Add custom serializer char/bool fields to accept null and coerce to appropriate type. Update validation for unique constraints so that error messages remain the same as before. Update key used in error response for non-field errors. Should address #791, #794, #809, #812 and #816.

awx/api/fields.py

@@ -0,0 +1,80 @@
+# Copyright (c) 2016 Ansible, Inc.
+# All Rights Reserved.
+
+# Django
+from django.utils.encoding import force_text
+
+# Django REST Framework
+from rest_framework import serializers
+
+__all__ = ['BooleanNullField', 'CharNullField', 'ChoiceNullField', 'EncryptedPasswordField']
+
+
+class NullFieldMixin(object):
+    '''
+    Mixin to prevent shortcutting validation when we want to allow null input,
+    but coerce the resulting value to another type.
+    '''
+
+    def validate_empty_values(self, data):
+        (is_empty_value, data) = super(NullFieldMixin, self).validate_empty_values(data)
+        if is_empty_value and data is None:
+            return (False, data)
+        return (is_empty_value, data)
+
+
+class BooleanNullField(NullFieldMixin, serializers.NullBooleanField):
+    '''
+    Custom boolean field that allows null and empty string as False values.
+    '''
+
+    def to_internal_value(self, data):
+        return bool(super(BooleanNullField, self).to_internal_value(data))
+
+
+class CharNullField(NullFieldMixin, serializers.CharField):
+    '''
+    Custom char field that allows null as input and coerces to an empty string.
+    '''
+
+    def __init__(self, **kwargs):
+        kwargs['allow_null'] = True
+        super(CharNullField, self).__init__(**kwargs)
+
+    def to_internal_value(self, data):
+        return super(CharNullField, self).to_internal_value(data or u'')
+
+
+class ChoiceNullField(NullFieldMixin, serializers.ChoiceField):
+    '''
+    Custom choice field that allows null as input and coerces to an empty string.
+    '''
+
+    def __init__(self, **kwargs):
+        kwargs['allow_null'] = True
+        super(ChoiceNullField, self).__init__(**kwargs)
+
+    def to_internal_value(self, data):
+        return super(ChoiceNullField, self).to_internal_value(data or u'')
+
+
+class EncryptedPasswordField(CharNullField):
+    '''
+    Custom field to handle encrypted password values (on credentials).
+    '''
+
+    def to_internal_value(self, data):
+        value = super(EncryptedPasswordField, self).to_internal_value(data or u'')
+        # If user submits a value starting with $encrypted$, ignore it.
+        if force_text(value).startswith('$encrypted$'):
+            raise serializers.SkipField
+        return value
+
+    def to_representation(self, value):
+        # Replace the actual encrypted value with the string $encrypted$.
+        if force_text(value).startswith('$encrypted$'):
+             return '$encrypted$'
+        return value
+
+    
+