Source code for wtforms.csrf.core

from wtforms.fields import HiddenField
from wtforms.validators import ValidationError

__all__ = ("CSRFTokenField", "CSRF")

[docs]class CSRFTokenField(HiddenField): """ A subclass of HiddenField designed for sending the CSRF token that is used for most CSRF protection schemes. Notably different from a normal field, this field always renders the current token regardless of the submitted value, and also will not be populated over to object data via populate_obj """ current_token = None
[docs] def __init__(self, *args, **kw): self.csrf_impl = kw.pop("csrf_impl") super().__init__(*args, **kw)
[docs] def _value(self): """ We want to always return the current token on render, regardless of whether a good or bad token was passed. """ return self.current_token
[docs] def populate_obj(self, *args): """ Don't populate objects with the CSRF token """ pass
[docs] def pre_validate(self, form): """ Handle validation of this token field. """ self.csrf_impl.validate_csrf_token(form, self)
[docs] def process(self, *args, **kwargs): super().process(*args, **kwargs) self.current_token = self.csrf_impl.generate_csrf_token(self)
[docs]class CSRF: field_class = CSRFTokenField
[docs] def setup_form(self, form): """ Receive the form we're attached to and set up fields. The default implementation creates a single field of type :attr:`field_class` with name taken from the ``csrf_field_name`` of the class meta. :param form: The form instance we're attaching to. :return: A sequence of `(field_name, unbound_field)` 2-tuples which are unbound fields to be added to the form. """ meta = form.meta field_name = meta.csrf_field_name unbound_field = self.field_class(label="CSRF Token", csrf_impl=self) return [(field_name, unbound_field)]
[docs] def generate_csrf_token(self, csrf_token_field): """ Implementations must override this to provide a method with which one can get a CSRF token for this form. A CSRF token is usually a string that is generated deterministically based on some sort of user data, though it can be anything which you can validate on a subsequent request. :param csrf_token_field: The field which is being used for CSRF. :return: A generated CSRF string. """ raise NotImplementedError()
[docs] def validate_csrf_token(self, form, field): """ Override this method to provide custom CSRF validation logic. The default CSRF validation logic simply checks if the recently generated token equals the one we received as formdata. :param form: The form which has this CSRF token. :param field: The CSRF token field. """ if field.current_token != raise ValidationError(field.gettext("Invalid CSRF Token."))