Validation rules in Flask - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the Flask-WTF form base class.

Flask

from flask_wtf import [1]

Drag options to blanks, or click blank then click option'

AFlaskForm

BForm

CBaseForm

DFormBase

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'Form' instead of 'FlaskForm' causes errors because Flask-WTF expects FlaskForm.

Importing 'BaseForm' or 'FormBase' are not valid in Flask-WTF.

The correct import for creating forms in Flask-WTF is FlaskForm.

2fill in blank

medium

Complete the code to add a required string field named 'username' to the form.

Flask

from wtforms import StringField
from wtforms.validators import [1]

class MyForm(FlaskForm):
    username = StringField('Username', validators=[[1]()])

Drag options to blanks, or click blank then click option'

ARequired

BInputRequired

CDataRequired

DNotEmpty

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'InputRequired' can cause issues with some form processing scenarios.

Using 'Required' or 'NotEmpty' are deprecated or invalid in Flask-WTF.

DataRequired validator ensures the field is not empty and is the recommended validator for required fields in Flask-WTF.

3fill in blank

hard

Fix the error in the code by completing the validator import correctly.

Flask

from wtforms.validators import [1]

class EmailForm(FlaskForm):
    email = StringField('Email', validators=[DataRequired(), [1]()])

Drag options to blanks, or click blank then click option'

AEmailField

BEmailValidator

CEmailCheck

DEmail

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'EmailValidator' causes import errors.

Using 'EmailField' is a field type, not a validator.

The correct validator to check email format is Email from wtforms.validators.

4fill in blank

hard

Fill both blanks to create a password field with length validation between 6 and 12 characters.

Flask

from wtforms import PasswordField
from wtforms.validators import DataRequired, [1]

class PasswordForm(FlaskForm):
    password = PasswordField('Password', validators=[DataRequired(), [2](min=6, max=12)])

Drag options to blanks, or click blank then click option'

ALength

BLengthValidator

CSize

DRange

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'LengthValidator' or 'Size' are invalid names.

Using 'Range' is for numeric ranges, not string length.

The Length validator checks the length of input. It is imported and used to enforce min and max length.

5fill in blank

hard

Fill all three blanks to create a form with a username field that is required, has a length between 4 and 25, and an email field that is required and validated.

Flask

from wtforms import StringField
from wtforms.validators import [1], [2], Email

class UserForm(FlaskForm):
    username = StringField('Username', validators=[[1](), [2](min=4, max=25)])
    email = StringField('Email', validators=[[1](), Email()])

Drag options to blanks, or click blank then click option'

ADataRequired

BLength

CInputRequired

DEmail

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'InputRequired' instead of 'DataRequired' can cause unexpected behavior.

Forgetting to add Email validator to the email field.

DataRequired ensures fields are not empty, Length enforces username length, and Email validates email format.