flasker 0.1.45 (beta)

Flask, SQLAlchemy, and Celery integration

Installation

Using pip:

.. code:: bash

  $ pip install flasker

Using easy_install:

.. code:: bash

   $ easy_install flasker

Quickstart

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

The basic folder hierarchy for a Flasker project looks something like this:

.. code:: bash

  project/
    conf.cfg    # configuration
    app.py      # code

Where conf.cfg is:

.. code:: cfg

  [PROJECT]
  MODULES = app

The MODULES option contains the list of python modules which belong to the project. Inside each of these modules we 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). This is the only option required in a Flasker project configuration file.

Here is a sample app.py:

.. code:: python

   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 'Hello World!'

Once these two files are in place, we can already start the server! We simply run (from the command line in the project/ directory):

.. code:: bash

   $ 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):

.. code:: python

   In [1]: import requests
   In [2]: print requests.get('http://localhost:5000/').text
   Hello World!

Configuring your project

In the previous example, the project was using the default configuration, this can easily be changed by adding options to the conf.cfg file. Here is an example of a customized configuration file:

.. code:: cfg

  [PROJECT]
  MODULES = app
  [ENGINE]
  URL = sqlite:///db.sqlite   # the engine to bind the session on
  [FLASK]
  DEBUG = true                # generic Flask options
  TESTING = true

For an exhaustive list of all the options available, please refer to the documentation on GitHub Pages.

Finally, of course, all your code doesn't have to be in a single file. You can specify a list of modules to import in the MODULES option, which will all be imported on project startup. For an example of a more complex application, you can check out the code in examples/flisker.

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:

  System Message: ERROR/3 (<string>, line 151)

  Unknown directive type "code".

  .. code:: bash
  
    $ 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:

  System Message: ERROR/3 (<string>, line 165)

  Unknown directive type "code".

  .. code:: bash
  
    $ 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.

  System Message: ERROR/3 (<string>, line 174)

  Unknown directive type "code".

  .. code:: python
  
     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)