Fixes tiny documentation error. Adds possibility to add custom validation methods to fields, e. g.:

class Customer(Document):
        country = StringField(validation=lambda value: value in ['DE', 'AT', 'CH'])

Replaced some str() with unicode() for i18n reasons.

docs/guide/defining-documents.rst

@@ -22,7 +22,7 @@ objects** as class attributes to the document class::
     
     class Page(Document):
         title = StringField(max_length=200, required=True)
-        date_modified = DateTimeField(default=datetime.now)
+        date_modified = DateTimeField(default=datetime.datetime.now)
 
 Fields
 ======

mongoengine/base.py

@@ -24,7 +24,7 @@ class BaseField(object):
     _index_with_types = True
     
     def __init__(self, db_field=None, name=None, required=False, default=None, 
-                 unique=False, unique_with=None, primary_key=False):
+                 unique=False, unique_with=None, primary_key=False, validation=None):
         self.db_field = (db_field or name) if not primary_key else '_id'
         if name:
             import warnings
@@ -36,6 +36,7 @@ class BaseField(object):
         self.unique = bool(unique or unique_with)
         self.unique_with = unique_with
         self.primary_key = primary_key
+        self.validation = validation
 
     def __get__(self, instance, owner):
         """Descriptor for retrieving a value from a field in a document. Do 
@@ -77,8 +78,8 @@ class BaseField(object):
     def validate(self, value):
         """Perform validation on a value.
         """
-        pass
+        if self.validation is not None and not self.validation(value):
-
+            raise ValidationError('Value does not match custom validation method.')
 
 class ObjectIdField(BaseField):
     """An field wrapper around MongoDB's ObjectIds.
@@ -91,10 +92,10 @@ class ObjectIdField(BaseField):
     def to_mongo(self, value):
         if not isinstance(value, pymongo.objectid.ObjectId):
             try:
-                return pymongo.objectid.ObjectId(str(value))
+                return pymongo.objectid.ObjectId(unicode(value))
             except Exception, e:
                 #e.message attribute has been deprecated since Python 2.6
-                raise ValidationError(str(e))
+                raise ValidationError(unicode(e))
         return value
 
     def prepare_query_value(self, op, value):
@@ -102,7 +103,7 @@ class ObjectIdField(BaseField):
 
     def validate(self, value):
         try:
-            pymongo.objectid.ObjectId(str(value))
+            pymongo.objectid.ObjectId(unicode(value))
         except:
             raise ValidationError('Invalid Object ID')
 
@@ -402,7 +403,7 @@ class BaseDocument(object):
         # class if unavailable
         class_name = son.get(u'_cls', cls._class_name)
 
-        data = dict((str(key), value) for key, value in son.items())
+        data = dict((unicode(key), value) for key, value in son.items())
 
         if '_types' in data:
             del data['_types']

mongoengine/fields.py

@@ -40,6 +40,8 @@ class StringField(BaseField):
             message = 'String value did not match validation regex'
             raise ValidationError(message)
         
+        super(StringField, self).validate(value)
+
     def lookup_member(self, member_name):
         return None
 
@@ -94,6 +96,8 @@ class URLField(StringField):
                 message = 'This URL appears to be a broken link: %s' % e
                 raise ValidationError(message)
         
+        super(URLField, self).validate(value)
+
 class EmailField(StringField):
     """A field that validates input as an E-Mail-Address.
     """
@@ -131,6 +135,7 @@ class IntField(BaseField):
         if self.max_value is not None and value > self.max_value:
             raise ValidationError('Integer value is too large')
         
+        super(IntField, self).validate(value)
 
 class FloatField(BaseField):
     """An floating point number field.
@@ -154,6 +159,8 @@ class FloatField(BaseField):
         if self.max_value is not None and value > self.max_value:
             raise ValidationError('Float value is too large')
         
+        super(FloatField, self).validate(value)
+
 
 class DecimalField(BaseField):
     """A fixed-point decimal number field.
@@ -188,6 +195,8 @@ class DecimalField(BaseField):
         if self.max_value is not None and value > self.max_value:
             raise ValidationError('Decimal value is too large')
         
+        super(DecimalField, self).validate(value)
+
 
 class BooleanField(BaseField):
     """A boolean field type.
@@ -201,6 +210,8 @@ class BooleanField(BaseField):
     def validate(self, value):
         assert isinstance(value, bool)
         
+        super(BooleanField, self).validate(value)
+
 
 class DateTimeField(BaseField):
     """A datetime field.
@@ -209,6 +220,8 @@ class DateTimeField(BaseField):
     def validate(self, value):
         assert isinstance(value, datetime.datetime)
         
