README

api_one_endpoint

Api one endpoint bundle allows you to create an api focusing on operations instead of resources. One endpoint is used as a resource and api looks into payload to extract what operation has to perform and what data needs to perform it.

Installation

Use composer to install this bundle:

composer require ict/api_one_endpoint:^1.0

Inputs and outputs

Inputs and outputs define operations I/O flow. Each operatios can require an input (if it needs data to perform it) and must define an output which will be returned back to the client. Input have to be sent as a POST Json request and must follow the next schema:

   {
     "$schema": "http://json-schema.org/draft-04/schema#",
     "type": "object",
     "properties": {
       "operation": {
         "type": "string"
       },
       "data": {
         "type": "object"
       }
     },
     "required": [
       "operation",
       "data"
     ]  
   }

As an example, let's see how a SendPaymentOperation input could looks like:

   {
      "operation" : "SendPaymentOperation",
      "data" : {
        "from" : "xxxx",
        "to" : "yyyy",
        "amount" : 6.35
      }
   }

As we can seein the above payload, we're sending an input which tells our api to perform SendPaymentOperation and use as data the following keys:

from: Who sends payment
To: Who receives payment
Amount: How much money xxxx sends to yyyy

Outputs must be wrapped with an Ict\ApiOneEndpoint\Model\Api\ApiOutput object. As a parameters, ApiOutput receives data which will be returned to client and http code which will be used in the response. Data can be an iterable (if we want to return a collection of data) or an object. This bundles relies on symfony serializer to send a json response to the client.

Let's see the following examples:

   
   class Hero {
      public function __construct(
         public readonly string $name,
         public readonly string $hero
      ){ }
   }

   $data = [
      new Hero('Peter Parker', 'spiderman'),
      new Hero('Clark Kent', 'superman')
   ];
   
   return new ApiOutput($data, 200);

   class PaymentDoneOutput {
       public function __construct(
          public readonly string paymentId,
          public readonly \DateTimeInmutable $date
       ){ }
   }
   
   $paymentOutput = new PaymentDoneOutput('899875557', new \DateTimeInmutable('2023-03-05 12:25');
   return new ApiOutput($paymentOutput, 202);

First example returns an array of Hero objects as an output and second example returns PaymentDoneOutput object.

If you want to use symfony serializer groups in your outputs, you can use the third ApiOutput parameter to pass the group name

return new ApiOutput($paymentOutput, 202, 'admin');

Defining input operations

Operation inputs must be defined creating simple objects with its getters and setters. You can use symfony validation constraints to define validation rules so your input must hold required and valid data. This bundle will validate input automatically and will throw an Ict\ApiOneEndpoint\Exception\OperationValidationException if validation fails.

As an example, let's see how a payment operation input would looks like:

use Symfony\Component\Validator\Constraints\GreaterThan;
use Symfony\Component\Validator\Constraints\NotBlank;

class SendPaymentOperationInput
{
    #[NotBlank(message: 'From cannot be empty')]
    private string $from;

    #[NotBlank(message: 'To cannot be empty')]
    private string $to;

    #[NotBlank(message: 'Amount cannot be empty')]
    #[GreaterThan(0, message: 'Amount must be greater then 0')]
    private string $amount;
    
    // getters & setters

}

Defining operations

Operations must implement Ict\ApiOneEndpoint\Contract\Operation\OperationInterface

use Ict\ApiOneEndpoint\Contract\Operation\OperationInterface;
use Ict\ApiOneEndpoint\Model\Api\ApiOutput;

class SendPaymentOperation implements OperationInterface
{

    public function perform(mixed $operationData): ApiOutput
    {
        // Perform operation ....
        // Sending bizum, BTC ......
        return new ApiOutput([], 200);
    }

    public function getName(): string
    {
        return 'SendPayment';
    }

    public function getInput(): ?string
    {
        return SendPaymentOperationInput::class;
    }

    public function getGroup(): ?string
    {
        return null;
    }
    
    public function getContext() : ?array
    {
        return null;
    }
}

Each operation must define the following methods (declared in OperationInterface):

perform: Executes operation
getName: Gets operation name
getInput: Gets input class. When an operation is executed, payload data will be deserialized to the input class and also validated.
getGroup: Gets operation group. We will cover it when seeing operation authorization.
getContext: Gets the operation context. We will cover it when seeing operation context separation

Protecting operations

This bundle relies on symfony voters to protect operations. Take a look to the following voter:

use Ict\ApiOneEndpoint\Model\Operation\OperationSubject;
use Symfony\Component\Security\Core\Authentication\Token\TokenInterface;
use Symfony\Component\Security\Core\Authorization\Voter\Voter;

class SendPaymentVoter extends Voter
{

    protected function supports(string $attribute, mixed $subject): bool
    {
        if(!$subject instanceof OperationSubject){
            return false;
        }

        return true;
    }

    protected function voteOnAttribute(string $attribute, mixed $subject, TokenInterface $token): bool
    {
        $user = $token->getUser();
        if(!in_array('ROLE_PAYMENT', $user->getRoles())){
            return false;
        }

        return true;
    }
}

If you want to protect you api from an autentication context (JWT token, user / pass) you can use symfony security

The bundle pass an Ict\ApiOneEndpoint\Model\Operation\OperationSubject as an attribute to the voter. This gives you access to operation name and operation group (if it's been defined in getGroup method). Groups could be useful when you want to grant access to a group of operations to certain role or roles. As an example, let's imagine you have the following operations:

