from wtforms import Form
from wtforms.fields import simple
from wtforms import validators
from wtforms import widgetsclass LoginForm(Form):user = simple.StringField(validators=[validators.DataRequired(message='不能为空')],widget=widgets.TextInput(),render_kw={'class': 'form-control'})pwd = simple.PasswordField(validators=[validators.DataRequired(message='不能为空')],widget=widgets.PasswordInput(),render_kw={'class': 'form-control'})

class Form(with_metaclass(FormMeta, BaseForm)):。。。。

class FormMeta(type):def __init__(cls, name, bases, attrs):type.__init__(cls, name, bases, attrs)cls._unbound_fields = Nonecls._wtforms_meta = None....

class Field(object):。。。def __new__(cls, *args, **kwargs):if '_form' in kwargs and '_name' in kwargs:return super(Field, cls).__new__(cls)else:return UnboundField(cls, *args, **kwargs)

 def __call__(cls, *args, **kwargs):"""Construct a new `Form` instance.Creates the `_unbound_fields` list and the internal `_wtforms_meta`subclass of the class Meta in order to allow a proper inheritancehierarchy."""if cls._unbound_fields is None:fields = []for name in dir(cls):if not name.startswith('_'):unbound_field = getattr(cls, name)if hasattr(unbound_field, '_formfield'):fields.append((name, unbound_field))# We keep the name as the second element of the sort# to ensure a stable sort.fields.sort(key=lambda x: (x[1].creation_counter, x[0]))cls._unbound_fields = fields# Create a subclass of the 'class Meta' using all the ancestors.if cls._wtforms_meta is None:bases = []for mro_class in cls.__mro__:if 'Meta' in mro_class.__dict__:bases.append(mro_class.Meta)cls._wtforms_meta = type('Meta', tuple(bases), {})return type.__call__(cls, *args, **kwargs)

class Form(with_metaclass(FormMeta, BaseForm)):Meta = DefaultMetadef __init__(self, formdata=None, obj=None, prefix='', data=None, meta=None, **kwargs):meta_obj = self._wtforms_meta()if meta is not None and isinstance(meta, dict):meta_obj.update_values(meta)super(Form, self).__init__(self._unbound_fields, meta=meta_obj, prefix=prefix)for name, field in iteritems(self._fields):# Set all the fields to attributes so that they obscure the class# attributes with the same names.setattr(self, name, field)self.process(formdata, obj, data=data, **kwargs)