Flask is a small and lightweight Python web framework that provides useful tools and features that make creating web applications in Python easier. It gives developers flexibility and is a more accessible framework for new developers since you can build a web application quickly using only a single Python file. Note that the FLASK_APP environment variable must be set according to the Flask documentation for this command to work. The contents of this folder need to be added to version control along with your other source files. When you installed Flask, you also installed the flask command-line script. Typing flask run will prompt the virtual environment's Flask package to run an HTTP server using the app object in whatever script the FLASK_APP environment variable points to.

You’ll install Flask, write and run a Flask application, and run the application in development mode. You’ll use routing to display various web pages that serve different purposes in your web application. You’ll also use view functions to allow users to interact with the application through dynamic routes. Whether you are a beginner or an experienced developer, this tutorial is specially designed to help you learn and master Flask and build your own real-world web applications.

Step 5 — Dynamic Routes

The simplest Flask application can be made using only one script! We will break down the program into steps and discuss each one. A template language is one that we can use inside HTML so that the content on the HTML page becomes dynamic. Use Flask in Python to create simple to fairly complex web applications or APIs that suits your own requirements. Defining datatype along with variable name enforces the user to follow the convention while passing the route name to the server. In the route captures a value from the URL and passes it to the function.

Note that this walkthrough doesn't attempt to demonstrate responsive design; these styles simply generate a reasonably interesting result. A snippet helps you avoid tedious and error-prone copy-paste operations. The following sections demonstrate both types of static files.

Flask by Example – Implementing a Redis Task Queue

While doing so, notice how these additions can contribute to a better user experience. After importing Blueprint, you create an instance of it named bp. You’ll use this name to identify this particular flask developer blueprint in your Flask project. You’ll use this later when you import pages into __init__.py. An application factory in Flask is a design pattern that’s highly beneficial for scaling Flask projects.

• Note that this walkthrough doesn't attempt to demonstrate responsive design; these styles simply generate a reasonably interesting result.
• The extensions integrate seamlessly with Flask so that they appear as if they were part of Flask itself.

Virtual environments are independent groups of Python libraries, one for each project. Packages installed for one project will not affect other projects or the operating system’s packages. You’ll choose from one of the many data centers available around the world for application hosting at Kinsta.

from flask import Flask, render_template, request, url_for, flash, redirect

Follow the official instructions for adding a database, remembering to select the same data center you chose for your Flask application. Kinsta’s Web Application Hosting platform deploys your code from your favorite Git host. Your next step is to configure your application environment to support that pathway and allow Kinsta to deploy your application with all its required dependencies. Start the application by running flask --app demo run in the terminal. The --app flag specifies the location of the application it’ll execute — here, the demo.py file. This hands-on article demonstrates how to develop a simple database-connected Python application using Flask.