Class CharField

django/forms/fields.py:276–309

class CharField(Field):
    def __init__(
        self, *, max_length=None, min_length=None, strip=True, empty_value="", **kwargs
    ):
        self.max_length = max_length
        self.min_length = min_length
        self.strip = strip
        self.empty_value = empty_value
        super().__init__(**kwargs)
        if min_length is not None:
            self.validators.append(validators.MinLengthValidator(int(min_length)))
        if max_length is not None:
            self.validators.append(validators.MaxLengthValidator(int(max_length)))
        self.validators.append(validators.ProhibitNullCharactersValidator())

    def to_python(self, value):
        """Return a string."""
        if value not in self.empty_values:
            value = str(value)
            if self.strip:
                value = value.strip()
        if value in self.empty_values:
            return self.empty_value
        return value

    def widget_attrs(self, widget):
        attrs = super().widget_attrs(widget)
        if self.max_length is not None and not widget.is_hidden:
            # The HTML attribute is maxlength, not max_length.
            attrs["maxlength"] = str(self.max_length)
        if self.min_length is not None and not widget.is_hidden:
            # The HTML attribute is minlength, not min_length.
            attrs["minlength"] = str(self.min_length)
        return attrs


class IntegerField(Field):