Add PSR-15 middleware

Author: odan

README.md

@@ -28,7 +28,7 @@ use Selective\Validation\ValidationResult;
 // ...
 
 // Get all POST values
-$data = $request->getParsedBody();
+$data = (array)$request->getParsedBody();
 
 $validation = new ValidationResult();
 
@@ -52,23 +52,49 @@ if ($validation->isFailed()) {
 }
 ```
 
-### PSR-7 Middleware
+### Middleware
 
-This validation middleware catches the `ValidationException` exception and converts it into a nice JSON response:
+The `ValidationExceptionMiddleware` PSR-15 middleware catches all exceptions and converts it into a nice JSON response.
+
+#### Slim 4 integration
+
+```php
+<?php
+
+use Selective\Validation\Middleware\ValidationExceptionMiddleware;
+use Slim\Factory\AppFactory;
+
+require_once __DIR__ . '/../vendor/autoload.php';
+
+$app = AppFactory::create();
+
+$app->add(ValidationExceptionMiddleware::class); // <--- add middleware
+
+// ...
+
+$app->run();
+```
+
+#### Usage
 
 ```php
-use Psr\Http\Message\ResponseInterface as Response;
-use Psr\Http\Message\ServerRequestInterface as Request;
 use Selective\Validation\ValidationException;
+use Selective\Validation\ValidationResult;
 
