flasker 0.1.23

Flask, SQLAlchemy and Celery integration tool.

Flasker
=======

Under development. Visit https://github.com/mtth/flasker for the latest version.

A Flask_ webapp project manager with built in ORM'ed database using SQLAlchemy_ and Celery_ backend support.

- What Flasker is!

- A transparent integration of Flask, SQLAlchemy and Celery which lets you
configure these individually according to your project needs via a single
``.cfg`` file (cf. `Config file API`_).

- A simple pattern to organize your project via the ``current_project`` proxy.
No more complicated import schemes!

- 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 (inspired by Flask-Script_).

- What Flasker isn't?

- A simplified version of Flask, SQLAlchemy and Celery. Flasker handles the
setup but intentionally leaves you free to interact with the raw Flask,
Celery and database objects. Some knowledge of these frameworks is
therefore required.

Flasker also comes with two optional extensions:

- `ReSTful API`_

- `Authentication`_


Quickstart
----------

- Installation::

$ pip install flasker

- To create a new project::

$ flasker new basic

This will create a project configuration file ``default.cfg`` in the
current directory and a basic Bootstrap_ themed app (this can be turned off
with the ``-a`` flag).

- Next steps::

$ flasker -h

This will list all commands now available for that project:

- ``server`` to run the 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 (useful for
debugging)

Extra help is available for each command by typing::

$ flasker <command> -h


Structuring your project
------------------------

Here is a sample minimalistic project configuration file::

[PROJECT]
NAME: My Project
MODULES: app.views, app.tasks
DB_URL: sqlite:///db/db.sqlite
[APP]
DEBUG: True
TESTING: True
[CELERY]
BROKER_URL: redis://

When it starts, the ``flasker`` command line tool imports all the modules
declared in the ``MODULES`` key of the configuration file (in the ``PROJECT``
section). Inside each of these you can use the ``current_project`` proxy to get
access to the Flask application object, the Celery application object and the
SQLAlchemy database sessions. Therefore a very simple pattern inside each module
is to do::

from flask import render_template
from flasker import current_project

# the Flask application
app = current_project.app

# the Celery application
celery = current_project.celery

# the SQLAlchemy scoped session maker is available on db.session
db = current_project.db

# normally you probably wouldn't need all three in a single file
# but you get the idea :). and now you can do stuff with each...

@app.route('/')
def index():
"""A random view."""
return render_template('index.html')

@celery.task
def task():
"""And a great task."""
pass

# and so on...

Once Flasker has finished importing all your project module files and configuring the applications, it handles startup.

Cf. the Wiki_ for all the available configuration options.


Extensions
----------

ReSTful API
***********

This extension is meant to very simply expose URL endpoints for your models.

There exist other great ReSTful extensions for Flask_. Here are the
main differences with two popular ones:

* FlaskRESTful_ works at a sligthly lower level. It provides great tools but it
would still require work to tie them with each model. Here, the extension uses
the Flasker model structure to do most of the work.

* Flask-Restless_ is similar in that it also intends to bridge the gap between
views and SQLAlchemy models. However this extension is built to provide:

* *Faster queries*: the 'jsonification' of model entities is heavily optimized
for large queries.
* *More flexibility*: API responses are not restricted to returning model columns but
also return properties.
* *Convenient access to nested models*: queries can go arbitrarily deep
within nested models (the extension takes care of not repeating information).
This is especially useful with a client-side library such as Backbone-Relational_.
* *More endpoints*: each one-to-many relation can have its own model specific endpoint.
* *Support for models with composite primary keys*

Nevertheless this extension is much younger and currently lacks several great
features offered by Flask-Restless (such as arbitrary queries and function
evaluation).

Here is a very simple sample file::

from flasker import current_project
from flasker.ext.api import APIManager
from flasker.util import Model
from sqlalchemy import Column, ForeignKey, Integer, Unicode

# Create the APIManager

api_manager = APIManager(add_all_models=True)
current_project.register_manager(api_manager)

# Define the models

class House(Model):

id = Column(Integer, primary_key=True)
address = Column(Unicode(128))

class Cat(Model):

name = Column(Unicode(64), primary_key=True)
house_id = Column(ForeignKey('houses.id'))
house = relationship('House', backref='cats')

Which will create the following endpoints:

* ``/api/houses/ (GET, POST)``
* ``/api/houses/<id> (GET, PUT, DELETE)``
* ``/api/houses/<id>/cats/ (GET, PUT)``
* ``/api/houses/<id>/cats/<position> (GET)``
* ``/api/cats/ (GET, POST)``
* ``/api/cats/<name> (GET, PUT, DELETE)``

Cf. the Wiki_ for the complete list of available options.


