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• What is Flask
• How can I install Flask
• A minimal Flask application
• Flask Project Structure

👉 Flask is a lightweight web application framework. It is designed to make getting started quick and easy, with the ability to scale up to complex applications. Compared to Django, Flask provides a lightweight codebase and more freedom to the developer.

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👉 The easiest way to install Flask is to use PIP the official package-management tool.

$ pip install Flask

How to check Flask version

Open a Python console (type python in terminal) and check the installed version as below:

>> import flask >> flask.__version__ '1.1.2' >>>

In this case the installed version is 1.1.2

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👉 Open a terminal and install Flask (if not already installed) using PIP:

$ pip install Flask

Use your preferred editor to create a file called hello.py with this content:

from flask import Flask app = Flask(__name__) @app.route('/') def hello(): return f'My first Flask!'

Save the file and start the app:

$ env FLASK_APP=hello.py flask run * Serving Flask app "hello" * Running on http://127.0.0.1:5000/

Above commnand does two things:

• Set the FLASK_APP variable (required by Flask)
• Execute our code with flask run command

By visiting the app in the browser localhost:5000 we should see My first Flask! message.

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👉 Being such a lightweight framework, Flask comes with great flexibility regarding the codebase structure of a project. We can use a single file and drop all the code or split the app logic in more files and directories. All variants works but we migth have issues once our project is getting bigger and migth become unreadable for others.

Well, this section presents a few options to keep in mind when we start a Flask project.

🔗 Read in detail: Flask Project Structure

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