Introduction

Flask is a web-development micro framework developed in Python. It is beginner friendly and easy to learn and use since it doesn’t have any boilerplate code and dependencies.

It was Developed by Armin Roancher as an April Fool’s joke which later gained massive popularity and is maintained till today as a Open-Source Project.

FullStack vs Micro Frameworks

FullStack Frameworks are bundled together with Request Routing , Request Processing, MVC, ORM, Security, Code Generation, Template Engines etc. which makes it easier to develop complex applications easy.

Similarly, Micro Framework is light-weight and come together with least routing processes to process incoming request and generate output. It only provides the necessary components for web development, such as routing, request handling, sessions, and so on. For the other functionalities such as data handling, the developer can write a custom module or use an extension.It is the first choice to develop REST application and provide REST services to various interface.

Flask is used by Netflix, Reddit, AirBnB, Lyft, Mozilla, MIT, Uber and so on…

Features

• It provies development server and debugger
• It uses Jinja2 templates
• It is compailent with WSGI 1.0.
• It provides integrated support for unit testing
• Many extensions are available to flask to enhance other functionalities.

WSGI and JINJA2

WSGI (Web Server Gateway Interface) describes specification concerning communication between web server and client application. Flask is 100% WSGI compliant.

Some benifits of WSGI are:

• Flexibility
• Interoperability
• Scalibility
• Efficiency

JINJA is a template language in python i.e. we can use it inside HTML so that the contents becomes dynamic.

Installation and Setup

Prerequisits

• System with Python Installed
• A text editor or IDE
• [I am using windows 11]

Process

• Install virtualenv

1
2
    py -2 -m pip install virtualenv
    

• Create an environment

1
2
    python3 -m venv <name_of_env>
    

• Activate it

1
2
    <name_of_env>\Scripts\activate
    

• Install flask

1
2
    pip install flask
    

• Create file hello.py

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
    # import FLask module form flask package
    from flask import Flask

    # create Flask object
    app = Flask(__name__)


    # assign url route
    @app.route("/")

    # create view function to tell application what to do
    def hello():
        return "Hello World!"


    # run the application in main
    if __name__ == "__main__":
        app.run(debug = True, host = "0.0.0.0", port = 3000)
    

• Run the code

1
2
3
4
5
    $env:FLASK_APP = "webapp"

    python -m flask run