DateTimeField validation error

[Greyvend]

Minimal working example:

from wtforms import DateTimeField, Form
from wtforms.validators import DataRequired
from wtforms_json import MultiDict


class MyForm(Form):
    timestamp = DateTimeField(validators=[DataRequired()])


data = {'timestamp': 'asd'}
formdata = MultiDict(data)

form = MyForm(formdata=formdata)
success = form.validate()

print('Success:', success)
print('Errors:', form.errors)
print(form.timestamp.data)

Execution environment: Docker container, image based on python:3.6.
Output:

Success?,  False
Errors: {'timestamp': ['This field is required.']}
None

You can see there is the wrong error message. It should mention wrong date format, not the missing field.

[whb07]

Thats because you're trying to validate a type string as a Datetime. The field doesn't accept the input so the form validation ends up being an empty field.

[Greyvend]

No, the field accepts the string and transforms it to the datetime.datetime during validation.

If we change the data to the following format: data = {'timestamp': '2018-04-13 10:03:08'}, it works fine:

Success: True
Errors: {}
2018-04-13 10:03:08

[azmeuk]

I could not reproduce:

>>> import wtforms
>>> import werkzeug.datastructures
>>> class F(wtforms.Form):
...    timestamp = wtforms.DateTimeField(validators=[wtforms.validators.DataRequired()])
>>> formdata = werkzeug.datastructures.ImmutableMultiDict({"timestamp": "asd"})
>>> F(formdata).validate()
False

I could reproduce with passing data instead of formdata, but this is because DateTimeField has no process_data method:

>>> import wtforms
>>> class F(wtforms.Form):
...     timestamp = wtforms.DateTimeField(validators=[wtforms.validators.DataRequired()])
>>> F(data=dict(timestamp='asd')).validate()
True