flasker 0.1.42

Flask, SQLAlchemy, and Celery integration

A configurable, lightweight framework that integrates Flask, SQLAlchemy and Celery.

• What Flasker is!

  • A one stop .cfg configuration file for Flask, Celery and the SQLAlchemy engine.

  • A simple pattern to organize your project via the flasker.current_project proxy (cf. Quickstart).

  • A command line tool from where you can create new projects, launch the Flask buit in Werkzeug server, start Celery workers and the Flower tool, and run a shell in the current project context.

• What Flasker isn’t?

  • A simplified version of Flask, Celery, and SQLAlchemy. Some knowledge of these frameworks is therefore required.

Flasker is under development. You can find the latest version on GitHub and read the documentation on GitHub pages.

Installation

Using pip:

$ pip install flasker

Using easy_install:

$ easy_install flasker

Quickstart

This short guide will show you how to get an application combining Flask, Celery and SQLAlchemy running in seconds (the code is available on GitHub in examples/basic/).

We start from an empty directory project/ and inside we create a basic configuration file project.cfg:

[PROJECT]
NAME = My Flasker Project
MODULES = app

The MODULES option contains the list of python modules which will be included in the project. Inside each of these modules you can use the flasker.current_project proxy to get access to the current project instance (which gives access to the configured Flask application, the Celery application and the SQLAlchemy database session registry). For now we only add a single module app:

from flask import jsonify
from flasker import current_project

flask_app = current_project.flask    # Flask app
celery_app = current_project.celery  # Celery app
session = current_project.session    # SQLAlchemy scoped session maker

# for this simple example we will only use flask_app

@flask_app.route('/')
def index():
 return jsonify({'message': 'Welcome!'})

Finally, we save this file to project/app.py and we’re all set! To start the server, we run (from the command line in the project/ directory):

$ flasker server
* Running on http://0.0.0.0:5000/

We can check that our server is running for example using Requests (if we navigate to the same URL in the browser, we would get similarly exciting results):

In [1]: import requests
In [2]: requests.get('http://localhost:5000/').json()
Out[2]: {u'message': u'Welcome!'}

Right now, the Flask app is running using the default configuration. We can change this by adding configuration options to the project.cfg file. For example, we will enable testing and debugging for easier bug tracking. At the same time, we tell our project to store the database on disk (instead of the default in memory SQLite store used by Flasker). Our configuration file now looks like this:

[PROJECT]
NAME = My Flasker Project
MODULES = app
[ENGINE]
URL = sqlite:///db.sqlite
[FLASK]
DEBUG = true
TESTING = true

Likewise, we could configure celery by adding options to a section CELERY. Any valid Flask, Celery or engine configuration option can go in their respective section. There are also a few other options available which are detailed in the project documentation.

Next steps

Under the hood, on project startup, Flasker configures Flask, Celery and the database engine and imports all the modules declared in MODULES (the configuration file’s directory is appended to the python path, so any module in our project/ directory will be accessible).

There are two ways to start the project.

• The simplest is to use the flasker console tool:

  $ flasker -h

  This will list all commands now available for that project:

  • server to run the Werkzeug app server

  • worker to start a worker for the Celery backend

  • flower to run the Flower worker management app

  • shell to start a shell in the current project context (using IPython if it is available)

  Extra help is available for each command by typing:

  $ flasker <command> -h

• Or you can load the project manually:

  This is useful for example if you are using a separate WSGI server or working from an IPython Notebook.

  from flasker import Project
  
  project = Project('path/to/default.cfg')

To read more on how to user Flasker and configure your Flasker project, refer to the documentation on GitHub pages.

Extensions

Flasker also comes with extensions for commonly needed functionalities:

• Expanded SQLAlchemy base and queries

• ReSTful API

• Authentication via OpenID (still alpha)