Flask Tutorials: Environment Variables 🎯

Welcome to our comprehensive guide on using Environment Variables in Flask! This tutorial is designed for beginners and intermediates, so let's dive right in. 🐳

What are Environment Variables? 📝

Environment variables are values that can be set to store configuration information for your Flask application. They are useful because they can be easily changed without modifying your code.

Why Use Environment Variables? 💡

Security: Keeping sensitive information like API keys as environment variables helps protect your code from being exposed.
Configuration Flexibility: You can easily change settings, such as database connections or third-party service credentials, without modifying your code.

Setting Environment Variables 📝

Flask applications can be run with environment variables by setting them in your system's environment or within your Flask application itself.

System Environment Variables 📝

On Unix-based systems like Linux and macOS, you can set environment variables using the export command:

bash

export MY_VARIABLE=my_value

On Windows, use the set command:

cmd

set MY_VARIABLE=my_value

Flask Application Environment Variables 📝

Flask provides a Flask.config object where you can store configuration settings, including environment variables.

python

from flask import Flask

app = Flask(__name__)
app.config['MY_VARIABLE'] = 'my_value'

💡 Pro Tip: You can access environment variables within your Flask application using app.config['KEY'].

Accessing Environment Variables 📝

To access environment variables, you can use the os module in Python.

python

import os

my_variable = os.getenv('MY_VARIABLE')

Practical Example 📝

Let's create a Flask app that retrieves data from an API using an API key stored as an environment variable.

python

import os
import requests
from flask import Flask, jsonify

app = Flask(__name__)
app.config['API_KEY'] = os.getenv('API_KEY')

@app.route('/api_data')
def api_data():
    if not app.config['API_KEY']:
        return 'Missing API Key', 500

    api_url = f'https://api.example.com/data?key={app.config["API_KEY"]}'
    response = requests.get(api_url)

    if response.status_code == 200:
        data = response.json()
        return jsonify(data)
    else:
        return 'Error fetching data', 500

if __name__ == '__main__':
    app.run()

Flask Tutorials: Environment Variables 🎯

Flask Tutorials: Environment Variables 🎯

What are Environment Variables? 📝

Why Use Environment Variables? 💡

Setting Environment Variables 📝

System Environment Variables 📝

Flask Application Environment Variables 📝

Accessing Environment Variables 📝

Practical Example 📝

Quiz 🎯