Idea: override the definition of an interface for a specific target-class

[rx-io]

It's very common to have multiple different logs within a single application, especially if it's a larger application. Therefore it would be nice if one could override an interface-definition just for a specific class.

Example: let's say we have two services: ServiceA and ServiceB. Both services demand a LoggerInterface via constructor but the actual logfiles have to be different (let's say "a.log" and "b.log"). Now it would be cool if I could express this requirement with a definition that looks something like that:

[
  'app.log' => \DI\factory(fn() => new FileLogger('app.log')),

  'a.log'   => \DI\factory(fn() => new FileLogger('a.log')),
  'b.log'   => \DI\factory(fn() => new FileLogger('b.log')),

  // Use "app.log" as default
  LoggerInterface::class => \DI\get('app.log'),

  // Use "a.log" for ServiceA
  ServiceA::class => \DI\autowire()
    ->inject(LoggerInterface::class, \DI\get('a.log')),

  // Use "b.log" for ServiceB
  ServiceB::class => \DI\autowire()
    ->inject(LoggerInterface::class, \DI\get('b.log')),
]

I'd really like to see such a feature in php-di.

My current solution to this is to move this very specific configuration into my service-classes, which feels very unclean to me.

EDIT: I forgot to mention that using constructorParameter also works here and helps keeping the class clean.

class ServiceA {
  public function __construct(
    #[Inject('a.log')]
    private LoggerInterface $log
  ){}
}

How would you guys solve this "problem"?

[mnapoli]

Just to mention an alternative (typing out of memory, might not be 100% exact):

[
  'app.log' => \DI\factory(fn() => new FileLogger('app.log')),

  'a.log'   => \DI\factory(fn() => new FileLogger('a.log')),
  'b.log'   => \DI\factory(fn() => new FileLogger('b.log')),

  // Use "app.log" as default
  LoggerInterface::class => \DI\get('app.log'),

  // Use "a.log" for ServiceA
  ServiceA::class => \DI\autowire()
    ->parameter('log', \DI\get('a.log')),

  // Use "b.log" for ServiceB
  ServiceB::class => \DI\autowire()
    ->parameter('log', \DI\get('b.log')),
]

WDYT?

[rx-io]

Thanks for your reply. Appreciate it!

This is actually my current solution in older projects. It kinda solves the problem and keeps the configuration aspect outside of the class. What I don‘t like about it is that it relies on the very specific parameter name. But maybe I‘m just too autistic here 😬

Do you think my idea is worth considering in future versions or is it too much off the rails / too niche?

[mnapoli]

I don't think what you suggest is a bad idea. Laravel supports that for example.

I just don't have time to invest into this right now, but let's keep this issue open 👍