An easier framework to build web apps with python

Introduction

Python as one of the most powerful backend framework, which are very easy to wrap your head around.

most porpular ones are:

• Django
• Flask
• CherryPy

For this tutorial we are going with Flask cause it the most lightweight and most beginner friendly

Writing your first Hello World in flask

To use flask we need to install it on our machine

Run this on your terminal/cmd

~$ pip install flask

create a new file and call it whatever you want

app.py

from flask import FLask
app = Flask(__name__)
app.run() # parse arguments ip,
# port if you want to specify

execute the python file

~$ python app.py

you should see an output like this

* Serving Flask app 'app'
* Debug mode: on
WARNING: This is a development server. Do not use it in a production deployment. Use a production WSGI server
instead.
    * Running on http://127.0.0.1:5000
Press CTRL+C to quit

At this point when we visit the url we se nothing because we have not created any view

Create views and routes

Edit app.py

from flask import FLask
app = Flask(__name__)

@app.route('/')
def index():
    return "Hello world"

@app.route('/blog'):
def blog():
    return "Hello Readers"

app.run()

our app currently now have two routes

• http://127.0.0.1:5000 -> this return Hello World to a GET request* http://127.0.0.1:5000/blog -> this returns Hello Readers to a GET request

Return HTML as view

We can parse html as a string to return function as a view or parse html file

Example:

from flask import FLask, render_template
app = Flask(__name__)

@app.route('/')
def index():
    return "Hello world"

@app.route('/blog'):
def blog():
    return render_templates('blog.html')

app.run()

Note: Create a `templates` folder in the directory where your app.py lives, flask looks for html files in the templates folder

Handling Requests

By default, route by default are GET only but we can specify the type of reqeust we want for a route

Example:

from flask import FLask, render_template, request
app = Flask(__name__)

@app.route('/' methods=['GET','POST'])
def index():
    if request.method == 'POST':
        return "Hello world from a POST request"
    return "Hello world from a GET reqeuest"

@app.route('/blog', methods=['POST']):
def blog():
    return render_templates('blog.html')

app.run()