Add error handling

Author: rgomezcasas

apps/backoffice/backend/config/services.yaml

@@ -47,6 +47,10 @@ services:
     tags:
       - { name: kernel.event_listener, event: kernel.request, method: onKernelRequest }
 
+  CodelyTv\Shared\Infrastructure\Symfony\ApiExceptionListener:
+    tags:
+      - { name: kernel.event_listener, event: kernel.exception, method: onException }
+
   CodelyTv\Shared\Infrastructure\Symfony\BasicHttpAuthMiddleware:
     tags:
       - { name: kernel.event_listener, event: kernel.request, method: onKernelRequest }

apps/backoffice/frontend/config/services.yaml

@@ -47,6 +47,10 @@ services:
   CodelyTv\Shared\Infrastructure\Doctrine\DatabaseConnections:
     arguments: [!tagged codely.database_connection]
 
+  CodelyTv\Shared\Infrastructure\Symfony\ApiExceptionListener:
+    tags:
+      - { name: kernel.event_listener, event: kernel.exception, method: onException }
+
   CodelyTv\Shared\Infrastructure\Symfony\AddJsonBodyToRequestListener:
     tags:
       - { name: kernel.event_listener, event: kernel.request, method: onKernelRequest }

apps/mooc/backend/config/services.yaml

@@ -50,6 +50,10 @@ services:
     tags:
       - { name: kernel.event_listener, event: kernel.request, method: onKernelRequest }
 
+  CodelyTv\Shared\Infrastructure\Symfony\ApiExceptionListener:
+    tags:
+      - { name: kernel.event_listener, event: kernel.exception, method: onException }
+
 
   # -- APP DEFINITIONS --
   # Command/Query Handlers

src/Shared/Domain/DomainError.php

@@ -0,0 +1,19 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace CodelyTv\Shared\Domain;
+
+use DomainException;
+
+abstract class DomainError extends DomainException
+{
+    public function __construct()
+    {
+        parent::__construct($this->errorMessage());
+    }
+
+    abstract public function errorCode(): string;
+
+    abstract protected function errorMessage(): string;
+}

src/Shared/Infrastructure/Symfony/ApiController.php

@@ -0,0 +1,50 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace CodelyTv\Shared\Infrastructure\Symfony;
+
+use CodelyTv\Shared\Domain\Bus\Command\Command;
+use CodelyTv\Shared\Domain\Bus\Command\CommandBus;
+use CodelyTv\Shared\Domain\Bus\Query\Query;
+use CodelyTv\Shared\Domain\Bus\Query\QueryBus;
+use CodelyTv\Shared\Domain\Bus\Query\Response;
+use function Lambdish\Phunctional\each;
+
+abstract class ApiController
+{
+    private $queryBus;
+    private $commandBus;
+    private $exceptionHandler;
+
+    public function __construct(
+        QueryBus $queryBus,
+        CommandBus $commandBus,
+        ApiExceptionsHttpStatusCodeMapping $exceptionHandler
+    ) {
+        $this->queryBus         = $queryBus;
+        $this->commandBus       = $commandBus;
+        $this->exceptionHandler = $exceptionHandler;
+
+        each($this->exceptionRegistrar(), $this->exceptions());
+    }
+
+    abstract protected function exceptions(): array;
+
+    protected function ask(Query $query): ?Response
+    {
+        return $this->queryBus->ask($query);
+    }
+
+    protected function dispatch(Command $command): void
+    {
+        $this->commandBus->dispatch($command);
+    }
+
+    private function exceptionRegistrar(): callable
+    {
+        return function ($httpCode, $exception): void {
+            $this->exceptionHandler->register($exception, $httpCode);
+        };
+    }
+}