+        super(DateTimeField, self).validate(value)
+
 
 class EmbeddedDocumentField(BaseField):
     """An embedded document field. Only valid values are subclasses of
@@ -240,6 +253,8 @@ class EmbeddedDocumentField(BaseField):
                                   'provided to an EmbeddedDocumentField')
         self.document.validate(value)
         
+        super(EmbeddedDocumentField, self).validate(value)
+
     def lookup_member(self, member_name):
         return self.document._fields.get(member_name)
 
@@ -316,6 +331,8 @@ class ListField(BaseField):
         except Exception, err:
             raise ValidationError('Invalid ListField item (%s)' % str(err))
         
+        super(ListField, self).validate(value)
+
     def prepare_query_value(self, op, value):
         if op in ('set', 'unset'):
             return [self.field.to_mongo(v) for v in value]
@@ -360,6 +377,8 @@ class DictField(BaseField):
             raise ValidationError('Invalid dictionary key name - keys may not '
                                   'contain "." or "$" characters')
         
+        super(DictField, self).validate(value)
+
     def lookup_member(self, member_name):
         return BaseField(db_field=member_name)
 
@@ -375,6 +394,8 @@ class GeoLocationField(DictField):
         if len(value) <> 2:
             raise ValidationError('GeoLocationField must have exactly two elements (x, y)')
         
+        super(GeoLocationField, self).validate(value)
+    
     def to_mongo(self, value):
         return {'x': value[0], 'y': value[1]}
     
@@ -444,6 +465,8 @@ class ReferenceField(BaseField):
     def validate(self, value):
         assert isinstance(value, (self.document_type, pymongo.dbref.DBRef))
         
+        super(ReferenceField, self).validate(value)
+
     def lookup_member(self, member_name):
         return self.document_type._fields.get(member_name)
 
@@ -506,10 +529,12 @@ class BinaryField(BaseField):
         return pymongo.binary.Binary(value)
 
     def to_python(self, value):
-        return str(value)
+        return unicode(value)
 
     def validate(self, value):
         assert isinstance(value, str)
 
         if self.max_bytes is not None and len(value) > self.max_bytes:
             raise ValidationError('Binary value is too long')
+        
+        super(BinaryField, self).validate(value)

mongoengine/queryset.py

@@ -123,7 +123,7 @@ class Q(object):
 
         # Comparing two ObjectIds in Javascript doesn't work..
         if isinstance(value, pymongo.objectid.ObjectId):
-            value = str(value)
+            value = unicode(value)
 
         # Perform the substitution
         operation_js = op_js % {
@@ -497,13 +497,13 @@ class QuerySet(object):
         map_f_scope = {}
         if isinstance(map_f, pymongo.code.Code):
             map_f_scope = map_f.scope
-            map_f = str(map_f)
+            map_f = unicode(map_f)
         map_f = pymongo.code.Code(self._sub_js_fields(map_f), map_f_scope)
 
         reduce_f_scope = {}
         if isinstance(reduce_f, pymongo.code.Code):
             reduce_f_scope = reduce_f.scope
-            reduce_f = str(reduce_f)
+            reduce_f = unicode(reduce_f)
         reduce_f_code = self._sub_js_fields(reduce_f)
         reduce_f = pymongo.code.Code(reduce_f_code, reduce_f_scope)
 
@@ -513,7 +513,7 @@ class QuerySet(object):
             finalize_f_scope = {}
             if isinstance(finalize_f, pymongo.code.Code):
                 finalize_f_scope = finalize_f.scope
-                finalize_f = str(finalize_f)
+                finalize_f = unicode(finalize_f)
             finalize_f_code = self._sub_js_fields(finalize_f)
             finalize_f = pymongo.code.Code(finalize_f_code, finalize_f_scope)
             mr_args['finalize'] = finalize_f
@@ -736,7 +736,7 @@ class QuerySet(object):
                 # Older versions of PyMongo don't support 'multi'
                 self._collection.update(self._query, update, safe=safe_update)
         except pymongo.errors.OperationFailure, e:
-            raise OperationError('Update failed [%s]' % str(e))
+            raise OperationError(u'Update failed [%s]' % unicode(e))
 
     def __iter__(self):
         return self
@@ -752,9 +752,9 @@ class QuerySet(object):
             field_name = match.group(1).split('.')
             fields = QuerySet._lookup_field(self._document, field_name)
             # Substitute the correct name for the field into the javascript
-            return '["%s"]' % fields[-1].db_field
+            return u'["%s"]' % fields[-1].db_field
 
-        return re.sub('\[\s*~([A-z_][A-z_0-9.]+?)\s*\]', field_sub, code)
+        return re.sub(u'\[\s*~([A-z_][A-z_0-9.]+?)\s*\]', field_sub, code)
 
     def exec_js(self, code, *fields, **options):
         """Execute a Javascript function on the server. A list of fields may be