[ExpressionLanguage] Add function `service`

[seb-jean]

Symfony version(s) affected

7.0.7

Description

I have an error :

The function "service" does not exist around position 1 for expression `service('App\Service\Generator').generate('songs_by_artist_' ~ entity.getId())`.

How to reproduce

I have the following entity:

<?php

namespace App\Entity;

use App\Repository\BookRepository;
use Doctrine\ORM\Mapping as ORM;
use Symfony\UX\Turbo\Attribute\Broadcast;

#[ORM\Entity(repositoryClass: BookRepository::class)]
#[Broadcast(topics: ["@=service('App\\Service\\Generator').generate('songs_by_artist_' ~ entity.getId())", 'books'], template: 'broadcast/Book.stream.html.twig', private: true)]
class Book
{
    #[ORM\Id]
    #[ORM\GeneratedValue]
    #[ORM\Column]
    private ?int $id = null;

    #[ORM\Column(length: 255)]
    private ?string $title = null;

    public function getId(): ?int
    {
        return $this->id;
    }

    public function getTitle(): ?string
    {
        return $this->title;
    }

    public function setTitle(string $title): static
    {
        $this->title = $title;

        return $this;
    }
}

But when I create a Book entity, I get the following error:

The function "service" does not exist around position 1 for expression `service('App\Service\Generator').generate('songs_by_artist_' ~ entity.getId())`.

In my case, $this->functions is enum and constant : https://github.com/symfony/symfony/blob/7.1/src/Symfony/Component/ExpressionLanguage/Parser.php#L242

Possible Solution

No response

Additional Context

No response

[Hugo Alliaume]

I think this is more something related to https://github.com/symfony/ux

[Simon André]

This has never been possible as i see it .. I believe expression language is used there to compose topic names based on the enttity props.

Or am i missing something ?

[seb-jean]

Yes but I saw in the documentation below that it was possible to use the service function in expression languages: https://symfony.com/doc/current/service_container/expression_language.html

[Simon André]

... in the service container:)

[Hugo Alliaume]

Yes, but the ExpressionLanguage used in the service container's configuration is configured to access the Symfony Container (or at least something to fetch services from), which was never the case here with Symfony\UX\Turbo\Attribute\Broadcast attribute.

Maybe you can achieve what you want by tweaking the Symfony Container by using some Compiler Pass, or maybe you can go for an easier solution by moving your logic into a (static?) method in your entity.

[seb-jean]

So, won't fix?

[Hugo Alliaume]

Maybe we can find another alternative, instead of passing the whole container, we can inject a service that could be configured under broadcard.topic_generator (or smth like that)?

[Simon André]

So, won't fix?

Maybe let's use another word than fix ... as this is a request for a feature (that has never existed in the first place, right ? 😅)

Could you give you the final usage you're looking after, so maybe we can suggest other ways to achieve it ?

[seb-jean]

Maybe we can find another alternative, instead of passing the whole container, we can inject a service that could be configured under broadcard.topic_generator (or smth like that)?

Yes, why not :).

Maybe let's use another word than fix ... as this is a request for a feature (that has never existed in the first place, right ? 😅)

Yes, it's true, you're right, sorry 😄.

Could you give you the final usage you're looking after, so maybe we can suggest other ways to achieve it ?

Currently, when I put:

<div id="book_{{ book.id }}" {{ turbo_stream_listen('book_detail_' ~ book.id) }}></div>

it becomes:

<div id="book_7" data-controller="symfony--ux-turbo--mercure-turbo-stream" data-symfony--ux-turbo--mercure-turbo-stream-topic-value="book_detail_7" data-symfony--ux-turbo--mercure-turbo-stream-hub-value="http://127.0.0.1:56215/.well-known/mercure"></div>

But with a generator, this will hash/encode the data-symfony--ux-turbo--mercure-turbo-stream-topic-value. It will then be more secure.

This line

<div id="book_{{ book.id }}" {{ turbo_stream_listen(('book_detail_' ~ book.id)|mercure_topic) }}></div>

will then become:

<div id="book_7" data-controller="symfony--ux-turbo--mercure-turbo-stream" data-symfony--ux-turbo--mercure-turbo-stream-topic-value="AiLvziwlkB5M9UpYKRyiHvDs/BK7t4T6B7CR48ropyA=" data-symfony--ux-turbo--mercure-turbo-stream-hub-value="http://127.0.0.1:56215/.well-known/mercure"></div>

[Simon André]

I like the idea, should it be something to add here or in the Mercure bundle ?

[seb-jean]

You might as well do it directly in MercureBundle. But is there a downside?