floof/forms/validators/unique.py

   1 from formencode import *
   2 from formencode import validators
   3 import pylons
   4
   5 _ = validators._ # dummy translation string
   6
   7 # Custom schemas
   8
   9 class FilteringSchema(Schema):
  10     "Schema with extra fields filtered by default"
  11     filter_extra_fields = True
  12     allow_extra_fields = True
  13
  14 # Model-based validators
  15
  16 class Unique(validators.FancyValidator):
  17
  18     """
  19     Checks if given value is unique to the model.Will check the state: if state object
  20     is the same as the instance, or the state contains a property with the same name
  21     as the context name. For example:
  22
  23     validator = validators.Unique(model.NewsItem, "title", context_name="news_item")
  24
  25     This will check if there is an existing instance with the same "title". If there
  26     is a matching instance, will check if the state passed into the validator is the
  27     same instance, or if the state contains a property "news_item" which is the same
  28     instance.
  29     """
  30
  31     __unpackargs__ = ('model', 'attr', "model_name", "context_name", "attribute_name")
  32     messages = {
  33         'notUnique' : _("%(modelName)s already exists with this %(attrName)s"),
  34     }
  35
  36     model_name = "Item"
  37     attribute_name = None
  38     context_name = None
  39
  40     def validate_python(self, value, state):
  41         instance = self.model.get_by(**{self.attr : value})
  42         if instance:
  43             context_name = self.context_name or self.model.__name__.lower()
  44             if state != instance and \
  45                 getattr(state, context_name, None) != instance:
  46                 attr_name = self.attribute_name or self.attr
  47                 raise Invalid(self.message('notUnique', state,
  48                                            modelName=self.model_name,
  49                                            attrName=attr_name),
  50                               value, state)
  51
  52 validators.Unique = Unique