src/Shared/Infrastructure/Symfony/ApiExceptionListener.php

@@ -0,0 +1,43 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace CodelyTv\Shared\Infrastructure\Symfony;
+
+use CodelyTv\Shared\Domain\DomainError;
+use CodelyTv\Shared\Domain\Utils;
+use Exception;
+use Symfony\Component\HttpFoundation\JsonResponse;
+use Symfony\Component\HttpKernel\Event\RequestEvent;
+
+final class ApiExceptionListener
+{
+    private $exceptionHandler;
+
+    public function __construct(ApiExceptionsHttpStatusCodeMapping $exceptionHandler)
+    {
+        $this->exceptionHandler = $exceptionHandler;
+    }
+
+    public function onException(RequestEvent $event): void
+    {
+        $exception = $event->getException();
+
+        $event->setResponse(
+            new JsonResponse(
+                [
+                    'code'    => $this->exceptionCodeFor($exception),
+                    'message' => $exception->getMessage(),
+                ],
+                $this->exceptionHandler->statusCodeFor(get_class($exception))
+            )
+        );
+    }
+
+    private function exceptionCodeFor(Exception $error)
+    {
+        $domainErrorClass = DomainError::class;
+
+        return $error instanceof $domainErrorClass ? $error->errorCode() : Utils::toSnakeCase(class_basename($error));
+    }
+}

src/Shared/Infrastructure/Symfony/ApiExceptionsHttpStatusCodeMapping.php

@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace CodelyTv\Shared\Infrastructure\Symfony;
+
+use InvalidArgumentException;
+use Symfony\Component\HttpFoundation\Response;
+use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
+use function Lambdish\Phunctional\get;
+
+final class ApiExceptionsHttpStatusCodeMapping
+{
+    private const DEFAULT_STATUS_CODE = Response::HTTP_INTERNAL_SERVER_ERROR;
+
+    private $exceptions = [
+        InvalidArgumentException::class => Response::HTTP_BAD_REQUEST,
+        NotFoundHttpException::class    => Response::HTTP_NOT_FOUND,
+    ];
+
+    public function register($exceptionClass, $statusCode): void
+    {
+        $this->exceptions[$exceptionClass] = $statusCode;
+    }
+
+    public function exists($exceptionClass): bool
+    {
+        return array_key_exists($exceptionClass, $this->exceptions);
+    }
+
+    public function statusCodeFor($exceptionClass): int
+    {
+        return get($exceptionClass, $this->exceptions, self::DEFAULT_STATUS_CODE);
+    }
+}

src/Shared/Infrastructure/Symfony/WebController.php

@@ -4,11 +4,8 @@
 
 namespace CodelyTv\Shared\Infrastructure\Symfony;
 
-use CodelyTv\Shared\Domain\Bus\Command\Command;
 use CodelyTv\Shared\Domain\Bus\Command\CommandBus;
-use CodelyTv\Shared\Domain\Bus\Query\Query;
 use CodelyTv\Shared\Domain\Bus\Query\QueryBus;
-use CodelyTv\Shared\Domain\Bus\Query\Response;
 use Symfony\Component\HttpFoundation\RedirectResponse;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\Response as SymfonyResponse;
@@ -17,26 +14,25 @@
 use Symfony\Component\Validator\ConstraintViolationListInterface;
 use Twig\Environment;
 
-abstract class WebController
+abstract class WebController extends ApiController
 {
     private $twig;
     private $router;
     private $session;
-    private $queryBus;
-    private $commandBus;
 
     public function __construct(
         Environment $twig,
         RouterInterface $router,
         SessionInterface $session,
         QueryBus $queryBus,
-        CommandBus $commandBus
+        CommandBus $commandBus,
+        ApiExceptionsHttpStatusCodeMapping $exceptionHandler
     ) {
-        $this->twig       = $twig;
-        $this->router     = $router;
-        $this->session    = $session;
-        $this->queryBus   = $queryBus;
-        $this->commandBus = $commandBus;
+        parent::__construct($queryBus, $commandBus, $exceptionHandler);
+
+        $this->twig    = $twig;
+        $this->router  = $router;
+        $this->session = $session;
     }
 
     public function render(string $templatePath, array $arguments = []): SymfonyResponse
@@ -67,16 +63,6 @@ public function redirectWithErrors(
         return new RedirectResponse($this->router->generate($routeName), 302);
     }
 
-    public function ask(Query $query): ?Response
-    {
-        return $this->queryBus->ask($query);
-    }
-
-    public function dispatch(Command $command): void
-    {
-        $this->commandBus->dispatch($command);
-    }
-
     private function formatFlashErrors(ConstraintViolationListInterface $violations): array
     {
         $errors = [];