How Flask works

When we open a browser we see a few things: Front-End - HTML displays the page elements like the actual text on the website - CSS styles the elemtns liek change font or sizeof the text - Bootstrap provides some automatic styling through CSS and Javascript

Every website will perform some main ops: - Accept info from user - Retrieve info from databse - Create/Update/Delee info in the database - Display information back to the user

To connect the front-end stuff to web database, we need a web framework. Web framework's job is to accept user information from website and connect to back-end database and report something relevant that can be stored in the db and communicate it to the front-end so user can see it.

Flask is a web framework. Allows to connect Python code to the web. Flask does has reputation for being not scalable.

Accepting user information

• Could be something like accepting query into Google search - instance of user filling out info. WTForms is a library that works well with flask
• Communicate with database and retrieve information. In this case its SQLite. SQLite can scale to quite a large website.
• SQLAlchemy allows us to write Python code instead of SQL queries
• Flask is like connector between front-end and back-end info that is stored
• Jinja templates grab info from Python and Flask ad send info back as HTML
• Flask renders HTML templates

Virtual Environment

Launched web app and want to use external python library, but the library gets updated. We can set up virtual environment to help manage dependencies.