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feature #51538 [HttpFoundation] Support root-level Generator in StreamedJsonResponse (Jeroeny)
This PR was merged into the 6.4 branch. Discussion ---------- [HttpFoundation] Support root-level Generator in StreamedJsonResponse | Q | A | ------------- | --- | Branch? | 6.4 | Bug fix? | no | New feature? | yes | Deprecations? | no | License | MIT Currently the `StreamedJsonResponse` only supports streaming nested Generators within an array data structure. However if a response is a list of items (for example database entities) on the root level, this isn't usable. I think both usecases can be supported with the change in this PR. The root level generator doesn't account for additional nested generators yet. I could add that by doing `is_array($item)` and the call the recursive placeholder logic. Link to first PR that introduced StreamedJsonResponse: symfony/symfony#47709 ~~Also something I noticed is I only got intermediate output, when adding a `flush()` call after each item has been echo'd (with a `sleep(1)` after each item to see it output the parts individually).~~ Edit: I see the class' PhpDoc describes this and it's probably expected to be done in userland implementations. Commits ------- 05e582f1a3 support root-level Generator in StreamedJsonResponse
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‎CHANGELOG.md

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

‎StreamedJsonResponse.php

Lines changed: 59 additions & 40 deletions
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@@ -47,13 +47,13 @@ class StreamedJsonResponse extends StreamedResponse
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private const PLACEHOLDER = '__symfony_json__';
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/**
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* @param mixed[] $data JSON Data containing PHP generators which will be streamed as list of data
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* @param mixed[] $data JSON Data containing PHP generators which will be streamed as list of data or a Generator
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* @param int $status The HTTP status code (200 "OK" by default)
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* @param array<string, string|string[]> $headers An array of HTTP headers
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* @param int $encodingOptions Flags for the json_encode() function
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*/
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public function __construct(
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private readonly array $data,
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private readonly iterable $data,
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int $status = 200,
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array $headers = [],
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private int $encodingOptions = JsonResponse::DEFAULT_ENCODING_OPTIONS,
@@ -66,11 +66,35 @@ public function __construct(
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}
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private function stream(): void
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{
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$jsonEncodingOptions = \JSON_THROW_ON_ERROR | $this->encodingOptions;
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$keyEncodingOptions = $jsonEncodingOptions & ~\JSON_NUMERIC_CHECK;
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$this->streamData($this->data, $jsonEncodingOptions, $keyEncodingOptions);
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}
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private function streamData(mixed $data, int $jsonEncodingOptions, int $keyEncodingOptions): void
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{
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if (\is_array($data)) {
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$this->streamArray($data, $jsonEncodingOptions, $keyEncodingOptions);
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return;
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}
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if (is_iterable($data) && !$data instanceof \JsonSerializable) {
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$this->streamIterable($data, $jsonEncodingOptions, $keyEncodingOptions);
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return;
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}
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echo json_encode($data, $jsonEncodingOptions);
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}
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private function streamArray(array $data, int $jsonEncodingOptions, int $keyEncodingOptions): void
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{
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$generators = [];
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$structure = $this->data;
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array_walk_recursive($structure, function (&$item, $key) use (&$generators) {
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array_walk_recursive($data, function (&$item, $key) use (&$generators) {
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if (self::PLACEHOLDER === $key) {
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// if the placeholder is already in the structure it should be replaced with a new one that explode
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// works like expected for the structure
@@ -88,56 +112,51 @@ private function stream(): void
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}
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});
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$jsonEncodingOptions = \JSON_THROW_ON_ERROR | $this->encodingOptions;
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$keyEncodingOptions = $jsonEncodingOptions & ~\JSON_NUMERIC_CHECK;
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$jsonParts = explode('"'.self::PLACEHOLDER.'"', json_encode($structure, $jsonEncodingOptions));
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$jsonParts = explode('"'.self::PLACEHOLDER.'"', json_encode($data, $jsonEncodingOptions));
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foreach ($generators as $index => $generator) {
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// send first and between parts of the structure
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echo $jsonParts[$index];
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if ($generator instanceof \JsonSerializable || !$generator instanceof \Traversable) {
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// the placeholders, JsonSerializable and none traversable items in the structure are rendered here
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echo json_encode($generator, $jsonEncodingOptions);
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continue;
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}
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$this->streamData($generator, $jsonEncodingOptions, $keyEncodingOptions);
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}
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$isFirstItem = true;
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$startTag = '[';
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foreach ($generator as $key => $item) {
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if ($isFirstItem) {
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$isFirstItem = false;
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// depending on the first elements key the generator is detected as a list or map
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// we can not check for a whole list or map because that would hurt the performance
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// of the streamed response which is the main goal of this response class
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if (0 !== $key) {
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$startTag = '{';
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}
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echo $startTag;
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} else {
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// if not first element of the generic, a separator is required between the elements
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echo ',';
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}
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// send last part of the structure
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echo $jsonParts[array_key_last($jsonParts)];
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}
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if ('{' === $startTag) {
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echo json_encode((string) $key, $keyEncodingOptions).':';
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private function streamIterable(iterable $iterable, int $jsonEncodingOptions, int $keyEncodingOptions): void
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{
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$isFirstItem = true;
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$startTag = '[';
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foreach ($iterable as $key => $item) {
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if ($isFirstItem) {
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$isFirstItem = false;
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// depending on the first elements key the generator is detected as a list or map
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// we can not check for a whole list or map because that would hurt the performance
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// of the streamed response which is the main goal of this response class
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if (0 !== $key) {
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$startTag = '{';
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}
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echo json_encode($item, $jsonEncodingOptions);
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echo $startTag;
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} else {
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// if not first element of the generic, a separator is required between the elements
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echo ',';
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}
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if ($isFirstItem) { // indicates that the generator was empty
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echo '[';
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if ('{' === $startTag) {
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echo json_encode((string) $key, $keyEncodingOptions).':';
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}
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echo '[' === $startTag ? ']' : '}';
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$this->streamData($item, $jsonEncodingOptions, $keyEncodingOptions);
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}
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// send last part of the structure
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echo $jsonParts[array_key_last($jsonParts)];
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if ($isFirstItem) { // indicates that the generator was empty
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echo '[';
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}
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echo '[' === $startTag ? ']' : '}';
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}
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}

‎Tests/StreamedJsonResponseTest.php

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Original file line numberDiff line numberDiff line change
@@ -30,6 +30,23 @@ public function testResponseSimpleList()
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$this->assertSame('{"_embedded":{"articles":["Article 1","Article 2","Article 3"],"news":["News 1","News 2","News 3"]}}', $content);
3131
}
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public function testResponseSimpleGenerator()
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{
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$content = $this->createSendResponse($this->generatorSimple('Article'));
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$this->assertSame('["Article 1","Article 2","Article 3"]', $content);
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}
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public function testResponseNestedGenerator()
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{
42+
$content = $this->createSendResponse((function (): iterable {
43+
yield 'articles' => $this->generatorSimple('Article');
44+
yield 'news' => $this->generatorSimple('News');
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})());
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$this->assertSame('{"articles":["Article 1","Article 2","Article 3"],"news":["News 1","News 2","News 3"]}', $content);
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}
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public function testResponseEmptyList()
3451
{
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$content = $this->createSendResponse(
@@ -220,9 +237,9 @@ public function testEncodingOptions()
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}
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/**
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* @param mixed[] $data
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* @param iterable<mixed> $data
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*/
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private function createSendResponse(array $data): string
242+
private function createSendResponse(iterable $data): string
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{
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$response = new StreamedJsonResponse($data);
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