Ivan Leon
Software Developer
Flask
Simple and Practical
But first...
...what is a Framework?
Merriam Webster
"a basic conceptional structure (as of ideas)"
"a set of beliefs, ideas or rules that is used as the basis for making judgements, decisions, etc."
Oxford
"a particular set of rules, ideas, or beliefs which can be used in order to deal with problems or to decide what to do."
Collins
And what about a Web Framework?
It's a solution designed with a standardized approach for handling HTTP requests and responses, used for building Web Applications and REST APIs. In it's essence, that's what a Web Framework is.
Ivan Leon, Software Developer
Flask is a lightweight WSGI web application framework. It is designed to make getting started quick and easy, with the ability to scale up to complex applications. It began as a simple wrapper around Werkzeug and Jinja and has become one of the most popular Python web application frameworks.
The Pallets Project
The “micro” means Flask aims to keep the core simple but extensible. Flask may be “micro”, but it’s ready for production use on a variety of needs.
Flask is a micro web framework written in Python.
Some Flask Extensions available at PyPi
- Flask-RESTful
- Flask-Admin
- Flask-Login
- Flask-Limiter
- Flask-Mail
- Flask-JIRA
- Flask-lambda
- Flask-ElasticUtils
- Flask-SQLAlchemy
- Flask-Session
- Flask-graphql
- Flask-Migrate
- Flask-Caching
- Flask-Analytics
- Flask-Debug-Toolbar
- flask2postman
A curated list of awesome Flask resources and plugins:
A Simple Application
""" Simple Flask Application """
from flask import Flask
app = Flask(__name__)
@app.route("/")
def f_index():
""" Returns the Index resource. """
return "Index\n"
if __name__ == "__main__":
app.run(debug=True)
""" Simple Flask Application """
from flask import Flask, request
app = Flask(__name__)
@app.route("/")
def f_index():
""" Returns the Index resource. """
return "Index\n"
@app.route("/home")
def f_home():
""" Returns the Home resource. """
username = request.args.get("username")
if username == "ivanleoncz":
return "Bem-vindo, Gaúcho!\n"
elif username == "abraham":
return "Bienvenido, Jarocho!\n"
else:
return "Welcome, whoever you are!\n"
if __name__ == "__main__":
app.run(debug=True)
Templates
ivanleoncz@ilex: ~/git/Cellar/xalapacode/ex_2 $ tree
.
├── app.py
└── templates
├── layout.html
└── todo.html
1 directory, 3 filesDirectory Structure
""" Simple Flask Application """
from flask import Flask, request, render_template
app = Flask(__name__)
todo = {
"1":"Prepare XalapaCode Presentation",
"2":"Clean My Bedroom",
"3":"Deliver Logiety Secret Project"
}
@app.route("/")
def f_index():
""" Returns the Index resource. """
return "Index\n"
@app.route("/todo")
def f_home():
""" Returns Todo List. """
return render_template('todo.html', todo_list=todo)
if __name__ == "__main__":
app.run(debug=True)app.py
<!DOCTYPE html>
<html>
<head>
<title>Flask Template Example</title>
</head>
<body>
<h2>This is part of my base template</h2>
<br>
{% block content %}{% endblock %}
<br>
<h2>This is part of my base template</h2>
</body>
</html>layout.html
{% extends "layout.html" %}
{% block content %}
<h3> This is the start of my child template</h3>
<p>Todo List</p>
<ul>
{% for key, value in todo_list.items() %}
<li>{{key}}, {{value}}</li>
{% endfor %}
</ul>
<h3> This is the end of my child template</h3>
{% endblock %}todo.html
InteRESTing
from flask import Flask, request
from flask_restful import Api, Resource
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker
from database_setup import Base, Todo
app = Flask(__name__)
api = Api(app)
engine = create_engine('sqlite:///todo.db')
Base.metadata.bind = engine
db_session = sessionmaker(bind=engine)
session = db_session()
class TodoList(Resource):
def get(self, _id):
task = session.query(Todo).filter_by(number=_id).one
return {_id: task}
def put(self, _id):
task = request.form['task']
query = session.query(Todo).filter_by(number=_id).one
new_task = Todo(number=_id, task=task)
session.add(new_task)
session.commit()
return {_id: task}
def delete(self, _id):
session.query(Todo).filter_by(number=_id).delete()
return {_id: "deleted"}
class TodoListAll(Resource):
def get(self):
all_tasks = {t.number:t.task for t in session.query(Todo).all()}
return {"tasks":all_tasks}
api.add_resource(TodoList, '/api/v1/todo/<string:_id>')
api.add_resource(TodoListAll, '/api/v1/todo/')
if __name__ == "__main__":
app.run(debug=True) import sys
from sqlalchemy import Column, ForeignKey, Integer, String
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import relationship
from sqlalchemy import create_engine
Base = declarative_base()
class Todo(Base):
__tablename__ = 'todo'
id = Column(Integer, primary_key=True)
number = Column(Integer, nullable=False)
task = Column(String(250), nullable=False)
engine = create_engine('sqlite:///todo.db')
Base.metadata.create_all(engine) database_setup.py
- Name: Ivan Leon
- Nationality: Brazilian (Gaúcho)
- Community Admin at XalapaCode
- Software Engineer at Logiety
- Contributor at StackOverflow
@ivanleoncz
Obrigado!
Flask
By Ivan Leon
Flask
Whats is Flask and how simple it is.
