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Flask-Injector 0.4.0

Adds Injector, a Dependency Injection framework, support to Flask.

Latest Version: 0.5.0

Adds Injector support to Flask, this way there’s no need to use global Flask objects, which makes testing simpler.

Injector is a dependency-injection framework for Python, inspired by Guice.

Flask-Injector is compatible with CPython 2.6-2.7, 3.3+ and PyPy 1.9+. As of version 0.3.0 it requires Injector version 0.7.4 or greater.

GitHub project page:

PyPI package page:



Flask-Injector lets you inject dependencies into:

  • views (functions and class-based)
  • before_request handlers
  • after_request handlers
  • teardown_request handlers
  • template context processors
  • error handlers
  • Jinja environment globals (functions in app.jinja_env.globals)

Example application using Flask-Injector

import sqlite3
from flask import Flask, Config
from flask.views import View
from flask_injector import FlaskInjector
from injector import inject

app = Flask(__name__)

# Configure your application by attaching views, handlers, context processors etc.:

def bar():
    return render("bar.html")

# Route with injection
def foo(db):
    users = db.execute('SELECT * FROM users').all()
    return render("foo.html")

# Class-based view with injected constructor
class Waz(View):
    def __init__(self, db):
        self.db = db

    def dispatch_request(self, key):
        users = self.db.execute('SELECT * FROM users WHERE name=?', (key,)).all()
        return 'waz'

app.add_url_rule('/waz/<key>', view_func=Waz.as_view('waz'))

# In the Injector world, all dependency configuration and initialization is
# performed in modules The
# same is true with Flask-Injector. You can see some examples of configuring
# Flask extensions through modules below.

# Accordingly, the next step is to create modules for any objects we want made
# available to the application. Note that in this example we also use the
# Injector to gain access to the `flask.Config`:

def configure(binder):

# Initialize Flask-Injector. This needs to be run *after* you attached all
# views, handlers, context processors and template globals.

FlaskInjector(app=app, modules=[configure])

# All that remains is to run the application

See for a more complete example, including Flask-SQLAlchemy and Flask-Cache integration.

Supporting Flask Extensions

Typically, Flask extensions are initialized at the global scope using a pattern similar to the following.

app = Flask(__name__)
ext = ExtClass(app)

def view():
    # Use ext object here...

As we don’t have these globals with Flask-Injector we have to configure the extension the Injector way - through modules. Modules can either be subclasses of injector.Module or a callable taking an injector.Binder instance.

def configure_ext(binder, app):
    binder.bind(ExtClass, to=ExtClass(app), scope=singleton)

def main():
    app = Flask(__name__)

    # attach your views etc. here

    FlaskInjector(app=app, modules=[configure_ext])

Make sure to bind extension objects as singletons.

File Type Py Version Uploaded on Size
Flask-Injector-0.4.0.tar.gz (md5) Source 2014-06-21 5KB
Flask_Injector-0.4.0-py2.py3-none-any.whl (md5) Python Wheel 2.7 2014-06-21 7KB
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