul Software.
*
* @category  Webkul
* @package   Test_TestGraphQl
* @author    Webkul
* @license   https://store.webkul.com/license.html
*/
-->
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Module/etc/module.xsd">
    <module name="Test_TestGraphQl" >
        <sequence>
            <module name="Magento_Customer"/>
            <module name="Magento_Authorization"/>
            <module name="Magento_GraphQl"/>
        </sequence>
    </module>
</config>

3 – First we have to define Schema of query. In this part we mention that which fields and which type of data return in response.

The schema is a container of your type hierarchy, which accepts root types in a constructor and provides methods for receiving information about your types to internal GrahpQL tools. The schema consists of two root types:

Query type is a surface of your read API
Mutation type (optional) exposes write API by declaring all possible mutations in your app

In this blog we learn about only Query type.

create schema.graphqls at this path app/code/Test/TestGraphQl/etc/

#Magento Customer GraphQl Schema

type Query {
    testcustomer: Testcustomer @resolver(class: "Test\\TestGraphQl\\Model\\Resolver\\Customer") @doc(description: "The testcustomer query returns information about a customer")
}

type Testcustomer @doc(description: "Testcustomer defines the customer name and other details") {
    entity_id: Int
    firstname: String
    lastname: String
    email: String
}

4 – Create Resolver Model class which is define in schema.In this resolve method we simply return data of login customer.

<?php

declare(strict_types=1);

namespace Test\TestGraphQl\Model\Resolver;

use Magento\Authorization\Model\UserContextInterface;
use Magento\Framework\GraphQl\Schema\Type\ResolveInfo;
use Test\TestGraphQl\Model\Resolver\Customer\CustomerDataProvider;
use Magento\Framework\Exception\NoSuchEntityException;
use Magento\Framework\Exception\LocalizedException;
use Magento\Framework\GraphQl\Config\Element\Field;
use Magento\Framework\GraphQl\Exception\GraphQlAuthorizationException;
use Magento\Framework\GraphQl\Exception\GraphQlNoSuchEntityException;
use Magento\Framework\GraphQl\Query\Resolver\ContextInterface;
use Magento\Framework\GraphQl\Query\Resolver\Value;
use Magento\Framework\GraphQl\Query\Resolver\ValueFactory;
use Magento\Framework\GraphQl\Query\ResolverInterface;
use Magento\Customer\Model\CustomerFactory;
use Magento\Customer\Api\CustomerRepositoryInterface;
use Magento\Customer\Api\Data\CustomerInterface;
use Magento\Framework\Webapi\ServiceOutputProcessor;
use Magento\Framework\Api\ExtensibleDataObjectConverter;

/**
 * Customers field resolver, used for GraphQL request processing.
 */
class Customer implements ResolverInterface
{
    /**
    * @var ValueFactory
    */
    private $valueFactory;

    /**
    * @var CustomerFactory
    */
    private $customerFactory;

    /**
    * @var ServiceOutputProcessor
    */
    private $serviceOutputProcessor;

    /**
    * @var ExtensibleDataObjectConverter
    */
    private $dataObjectConverter;

    /**
    * @var \Psr\Log\LoggerInterface
    */
    private $logger;

    /**
     *
     * @param ValueFactory $valueFactory
     * @param CustomerFactory $customerFactory
     * @param ServiceOutputProcessor $serviceOutputProcessor
     * @param ExtensibleDataObjectConverter $dataObjectConverter
     */
    public function __construct(
        ValueFactory $valueFactory,
        CustomerFactory $customerFactory,
        ServiceOutputProcessor $serviceOutputProcessor,
        ExtensibleDataObjectConverter $dataObjectConverter,
        CustomerRepositoryInterface $customerRepository,
        \Psr\Log\LoggerInterface $logger
    ) {
        $this->valueFactory = $valueFactory;
        $this->customerFactory = $customerFactory;
        $this->serviceOutputProcessor = $serviceOutputProcessor;
        $this->dataObjectConverter = $dataObjectConverter;
        $this->customerRepository = $customerRepository;
        $this->logger = $logger;
    }

    /**
    * {@inheritdoc}
    */
    public function resolve(
        Field $field,
        $context,
        ResolveInfo $info,
        array $value = null,
        array $args = null
    ) : Value {
        if ((!$context->getUserId()) || $context->getUserType() == UserContextInterface::USER_TYPE_GUEST) {
            throw new GraphQlAuthorizationException(
                __(
                    'Current customer does not have access to the resource "%1"',
                    [\Magento\Customer\Model\Customer::ENTITY]
                )
            );
        }

        try {
            $data = $this->getCustomerData($context->getUserId());
            $result = function () use ($data) {
                return !empty($data) ? $data : [];
            };
            return $this->valueFactory->create($result);
        } catch (NoSuchEntityException $exception) {
            throw new GraphQlNoSuchEntityException(__($exception->getMessage()));
        } catch (LocalizedException $exception) {
            throw new GraphQlNoSuchEntityException(__($e->getMessage()));
        }
    }

    /**
    *
    * @param int $context
    * @return array
    * @throws NoSuchEntityException|LocalizedException
    */
    private function getCustomerData($customerId) : array
    {
        try {
            $customerData = [];
            $customerColl = $this->customerFactory->create()->getCollection()
                                                    ->addFieldToFilter("entity_id", ["eq"=>$customerId]);
            foreach ($customerColl as $customer) {
                array_push($customerData, $customer->getData());
            }
            return isset($customerData[0])?$customerData[0]:[];
        } catch (NoSuchEntityException $e) {
           return [];
        } catch (LocalizedException $e) {
            throw new NoSuchEntityException(__($e->getMessage()));
        }
    }
}

Please run following command to install this module.

1 – php bin/magento setup:upgrade

2 – php bin/magento cache:flush

You can check your GraphQL query response by installing chrome extension ChromeiQL.