Django Form 소스 분석의 BaseForm 검증 논리

class Form(six.with_metaclass(DeclarativeFieldsMetaclass, BaseForm)):
    "A collection of Fields, plus their associated data."
    # This is a separate class from BaseForm in order to abstract the way
    # self.fields is specified. This class (Form) is the one that does the
    # fancy metaclass stuff purely for the semantic sugar -- it allows one
    # to define a form using declarative syntax.
    # BaseForm itself has no way of designating self.fields.

def __init__(self, data=None, files=None, auto_id='id_%s', prefix=None,
                 initial=None, error_class=ErrorList, label_suffix=None,
                 empty_permitted=False, field_order=None):
        self.is_bound = data is not None or files is not None
        self.data = data or {}
        self.files = files or {}
        self.auto_id = auto_id
        if prefix is not None:
            self.prefix = prefix
        self.initial = initial or {}
        self.error_class = error_class
        # Translators: This is the default suffix added to form field labels
        self.label_suffix = label_suffix if label_suffix is not None else _(':')
        self.empty_permitted = empty_permitted
        self._errors = None  # Stores the errors after clean() has been called.

        # The base_fields class attribute is the *class-wide* definition of
        # fields. Because a particular *instance* of the class might want to
        # alter self.fields, we create self.fields here by copying base_fields.
        # Instances should always modify self.fields; they should not modify
        # self.base_fields.
        self.fields = copy.deepcopy(self.base_fields)
        self._bound_fields_cache = {}
        self.order_fields(self.field_order if field_order is None else field_order)

 self.is_bound = data is not None or files is not None

>>> not_bound = exampleForm()
>>> not_bound.is_bound
False
>>> is_bound = exampleForm({})
>>> is_bound.is_bound
True

def is_valid(self):
        """ Returns True if the form has no errors. Otherwise, False. If errors are being ignored, returns False. """
        return self.is_bound and not self.errors

@property
    def errors(self):
        "Returns an ErrorDict for the data provided for the form"
        if self._errors is None:
            self.full_clean()
        return self._errors

 def full_clean(self):
        """ Cleans all of self.data and populates self._errors and self.cleaned_data. """
        self._errors = ErrorDict()
        if not self.is_bound:  # Stop further processing.
            return
        self.cleaned_data = {}
        # If the form is permitted to be empty, and none of the form data has
        # changed from the initial data, short circuit any validation.
        if self.empty_permitted and not self.has_changed():
            return

        self._clean_fields()
        self._clean_form()
        self._post_clean()

# ErrorDict.as_data()

def as_data(self):
        return {f: e.as_data() for f, e in self.items()}

# ErrorList.as_data()

def as_data(self):
        return ValidationError(self.data).error_list

 def _clean_form(self):
        try:
            cleaned_data = self.clean()
        except ValidationError as e:
            self.add_error(None, e)
        else:
            if cleaned_data is not None:
                self.cleaned_data = cleaned_data

    def clean(self):
        """ Hook for doing any extra form-wide cleaning after Field.clean() has been called on every field. Any ValidationError raised by this method will not be associated with a particular field; it will have a special-case association with the field named '__all__'. """
        return self.cleaned_data

    def add_error(self, field, error):
        """
        Update the content of `self._errors`. The `field` argument is the name of the field to which the errors should be added. If its value is None the errors will be treated as NON_FIELD_ERRORS. The `error` argument can be a single error, a list of errors, or a dictionary that maps field names to lists of errors. What we define as an "error" can be either a simple string or an instance of ValidationError with its message attribute set and what we define as list or dictionary can be an actual `list` or `dict` or an instance of ValidationError with its `error_list` or `error_dict` attribute set. If `error` is a dictionary, the `field` argument *must* be None and errors will be added to the fields that correspond to the keys of the dictionary. """ if not isinstance(error, ValidationError): # Normalize to ValidationError and let its constructor # do the hard work of making sense of the input. error = ValidationError(error) if hasattr(error, 'error_dict'): if field is not None: raise TypeError( "The argument `field` must be `None` when the `error` " "argument contains errors for multiple fields." ) else: error = error.error_dict else: error = {field or NON_FIELD_ERRORS: error.error_list} for field, error_list in error.items(): if field not in self.errors: if field != NON_FIELD_ERRORS and field not in self.fields: raise ValueError( "'%s' has no field named '%s'." % (self.__class__.__name__, field)) if field == NON_FIELD_ERRORS: self._errors[field] = self.error_class(error_class='nonfield') else: self._errors[field] = self.error_class() self._errors[field].extend(error_list) if field in self.cleaned_data: del self.cleaned_data[field]

def _clean_fields(self):
    for name, field in self.fields.items():
        # value_from_datadict() gets the data from the data dictionaries.
        # Each widget type knows how to retrieve its own data, because some
        # widgets split data over several HTML fields.
        if field.disabled:
            value = self.initial.get(name, field.initial)

class QueryForm(forms.Form): limit = forms.IntegerField(required=False) offset = forms.IntegerField(required=False)

>>> f = QueryForm(data={}, initial={'limit': 20, 'offset': 0})
>>> f.is_bound
True
>>> f.is_valid()
True
>>> f.cleaned_data
{'limit': None, 'offset': None}