Implement basic formatters

src/Formatter/Json.php

@@ -0,0 +1,57 @@
+<?php
+declare(strict_types=1);
+
+namespace Lcobucci\ContentNegotiation\Formatter;
+
+use Lcobucci\ContentNegotiation\ContentCouldNotBeFormatted;
+use Lcobucci\ContentNegotiation\Formatter;
+use Throwable;
+use const JSON_HEX_AMP;
+use const JSON_HEX_APOS;
+use const JSON_HEX_QUOT;
+use const JSON_HEX_TAG;
+use const JSON_UNESCAPED_SLASHES;
+use function json_encode;
+use function json_last_error;
+use function json_last_error_msg;
+use function sprintf;
+
+final class Json implements Formatter
+{
+    private const DEFAULT_FLAGS = JSON_HEX_TAG | JSON_HEX_APOS | JSON_HEX_AMP | JSON_HEX_QUOT | JSON_UNESCAPED_SLASHES;
+
+    /**
+     * @var int
+     */
+    private $flags;
+
+    public function __construct(int $flags = self::DEFAULT_FLAGS)
+    {
+        $this->flags = $flags;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function format($content): string
+    {
+        try {
+            $encoded = json_encode($content, $this->flags);
+        } catch (Throwable $exception) {
+            throw new ContentCouldNotBeFormatted(
+                'An exception was thrown during JSON formatting',
+                $exception->getCode(),
+                $exception
+            );
+        }
+
+        if ($encoded === false) {
+            throw new ContentCouldNotBeFormatted(
+                sprintf('Given data cannot be formatted as JSON: %s', json_last_error_msg()),
+                json_last_error()
+            );
+        }
+
+        return $encoded;
+    }
+}

src/Formatter/StringCast.php

@@ -0,0 +1,24 @@
+<?php
+declare(strict_types=1);
+
+namespace Lcobucci\ContentNegotiation\Formatter;
+
+use Lcobucci\ContentNegotiation\ContentCouldNotBeFormatted;
+use Lcobucci\ContentNegotiation\Formatter;
+use function is_object;
+use function method_exists;
+
+final class StringCast implements Formatter
+{
+    /**
+     * {@inheritdoc}
+     */
+    public function format($content): string
+    {
+        if (is_object($content) && ! method_exists($content, '__toString')) {
+            throw new ContentCouldNotBeFormatted('Given data could not be cast to string');
+        }
+
+        return (string) $content;
+    }
+}

tests/ContentTypeMiddlewareTest.php

@@ -14,7 +14,6 @@
 use Zend\Diactoros\Response;
 use Zend\Diactoros\Response\EmptyResponse;
 use Zend\Diactoros\ServerRequest;
-use function json_encode;
 
 /**
  * @coversDefaultClass \Lcobucci\ContentNegotiation\ContentTypeMiddleware
@@ -27,6 +26,8 @@ final class ContentTypeMiddlewareTest extends TestCase
      * @covers ::__construct()
      * @covers ::fromRecommendedSettings()
      * @covers ::process()
+     *
+     * @uses \Lcobucci\ContentNegotiation\Formatter\Json
      */
     public function processShouldReturnFormattedResponseDirectly(): void
     {
@@ -48,6 +49,7 @@ public function processShouldReturnFormattedResponseDirectly(): void
      * @covers ::formatResponse()
      *
      * @uses \Lcobucci\ContentNegotiation\UnformattedResponse
+     * @uses \Lcobucci\ContentNegotiation\Formatter\Json
      */
     public function processShouldReturnAResponseWithErrorWhenFormatterWasNotFound(): void
     {
@@ -75,6 +77,7 @@ public function processShouldReturnAResponseWithErrorWhenFormatterWasNotFound():
      * @covers ::formatResponse()
      *
      * @uses \Lcobucci\ContentNegotiation\UnformattedResponse
+     * @uses \Lcobucci\ContentNegotiation\Formatter\Json
      */
     public function processShouldReturnAResponseWithFormattedContent(): void
     {
@@ -90,7 +93,7 @@ public function processShouldReturnAResponseWithFormattedContent(): void
         self::assertInstanceOf(UnformattedResponse::class, $response);
         self::assertSame(StatusCodeInterface::STATUS_OK, $response->getStatusCode());
         self::assertSame('application/json; charset=UTF-8', $response->getHeaderLine('Content-Type'));
-        self::assertSame('{"id":1,"name":"Testing"}', (string) $response->getBody());
+        self::assertJsonStringEqualsJsonString('{"id":1,"name":"Testing"}', (string) $response->getBody());
     }
 
     /**
@@ -103,6 +106,7 @@ public function processShouldReturnAResponseWithFormattedContent(): void
      * @covers ::formatResponse()
      *
      * @uses \Lcobucci\ContentNegotiation\UnformattedResponse
+     * @uses \Lcobucci\ContentNegotiation\Formatter\Json
      */
     public function processShouldReturnAResponseWithFormattedContentEvenWithoutForcingTheCharset(): void
     {
@@ -118,7 +122,7 @@ public function processShouldReturnAResponseWithFormattedContentEvenWithoutForci
         self::assertInstanceOf(UnformattedResponse::class, $response);
         self::assertSame(StatusCodeInterface::STATUS_OK, $response->getStatusCode());
         self::assertSame('application/json', $response->getHeaderLine('Content-Type'));
-        self::assertSame('{"id":1,"name":"Testing"}', (string) $response->getBody());
+        self::assertJsonStringEqualsJsonString('{"id":1,"name":"Testing"}', (string) $response->getBody());
     }
 
