Overview

This guide shows how to install and run a basic Flask application. Flask is a Python framework that can be used to create Web and API application.

Prerequisites

• Python has been installed
  • Installation on Ubuntu
  • Installation on Windows
• Optional but recommended. Setup a VirtualEnvironment and Pip has been installed.
  • VirtualEnvironment for Ubuntu

Installation

01. Activate your virtual environment, or skip this step if not using virtual environment.

$ source {{virtual-env-directory}}/bin/activate

02. Install the Flask package

(geek-venv) $ pip install -U Flask

03. Verify the Flask has been installed by creating a sample application

(geek-venv) $ nano geek_flask_api.py

Set the content as follows

from flask import Flask
from flask import jsonify
application = Flask(__name__)

@application.route(“/”, methods=['GET'])
def root_path():
  app_properties = \
  {
    ‘name’ : ‘geek-flask-api’
    , ‘version’ : ‘1.0.0.’
  }
  return jsonify(app_properties)

04. Run the application

(geek-venv) $ env FLASK_APP=geek_flask_api.py flask run

05. Open a CLI window and use cURL to view the response of the application. In this example http://127.0.0.1:5000

Press Ctrl+C to terminate the application.

06. Congratulations! Flask has been installed