Fixes #111

Changelog

@@ -1,3 +1,6 @@
+Version 1.0.3 unreleased
+ * add support for choices on string properites.
+
 Version 1.0.2 2014-10-21
  * updated documentation
  * sphinx and rtd

doc/source/properties.rst

@@ -20,6 +20,24 @@ You may provide arguments using a wrapper function or lambda::
 
         my_datetime = DateTimeProperty(default=lambda: datetime.now(pytz.utc))
 
+Choices
+=======
+
+You can specify a list of valid values for a `StringProperty` using choices::
+
+    class Person(StructuredNode):
+        SEXES = (
+            ('M', 'Male'),
+            ('F', 'Female')
+        )
+        sex = StringProperty(required=True, choices=SEXES)
+
+    tim = Person(sex='M').save()
+    tim.sex # M
+    tim.get_sex_display() # 'Male'
+
+The value will be checked both when saved and loaded from neo4j.
+
 Dates and times
 ===============
 

neomodel/properties.py

@@ -12,6 +12,10 @@
 if sys.version_info >= (3, 0):
     unicode = lambda x: str(x)
 
+def display_for(key):
+    def display_choice(self):
+        return getattr(self.__class__, key).choice_map[getattr(self, key)]
+    return display_choice
 
 class PropertyManager(object):
     """Common stuff for handling properties in nodes and relationships"""
@@ -27,6 +31,10 @@ def __init__(self, *args, **kwargs):
             else:
                 setattr(self, key, kwargs[key])
 
+            if hasattr(val, 'choices') and getattr(val, 'choices'):
+                setattr(self, 'get_{}_display'.format(key),
+                        types.MethodType(display_for(key), self))
+
             if key in kwargs:
                 del kwargs[key]
 
@@ -97,7 +105,7 @@ def validator(self, value, obj=None):
 
 
 class Property(object):
-    def __init__(self, unique_index=False, index=False, required=False, default=None):
+    def __init__(self, unique_index=False, index=False, required=False, default=None, **kwargs):
         if default and required:
             raise Exception("required and default are mutually exclusive")
 
@@ -125,12 +133,30 @@ def is_indexed(self):
 
 
 class StringProperty(Property):
+    def __init__(self, **kwargs):
+        super(StringProperty, self).__init__(**kwargs)
+        self.choices = kwargs.get('choices', None)
+
+        if self.choices:
+            if not isinstance(self.choices, tuple):
+                raise ValueError("Choices must be a tuple of tuples")
+
+            self.choice_map = dict(self.choices)
+
     @validator
     def inflate(self, value):
+        if self.choices and value not in self.choice_map:
+            raise ValueError("Invalid choice {} not in {}".format(
+                value, ', '.join(self.choice_map.keys())))
+
         return unicode(value)
 
     @validator
     def deflate(self, value):
+        if self.choices and value not in self.choice_map:
+            raise ValueError("Invalid choice {} not in {}".format(
+                value, ','.join(self.choice_map.keys())))
+
         return unicode(value)
 
     def default_value(self):

test/test_properties.py

@@ -10,6 +10,23 @@ class FooBar(object):
     pass
 
 
+def test_string_property_w_choice():
+    class TestChoices(StructuredNode):
+        SEXES = (('M', 'Male'), ('F', 'Female'))
+        sex = StringProperty(required=True, choices=SEXES)
+
+    try:
+        TestChoices(sex='Z').save()
+    except DeflateError as e:
+        assert True
+        assert str(e).index('choice')
+    else:
+        assert False
+
+    node = TestChoices(sex='M').save()
+    assert node.get_sex_display() == 'Male'
+
+
 def test_deflate_inflate():
     prop = IntegerProperty(required=True)
     prop.name = 'age'