Flask Intro..

Creating a Virtual env in Ubuntu

Open terminal and type the following command

python3 -m venv name_of_virtual_env

Making a virtual environment named ‘Flask_tutorial’

 python3 -m venv Flask_tutorial

Activating the virtual environment

source Flask_tutorial/bin/activate

Installing Flask

pip3 install user flask

Hello Flask

#imports Flask from the package flask
from flask import Flask

#This creates an instance of the Flask object using #our module's name as a parameter.
#Flask uses this to resolve resources

app = Flask(__name__)

#Following line is python decorator.
#Flask uses decorators for URL routing, so this line #of code means that the function directly below it #should be called whenever a user visits the main #root page of our web application.
@app.route("/")

#Following line define a function and returns our #message.
def index():
    return "I am learning Flask"

#Following line is a simple conditional statement #that evaluates to True if our application is run #directly.
#It is used to prevent Python scripts from being #unintentionally run when they are imported into #other Python files.
if __name__ == '__main__':
    #This line kicks off Flask's development server           #on our local machine. We set it to run on port 5000 #and set debug to True, which will help us see #detailed errors directly in our web browser.  
    app.run(port=5000,debug=True)

We save above program as ‘my_flask.py’ and type following command in terminal to run the above program.

python3 my_flask.py

Output