Flask Tutorials

Flask Tutorials Roadmap

What is Flask?
- Understanding Flask's nature: a micro-framework.
- Why choose Flask? (Lightweight, Flexible, Minimalistic).
- Comparing Flask to other Python web frameworks (Django).
- Key components: Werkzeug (WSGI utility library), Jinja2 (templating engine).
Setting up the Development Environment:
- Installing Python.
- Understanding Virtual Environments (venv or virtualenv).
- Creating and activating a virtual environment.
- Installing Flask (pip install Flask).
Your First Flask Application:
- Creating a simple "Hello, World!" Flask app.
- Understanding the basic structure: importing Flask, creating an app instance, defining a route, running the app.
- Running the application (python your_app_file.py).
- Exploring the default development server.
Understanding Routes and Views:
- Defining routes using the @app.route() decorator.
- Mapping URLs to Python functions (view functions).
- Returning responses from view functions (strings, HTML).

Accessing Request Data:
- Using the request object (from flask).
- Accessing query parameters (request.args).
- Accessing form data (request.form).
- Accessing JSON data (request.json).
- Accessing headers (request.headers).
- Accessing cookies (request.cookies).
- Understanding different HTTP methods (GET, POST, PUT, DELETE).
Generating Responses:
- Returning strings and simple HTML.
- Using the jsonify() function for JSON responses.
- Returning custom status codes.
- Setting headers in responses.
- Setting cookies in responses.
Redirects and Errors:
- Redirecting users using redirect().
- Handling common HTTP errors (404 Not Found, 500 Internal Server Error).
- Customizing error pages.

Introduction to Jinja2:
- Understanding the need for templates.
- Basic Jinja2 syntax (variables, tags, comments).
Rendering Templates:
- Using the render_template() function.
- Passing data from view functions to templates.
Template Inheritance:
- Creating base templates.
- Using {% extends %} and {% block %} for code reuse.
Control Structures:
- Conditional statements ({% if %}, {% elif %}, {% else %}).
- Loops ({% for %}).
Filters and Macros:
- Using built-in Jinja2 filters (e.g., |safe, |length).
- Creating custom filters.
- Using macros for reusable template snippets.
Static Files:
- Serving static files (CSS, JavaScript, images).
- Using the url_for() function with 'static' endpoint.

Introduction to Flask-WTF:
- Understanding the need for form handling libraries.
- Installing Flask-WTF (pip install Flask-WTF).
Creating Forms:
- Defining form classes using Flask-WTF.
- Adding fields (StringField, SubmitField, etc.).
- Adding validators (DataRequired, Email, Length, etc.).
Rendering Forms in Templates:
- Passing form objects to templates.
- Rendering form fields individually or using loops.
- Handling CSRF protection.
Processing Form Data:
- Validating form submissions (form.validate_on_submit()).
- Accessing validated data (form.field_name.data).
- Handling form submission logic.

Introduction to Databases:
- Understanding different types of databases (SQL, NoSQL).
- Choosing a database for your Flask application (SQLite, PostgreSQL, MySQL, MongoDB).
Using an ORM (Object-Relational Mapper) - Flask-SQLAlchemy:
- Understanding ORMs.
- Installing Flask-SQLAlchemy (pip install Flask-SQLAlchemy).
- Configuring the database connection.
Defining Models:
- Creating database models as Python classes.
- Defining columns and data types.
- Defining relationships between models.
Creating and Managing the Database:
- Creating database tables (db.create_all()).
- Using Flask-Migrate for database migrations (pip install Flask-Migrate).
- Generating and applying migrations.
Performing CRUD Operations:
- Adding new records to the database.
- Querying records (filtering, sorting).
- Updating existing records.
- Deleting records.

Introduction to Authentication and Authorization:
- Understanding the difference.
Using Flask-Login:
- Installing Flask-Login (pip install Flask-Login).
- Setting up Flask-Login.
User Models:
- Integrating Flask-Login with your database user model.
- Implementing required methods (is_authenticated, is_active, is_anonymous, get_id).
- Creating a user loader function.
Login and Logout Functionality:
- Creating login and logout routes.
- Using login_user() and logout_user().
- Hashing passwords (using libraries like Werkzeug.security or bcrypt).
Protecting Routes:
- Using the @login_required decorator.
- Redirecting unauthorized users.
Basic Authorization:
- Checking user roles or permissions within view functions.

Application Context and Request Context:
- Understanding the purpose of contexts.
- Working with current_app and g.
Blueprints:
- Organizing large applications into modular components.
- Creating and registering Blueprints.
- Defining routes and templates within Blueprints.
Working with APIs:
- Building RESTful APIs with Flask.
- Using Flask-RESTful or Flask-RESTX (optional).
- Handling API request/response formats (JSON).
Background Tasks:
- Understanding the need for background tasks.
- Using libraries like Celery or Redis Queue (RQ) with Flask.
Caching:
- Implementing caching to improve performance (using Flask-Caching).
Logging:
- Setting up and using logging in your Flask application.
Testing Flask Applications:
- Writing unit tests for view functions and models.
- Using Flask's test client.
- Writing integration tests.

Preparing for Production:
- Understanding WSGI servers (Gunicorn, uWSGI).
- Serving static files efficiently.
- Environment variables for configuration.
Deployment Options:
- Deploying to Platform as a Service (PaaS) like Heroku, Render, PythonAnywhere.
- Deploying to Infrastructure as a Service (IaaS) like AWS (EC2, Elastic Beanstalk), Google Cloud, Azure.
- Deploying with Docker.
Using a Production WSGI Server:
- Running your Flask app with Gunicorn or uWSGI.
Using a Reverse Proxy:
- Setting up Nginx or Apache as a reverse proxy.
- Handling SSL/TLS.

Exploring Flask Extensions:
- Discovering useful extensions for various tasks (debugging, mail, etc.).
Staying Updated:
- Following the Flask documentation and release notes.
- Engaging with the Flask community (forums, Stack Overflow, Discord).