CreateAccount
UpdateAccount
RemoveAccount

If you would want to restrict access to admin role, you would have to return the same group in getGroup method and then check the group in your voter.

use Ict\ApiOneEndpoint\Model\Operation\OperationSubject;
use Symfony\Component\Security\Core\Authentication\Token\TokenInterface;
use Symfony\Component\Security\Core\Authorization\Voter\Voter;

class AccountManagementVoter extends Voter
{

    protected function supports(string $attribute, mixed $subject): bool
    {
        if(!$subject instanceof OperationSubject){
            return false;
        }

        return $subject->group === 'ACCOUNT';
    }

    protected function voteOnAttribute(string $attribute, mixed $subject, TokenInterface $token): bool
    {
        $user = $token->getUser();
        if(!in_array('ROLE_ADMIN', $user->getRoles())){
            return false;
        }

        return true;
    }
}

The operation subject contains the following information (as public and readonly properties):

operation: Fully qualified operation class name
operationName: Operation Name (Value returned by method getName)
group: Operation group (Value returned by method getGroup)
data: Data to perform operation

This bundle always check operation authorization by it's possible there are no voters defined or no voters supporting conditions. To avoid getting denied access when no voters executed, set the following access decision strategy in your security.yaml file:

security:
   ......
   access_decision_manager:
      strategy: unanimous
      allow_if_all_abstain: true

You can find more information about access decision strategy in symfony docs

Sending operations to the background

In order to allow developers to configure some operations to be executed in the background, this bundle relies on:

Symfony messenger
Ict\ApiOneEndpoint\Model\Attribute\IsBackground attribute

Let's go back to SendPayment operation

use Ict\ApiOneEndpoint\Contract\Operation\OperationInterface;
use Ict\ApiOneEndpoint\Model\Api\ApiOutput;
use Ict\ApiOneEndpoint\Model\Attribute\IsBackground;

#[IsBackground]
class SendPaymentOperation implements OperationInterface
{
   .......
}

When an operation is annotated with IsBackground attribute, it's execution will be performed in the background and the client will no have to wait until it finishes. It can be useful for operations which can take more time to finish. Sending an email or a payment would be examples of this kind of operations.

After an operation is sent to the background, a 202 (Accepted) http request is returned to the client with the following content:

  {
     "status" : "QUEUED"
  }

If you want to delay the execution some time, you can add the delay property to the attribute:

use Ict\ApiOneEndpoint\Contract\Operation\OperationInterface;
use Ict\ApiOneEndpoint\Model\Api\ApiOutput;
use Ict\ApiOneEndpoint\Model\Attribute\IsBackground;

#[IsBackground(delay: 300)]
class SendPaymentOperation implements OperationInterface
{
   .......
}

It will delay the execution 300 seconds (5 minutes).

Let's see how you should configure your messenger.yaml file to queue operations:

messenger:
  transports:
      your_transport_name: "%env(MESSENGER_TRANSPORT_DSN)%"

      routing:
        'Ict\ApiOneEndpoint\Message\OperationMessage': your_transport_name

With the above configuration, you will be able to route operations to your transport.

Events

After an operation is performed, this bundle dispatches an \Ict\ApiOneEndpoint\EventSubscriber\Event\OperationPerformedEvent so the developer can listen to it and execute some task, for instance sending a notification to the user

class OperationSubscriber implements EventSubscriberInterface {

    public static function getSubscribedEvents(): array
    {
        return [
            OperationPerformedEvent::class => ['onOperationPerformed']    
        ]

    }
    
    public function onOperationPerformed(OperationPerformedEvent $event): void
    {
         // events gives you access to operation name and operation result:
         $opName   = $event->operation;
         $opResult = $event->operationResult;
         
         // some stuff here .....
    }
}

If you are interested on sending notifications to the user, consider using this symfony notifier

Operations contexts

As we can see before, OperationInterface has a method getContext which can returns an array holding the allowed contexts or null. Let's imagine we want to keep two endpoints: one for clients and another one for providers. If we want an operation to allow only client context, we would write getContext method as follows:

public function getContext(): ?array
{
    return ['client'];
}

In the next section we will se how to set up an endpoint context.

The controller

Setting up your controller is a really easy task. Let's take a look

use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
use Ict\ApiOneEndpoint\Operation\OperationHandler;
use Symfony\Component\HttpFoundation\JsonResponse;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\Routing\Annotation\Route;
use Symfony\Component\Serializer\SerializerInterface;
use Ict\ApiOneEndpoint\Model\Api\Context;

#[Route('/api/v1')]
class BackendController extends AbstractController
{
    use \Ict\ApiOneEndpoint\Controller\OperationControllerTrait;

    #[Route('', name: 'api_backend_v1_process_operation', methods: ['POST'])]
    public function processOperation(Request $request, SerializerInterface $serializer, OperationHandler $operationHandler): JsonResponse
    {
        return $this->executeOperation($request, $serializer, $operationHandler, new Context());
    }
}

You simply have to create your controller and use trait \Ict\ApiOneEndpoint\Controller\OperationControllerTrait. Then use the method executeOperation passing to it $request, $serializer and $operationHandler as an arguments and your operation will be executed. What about we want to limit our endpoint to manage only client context operations? We only would have to pass the context name to the Context object constructor

return $this->executeOperation($request, $serializer, $operationHandler, new Context('client'));

Now, this controller would only execute client context operations.

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