Let’s take a look at the architecture of a typical Flask application.

A typical Flask application follows a fairly straightforward architecture. Flask is a micro web framework for Python, which means it provides the basic tools to build a web application, but leaves many decisions to the developer, allowing for flexibility and customization. Here’s a high-level overview of the architecture:

1. Application Object: At the heart of every Flask application is an instance of the Flask class. This object is where you configure your application, define routes, and perform other setup tasks.

2. Routing: Flask uses routes to map URLs to Python functions. When a user visits a particular URL, Flask calls the corresponding Python function (also known as a view function) to handle the request. You define routes using decorators (@app.route('/')) or the app.add_url_rule() method.

3. Views: Views are the Python functions that handle incoming requests and return responses. These functions typically take user input from the request, process it (if necessary), and generate a response, which is sent back to the client.

4. Templates: Flask supports the use of templates, which are HTML files with placeholders for dynamic content. Templates allow you to separate the presentation layer from your Python code, making your application more maintainable. Flask uses the Jinja2 template engine by default.

5. Static Files: Flask can serve static files such as CSS, JavaScript, and images directly from the filesystem. You typically place these files in a directory called static within your application package, and Flask will automatically serve them at the specified URLs.

6. Request and Response: Flask provides request and response objects to represent HTTP requests and responses, respectively. These objects provide convenient access to request data (e.g., form data, query parameters) and allow you to construct responses with custom headers and content.

7. Extensions: Flask has a rich ecosystem of extensions that add additional functionality to your application. These extensions can handle tasks like form validation, authentication, database integration, and more. Examples of popular Flask extensions include Flask-WTF (for forms), Flask-SQLAlchemy (for database access), and Flask-Login (for user authentication).

8. Configuration: Flask applications can be configured using a variety of methods, including environment variables, configuration files, and Python code. Configuration options include settings like the secret key (used for session management), database connection details, debug mode, and more.

9. Middleware: Flask supports middleware, which are functions that run before or after each request. Middleware can be used for tasks like logging, authentication, error handling, and more. You can add middleware to your Flask application using the @app.before_request and @app.after_request decorators.

10. Deployment: Flask applications can be deployed using a variety of web servers and deployment strategies. Common choices include uWSGI, Gunicorn, and the built-in Flask development server for development purposes. Flask applications are often deployed behind a reverse proxy like Nginx or Apache for additional security and performance.

Overall, Flask provides a flexible and lightweight framework for building web applications in Python, with a simple and modular architecture that allows developers to customize their applications to suit their specific requirements.

FYI: Flask is a web framework that allows web developers to build lightweight web applications quickly and easily with Flask Libraries. You can read more about it from these 2 weblinks:

• Flask Tutorial on Geeks for Geeks
• Official Flask website

If you are interested in studying Flask, I highly recommend this book:

The Flask Mega-Tutorial

by Miguel Grinberg Available on Amazon!