Flask

Flask is a lightweight WSGI web application framework. It is designed to make getting started quick and easy, with the ability to scale up to complex applications. It began as a simple wrapper around Werkzeug and Jinja, and has become one of the most popular Python web application frameworks.

Flask offers suggestions, but doesn't enforce any dependencies or project layout. It is up to the developer to choose the tools and libraries they want to use. There are many extensions provided by the community that make adding new functionality easy.

A Simple Example

# save this as app.py
from flask import Flask

app = Flask(__name__)

@app.route("/")
def hello():
    return "Hello, World!"

$ flask run
  * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)

Installation Instructions

To install Flask, pip, the package manager included with Python, is used. It is considered best practice to start a Flask project within a virtual environment. This practice ensures that any packages installed are confined to the virtual environment, keeping them separate from the global environment of the system. By doing so, it prevents potential conflicts between package versions, maintaining compatibility and stability across different projects.

To create a virtual environment run the command:

python -m venv venv

To activate a virtual environment on Windows:

.\venv\Scripts\activate

To activate a virtual environment on macOS and Linux:

source venv/bin/activate

To install the flask python package run the command:

pip install flask

To deactivate the virtual environment run the command:

deactivate

Donate

The Pallets organization develops and supports Flask and the libraries it uses. In order to grow the community of contributors and users, and allow the maintainers to devote more time to the projects, please donate today.