Update changeRedirectCode method in InertiaMiddleware

Continue the improvement of the library based on Inertia Laravel Library and what the documentation states. A 409 with a X-Inertia-Location Header should produce an external redirect in the inertia.js library. But for this to happen we need to remove the X-Inertia header, if not, inertia.js won't handle the external redirect.

Add a test for this path inside changeRedirectCode method of the InertiaMiddleware

src/Middleware/InertiaMiddleware.php

@@ -103,6 +103,15 @@ private function changeRedirectCode(Request $request, Response $response): Respo
             return $response->withStatus(303);
         }
 
+        // For External redirects
+        // https://inertiajs.com/redirects#external-redirects
+        if (
+            409 === $response->getStatusCode()
+            && $response->hasHeader('X-Inertia-Location')
+        ) {
+            return $response->withoutHeader('X-Inertia');
+        }
+
         return $response;
     }
 }

test/Middleware/InertiaMiddlewareTest.php

@@ -131,4 +131,35 @@ public function testItChangesResponseCodeTo303WhenRedirectHappensForPutPatchDele
 
         $this->assertSame($response->reveal(), $middleware->process($request->reveal(), $handler->reveal()));
     }
-}
+
+    public function testItRemovesInertiaHeaderForExternalRedirects()
+    {
+        $factory = $this->prophesize(InertiaFactoryInterface::class);
+        $inertia = $this->prophesize(InertiaInterface::class);
+        $inertia->getVersion()->willReturn('12345');
+
+        $request = $this->prophesize(ServerRequestInterface::class);
+        $request->withAttribute(InertiaMiddleware::INERTIA_ATTRIBUTE, $inertia->reveal())->willReturn($request);
+        $request->hasHeader('X-Inertia')->willReturn(true);
+        $request->getHeader('X-Inertia-Version')->willReturn('12345');
+        $request->getMethod()->willReturn('POST');
+
+        $factory->fromRequest($request)->willReturn($inertia);
+
+        $response = $this->prophesize(ResponseInterface::class);
+
+        $response->withAddedHeader('Vary', 'Accept')->willReturn($response);
+        $response->withAddedHeader('X-Inertia', 'true')->willReturn($response);
+        $response->hasHeader('X-Inertia-Location')->willReturn(true);
+        $response->getStatusCode()->willReturn(409);
+        $response->withoutHeader('X-Inertia')->shouldBeCalled();
+        $response->withoutHeader('X-Inertia')->willReturn($response);
+
+        $handler = $this->prophesize(RequestHandlerInterface::class);
+        $handler->handle(Argument::that([$request, 'reveal']))->willReturn($response);
+
+        $middleware = new InertiaMiddleware($factory->reveal());
+
+        $this->assertSame($response->reveal(), $middleware->process($request->reveal(), $handler->reveal()));
+    }
+}