Authentication
**************

This extension uses Flask-Login_ to handle sessions and `Google OAuth 2`_ to handle
authentication.

Adding the following code to any one of your modules will allow you to restrict
access to your application::

from flasker import current_project
from flasker.ext.auth import GoogleAuthManager

auth_manager = GoogleAuthManager(
client_id='your_google_client_id',
authorized_emails=['[e-mail]', '[e-mail]', ...]
)
current_project.register_manager(auth_manager)

Cf. the Wiki_ for the complete list of available options.


Utilities
---------

Available utilities include:

* Caching
* Jsonifying
* Logging

Cf. the Wiki_.


Other stuff
-----------

- Setting up Redis::

$ curl -O http://download.redis.io/redis-stable.tar.gz
$ tar xvzf redis-stable.tar.gz
$ cd redis-stable
$ make
$ make test
$ sudo cp redis-server /usr/local/bin/
$ sudo cp redis-cli /usr/local/bin/

To daemonize redis on a mac:

Create a plist file::

$ sudo vim /Library/LaunchDaemons/io.redis.redis-server.plist

Copy the following contents::

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>Label</key>
<string>io.redis.redis-server</string>
<key>ProgramArguments</key>
<array>
<string>/usr/local/bin/redis-server</string>
</array>
<key>RunAtLoad</key>
<true/>
</dict>
</plist>

- Running the server on Apache:

Create a file called `run.wsgi` in the main directory with the following contents::

# Virtualenv activation
from os.path import abspath, dirname, join
activate_this = abspath(join(dirname(__file__), 'venv/bin/activate_this.py'))
execfile(activate_this, dict(__file__=activate_this))

# Since the application isn't on the path
import sys
sys.path.insert(0, abspath(join(dirname(__file__)))

# App factory
from app import make_app
application = make_app()

Then add a virtualhost in your Apache virtual host configuration file (often found at `/etc/apache2/extra/httpd-vhosts.conf`) with the following configuration::

<VirtualHost *:80>
ServerName [server_name]
WSGIDaemonProcess [process_name] user=[process_user] threads=5
WSGIScriptAlias / [path_to_wsgi_file]
<Directory [path_to_root_directory]>
WSGIProcessGroup [process_name]
WSGIApplicationGroup %{GLOBAL}
Order deny,allow
Allow from all
</Directory>
ErrorLog "[path_to_error_log]"
CustomLog "[path_to_access_log]" combined
</VirtualHost>

Sources
-------

- http://redis.io/topics/quickstart
- http://naleid.com/blog/2011/03/05/running-redis-as-a-user-daemon-on-osx-with-launchd/
- http://infinitemonkeycorps.net/docs/pph/
- https://google-developers.appspot.com/chart/interactive/docs/index
- http://codemirror.net/
- http://networkx.lanl.gov/index.html

.. _Bootstrap: http://twitter.github.com/bootstrap/index.html
.. _Flask: http://flask.pocoo.org/docs/api/
.. _Flask-Script: http://flask-script.readthedocs.org/en/latest/
.. _Flask-Login: http://packages.python.org/Flask-Login/
.. _Flask-Restless: https://flask-restless.readthedocs.org/en/latest/
.. _Jinja: http://jinja.pocoo.org/docs/
.. _Celery: http://docs.celeryproject.org/en/latest/index.html
.. _Flower: https://github.com/mher/flower
.. _Datatables: http://datatables.net/examples/
.. _SQLAlchemy: http://docs.sqlalchemy.org/en/rel_0_7/orm/tutorial.html
.. _MySQL: http://dev.mysql.com/doc/
.. _Google OAuth 2: https://developers.google.com/accounts/docs/OAuth2
.. _Google API console: https://code.google.com/apis/console
.. _jQuery: http://jquery.com/
.. _jQuery UI: http://jqueryui.com/
.. _Backbone-Relational: https://github.com/PaulUithol/Backbone-relational
.. _FlaskRESTful: http://flask-restful.readthedocs.org/en/latest/index.html
.. _Wiki: https://github.com/mtth/flasker/wiki