Source code for flask_unchained.forms.flask_form

from flask_unchained.string_utils import snake_case
from flask_wtf import FlaskForm as BaseForm


class FlaskForm(BaseForm):
    """
    Base form class extending :class:`flask_wtf.FlaskForm`. Adds support for
    specifying the field order via a ``field_order`` class attribute.

    :param formdata: Used to pass data coming from the end user, usually
                     ``request.POST`` or equivalent. formdata should be some
                     sort of request-data wrapper which can get multiple
                     parameters from the form input, and values are unicode
                     strings, e.g. a Werkzeug/Django/WebOb MultiDict
    :param obj: If ``formdata`` is empty or not provided, this object is
                checked for attributes matching form field names, which will
                be used for field values.
    :param prefix: If provided, all fields will have their name prefixed with
                   the value.
    :param data: Accept a dictionary of data. This is only used if ``formdata``
                 and `obj` are not present.
    :param meta: If provided, this is a dictionary of values to override
                 attributes on this form's meta instance.
    :param `**kwargs`: If `formdata` is empty or not provided and `obj` does
                       not contain an attribute named the same as a field,
                       form will assign the value of a matching keyword
                       argument to the field, if one exists.
    """

    field_order = ()
    """
    An ordered list of field names. Fields not listed here will be rendered first.
    """

    def __init__(self, formdata=None, obj=None, prefix='', data=None, meta=None,
                 **kwargs):
        super().__init__(formdata=formdata, obj=obj, prefix=prefix, data=data, meta=meta,
                         **kwargs)
        self._name = bytes(snake_case(self.__class__.__name__), 'utf-8')

    def __iter__(self):
        if not self.field_order:
            return super().__iter__()
        return iter([field for name, field in self._fields.items()
                     if name not in self.field_order]
                    + [self._fields[f] for f in self.field_order])