support root-level Generator in StreamedJsonResponse

Author: Jeroeny

CHANGELOG.md

@@ -5,6 +5,7 @@ CHANGELOG
 ---
 
  * Make `HeaderBag::getDate()`, `Response::getDate()`, `getExpires()` and `getLastModified()` return a `DateTimeImmutable`
+ * Support root-level `Generator` in `StreamedJsonResponse`
 
 6.3
 ---

StreamedJsonResponse.php

@@ -47,13 +47,13 @@ class StreamedJsonResponse extends StreamedResponse
     private const PLACEHOLDER = '__symfony_json__';
 
     /**
-     * @param mixed[]                        $data            JSON Data containing PHP generators which will be streamed as list of data
+     * @param mixed[]                        $data            JSON Data containing PHP generators which will be streamed as list of data or a Generator
      * @param int                            $status          The HTTP status code (200 "OK" by default)
      * @param array<string, string|string[]> $headers         An array of HTTP headers
      * @param int                            $encodingOptions Flags for the json_encode() function
      */
     public function __construct(
-        private readonly array $data,
+        private readonly iterable $data,
         int $status = 200,
         array $headers = [],
         private int $encodingOptions = JsonResponse::DEFAULT_ENCODING_OPTIONS,
@@ -66,11 +66,35 @@ public function __construct(
     }
 
     private function stream(): void
+    {
+        $jsonEncodingOptions = \JSON_THROW_ON_ERROR | $this->encodingOptions;
+        $keyEncodingOptions = $jsonEncodingOptions & ~\JSON_NUMERIC_CHECK;
+
+        $this->streamData($this->data, $jsonEncodingOptions, $keyEncodingOptions);
+    }
+
+    private function streamData(mixed $data, int $jsonEncodingOptions, int $keyEncodingOptions): void
+    {
+        if (\is_array($data)) {
+            $this->streamArray($data, $jsonEncodingOptions, $keyEncodingOptions);
+
+            return;
+        }
+
+        if (is_iterable($data) && !$data instanceof \JsonSerializable) {
+            $this->streamIterable($data, $jsonEncodingOptions, $keyEncodingOptions);
+
+            return;
+        }
+
+        echo json_encode($data, $jsonEncodingOptions);
+    }
+
+    private function streamArray(array $data, int $jsonEncodingOptions, int $keyEncodingOptions): void
     {
         $generators = [];
-        $structure = $this->data;
 
-        array_walk_recursive($structure, function (&$item, $key) use (&$generators) {
+        array_walk_recursive($data, function (&$item, $key) use (&$generators) {
             if (self::PLACEHOLDER === $key) {
                 // if the placeholder is already in the structure it should be replaced with a new one that explode
                 // works like expected for the structure
@@ -88,56 +112,51 @@ private function stream(): void
             }
         });
 
-        $jsonEncodingOptions = \JSON_THROW_ON_ERROR | $this->encodingOptions;
-        $keyEncodingOptions = $jsonEncodingOptions & ~\JSON_NUMERIC_CHECK;
-
-        $jsonParts = explode('"'.self::PLACEHOLDER.'"', json_encode($structure, $jsonEncodingOptions));
+        $jsonParts = explode('"'.self::PLACEHOLDER.'"', json_encode($data, $jsonEncodingOptions));
 
         foreach ($generators as $index => $generator) {
             // send first and between parts of the structure
             echo $jsonParts[$index];
 
-            if ($generator instanceof \JsonSerializable || !$generator instanceof \Traversable) {
-                // the placeholders, JsonSerializable and none traversable items in the structure are rendered here
-                echo json_encode($generator, $jsonEncodingOptions);
-
-                continue;
-            }
+            $this->streamData($generator, $jsonEncodingOptions, $keyEncodingOptions);
+        }
 
-            $isFirstItem = true;
-            $startTag = '[';
-
-            foreach ($generator as $key => $item) {
-                if ($isFirstItem) {
-                    $isFirstItem = false;
-                    // depending on the first elements key the generator is detected as a list or map
-                    // we can not check for a whole list or map because that would hurt the performance
-                    // of the streamed response which is the main goal of this response class
-                    if (0 !== $key) {
-                        $startTag = '{';
-                    }
-
-                    echo $startTag;
-                } else {
-                    // if not first element of the generic, a separator is required between the elements
-                    echo ',';
-                }
+        // send last part of the structure
+        echo $jsonParts[array_key_last($jsonParts)];
+    }
 
-                if ('{' === $startTag) {
-                    echo json_encode((string) $key, $keyEncodingOptions).':';
+    private function streamIterable(iterable $iterable, int $jsonEncodingOptions, int $keyEncodingOptions): void
+    {
+        $isFirstItem = true;
+        $startTag = '[';
+
+        foreach ($iterable as $key => $item) {
+            if ($isFirstItem) {
+                $isFirstItem = false;
+                // depending on the first elements key the generator is detected as a list or map
+                // we can not check for a whole list or map because that would hurt the performance
+                // of the streamed response which is the main goal of this response class
+                if (0 !== $key) {
+                    $startTag = '{';
                 }
 
-                echo json_encode($item, $jsonEncodingOptions);
+                echo $startTag;
+            } else {
+                // if not first element of the generic, a separator is required between the elements
+                echo ',';
             }
 
-            if ($isFirstItem) { // indicates that the generator was empty
-                echo '[';
+            if ('{' === $startTag) {
+                echo json_encode((string) $key, $keyEncodingOptions).':';
             }
 
-            echo '[' === $startTag ? ']' : '}';
+            $this->streamData($item, $jsonEncodingOptions, $keyEncodingOptions);
         }
 
-        // send last part of the structure
-        echo $jsonParts[array_key_last($jsonParts)];
+        if ($isFirstItem) { // indicates that the generator was empty
+            echo '[';
+        }
+
+        echo '[' === $startTag ? ']' : '}';
     }
 }

Tests/StreamedJsonResponseTest.php

@@ -30,6 +30,23 @@ public function testResponseSimpleList()
         $this->assertSame('{"_embedded":{"articles":["Article 1","Article 2","Article 3"],"news":["News 1","News 2","News 3"]}}', $content);
     }
 
+    public function testResponseSimpleGenerator()
+    {
+        $content = $this->createSendResponse($this->generatorSimple('Article'));
+
+        $this->assertSame('["Article 1","Article 2","Article 3"]', $content);
+    }
+
+    public function testResponseNestedGenerator()
+    {
+        $content = $this->createSendResponse((function (): iterable {
+            yield 'articles' => $this->generatorSimple('Article');
+            yield 'news' => $this->generatorSimple('News');
+        })());
+
+        $this->assertSame('{"articles":["Article 1","Article 2","Article 3"],"news":["News 1","News 2","News 3"]}', $content);
+    }
+
     public function testResponseEmptyList()
     {
         $content = $this->createSendResponse(
@@ -220,9 +237,9 @@ public function testEncodingOptions()
     }
 
     /**
-     * @param mixed[] $data
+     * @param iterable<mixed> $data
      */
-    private function createSendResponse(array $data): string
+    private function createSendResponse(iterable $data): string
     {
         $response = new StreamedJsonResponse($data);