New in Symfony 6.3: DX Improvements (Part 2)

Display Invisible Characters in Dumped Contents

Contributed by Antoine Lamirault in #48748

Unicode defines tens of different invisible characters like white spaces. These characters are problematic because they can result in impossible to debug issues where e.g. two strings look identical but your code says that they are not the same.

In Symfony 6.3 we're improving the VarDumper component to always highlight the invisible characters of the contents. For example, if the string Lorem Ipsum contains a zero-width non-breaking space (Unicode character U+FEFF) after the letter o, you'll see this: Lo\u{FEFF}rem Ipsum.

Allow Milliseconds and Microseconds in YAML Dates

Contributed by Dustin Wilson in #49164

The Yaml Component can process dates with milliseconds/microseconds but that information is lost when dumping the dates again. In Symfony 6.3, we're improving the Yaml dumper to detect if the dates have that information. This new behavior is automatic, so you don't need to add any config flag to the ->dump() call:

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// BEFORE
date: 2023-01-08T16:18:25Z
# dumped as: 2023-01-08T16:18:25+00:00
date_with_milliseconds: 2023-01-08T16:18:25.213Z
# dumped as: 2023-01-08T16:18:25+00:00
date_with_microseconds: 2023-01-08T16:18:25.718800Z
# dumped as: 2023-01-08T16:18:25+00:00

// AFTER
date: 2023-01-08T16:18:25Z
# dumped as: 2023-01-08T16:18:25+00:00
date_with_milliseconds: 2023-01-08T16:18:25.213Z
# dumped as: 2023-01-08T16:18:25.213+00:00
date_with_microseconds: 2023-01-08T16:18:25.718800Z
# dumped as: 2023-01-08T16:18:25.718800+00:00

Build Parameters in Service Container

Contributed by Jules Pietri in #47680

The Service Container compilation is one of the most critical parts of a Symfony application. It allows to build and optimize the services/parameters of your applications and it's the reason why Symfony is so fast.

During the compilation phase, it's common to create temporary parameters in the container that you later delete when the compilation is finished. That's why in Symfony 6.3 we've introduced build-only parameters. Prefix your parameter name with a dot (e.g. .name) and it will be automatically removed when the compilation finishes:

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// normal parameter (you can delete it manually if you want)
$containerBuilder->setParameter('foo');

// this won't be available in the built container (it's deleted after the compilation)
$containerBuilder->setParameter('.bar');

Streamed JSON Responses

Contributed by Alexander Schranz in #47709

When you stream lots of data via a JSON API, it's difficult to keep low the consumption of resources such as memory. In Symfony 6.3 we're introducing a new StreamedJsonResponse that uses a structure and generics to create an efficient resource-saving JSON response.

Imagine that you have a content generator like this:

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public function loadArticles(): \Generator
{
    // generate contents somehow...
    yield ['title' => 'Article 1'];
    yield ['title' => 'Article 2'];
    yield ['title' => 'Article 3'];

    // it's recommended to use flush() after every specific number of items
}

In Symfony 6.3, you can use the following in your controller to stream these JSON contents:

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return new StreamedJsonResponse([
    '_embedded' => [
        'articles' => loadArticles(),
    ],
]);

That's all. Symfony will take care of all the needed logic to stream this efficiently.