Transient or Scoped dependency support

[sparky2708]

Is there a way to implement transient or scoped dependency? I am thinking of a way to create services that would only exist for the life of the api request in FastApi. E.g. let’s say you get a message with 2 different sections:

[
{trees: [ {tree: {id: 1, desc: “pine”}, …]
{dogs: [ {dog: {id: 1, name: “potato”}, …]
]

When I receive this message I want to use a TreeProvider and DogProvider that source their data from the above message and can be injected just for processing that request and not for other requests.

@inject() #message will be injected
def class DogProvider(IDogProvider):
     def __init__(self, message):
          …

     def get_dogs() -> Dog:
          …

@inject() #message will be injected
def class TreeProvider(ITreeProvider):
     def __init__(self, message)
          …

     def get_trees() -> Tree:
          …

This is similar to a C# scoped or transient registration.

[dkraczkowski]

@sparky2708 I think it can be done, my only concern is that I don't think I will be able to find time to work on it. The way I use kink in my professional work differs slightly, and since I don't need this feature, its development might not be prioritized from my side. However, I'm happy to collaborate with you on it and provide my feedback.

[sparky2708]

For process-scope I have figured out how to achieve it:

import threading

class MyController:
     def __init__():
           self.context = threading.local()
           di[IMyService] = lambda _: self.context.my_service

    def process_api_request(self, request):
           self.context.my_service = inject()(MyService)(date=request.date)
           . . .

[sparky2708]

Ideally I’d like to see it like the following - will try to work on it when I have some free time and create a PR:

class MyController:    
    def process_api_request(self, request):
           with di.create_scope() as scope:
                scope[IMyService] = inject()(MyService)(date=request.date)
                . . .
           #scope is destroyed 
           . . .