Django injector

Django injector is an app for Django that integrates injector with Django.

Injector is a simple and easy to use dependency injection framework.

Installation

$ pip install django_injector

Then add django_injector to INSTALLED_APPS and 'django_injector.middleware.inject_request_middleware' to MIDDLEWARE in your Django configuration.

Configuration

django_injector uses the module mechanism from injector. Desired modules should be listed in the INJECTOR_MODULES setting, each item must be either a subclass of injector.Module or a callable that can receive a binder as its only argument.

Modules are loaded when the app is loaded.

Usage

To use the injector decorate functions or methods with django_injector.inject. Decorated methods or functions can receive additional, non-injected, arguments, they should be listed before injected arguments.

Example

This is an example of a view function that receives a request from Django and an injected argument.

from django_injector import inject

from my_app.services import SomeService


@inject
def my_view(request, some_service: SomeService):
    """Will receive a `request` from Django and `some_service` from the injector."""
    return some_service.do_something(request)

Request scope

A custom Injector scope is provided – it's the request scope. Types bound in the request scope share instances during handling a single request but don't cross request handling boundary. It's similar to Flask-Injector's request scope.

The request scope depends on only single request being handled by a single thread (green threads, when gevent or Eventlet monkey patching is used, are also supported) at a time.

Example:

from django_injector import request_scope
from django_injector import inject

class Service:
    pass


class RequiresService:
    @inject
    def __init__(self, service: Service):
        self.service = service


class AlsoRequiresService:
    @inject
    def __init__(self, service: Service):
        self.service = service


@inject
def my_view(request, service: Service, rs: RequiresService, ars: AlsoRequiresService):
    # The same Service instance everywhere
    assert service is rs.service
    assert rs.service is ars.service
    # ...

Builtin bindings

One can inject django.http.HttpRequest and it'll be the same object as the request argument inside the views. The binding can be used to provide HttpRequest deep in the object hierarchy without having to pass it manually.

Example:

from django.http import HttpRequest
from django_injector import inject


class RequiresRequest:
    @inject
    def __init__(self, request: HttpRequest):
        self.request = request


@inject
def my_view(request, rr: RequiresRequest):
    # The same request everywhere
    assert rr.request is request
    # ...