Flask-WTForms throws error for IntegerField instead of failing validation
Solution 1
The error below means that you are trying to check the length of an integer which is not allowed by python. If you want to check length, then it must be a string. IntegerField() however by definition is an integer
object of type 'int' has no len()
You need to create something like below. NumberRange takes a range of numbers.
IntegerField('Telephone', [validators.NumberRange(min=0, max=10)])
Alternatively,I suggest you use a FormField and define your own telephone field. There is an exact example here to create a telephone field:
http://wtforms.simplecodes.com/docs/0.6.1/fields.html#wtforms.fields.FormField
Solution 2
From the http://wtforms.readthedocs.org/en/latest/validators.html#wtforms.validators.Length
"Validates the length of a string."
Also i dont think it is a good idea to store/validate telephone numbers as integers. You should probably use wtforms.validators.Regexp
to validate the number.
Sixhobbits
Updated on July 28, 2022Comments
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Sixhobbits almost 2 years
When I create a form using wtf_forms and Flask-WTF and use the IntegerField input, I can't use it in combination with the Length validator
If I remove the Length restriction then it works fine. Surely I should be able to apply a Length validation to an IntegerField?
Python Code.
from flask_wtf import Form from wtforms import TextField, PasswordField, IntegerField, validators class RegistrationForm(Form): firstname = TextField('First Name', [validators.Required()]) lastname = TextField('Last Name', [validators.Required()]) telephone = IntegerField('Telephone', [validators.Length(min=10, max=10, message="Telephone should be 10 digits (no spaces)")]) TypeError TypeError: object of type 'int' has no len() Traceback (most recent call last) File "C:\Python27\lib\site-packages\flask\app.py", line 1701, in __call__ return self.wsgi_app(environ, start_response) File "C:\Python27\lib\site-packages\flask\app.py", line 1689, in wsgi_app response = self.make_response(self.handle_exception(e)) File "C:\Python27\lib\site-packages\flask\app.py", line 1687, in wsgi_app response = self.full_dispatch_request() File "C:\Python27\lib\site-packages\flask\app.py", line 1360, in full_dispatch_request rv = self.handle_user_exception(e) File "C:\Python27\lib\site-packages\flask\app.py", line 1358, in full_dispatch_request rv = self.dispatch_request() File "C:\Python27\lib\site-packages\flask\app.py", line 1344, in dispatch_request return self.view_functions[rule.endpoint](**req.view_args) File "C:\index.py", line 45, in submit if form.validate_on_submit(): File "C:\Python27\lib\site-packages\flask_wtf\form.py", line 156, in validate_on_submit return self.is_submitted() and self.validate() File "C:\Python27\lib\site-packages\wtforms\form.py", line 271, in validate return super(Form, self).validate(extra) File "C:\Python27\lib\site-packages\wtforms\form.py", line 130, in validate if not field.validate(self, extra): File "C:\Python27\lib\site-packages\wtforms\fields\core.py", line 175, in validate stop_validation = self._run_validation_chain(form, chain) File "C:\Python27\lib\site-packages\wtforms\fields\core.py", line 195, in _run_validation_chain validator(form, self) File "C:\Python27\lib\site-packages\wtforms\validators.py", line 91, in __call__ l = field.data and len(field.data) or 0 TypeError: object of type 'long' has no len()