How can I handle errors in WTForms?

How can I handle errors in WTForms?

You can handle errors in WTForms by using the validate_on_submit() method and checking the errors attribute of the form.

Can you show me an example of how to implement that?

Sure! Here's a simple example:

if form.validate_on_submit():
    # process the data
else:
    # handle errors
    print(form.errors)

What types of errors can I expect?

You can expect validation errors like required fields, incorrect data types, or custom validation failures.

How can I customize error messages?

You can customize error messages by setting the message parameter in the field definition, like this:

username = StringField('Username', validators=[DataRequired(message='Please enter your username.')])