Added get URL rest endpoint

config/autoload/routes.global.php

@@ -19,6 +19,12 @@ return [
             'middleware' => Rest\CreateShortcodeMiddleware::class,
             'allowed_methods' => ['POST'],
         ],
+        [
+            'name' => 'rest-resolve-url',
+            'path' => '/rest/short-code/{shortCode}',
+            'middleware' => Rest\ResolveUrlMiddleware::class,
+            'allowed_methods' => ['GET'],
+        ],
     ],
 
 ];

config/autoload/services.global.php

@@ -44,6 +44,8 @@ return [
 
             // Middleware
             Middleware\Routable\RedirectMiddleware::class => AnnotatedFactory::class,
+            Middleware\Rest\CreateShortcodeMiddleware::class => AnnotatedFactory::class,
+            Middleware\Rest\ResolveUrlMiddleware::class => AnnotatedFactory::class,
         ],
         'aliases' => [
             'em' => EntityManager::class,

src/Middleware/Rest/CreateShortcodeMiddleware.php

@@ -91,7 +91,7 @@ class CreateShortcodeMiddleware implements MiddlewareInterface
         } catch (\Exception $e) {
             return new JsonResponse([
                 'error' => RestUtils::UNKNOWN_ERROR,
-                'message' => sprintf('Provided URL "%s" is invalid. Try with a different one.', $longUrl),
+                'message' => 'Unexpected error occured',
             ], 500);
         }
     }

src/Middleware/Rest/ResolveUrlMiddleware.php

@@ -0,0 +1,85 @@
+<?php
+namespace Acelaya\UrlShortener\Middleware\Rest;
+
+use Acelaya\UrlShortener\Exception\InvalidShortCodeException;
+use Acelaya\UrlShortener\Service\UrlShortener;
+use Acelaya\UrlShortener\Service\UrlShortenerInterface;
+use Acelaya\UrlShortener\Util\RestUtils;
+use Acelaya\ZsmAnnotatedServices\Annotation\Inject;
+use Psr\Http\Message\ResponseInterface as Response;
+use Psr\Http\Message\ServerRequestInterface as Request;
+use Zend\Diactoros\Response\JsonResponse;
+use Zend\Stratigility\MiddlewareInterface;
+
+class ResolveUrlMiddleware implements MiddlewareInterface
+{
+    /**
+     * @var UrlShortenerInterface
+     */
+    private $urlShortener;
+
+    /**
+     * ResolveUrlMiddleware constructor.
+     * @param UrlShortenerInterface|UrlShortener $urlShortener
+     *
+     * @Inject({UrlShortener::class})
+     */
+    public function __construct(UrlShortenerInterface $urlShortener)
+    {
+        $this->urlShortener = $urlShortener;
+    }
+
+    /**
+     * Process an incoming request and/or response.
+     *
+     * Accepts a server-side request and a response instance, and does
+     * something with them.
+     *
+     * If the response is not complete and/or further processing would not
+     * interfere with the work done in the middleware, or if the middleware
+     * wants to delegate to another process, it can use the `$out` callable
+     * if present.
+     *
+     * If the middleware does not return a value, execution of the current
+     * request is considered complete, and the response instance provided will
+     * be considered the response to return.
+     *
+     * Alternately, the middleware may return a response instance.
+     *
+     * Often, middleware will `return $out();`, with the assumption that a
+     * later middleware will return a response.
+     *
+     * @param Request $request
+     * @param Response $response
+     * @param null|callable $out
+     * @return null|Response
+     */
+    public function __invoke(Request $request, Response $response, callable $out = null)
+    {
+        $shortCode = $request->getAttribute('shortCode');
+
+        try {
+            $longUrl = $this->urlShortener->shortCodeToUrl($shortCode);
+            if (! isset($longUrl)) {
+                return new JsonResponse([
+                    'error' => RestUtils::INVALID_ARGUMENT_ERROR,
+                    'message' => sprintf('No URL found for shortcode "%s"', $shortCode),
+                ], 400);
+            }
+
+            return new JsonResponse([
+                'longUrl' => $longUrl,
+            ]);
+        } catch (InvalidShortCodeException $e) {
+            return new JsonResponse([
+                'error' => RestUtils::getRestErrorCodeFromException($e),
+                'message' => sprintf('Provided short code "%s" has an invalid format', $shortCode),
+            ], 400);
+        } catch (\Exception $e) {
+            return new JsonResponse([
+                'error' => RestUtils::UNKNOWN_ERROR,
+                'message' => 'Unexpected error occured',
+            ], 500);
+        }
+    }
+}