Flask Series: Sample Project

This repository contains the code for the board Flask sample project.

Setup

You can run the provided example project on your local machine by following the steps outlined below.

Create a new virtual environment:

python3 -m venv venv/

Activate the virtual environment:

source ./venv/bin/activate

Navigate to the folder for the step that you're currently on.

Install the dependencies for this project if you haven't installed them yet:

(venv) $ python -m pip install -r requirements.txt

Environment Variables

This project works with environment variables that the application expects in a .env file inside the root directory of your project.

Create a .env file with this content:

FLASK_SECRET_KEY="mysecretkey"
FLASK_DATABASE="board.sqlite"

You can add your own content there, but you must define it before running the Flask application.

Secret Key

If you want to deploy your Flask app later, then it's a good idea to generate a proper secret key.

If you need to create cryptographically sound data like a Flask secret key, then you can use Python's secrets module:

>>> import secrets
>>> secrets.token_hex()
'2e9ac41b1e0b66a8d93d66400e2300c4b4c2953f'

The .token_hex() method returns a hexadecimal string containing random numbers and letters from 0 to 9 and a to f. Use the value that secrets.token_hex() outputs for you and add it to your Flask project's .env file:

# .env

FLASK_SECRET_KEY="2e9ac41b1e0b66a8d93d66400e2300c4b4c2953f"
FLASK_DATABASE="board.sqlite"

To avoid saving the secret key directly in your code, it may be a good idea to work with environment variables. You can learn more about that in the Flask documentation on configuration handling.

Database

To initialize the database, run this command:

(venv) $ python -m flask --app board init-db

If you used the content for the .env file from above, then you can find a board.sqlite database in the root directory of your project.

Development Server

To run the Flask development server, enter this command in your terminal while being in the root directory of your project:

(venv) $ python -m flask --app board run --debug

Now you can navigate to the address that's shown in the output when you start the server. Commonly, that's http://localhost:5000/.