[8.x] Support JSON encoding Stringable (#36012)

* Support JSON encoding Stringable

* Call __toString() from jsonSerialize() in Stringable class

* Update router to properly handle Stringable instances

Author: reinink

src/Illuminate/Routing/Router.php

@@ -18,6 +18,7 @@
 use Illuminate\Routing\Events\RouteMatched;
 use Illuminate\Support\Collection;
 use Illuminate\Support\Str;
+use Illuminate\Support\Stringable;
 use Illuminate\Support\Traits\Macroable;
 use JsonSerializable;
 use Psr\Http\Message\ResponseInterface as PsrResponseInterface;
@@ -769,6 +770,8 @@ public static function toResponse($request, $response)
             $response = (new HttpFoundationFactory)->createResponse($response);
         } elseif ($response instanceof Model && $response->wasRecentlyCreated) {
             $response = new JsonResponse($response, 201);
+        } elseif ($response instanceof Stringable) {
+            $response = new Response($response->__toString(), 200, ['Content-Type' => 'text/html']);
         } elseif (! $response instanceof SymfonyResponse &&
                    ($response instanceof Arrayable ||
                     $response instanceof Jsonable ||

src/Illuminate/Support/Stringable.php

@@ -5,9 +5,10 @@
 use Closure;
 use Illuminate\Support\Traits\Macroable;
 use Illuminate\Support\Traits\Tappable;
+use JsonSerializable;
 use Symfony\Component\VarDumper\VarDumper;
 
-class Stringable
+class Stringable implements JsonSerializable
 {
     use Macroable, Tappable;
 
@@ -734,6 +735,16 @@ public function dd()
         exit(1);
     }
 
+    /**
+     * Convert the object to a string when JSON encoded.
+     *
+     * @return string
+     */
+    public function jsonSerialize()
+    {
+        return $this->__toString();
+    }
+
     /**
      * Proxy dynamic properties onto methods.
      *

tests/Support/SupportStringableTest.php

@@ -546,6 +546,11 @@ public function testChunk()
         $this->assertSame(['foo', 'bar', 'baz'], $chunks->all());
     }
 
+    public function testJsonSerialize()
+    {
+        $this->assertSame('"foo"', json_encode($this->stringable('foo')));
+    }
+
     public function testTap()
     {
         $stringable = $this->stringable('foobarbaz');