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https://github.com/bouncer-app/flask-bouncer

Flask declarative authorization
https://github.com/bouncer-app/flask-bouncer

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Flask declarative authorization

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README 

        
flask-bouncer

=============



Flask declarative authorization leveraging `bouncer`_



|Build Status|



**flask-bouncer** is an authorization library for Flask which restricts

what resources a given user is allowed to access. All the permissions

are defined in a **single location**.



Enough chit-chat – show me the code …



Installation

------------



.. code:: bash



    pip install flask-bouncer



Usage

-----



.. code:: python



    from flask_bouncer import requires, ensure, Bouncer

    app = Flask()

    bouncer = Bouncer(app)



    # Define your authorization in one place and in english ...

    @bouncer.authorization_method

    def define_authorization(user, they):

        if user.is_admin:

            they.can(MANAGE, ALL)

        else:

            they.can(READ, ('Article', 'BlogPost'))

            they.can(EDIT, 'Article', lambda a: a.author_id == user.id)



    # Then decorate your routes with your conditions.

    # If it fails it will return a 403

    @app.route("/articles")

    @requires(READ, Article)

    def articles_index():

        return "A bunch of articles"



    @app.route("/topsecret")

    @requires(READ, TopSecretFile)

    def topsecret_index():

        return "A bunch of top secret stuff that only admins should see"



-  When you are dealing with a specific resource, then use the

   ``ensure`` method



.. code:: python



    from flask_bouncer import requires, ensure

    @app.route("/articles/")

    @requires(READ, Article)

    def show_article(article_id):

        article = Article.find_by_id(article_id)



        # can the current user 'read' the article, if not it will throw a 403

        ensure(READ,article)

        return render_template('article.html', article=article)



-  When you want to conditionally check 

   ``can`` method



.. code:: python



    from flask_bouncer import requires, can

    @app.route("/articles/")

    @requires(READ, Article)

    def show_article(article_id):

        article = Article.find_by_id(article_id)



        # can the current user 'read' the article

        if can(MANAGE,  article):

            return render_template('article-detailed.html', article=article)

        return render_template('article.html')



-  Check out `bouncer`_ with more details about defining Abilities

-  flask-bouncer by default looks for ``current_user`` or ``user``

   stored in flask’s `g`_



Lock It Down

------------

You can use the `ensure_authorization` feature to ensure that all of your routes in your application have been

authorized



.. code:: python



    bouncer = Bouncer(app, ensure_authorization=True)



This will check each request to ensure that an authorization check (either `ensure` or `requires`) has been made



If you want to skip a certain route, decorate your route with `@skip_authorization`.  Like so:



.. code:: python



    @app.route("/articles")

    @skip_authorization

    def articles_index():

        return "A bunch of articles"



Flask-Classy Support

--------------------



I ❤ `Flask-Classy`_ Like a lot. Flask-Classy is an extension that adds

class-based REST views to Flask.



1) Define you View similarly as you would with flask-classy

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~



.. code:: python



    from flask_classy import FlaskView

    from yourapp.models import Article



    class ArticleView(FlaskView)



        # an additional class attribute that you need to add for flask-bouncer

        __target_model__ = Article



        def index(self)

            return "Index"



        def get(self, obj_id):

            return "Get "



        # ... methods for post, delete (and even put, and patch if you so like



2) Register the View with flask and bouncer

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~



.. code:: python



    # in your application.py or the like



    app = Flask("classy")

    bouncer = Bouncer(app)

    ArticleView.register(app)



    # Which classy views do you want to lock down, you can pass multiple

    bouncer.monitor(ArticleView)



.. _bouncer: https://github.com/bouncer-app/bouncer

.. _g: http://flask.pocoo.org/docs/api/#flask.g

.. _Flask-Classy: https://pythonhosted.org/Flask-Classy/



.. |Build Status| image:: https://travis-ci.org/bouncer-app/flask-bouncer.svg?branch=master

    :target: https://travis-ci.org/bouncer-app/flask-bouncer



Then voila – flask-bouncer will implicitly add the following conditions

to the routes:



-  You need ‘READ’ privileges for ‘index’,‘show’ and ‘get’

-  You need ‘CREATE’ privileges for ‘new’,‘put’ and ‘post’

-  You need ‘UPDATE’ privileges for ‘edit’ and ‘patch’



If you want to over-write the default requirements, just add the

``@requires`` decorator to the function



Configuration

-------------



current\_user

~~~~~~~~~~~~~



By default flask-bouncer will inspect ``g`` for user or current\_user.

You can add your custom loader by decorating a function with

``@bouncer.user_loader``



Other Features

--------------



-  Plays nice with `flask-login`_

-  Plays nice with blueprints

-  Plays nice with `flask-classy`_



Notes

-----



-  This library focusing only on **Authorization**, we leave

   **Authentication** to other libraries such as `flask-login`_.



Thank You!

----------



-  Ryan Bates, and his excellent CanCan ruby library which this the

   inspiration for this library



Questions / Issues

------------------



Feel free to ping me on twitter: `@tushman`_

or add issues or PRs at https://github.com/bouncer-app/flask-bouncer



.. _flask-login: http://flask-login.readthedocs.org/en/latest/

.. _flask-classy: https://pythonhosted.org/Flask-Classy/

.. _@tushman: http://twitter.com/tushman