Given this Flask form code snippet, what happens if the CSRF token is missing or invalid when submitting the form?

medium📝 component behavior Q13 of 15

Flask - Security Best Practices

from flask_wtf import FlaskForm
from wtforms import StringField, SubmitField

class MyForm(FlaskForm):
    name = StringField('Name')
    submit = SubmitField('Send')

AThe form submission is accepted without any error

BThe form automatically regenerates a new CSRF token and retries

CA CSRFError is raised and the request is rejected

DThe form data is saved but a warning is logged

Step-by-Step Solution

Solution:

Step 1: Understand FlaskForm CSRF behavior
FlaskForm automatically checks for a valid CSRF token on submission.
Step 2: Effect of missing/invalid token
If the token is missing or wrong, Flask-WTF raises a CSRFError and rejects the request.
Final Answer:
A CSRFError is raised and the request is rejected -> Option C
Quick Check:
Invalid CSRF token = CSRFError raised [OK]

Quick Trick: Missing CSRF token causes error and blocks form [OK]

Common Mistakes:

MISTAKES

Assuming form submits anyway without token
Thinking token regenerates automatically on failure
Believing data saves with just a warning

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More Flask Quizzes

Given this Flask form code snippet, what happens if the CSRF token is missing or invalid when submitting the form?

Step 1: Understand FlaskForm CSRF behavior

Step 2: Effect of missing/invalid token

Final Answer:

Quick Check:

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