     private function createRequestHandler(ResponseInterface $response): RequestHandlerInterface
@@ -160,18 +164,7 @@ private function createMiddleware(bool $forceCharset = true): ContentTypeMiddlew
                     'charset' => $forceCharset,
                 ],
             ],
-            [
-                'application/json' => new class implements Formatter
-                {
-                    /**
-                     * {@inheritdoc}
-                     */
-                    public function format($content): string
-                    {
-                        return (string) json_encode($content);
-                    }
-                },
-            ]
+            ['application/json' => new Formatter\Json()]
         );
     }
 }

tests/Formatter/JsonTest.php

@@ -0,0 +1,111 @@
+<?php
+declare(strict_types=1);
+
+namespace Lcobucci\ContentNegotiation\Tests\Formatter;
+
+use JsonSerializable;
+use Lcobucci\ContentNegotiation\ContentCouldNotBeFormatted;
+use Lcobucci\ContentNegotiation\Formatter\Json;
+use Lcobucci\ContentNegotiation\Tests\PersonDto;
+use PHPUnit\Framework\TestCase;
+use RuntimeException;
+use const JSON_HEX_AMP;
+use const JSON_HEX_APOS;
+use const JSON_HEX_QUOT;
+use const JSON_HEX_TAG;
+use const JSON_UNESCAPED_SLASHES;
+use function acos;
+
+/**
+ * @coversDefaultClass \Lcobucci\ContentNegotiation\Formatter\Json
+ */
+final class JsonTest extends TestCase
+{
+    /**
+     * @test
+     *
+     * @covers ::__construct()
+     */
+    public function constructorShouldAllowTheConfigurationOfEncodingFlags(): void
+    {
+        self::assertAttributeSame(JSON_UNESCAPED_SLASHES, 'flags', new Json(JSON_UNESCAPED_SLASHES));
+    }
+
+    /**
+     * @test
+     *
+     * @covers ::__construct()
+     */
+    public function constructorShouldUseDefaultFlagsWhenNothingWasSet(): void
+    {
+        self::assertAttributeSame(
+            JSON_HEX_TAG | JSON_HEX_APOS | JSON_HEX_AMP | JSON_HEX_QUOT | JSON_UNESCAPED_SLASHES,
+            'flags',
+            new Json()
+        );
+    }
+
+    /**
+     * @test
+     *
+     * @covers ::format()
+     *
+     * @uses \Lcobucci\ContentNegotiation\Formatter\Json::__construct()
+     *
+     */
+    public function formatShouldReturnAJsonEncodedValue(): void
+    {
+        self::assertJsonStringEqualsJsonString(
+            '{"id":1,"name":"Test"}',
+            $this->format(new PersonDto(1, 'Test'))
+        );
+    }
+
+    /**
+     * @test
+     *
+     * @covers ::format()
+     *
+     * @uses \Lcobucci\ContentNegotiation\Formatter\Json::__construct()
+     */
+    public function formatShouldRaiseExceptionWhenContentCouldNotBeEncoded(): void
+    {
+        $this->expectException(ContentCouldNotBeFormatted::class);
+        $this->expectExceptionMessage('Inf and NaN cannot be JSON encoded');
+
+        $this->format(acos(8));
+    }
+
+    /**
+     * @test
+     *
+     * @covers ::format()
+     *
+     * @uses \Lcobucci\ContentNegotiation\Formatter\Json::__construct()
+     */
+    public function formatShouldConvertAnyExceptionDuringJsonSerialization(): void
+    {
+        $this->expectException(ContentCouldNotBeFormatted::class);
+        $this->expectExceptionMessage('An exception was thrown during JSON formatting');
+
+        $this->format(
+            new class implements JsonSerializable
+            {
+                public function jsonSerialize(): void
+                {
+                    throw new RuntimeException('This should be converted');
+                }
+            }
+        );
+    }
+
+    /**
+     * @param mixed $content
+     */
+    private function format($content): string
+    {
+        $formatter = new Json();
+
+        return $formatter->format($content);
+    }
+}

tests/Formatter/StringCastTest.php

@@ -0,0 +1,71 @@
+<?php
+declare(strict_types=1);
+
+namespace Lcobucci\ContentNegotiation\Tests\Formatter;
+
+use Lcobucci\ContentNegotiation\ContentCouldNotBeFormatted;
+use Lcobucci\ContentNegotiation\Formatter\StringCast;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * @coversDefaultClass \Lcobucci\ContentNegotiation\Formatter\StringCast
+ */
+final class StringCastTest extends TestCase
+{
+    /**
+     * @test
+     * @dataProvider validData
+     *
+     * @covers ::format()
+     *
+     * @param mixed $content
+     */
+    public function formatShouldSimplyReturnTheStringRepresentationOfTheContent(
+        string $expected,
+        $content
+    ): void {
+        $formatter = new StringCast();
+
+        self::assertSame($expected, $formatter->format($content));
+    }
+
+    /**
+     * @return mixed[][]
+     */
+    public function validData(): array
+    {
+        $test = new class
+        {
+            public function __toString(): string
+            {
+                return 'test';
+            }
+        };
+
+        return [
+            ['test',  'test'],
+            ['test',  $test],
+            ['1',  1],
+            ['1',  true],
+            ['',  false],
+            ['',  null],
+        ];
+    }
+
+    /**
+     * @test
+     *
+     * @covers ::format()
+     */
+    public function formatShouldRaiseExceptionWhenContentCouldNotBeCastToString(): void
+    {
+        $this->expectException(ContentCouldNotBeFormatted::class);
+
+        $content = new class
+        {
+        };
+
+        $formatter = new StringCast();
+        $formatter->format($content);
+    }
+}