How to create REST API's in Magento 2?

Question

I have to create a REST API that can be used in android phone to list all the products including product image using category id ?

Answer 1

There are many tutorials which guides how to create the rest api.

you can have a look a these.

http://inchoo.net/magento/api-magento/magento-2-custom-api/

https://webkul.com/blog/magento2-custom-rest-api/

Create Custom Rest Api in Magento2 and solution for "InvalidArgumentException" error

There is official magento document for this.

http://devdocs.magento.com/guides/v2.0/get-started/bk-get-started-api.html

For your requirement API's are already available, you can refer below.

http://devdocs.magento.com/guides/v2.0/rest/list.html

Answer 2

You can use these samples using:

• REST Token-based
• REST OAuth-based
• SOAP

https://gist.github.com/rafaelstz/ecab668b80fece4d9acdb9c5358b3173

Answer 3

Create REST API using standard ways in Magento2.

Here is the directories structure of a create the Magento2 module:

<Vendor>/<ModuleName>
API/
---Data/
-------CustomerInterface.php
---CustomerRepositoryInterface.php
etc/
di.xml
webapi.xml
module.xml
Model/
-----CustomerRepository.php
-----Customer.php
registration.php

Create a Customer interface.

<?php
namespace Practice\Customer\Api\Data;

interface CustomerInterface
{
    const ID = 'id';
    const NAME = 'name';

    /**
     * @return int
     */
    public function getId();

    /**
     * @param int $id
     * @return \Practice\Customer\Api\Data\CustomerInterface
     */
    public function setId($id);

    /**
     * @return string
     */
    public function getName();

    /**
     * @param string $name
     * @return \Practice\Customer\Api\Data\CustomerInterface
     */
    public function setName($name);
}

Create a Customer repository interface.

<?php
namespace Practice\Customer\Api;

/**
 * Collection Repository Interface
 * @api
 */
interface CustomerRepositoryInterface
{
    /**
     * Update the Collection Items
     *
     * @param \Practice\Customer\Api\Data\CustomerInterface[] $collection
     * @return array
     * @throws \Magento\Framework\Exception\LocalizedException
     */
    public function collectionUpdate(array $collection);

    /**
     * Delete the collection Items
     *
     * @param \Practice\Customer\Api\Data\CustomerInterface[] $collection
     * @return array
     * @throws \Magento\Framework\Exception\LocalizedException
     */
    public function collectionDelete(array $collection);
}

Create a Customer model.

<?php
namespace Practice\Customer\Model;

use Magento\Framework\Data\Collection\AbstractDb;
use Magento\Framework\Model\AbstractModel;
use Magento\Framework\Model\Context;
use Magento\Framework\Model\ResourceModel\AbstractResource;
use Magento\Framework\Registry;
use Practice\Customer\Model\ResourceModel\Collection as LoggingCollection;
use Practice\Customer\Api\Data\CustomerInterface;

/**
 * Class Customer
 */
class Customer extends AbstractModel implements CustomerInterface
{
    /**
     * OrderHistoryList constructor.
     * @param Context $context
     * @param Registry $registry
     * @param AbstractResource|null $resource
     * @param AbstractDb|null $resourceCollection
     * @param array $data
     */
    public function __construct(
        Context $context,
        Registry $registry,
        AbstractResource $resource = null,
        AbstractDb $resourceCollection = null,
        array $data = []
    ) {
        parent::__construct(
            $context,
            $registry,
            $resource,
            $resourceCollection,
            $data
        );
    }

    /**
     * Initialize resource
     * @return void
     */
    // phpcs:ignore PSR2.Methods.MethodDeclaration
    protected function _construct()
    {
        $this->_init(LoggingCollection::class);
    }

    /**
     * @inheritdoc
     */
    public function getId()
    {
        return $this->getData(self::ID);
    }

    /**
     * @inheritdoc
     */
    public function setId($id)
    {
        $this->setData(self::ID, $id);
    }

    /**
     * @inheritdoc
     */
    public function setName($name)
    {
        $this->setData(self::NAME, $name);
    }

    /**
     * @inheritdoc
     */
    public function getName()
    {
        return $this->getData(self::NAME);
    }
}

Create a Customer repository model.

<?php 
namespace Practice\Customer\Model;

use Magento\Framework\Webapi\Exception;

/**
 * Class CustomerRepository
 * @package Practice\Customer\Model
 */
class CustomerRepository implements CustomerRepositoryInterface
{
    /**
     * Update Customer.
     *
     * @param array $collection
     * @return array
     */
    public function collectionUpdate(array $collection)
    {
        // Write here business logic
    }

    /**
     * Delete Customer Collection.
     *
     * @param array $collection
     * @return array
     */
    public function collectionDelete(array $collection)
    {
         // Write here business logic
    }
}

Bind Customer interface with customer model and customer repository interface and customer repository model.

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"   xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <preference for="Practice\Customer\Api\Data\CustomerInterface" type="Practice\Customer\Model\Customer"/>
    <preference for="Practice\Customer\Api\CustomerRepositoryInterface" type="Practice\Customer\Model\CustomerRepository"/>
</config>

Web API manage

<?xml version="1.0"?>
<routes xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Webapi:etc/webapi.xsd">
    <route url="/V1/customer/update" method="PUT">
        <service class="Practice\Customer\Api\CustomerRepositoryInterface" method="collectionUpdate"/>
        <resources>
            <resource ref="anonymous"/>
        </resources>
    </route>
    <route url="/V1/Customer/delete" method="POST">
        <service class="Practice\Customer\Api\CustomerRepositoryInterface" method="collectionDelete"/>
        <resources>
            <resource ref="anonymous"/>
        </resources>
    </route>
</routes>