Add strategy to extract the status code from errors

One of the main differentiators of this package is the usage of marker
interfaces to perform the translation from error/exception to HTTP
responses.

This provides the extension point for that operation and a default
strategy using a translation map (class/interface -> HTTP status code).

Author: lcobucci

src/StatusCodeExtractionStrategy.php

@@ -0,0 +1,11 @@
+<?php
+declare(strict_types=1);
+
+namespace Lcobucci\ErrorHandling;
+
+use Throwable;
+
+interface StatusCodeExtractionStrategy
+{
+    public function extractStatusCode(Throwable $error): int;
+}

src/StatusCodeExtractionStrategy/ClassMap.php

@@ -0,0 +1,47 @@
+<?php
+declare(strict_types=1);
+
+namespace Lcobucci\ErrorHandling\StatusCodeExtractionStrategy;
+
+use Fig\Http\Message\StatusCodeInterface;
+use Lcobucci\ErrorHandling\Problem;
+use Lcobucci\ErrorHandling\StatusCodeExtractionStrategy;
+use Throwable;
+
+final class ClassMap implements StatusCodeExtractionStrategy
+{
+    private const DEFAULT_MAP = [
+        Problem\InvalidRequest::class => StatusCodeInterface::STATUS_BAD_REQUEST,
+        Problem\AuthorizationRequired::class => StatusCodeInterface::STATUS_UNAUTHORIZED,
+        Problem\Forbidden::class => StatusCodeInterface::STATUS_FORBIDDEN,
+        Problem\ResourceNotFound::class => StatusCodeInterface::STATUS_NOT_FOUND,
+        Problem\Conflict::class => StatusCodeInterface::STATUS_CONFLICT,
+        Problem\ResourceNoLongerAvailable::class => StatusCodeInterface::STATUS_GONE,
+        Problem\UnprocessableRequest::class => StatusCodeInterface::STATUS_UNPROCESSABLE_ENTITY,
+        Problem\ServiceUnavailable::class => StatusCodeInterface::STATUS_SERVICE_UNAVAILABLE,
+    ];
+
+    /**
+     * @var array<string, int>
+     */
+    private $conversionMap;
+
+    /**
+     * @param array<string, int> $conversionMap
+     */
+    public function __construct(array $conversionMap = self::DEFAULT_MAP)
+    {
+        $this->conversionMap = $conversionMap;
+    }
+
+    public function extractStatusCode(Throwable $error): int
+    {
+        foreach ($this->conversionMap as $class => $code) {
+            if ($error instanceof $class) {
+                return $code;
+            }
+        }
+
+        return $error->getCode() ?: StatusCodeInterface::STATUS_INTERNAL_SERVER_ERROR;
+    }
+}

tests/StatusCodeExtractionStrategy/ClassMapTest.php

@@ -0,0 +1,127 @@
+<?php
+declare(strict_types=1);
+
+namespace Lcobucci\ErrorHandling\Tests\StatusCodeExtractionStrategy;
+
+use Fig\Http\Message\StatusCodeInterface;
+use Lcobucci\ErrorHandling\Problem;
+use Lcobucci\ErrorHandling\StatusCodeExtractionStrategy\ClassMap;
+use PHPUnit\Framework\TestCase;
+use RuntimeException;
+use Throwable;
+
+/**
+ * @coversDefaultClass \Lcobucci\ErrorHandling\StatusCodeExtractionStrategy\ClassMap
+ */
+final class ClassMapTest extends TestCase
+{
+    /**
+     * @test
+     *
+     * @covers ::__construct
+     * @covers ::extractStatusCode
+     */
+    public function extractStatusCodeShouldUseGivenMapToRetrieveTheCode(): void
+    {
+        $extractor = new ClassMap([RuntimeException::class => StatusCodeInterface::STATUS_SERVICE_UNAVAILABLE]);
+
+        self::assertSame(
+            StatusCodeInterface::STATUS_SERVICE_UNAVAILABLE,
+            $extractor->extractStatusCode(new RuntimeException())
+        );
+    }
+
+    /**
+     * @test
+     *
+     * @covers ::__construct
+     * @covers ::extractStatusCode
+     */
+    public function extractStatusCodeShouldUseExceptionCodeWhenItIsNotSetInTheMap(): void
+    {
+        $extractor = new ClassMap([]);
+
+        self::assertSame(
+            StatusCodeInterface::STATUS_SERVICE_UNAVAILABLE,
+            $extractor->extractStatusCode(new RuntimeException('', StatusCodeInterface::STATUS_SERVICE_UNAVAILABLE))
+        );
+    }
+
+    /**
+     * @test
+     *
+     * @covers ::__construct
+     * @covers ::extractStatusCode
+     */
+    public function extractStatusCodeShouldFallbackToInternalServerError(): void
+    {
+        $extractor = new ClassMap([]);
+
+        self::assertSame(
+            StatusCodeInterface::STATUS_INTERNAL_SERVER_ERROR,
+            $extractor->extractStatusCode(new RuntimeException())
+        );
+    }
+
+    /**
+     * @test
+     * @dataProvider defaultConversions
+     *
+     * @covers ::__construct
+     * @covers ::extractStatusCode
+     */
+    public function extractStatusCodeShouldUseDefaultClassMapWhenNothingIsProvided(
+        Throwable $error,
+        int $expected
+    ): void {
+        $extractor = new ClassMap();
+
+        self::assertSame($expected, $extractor->extractStatusCode($error));
+    }
+
+    /**
+     * @return array<string, array<Throwable|int>>
+     */
+    public function defaultConversions(): iterable
+    {
+        yield Problem\InvalidRequest::class => [
+            $this->createMock(Problem\InvalidRequest::class),
+            StatusCodeInterface::STATUS_BAD_REQUEST,
+        ];
+
+        yield Problem\AuthorizationRequired::class => [
+            $this->createMock(Problem\AuthorizationRequired::class),
+            StatusCodeInterface::STATUS_UNAUTHORIZED,
+        ];
+
+        yield Problem\Forbidden::class => [
+            $this->createMock(Problem\Forbidden::class),
+            StatusCodeInterface::STATUS_FORBIDDEN,
+        ];
+
+        yield Problem\ResourceNotFound::class => [
+            $this->createMock(Problem\ResourceNotFound::class),
+            StatusCodeInterface::STATUS_NOT_FOUND,
+        ];
+
+        yield Problem\Conflict::class => [
+            $this->createMock(Problem\Conflict::class),
+            StatusCodeInterface::STATUS_CONFLICT,
+        ];
+
+        yield Problem\ResourceNoLongerAvailable::class => [
+            $this->createMock(Problem\ResourceNoLongerAvailable::class),
+            StatusCodeInterface::STATUS_GONE,
+        ];
+
+        yield Problem\UnprocessableRequest::class => [
+            $this->createMock(Problem\UnprocessableRequest::class),
+            StatusCodeInterface::STATUS_UNPROCESSABLE_ENTITY,
+        ];
+
+        yield Problem\ServiceUnavailable::class => [
+            $this->createMock(Problem\ServiceUnavailable::class),
+            StatusCodeInterface::STATUS_SERVICE_UNAVAILABLE,
+        ];
+    }
+}