This content originally appeared on DEV Community and was authored by Billy
Contents
Definition
You can develop for the web using Django, fast-api && flask
Flask is a Python web-framework, it is a third party library used for web development.
Flask focuses on step-by-step web development.
It is light weight micro-web framework based on two libraries werkzeug WSGI toolkit && Jinja2 templates
Setting up Flask
Before installation of flask, make sure you are in your virtual environment.
pip install virualenv
#activating:Linux
env/bin/activate
#windows
cd env\Scripts\activate
When you are in your virtual env run:
pip install flask
# or
pip3 install flask
Introduction
All things set?! now we create a hello world app.✨
# import Flask class
from flask import Flask
#instantiate flask app obj
app = Flask(__name__)
# decorator function(routing)
@app.route('/')
def index():
return 'Hello world!'
if __name__ == '__main__':
app.run(debug=True)
Go ahead and type this in a text editor save as app.py
The condition checks if the code is a flask app .
if __name__ == '__main__':
app.run()
Running a flask app.
type the following commands in terminal
#first we set the flask_app variable
# Linux
export FLASK_APP=app.run
#window
set FLASK_APP=app.run
# run it
flask run
Yaaay! ? our hello world is live and running on: http://127.0.0.1:5000
Creating a route
A route is a URL to a location in the browser.
Routes are created with the route() decorator, they handle requests for the flask app.
@app.route('/')
def index():
return 'Hello world!'
This opens the home page in our app.
Rendering HTML from flask
To render html flask uses Jinja2 templating engine.
from flask import Flask, render_template
@app.route('/about')
def about():
return render_template('about.html')
Variable rules in Flask.
Variables create a dynamic URL route for a flask app, a variable section is marked with angle brackets <variable_name>.
The function receives the variable as a keyword argument, Optionally you can specify a converter for a variable <converter:variable_name>
@app.route('/age/<int:num>')
def age(num):
return f'<p>This Blog is {num} old.</p>'
Summary
In this article we have gone through web development with Flask a python web-framework.
- Installation
- Hello world application.
- Dynamic URLS.
In the next article, I'll write on connecting Flask to a database.
Thank you for reading, I'd really love your feedback or guidance.
Be cool, Keep coding!
This content originally appeared on DEV Community and was authored by Billy
Billy | Sciencx (2021-08-11T18:27:49+00:00) Web development using Python.. Retrieved from https://www.scien.cx/2021/08/11/web-development-using-python/
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