-// Validation middleware
-$app->add(function (Request $request, Response $response, $next) {
-    try{
-        return $next($request, $response);
-    } catch (ValidationException $exception) {
-        return $response->withStatus(422)->withJson(['error' => $exception->getValidation()->toArray()]);
-    }
-});
+$validation = new ValidationResult();
+
+// Validate username
+if (empty($data->username)) {
+    $validation->addError('username', 'Input required');
+}
+
+// Check validation result
+if ($validation->isFailed()) {
+    $validation->setMessage('Please check your input');
+
+    // Trigger the validation middleware
+    throw new ValidationException($validation);
+}
 ```
 
 ## License

composer.json

@@ -8,12 +8,17 @@
     ],
     "license": "MIT",
     "require": {
-        "php": ">=7.1"
+        "php": ">=7.1",
+        "psr/http-factory": "^1.0",
+        "psr/http-server-middleware": "^1.0"
     },
     "require-dev": {
+        "fig/http-message-util": "^1.1",
         "overtrue/phplint": "^1.1",
         "phpstan/phpstan-shim": "^0.11",
         "phpunit/phpunit": "^7.0",
+        "relay/relay": "^2.0",
+        "slim/psr7": "^0.6.0",
         "squizlabs/php_codesniffer": "^3.4"
     },
     "scripts": {

src/Validation/Encoder/EncoderInterface.php

@@ -0,0 +1,22 @@
+<?php
+
+namespace Selective\Validation\Encoder;
+
+use UnexpectedValueException;
+
+/**
+ * Encoder interface.
+ */
+interface EncoderInterface
+{
+    /**
+     * Encode the given data to string.
+     *
+     * @param mixed $data The data
+     *
+     * @throws UnexpectedValueException
+     *
+     * @return string The encoded string
+     */
+    public function encode($data): string;
+}

src/Validation/Encoder/JsonEncoder.php

@@ -0,0 +1,37 @@
+<?php
+
+namespace Selective\Validation\Encoder;
+
+use UnexpectedValueException;
+
+/**
+ * Encoder interface.
+ */
+final class JsonEncoder implements EncoderInterface
+{
+    /**
+     * Encode the given data to string.
+     *
+     * @param mixed $data The data
+     *
+     * @throws UnexpectedValueException
+     *
+     * @return string The encoded string
+     */
+    public function encode($data): string
+    {
+        $result = json_encode($data);
+
+        if ($result === false) {
+            throw new UnexpectedValueException(
+                sprintf(
+                    'JSON encoding failed. Code: %s. Error: %s.',
+                    json_last_error(),
+                    json_last_error_msg()
+                )
+            );
+        }
+
+        return $result;
+    }
+}

src/Validation/Middleware/ValidationExceptionMiddleware.php

@@ -0,0 +1,64 @@
+<?php
+
+namespace Selective\Validation\Middleware;
+
+use Psr\Http\Message\ResponseFactoryInterface;
+use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Message\ServerRequestInterface;
+use Psr\Http\Server\MiddlewareInterface;
+use Psr\Http\Server\RequestHandlerInterface;
+use Selective\Validation\Encoder\EncoderInterface;
+use Selective\Validation\ValidationException;
+
+/**
+ * A JSON validation exception middleware.
+ */
+final class ValidationExceptionMiddleware implements MiddlewareInterface
+{
+    /**
+     * @var ResponseFactoryInterface
+     */
+    private $responseFactory;
+
+    /**
+     * @var EncoderInterface
+     */
+    private $encoder;
+
+    /**
+     * Constructor.
+     *
+     * @param ResponseFactoryInterface $responseFactory The response factory
+     * @param EncoderInterface $encoder The encoder
+     */
+    public function __construct(
+        ResponseFactoryInterface $responseFactory,
+        EncoderInterface $encoder
+    ) {
+        $this->responseFactory = $responseFactory;
+        $this->encoder = $encoder;
+    }
+
+    /**
+     * Invoke middleware.
+     *
+     * @param ServerRequestInterface $request The request
+     * @param RequestHandlerInterface $handler The handler
+     *
+     * @return ResponseInterface The response
+     */
+    public function process(ServerRequestInterface $request, RequestHandlerInterface $handler): ResponseInterface
+    {
+        try {
+            return $handler->handle($request);
+        } catch (ValidationException $exception) {
+            $response = $this->responseFactory->createResponse()->withStatus(422);
+
+            $response->getBody()->write($this->encoder->encode([
+                'error' => $exception->getValidation()->toArray(),
+            ]));
+
+            return $response;
+        }
+    }
+}

tests/Encoder/JsonEncoderTest.php

@@ -0,0 +1,42 @@
+<?php
+
+namespace Selective\Validation\Test\Encoder;
+
+use PHPUnit\Framework\TestCase;
+use Selective\Validation\Encoder\JsonEncoder;
+use UnexpectedValueException;
+
+/**
+ * Tests.
+ *
+ * @coversDefaultClass \Selective\Validation\Encoder\JsonEncoder
+ */
+class JsonEncoderTest extends TestCase
+{
+    /**
+     * Test.
+     *
+     * @return void
+     */
+    public function testEncode()
+    {
+        $encoder = new JsonEncoder();
+        $actual = $encoder->encode(['key' => 'value']);
+
+        static::assertSame('{"key":"value"}', $actual);
+    }
+
+    /**
+     * Test.
+     *
+     * @return void
+     */
+    public function testInvalidEncoding(): void
+    {
+        $this->expectException(UnexpectedValueException::class);
+        $this->expectExceptionMessage('JSON encoding failed. Code: 5. Error: Malformed UTF-8 characters, possibly incorrectly encoded.');
+
+        $encoder = new JsonEncoder();
+        $encoder->encode(['key' => "\x00\x81"]);
+    }
+}

tests/Middleware/ErrorMiddleware.php

@@ -0,0 +1,36 @@
+<?php
+
+namespace Selective\Validation\Test\Middleware;
+
+use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Message\ServerRequestInterface;
+use Psr\Http\Server\MiddlewareInterface;
+use Psr\Http\Server\RequestHandlerInterface;
+use Selective\Validation\ValidationException;
+use Selective\Validation\ValidationResult;
+
+/**
+ * Middleware.
+ */
+final class ErrorMiddleware implements MiddlewareInterface
+{
+    /**
+     * Invoke middleware.
+     *
+     * @param ServerRequestInterface $request The request
+     * @param RequestHandlerInterface $handler The handler
+     *
+     * @throws ValidationException
+     *
+     * @return ResponseInterface The response
+     */
+    public function process(ServerRequestInterface $request, RequestHandlerInterface $handler): ResponseInterface
+    {
+        $validation = new ValidationResult();
+
+        $validation->addError('username', 'Input required');
+        $validation->setMessage('Please check your input');
+
+        throw new ValidationException($validation);
+    }
+}

tests/Middleware/MiddlewareTestTrait.php

@@ -0,0 +1,41 @@
+<?php
+
+namespace Selective\Validation\Test\Middleware;
+
+use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Message\ServerRequestInterface;
+use Relay\Relay;
+use Slim\Psr7\Factory\ServerRequestFactory;
+
+/**
+ * Test.
+ */
+trait MiddlewareTestTrait
+{
+    /**
+     * Run middleware stack.
+     *
+     * @param array $queue The queue
+     *
+     * @return ResponseInterface The response
+     */
+    protected function runQueue(array $queue): ResponseInterface
+    {
+        $queue[] = new ResponseFactoryMiddleware();
+
+        $request = $this->createRequest();
+        $relay = new Relay($queue);
+
+        return $relay->handle($request);
+    }
+
+    /**
+     * Factory.
+     *
+     * @return ServerRequestInterface
+     */
+    protected function createRequest(): ServerRequestInterface
+    {
+        return (new ServerRequestFactory())->createServerRequest('GET', '/');
+    }
+}

tests/Middleware/ResponseFactoryMiddleware.php

@@ -0,0 +1,28 @@
+<?php
+
+namespace Selective\Validation\Test\Middleware;
+
+use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Message\ServerRequestInterface;
+use Psr\Http\Server\MiddlewareInterface;
+use Psr\Http\Server\RequestHandlerInterface;
+use Slim\Psr7\Factory\ResponseFactory;
+
+/**
+ * Middleware.
+ */
+final class ResponseFactoryMiddleware implements MiddlewareInterface
+{
+    /**
+     * Invoke middleware.
+     *
+     * @param ServerRequestInterface $request The request
+     * @param RequestHandlerInterface $handler The handler
+     *
+     * @return ResponseInterface The response
+     */
+    public function process(ServerRequestInterface $request, RequestHandlerInterface $handler): ResponseInterface
+    {
+        return (new ResponseFactory())->createResponse();
+    }
+}