flask-tutorial
https://flask.palletsprojects.com/en/3.0.x/tutorial
https://flask.palletsprojects.com/en/3.0.x/tutorial/next/
Installation
python -m venv .venv
source .venv/bin/activate
pip install -r requirements.txt
flask --app ustayml run --debug
Build
pip install build
python -m build --wheel
Deploy: https://flask.palletsprojects.com/en/3.0.x/deploying/
Learning resources
- Flask user guide
- DB: https://sqlite.org/lang.html
- Jinja Template
- For loops
- Python packaging tutorial
Concepts:
- flask.g: Store data. Unique for each request
- flask.current_app: Link to Flask app
- flask.open_resource: From app package path
- request: HTML request???
- Factory function > registered functions and blueprints.
- Blueprint: groups views & other code
- View: function that returns HTML
- flask.session: dict that stores data across requests (cookies) (securely signed with SECRET_KEY)
- endpoint: name associated with a view,
<blueprint_name>.<view_function_name> - Templates: Used to render HTML. Uses Jinja template library. Autoscapes any data that is rendered in HTML templates, so it's safe to render user input.
{{ }}denotes expressions (output) (similar to python){% %}denotes control flow statements (similar to pseudo-code){# #}denotes a comment- Automatically available:
g,url_for,request, and more - In base.html you define "blocks" placeholder which are later defined in other templates that extend base.html
Gotchas:
- Remember to call db.commit() after modifying DB (DML).
Browser warnings and errors:
- https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Set-Cookie#samesitesamesite-value
Discussion
Pros:
- Flask is AWESOME, it's simple, it's elegant, it's enjoyable to code with. Following the tutorial provides you all the basic tools to begin creating projects with flask.
- It's secure, provides you with cryptographic signature for cookies and escapes HTML transparently to the developer.
Cons:
- Maybe scalability and performance is lower compared to PHP or Javascript web applications.
Next Steps
- https://www.sqlalchemy.org/
- https://stackoverflow.com/questions/10434599/get-the-data-received-in-a-flask-request