Web Development with Flask
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.
1. Installation
You can install Flask using pip:
pip install Flask2. A Minimal Application
A minimal Flask application looks something like this:
from flask import Flask
app = Flask(__name__)
@app.route("/")
def hello_world():
return "<p>Hello, World!</p>"
if __name__ == '__main__':
app.run(debug=True)3. Routing
Modern web frameworks use routing techniques to help a user remember application URLs. You can use the route() decorator to bind a function to a URL.
@app.route('/')
def index():
return 'Index Page'
@app.route('/hello')
def hello():
return 'Hello, World'4. Variable Rules
You can add variable sections to a URL by marking sections with <variable_name>. Your function then receives the <variable_name> as a keyword argument.
@app.route('/user/<username>')
def show_user_profile(username):
# show the user profile for that user
return f'User {username}'
@app.route('/post/<int:post_id>')
def show_post(post_id):
# show the post with the given id, the id is an integer
return f'Post {post_id}'