feat(Front Controller): Allow blueprint via GET request (#2864903 by e0ipso)

In order to improve performance allow requesting a blueprint via a GET request so the whole response
can be cached.

Closes 2864903

src/Blueprint/Parser.php

@@ -3,6 +3,8 @@
 
 namespace Drupal\subrequests\Blueprint;
 
+use Drupal\Core\Cache\CacheableResponse;
+use Drupal\Core\Cache\CacheableResponseInterface;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\Serializer\SerializerInterface;
@@ -42,8 +44,15 @@ class Parser {
    *     - Request mime-type.
    */
   public function parseRequest(Request $request) {
+    $data = '';
+    if ($request->getMethod() === Request::METHOD_POST) {
+      $data = $request->getContent();
+    }
+    else if ($request->getMethod() === Request::METHOD_GET) {
+      $data = $request->query->get('query', '');
+    }
     $tree = $this->serializer->deserialize(
-      $request->getContent(),
+      $data,
       RequestTree::class,
       $request->getRequestFormat(),
       ['master_request' => $request]
@@ -72,8 +81,18 @@ class Parser {
     $headers = ['Content-Type' => $content_type];
 
     $context = ['delimiter' => $delimiter];
+    // Set the content.
     $content = $this->serializer->normalize($responses, 'multipart-related', $context);
-    return Response::create($content, 207, $headers);
+    $response = CacheableResponse::create($content, 207, $headers);
+    // Set the cacheability metadata.
+    $cacheable_responses = array_filter($responses, function ($response) {
+      return $response instanceof CacheableResponseInterface;
+    });
+    array_walk($cacheable_responses, function (CacheableResponseInterface $partial_response) use ($response) {
+      $response->addCacheableDependency($partial_response->getCacheableMetadata());
+    });
+
+    return $response;
   }
 
   /**

src/Blueprint/RequestTree.php

@@ -158,8 +158,13 @@ class RequestTree {
       $uri = $request->getUri();
       $changes += static::replaceAllOccurrences($responses, $uri);
       foreach ($request->query as $key => $value) {
-        $changes += static::replaceAllOccurrences($responses, $value);
-        $request->query->set($key, $value);
+        $new_key = $key;
+        $query_changes = static::replaceAllOccurrences($responses, $new_key);
+        $query_changes += static::replaceAllOccurrences($responses, $value);
+        if ($query_changes) {
+          $request->query->remove($key);
+          $request->query->set($new_key, $value);
+        }
       }
 
       // If there is anything to update.
@@ -211,6 +216,21 @@ class RequestTree {
    *   The number of replacements made.
    */
   public static function replaceAllOccurrences(array $responses, &$input) {
+    if (is_array($input)) {
+      $changes = 0;
+      // Apply the replacement recursively on the array keys and values.
+      foreach ($input as $key => $value) {
+        $new_key = $key;
+        $local_changes = static::replaceAllOccurrences($responses, $new_key);
+        $local_changes += static::replaceAllOccurrences($responses, $value);
+        $changes += $local_changes;
+        if ($local_changes) {
+          unset($input[$key]);
+          $input[$new_key] = $value;
+        }
+      }
+      return $changes;
+    }
     // Detect {{/foo#/bar}}
     $pattern = '/\{\{\/([^\{\}]+)@(\/[^\{\}]+)\}\}/';
     $matches = [];

src/Controller/FrontController.php

@@ -8,6 +8,7 @@ use Drupal\subrequests\Blueprint\Parser;
 use Drupal\subrequests\Blueprint\RequestTree;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpKernel\Event\GetResponseForExceptionEvent;
 use Symfony\Component\HttpKernel\HttpKernelInterface;
 
 class FrontController extends ControllerBase {

src/Normalizer/JsonSubrequestDenormalizer.php

@@ -27,7 +27,7 @@ class JsonSubrequestDenormalizer implements DenormalizerInterface {
       throw new \RuntimeException('The provided blueprint contains an invalid subrequest.');
     }
     $data['path'] = parse_url($data['uri'], PHP_URL_PATH);
-    $data['query'] = parse_url($data['uri'], PHP_URL_QUERY);
+    $data['query'] = parse_url($data['uri'], PHP_URL_QUERY) ?: [];
     if (isset($data['query']) && !is_array($data['query'])) {
       $query = [];
       parse_str($data['query'], $query);
@@ -35,7 +35,6 @@ class JsonSubrequestDenormalizer implements DenormalizerInterface {
     }
     $data = NestedArray::mergeDeep([
       'body' => '',
-      'query' => [],
       'headers' => [],
     ], $data, parse_url($data['path']));
 
@@ -48,13 +47,15 @@ class JsonSubrequestDenormalizer implements DenormalizerInterface {
       empty($data['body']) ? $data['query'] : Json::decode($data['body']),
       $master_request->cookies ? (array) $master_request->cookies->getIterator() : [],
       $master_request->files ? (array) $master_request->files->getIterator() : [],
-      $master_request->server ? (array) $master_request->server->getIterator() : [],
+      [],
       empty($data['body']) ? '' : $data['body']
     );
     // Maintain the same session as in the master request.
     $request->setSession($master_request->getSession());
     // Replace the headers by the ones in the subrequest.
-    $request->headers = new HeaderBag($data['headers']);
+    foreach ($data['headers'] as $name => $value) {
+      $request->headers->set($name, $value);
+    }
     $this::fixBasicAuth($request);
 
     // Add the content ID to the sub-request.

subrequests.routing.yml

@@ -3,9 +3,8 @@ subrequests.front-controller:
   defaults:
     _title: 'Returns the trace recorded by test proxy session handlers as JSON'
     _controller: '\Drupal\subrequests\Controller\FrontController::handle'
-  methods: [POST]
+  methods: [GET, POST]
   options:
-    no_cache: TRUE
     _auth: ['basic_auth', 'cookie', 'oauth2']
   requirements:
     _permission: 'issue subrequests'