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Python dependency injection library

Project description

pythondi

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pythondi is a lightweight dependency injection library for python

Installation

pip3 install pythondi

Usage

Binding classes and configure

from pythondi import Provider, configure, configure_after_clear


# Init provider
provider = Provider()

# Bind `Impl` class to `Interface` class
provider.bind(Repo, SQLRepo)

# Inject with configure
configure(provider=provider)

# Or if you want to fresh inject, use `configure_after_clear`
configure_after_clear(provider=provider)

Import inject

from pythondi import inject

Add type annotations that you want to inject dependencies

class Usecase:
    def __init__(self, repo: Repo):
        self.repo = repo

Add decorator

class Usecase:
    @inject()
    def __init__(self, repo: Repo):
        self.repo = repo

Initialize class with no arguments

usecase = Usecase()

Or, you can also inject manually through decorator arguments

class Usecase:
    @inject(repo=SQLRepo)
    def __init__(self, repo):
        self.repo = repo

In this case, do not have to configure providers and type annotation.

Note

At the moment of inject, class is automatically initialized.

So you don't have to initialize your class inside of code.

Yes:

@inject()
def __init__(self, repo: Repo):
    self.repo = repo

No:

@inject()
def __init__(self, repo: Repo):
    self.repo = repo()

General example

import abc

from pythondi import Provider, configure, configure_after_clear, inject


class Repo:
    """Interface class"""
    __metaclass__ = abc.ABCMeta

    @abc.abstractmethod
    def get(self):
        pass


class SQLRepo(Repo):
    """Impl class"""
    def get(self):
        print('SQLRepo')


class Usecase:
    @inject()
    def __init__(self, repo: Repo):
        self.repo = repo


if __name__ == '__main__':
    # Init provider
    provider = Provider()

    # Bind `Impl` class to `Interface` class
    provider.bind(Repo, SQLRepo)

    # Inject with configure
    configure(provider=provider)

    # Or if you want to fresh injection, use `configure_after_clear`
    configure_after_clear(provider=provider)

    # Init class without arguments
    u = Usecase()

Flask example

from flask import Flask, Blueprint, jsonify

from pythondi import Provider, configure, inject
from .repo import Repo, SQLRepo

bp = Blueprint('home', __name__)


@bp.route('/')
def home():
    usecase = Usecase()
    usecase.repo.get()
    return jsonify({'hello': 'world'})


class Usecase:
    @inject()
    def __init__(self, repo: Repo):
        self.repo = repo


def create_app():
    provider = Provider()
    provider.bind(Repo, SQLRepo)
    configure(provider=provider)
    app = Flask(__name__)
    app.register_blueprint(bp)
    return app


if __name__ == '__main__':
    app = create_app()
    app.run(debug=True)

Sanic example

import abc

from sanic import Sanic, Blueprint
from sanic.response import json
from pythondi import Provider, configure, inject


class Repo:
    """Interface class"""
    __metaclass__ = abc.ABCMeta

    @abc.abstractmethod
    def get(self):
        pass


class SQLRepo(Repo):
    """Impl class"""
    def __init__(self):
        pass

    def get(self):
        print('SQLRepo')


bp = Blueprint('home', url_prefix='/')


@bp.route('/')
async def home(request):
    usecase = Usecase()
    usecase.repo.get()
    return json({'hello': 'world'})


class Usecase:
    @inject()
    def __init__(self, repo: Repo):
        self.repo = repo


def create_app():
    provider = Provider()
    provider.bind(Repo, SQLRepo)
    configure(provider=provider)
    app = Sanic(__name__)
    app.blueprint(bp)
    return app


if __name__ == '__main__':
    app = create_app()
    app.run(debug=True)

Django example

"""
In case of django, just put the initializing code inside of django startup

You can use project folder's __init__.py or urls.py
"""

Project details


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