“Hello World !” using python flask framework

In this article we will create a simplest application using pything flask. This will display nothing but simple ” hello world on the page.

Here is the code

from flask import Flask
app = Flask(__name__)

@app.route('/')
def index():
    return 'Hello, World'

This is cleanest code for any framework that I have seen.

Now go to terminal and type following commands

conquistador@inspiron-3542:~/code/flask/tutorial$ export FLASK_APP=hello_world.py
conquistador@inspiron-3542:~/code/flask/tutorial$ flask run
* Serving Flask app "hello_world.py" (lazy loading)
* Environment: development
* Debug mode: on
* Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)
* Restarting with stat
* Debugger is active!
* Debugger PIN: 189-606-216

Now go to http://127.0.0.1:5000/ and  you will see following page

Adding few more pages.

Let us add aboutus and contact us pages. To add routing, you simple need to add 3 line to the same file. You need to add @app.route(‘/contactus’)

Here is updated hello world file

from flask import Flask
app = Flask(__name__)

@app.route('/')
def index():
   return 'Hello, World'

@app.route('/aboutus')
def aboutus():
   return 'This is about us page'

@app.route('/contactus')
def contactus():
   return 'This is contact us page'

Now you can access about us page at http://127.0.0.1:5000/aboutus and contact us page at  http://127.0.0.1:5000/contactus