Flask web development, one drop at a time

A really quick intro to Flask.

Presented during the Python Web Framework Royal Rumble @ PyCon Sette, 2016. Competitors where Django, Pyramid and TurboGears.

Alex Martelli being in the room and validating his own quote did help to win the cause /me smirks

Transcript

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2. HELLO.PY
   from flask import Flask
   app = Flask(__name__)
   @app.route("/")
   def hello():
   return "hello world"
   if __name__ == "__main__":
   app.run()
   

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3. ABOUT
   

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4. BSD LICENSED
   

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5. BUILT BY THE PROS
   Created by Armin Ronacher
   Pygments, Sphinx, Jinja2, Werkzeug, Click
   

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6. USED BY THE PROS
   Pinterest, Twilio, Linked-in, President Obama
   Campaign, Reddit, Uber, etc.
   

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7. DEAD SIMPLE
   hello word in 7 lines of code in a single file
   

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8. EASY TO UNDERSTAND
   just write your ordinary Python code
   no pseudo-language to undestand
   

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9. MANAGEABLE
   LEARNING CURVE
   learn as you go, don’t feel overwhelmed
   

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10. NO IMPOSED STRUCTURE
    no need to understand things are the wey they are: they aren’t
    

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11. SMALL API
    800 LOC, 1500 LOC Tests
    

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12. WELL DOCUMENTED
    the equivalent of 200 A4 pages of excellent documentation
    

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13. FEATURES
    

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14. WERKZEUG
    It's hard to find anything that's simpler, more self-contained, or
    purer-WSGI than Werkzeug — Alex Martelli
    

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15. JINJA2
    modern, fast, designer-friendly templating
    language inspired by Django templates (!)
    

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16. DEVELOPMENT SERVER
    app.run()
    

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17. DEBUGGER
    app.run(debug=True)
    

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18. UNIT TESTING
    flask.app.test_client()
    

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19. RESTFUL REQUEST
    DISPATCHING
    modern web applications have beautiful URLs
    

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20. SIGNED
    SESSION COOKIES
    session allows you to securely store information
    specific to a user from one request to the next
    

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21. 100% WSGI COMPLIANT
    

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22. VERY STABLE
    (despite being in beta)
    

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23. RICH ECOSYSTEM
    Flask-SQLAlchemy, Flask-Admin, Flask-Cache,
    Flask-Cors, Flask-Login, Flask-Mail, etc.
    

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24. HELLO WORLD
    

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25. HELLO.PY
    from flask import Flask
    app = Flask(__name__)
    @app.route("/")
    def hello():
    return render_template('hello.html')
    if __name__ == "__main__":
    app.run()
    

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26. HELLO.HTML
    {% extends 'layout.html' %}
    {% block title %}Greetings{% endblock %}
    {% block body %}
    Hello {{ name }}!
    {% endblock
    

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27. LAYOUT.HTML
    
    
    {% block title %}{% endblock %}
    
    
    {% block body %}{% endblock %}
    
    

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28. INSTALL AND RUN
    $ pip install Flask
    $ python hello.py
    * Running on http://localhost:5000/
    

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29. EXTENSIONS RUNDOWN: FLASK-SQLALCHEMY
    from flask import Flask
    from flaskext.sqlalchemy import SQLAlchemy
    app = Flask(__name__)
    db = SQLAlchemy(app)
    class User(db.Model):
    name = db.Column(db.String(40), primary_key=True)
    email = db.Column(db.String(100))
    @app.route('/user/')
    def show_user(name):
    user = User.query.filter_by(name=name).first_or_404()
    return render_template('user.html', user=user)
    

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