问题
I am trying to provide privacy settings at the model's field level for users. So a user can decide which data he wants to display and which data he wants to hide.
Example:
class Foo(models.Model):
user = models.OneToOneField("auth.User")
telephone_number = models.CharField(blank=True, null=True, max_length=10)
image = models.ImageField(upload_to=get_photo_storage_path, null=True, blank=True)
I want to provide an option to the user to select the fields which he wants to display and which he doesn't. Consider a user doesn't want to display telephone_number, so he should have the option for that.
Which is the best way to approach this?
回答1:
You can create a CommaSeparatedIntegerField field inside the model, and use it to store a list of field_names (Integers that denote a field_name) that the user wants to hide.
You can create a mapping between the field_names and integers as a constant inside your models.py. And check whichever field_names are those the the user had checked.
Example mapping:
FIELD_NAME_CHOICES = (
(1, Foo._meta.get_field('telephone_number')),
(2, Foo._meta.get_field('name')),
.
.
)
Check the following link for reference https://docs.djangoproject.com/en/1.8/ref/models/fields/#commaseparatedintegerfield
回答2:
The very obvious plain stupid solution would be to add a boolean 'show_xxx' for each field, ie:
class Foo(models.Model):
user = models.OneToOneField("auth.User")
telephone_number = models.CharField(blank=True, null=True, max_length=10)
show_telephone_number = models.BooleanField(default=True)
image = models.ImageField(upload_to=get_photo_storage_path, null=True, blank=True)
show_image = models.BooleanField(default=True)
Then in your templates check for the show_xxx field's value:
{% if foo.telephone_number and foo.show_telephone_number %}
<p>Telephone number: {{ foo.telephone_number }}</p>
{% endif %}
etc...
Of course you can also use a single integer field and the old bitmask trick:
class Foo(models.Model):
user = models.OneToOneField("auth.User")
telephone_number = models.CharField(blank=True, null=True, max_length=10)
image = models.ImageField(upload_to=get_photo_storage_path, null=True, blank=True)
foo = models.TextField(blank=True)
perms = models.IntegerField(default=0)
SHOW_TEL = 1
SHOW_IMG = 2
SHOW_FOO = 4
def _show(self, flag):
return (self.perms & flag) == flag
def show_telephone_number(self):
return self._show(self.SHOW_TEL)
def show_image(self):
return self._show(self.SHOW_IMG)
def show_foo(self):
return self._show(self.SHOW_FOO)
but I'm not sure this really is an "optimisation"... And you'll have to manually take care of the checkboxes etc in your edit forms.
回答3:
You could also use a MultiSelectField... The code below is from a Django Snippets, so please no credits to me as I'm only sharing the work of someone else!
class MultiSelectField(models.CharField):
""" Choice values can not contain commas. """
def __init__(self, *args, **kwargs):
self.max_choices = kwargs.pop('max_choices', None)
super(MultiSelectField, self).__init__(*args, **kwargs)
self.max_length = get_max_length(self.choices, self.max_length)
self.validators[0] = MaxValueMultiFieldValidator(self.max_length)
if self.max_choices is not None:
self.validators.append(MaxChoicesValidator(self.max_choices))
@property
def flatchoices(self):
return None
def get_choices_default(self):
return self.get_choices(include_blank=False)
def get_choices_selected(self, arr_choices):
choices_selected = []
for choice_selected in arr_choices:
choices_selected.append(string_type(choice_selected[0]))
return choices_selected
def value_to_string(self, obj):
value = self._get_val_from_obj(obj)
return self.get_prep_value(value)
def validate(self, value, model_instance):
arr_choices = self.get_choices_selected(self.get_choices_default())
for opt_select in value:
if (opt_select not in arr_choices):
if django.VERSION[0] == 1 and django.VERSION[1] >= 6:
raise ValidationError(self.error_messages['invalid_choice'] % {"value": value})
else:
raise ValidationError(self.error_messages['invalid_choice'] % value)
def get_default(self):
default = super(MultiSelectField, self).get_default()
if isinstance(default, (int, long)):
default = string_type(default)
return default
def formfield(self, **kwargs):
defaults = {'required': not self.blank,
'label': capfirst(self.verbose_name),
'help_text': self.help_text,
'choices': self.choices,
'max_length': self.max_length,
'max_choices': self.max_choices}
if self.has_default():
defaults['initial'] = self.get_default()
defaults.update(kwargs)
return MultiSelectFormField(**defaults)
def get_prep_value(self, value):
return '' if value is None else ",".join(value)
def to_python(self, value):
if value:
return value if isinstance(value, list) else value.split(',')
def contribute_to_class(self, cls, name):
super(MultiSelectField, self).contribute_to_class(cls, name)
if self.choices:
def get_list(obj):
fieldname = name
choicedict = dict(self.choices)
display = []
if getattr(obj, fieldname):
for value in getattr(obj, fieldname):
item_display = choicedict.get(value, None)
if item_display is None:
try:
item_display = choicedict.get(int(value), value)
except (ValueError, TypeError):
item_display = value
display.append(string_type(item_display))
return display
def get_display(obj):
return ", ".join(get_list(obj))
setattr(cls, 'get_%s_list' % self.name, get_list)
setattr(cls, 'get_%s_display' % self.name, get_display)
MultiSelectField = add_metaclass(models.SubfieldBase)(MultiSelectField)
来源：https://stackoverflow.com/questions/30499049/best-way-to-implement-privacy-on-each-field-in-model-django