Python is being widely used to develop impressive web applications. Making a website with python can be easily done with Flask. Flask is a micro-framework. It provides with a very minimal structure for creating a web application. Such an application can be extended by importing required packages or modules as required. In this tutorial you will learn to Create Python Website using Flask. It’s a first step towards build website with python.
Prerequisite for this tutorial is basic knowledge of HTML, CSS and Python.
Step-1 Create a Virtual Environment for a Python Website
In the first step you will prepare the virtual development environment for your web application. It will be constituted of a group of packages/ libraries that are required by the current application. This eliminates interference of shared libraries among multiple projects. Check this out for details and requirements of your OS/system.
- Create the project folder and open that folder in command window
- Run this command to create the virtual environment. After the command is executed, Check that env folder will appear in your application folder
py –m venv env
- Execute this command to activate the environment
With this the command prompt of will change to (env) f:\flask\myproject\
Step-2 Install Flask
Run pip command to install Flask (you have to be connected with internet while doing this).
On the command prompt available after 3rd sub-step of the first step, execute this command (for windows)
Pip install flask
After this step you will be able to see the following dependencies in your application folder under F:\Flask\myproject\env\Lib\site-packages
- Werkzeug – WSGI – Python interface between applications and servers.
- Jinja – template language for rendering pages requested by users.
- MarkupSafe to protect your application against SQL injection threats.
- ItsDangerous –for integrity and protecting session cookie.
- Click- framework for coding command line applications. It helps in executing the flask commands on command line
Note-do not delete anything from these
Now you are ready to write your first Flask-Python code
Step-3 Create a basic Flask application
Create a file named application.py in your application folder(for this example f:\flask\myproject) and copy the following code
# import the flask class from flask import Flask # create an instance of the flask class app=Flask(__name__) # define the route() decorator to link with a valid URL in the application @app.route('/') # define a function that is triggered when this URL appears in the browser address bar def index(): # return something when this function is called return "Welcome to your Python Flask Website"
Step-4 Set FLASK_APP Environment Variable
Set the FLASK_APP Environment Variable with the name of the python file you have just created as your application file. This will define entry point of your web application
(env) f:\flask\myproject\Set FLASK_APP= application.py
Step-5 Run Flask
Execute this command to start the application.
(env) f:\flask\myproject\flask run
Your Flask application will start. You will get a URL as seen in the last line in below image. Copy it and paste in your browser.
Output in Browser
Note: Each time you make changes in your Web Application you need to stop it and start again to see the result. Press CTRL+C for quitting flask application. Execute flask run command again. The command window will remain open when you are running the application.