Workflow bridge for api platform

README.md

Just load the WorkflowPass compiler pass and the services.yaml in your project.

After that, when a class supports workflow it'll have two routes (assuming entity dummy):

api_dummies_state_item                                        PATCH    ANY      ANY    /api/dummies/{id}/state.{_format}

PATCH with data (must be state key) {"state": "state_name"} to change a given resource's state to state_name.

api_dummies_state_get_item                                    GET      ANY      ANY    /api/dummies/{id}/state.{_format}

GET receives available states for the given resource.

OperationPathResolver.php

<?php

declare(strict_types=1);

namespace ApiPlatform\Workflow\PathResolver;

use ApiPlatform\Core\PathResolver\OperationPathResolverInterface;

final class OperationPathResolver implements OperationPathResolverInterface
{
    private $decorated;

    public function __construct(OperationPathResolverInterface $decorated)
    {
        $this->decorated = $decorated;
    }

    public function resolveOperationPath(string $resourceShortName, array $operation, $operationType/*, string $operationName = null*/): string
    {
        $path = $this->decorated->resolveOperationPath($resourceShortName, $operation, $operationType, null);

        if (!isset($operation['_path_suffix'])) {
            return $path;
        }

        return str_replace('{id}', '{id}'.$operation['_path_suffix'], $path);
    }
}

services.yaml

services:
    _defaults:
        autowire: true
        public: false

    ApiPlatform\Workflow\Metadata\Resource\Factory\WorkflowOperationResourceMetadataFactory:
        decorates: 'api_platform.metadata.resource.metadata_factory'
        arguments:
          - []
          - '@ApiPlatform\Workflow\Metadata\Resource\Factory\WorkflowOperationResourceMetadataFactory.inner'

    ApiPlatform\Workflow\PathResolver\OperationPathResolver:
        decorates: 'api_platform.operation_path_resolver.generator'
        arguments:
          - '@ApiPlatform\Workflow\PathResolver\OperationPathResolver.inner'

    ApiPlatform\Workflow\EventListener\WorkflowStateListener:
        # ReadListener in api platform is 4
        # DeserializeListener in api platform is 2
        tags:
            - { name: kernel.event_listener, event: kernel.request, priority: 1 }

    ApiPlatform\Workflow\EventListener\WorkflowEnabledTransitionsListener:
        tags:
            - { name: kernel.event_listener, event: kernel.view, priority: 21 }

WorkflowEnabledTransitionsListener.php

<?php

declare(strict_types=1);

namespace ApiPlatform\Workflow\EventListener;

use ApiPlatform\Core\Util\RequestAttributesExtractor;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\HttpKernel\Event\GetResponseForControllerResultEvent;
use Symfony\Component\Serializer\SerializerInterface;
use Symfony\Component\Workflow\Registry;

final class WorkflowEnabledTransitionsListener
{
    private $workflows;
    private $serializer;

    public function __construct(SerializerInterface $serializer, Registry $workflows)
    {
        $this->workflows = $workflows;
        $this->serializer = $serializer;
    }

    public function onKernelView(GetResponseForControllerResultEvent $event)
    {
        $request = $event->getRequest();

        $attributes = RequestAttributesExtractor::extractAttributes($request);

        if (!$request->isMethod(Request::METHOD_GET)
            || !($attributes = RequestAttributesExtractor::extractAttributes($request))
            || !isset($attributes['item_operation_name'])
            || 'state_get' !== $attributes['item_operation_name']
        ) {
            return;
        }

        $class = $request->attributes->get('data');
        $workflow = $this->workflows->get($class);
        $event->setResponse(new Response($this->serializer->serialize($workflow->getEnabledTransitions($class), 'json')));
    }
}

WorkflowOperationResourceMetadataFactory.php

<?php

declare(strict_types=1);

namespace ApiPlatform\Workflow\Metadata\Resource\Factory;

use ApiPlatform\Core\Metadata\Resource\Factory\ResourceMetadataFactoryInterface;
use ApiPlatform\Core\Metadata\Resource\ResourceMetadata;

final class WorkflowOperationResourceMetadataFactory implements ResourceMetadataFactoryInterface
{
    private $supportsWorkflow;
    private $decorated;

    public function __construct(array $supportsWorkflow = [], ResourceMetadataFactoryInterface $decorated)
    {
        $this->supportsWorkflow = $supportsWorkflow;
        $this->decorated = $decorated;
    }

    /**
     * {@inheritdoc}
     */
    public function create(string $resourceClass): ResourceMetadata
    {
        $resourceMetadata = $this->decorated->create($resourceClass);

        if (!in_array($resourceClass, $this->supportsWorkflow, true)) {
            return $resourceMetadata;
        }

        $operations = $resourceMetadata->getItemOperations();

        $operations['state'] = [
            'method' => 'PATCH',
            '_path_suffix' => '/state',
        ];

        $operations['state_get'] = [
            'method' => 'GET',
            '_path_suffix' => '/state',
        ];

        return $resourceMetadata->withItemOperations($operations);
    }
}

WorkflowPass.php

<?php

declare(strict_types=1);

namespace ApiPlatform\Workflow\DependencyInjection\Compiler;

use ApiPlatform\Workflow\Metadata\Resource\Factory\WorkflowOperationResourceMetadataFactory;
use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
use Symfony\Component\DependencyInjection\ContainerBuilder;

final class WorkflowPass implements CompilerPassInterface
{
    /**
     * {@inheritdoc}
     */
    public function process(ContainerBuilder $container)
    {
        $registry = $container->getDefinition('workflow.registry');
        $factory = $container->getDefinition(WorkflowOperationResourceMetadataFactory::class);
        $arguments = [];

        foreach ($registry->getMethodCalls() as $methodCall) {
            $supportsStrategy = $methodCall[1][1];
            $arguments[] = $supportsStrategy->getArguments()[0];
        }

        $factory->setArgument(0, $arguments);
    }
}

WorkflowStateListener.php

<?php

declare(strict_types=1);

namespace ApiPlatform\Workflow\EventListener;

use ApiPlatform\Core\Util\RequestAttributesExtractor;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpKernel\Event\GetResponseEvent;
use Symfony\Component\HttpKernel\Exception\BadRequestHttpException;
use Symfony\Component\HttpKernel\Exception\UnprocessableEntityHttpException;
use Symfony\Component\Workflow\Registry;

final class WorkflowStateListener
{
    private $workflows;

    public function __construct(Registry $workflows)
    {
        $this->workflows = $workflows;
    }

    public function onKernelRequest(GetResponseEvent $event)
    {
        $request = $event->getRequest();

        $attributes = RequestAttributesExtractor::extractAttributes($request);

        if (!$request->isMethod(Request::METHOD_PATCH)
            || !($attributes = RequestAttributesExtractor::extractAttributes($request))
            || !isset($attributes['item_operation_name'])
            || 'state' !== $attributes['item_operation_name']
        ) {
            return;
        }

        $requestContent = json_decode($request->getContent());

        if (!isset($requestContent->state) || !($state = $requestContent->state)) {
            throw new BadRequestHttpException('State is required.');
        }

        $class = $request->attributes->get('data');
        $workflow = $this->workflows->get($class);

        // @TODO replace by violation of some sort (validator?)
        // if (!$workflow->can($class, $state)) {
        //     throw new UnprocessableEntityHttpException("Can not process to state '$state'");
        // }

        $workflow->apply($class, $state);
    }
}