Form handling is an integral part of any web application. There can be innumerable cases that make the presence of forms in any web app very important. Some cases can be where users need to log in or submit some data or cases where applications might require input from users. As important as the forms are, their validation holds equal importance, if not more. Presenting this information to users in an interactive fashion adds a lot of value to the application.
In this chapter, we will cover the following recipes:
SQLAlchemy model data as form representation
Validating fields on the server side
Creating a common forms set
Creating custom fields and validation
Creating a custom widget
Uploading files via forms
Cross-site Request Forgery protection