djommon: add JSON serializer supporting natural primary keys

entrouvert/djommon/serializers/json.py

@@ -0,0 +1,37 @@
+import json
+
+from django.utils import six
+from django.core.serializers.json import Serializer as JSONSerializer
+from django.core.serializers.python import Deserializer as \
+    PythonDeserializer, _get_model
+from django.core.serializers.base import DeserializationError
+
+class Serializer(JSONSerializer):
+    def get_dump_object(self, obj):
+        d = super(Serializer, self).get_dump_object(obj)
+        if self.use_natural_keys and hasattr(obj, 'natural_key'):
+            d['pk'] = obj.natural_key()
+        return d
+
+def Deserializer(stream_or_string, **options):
+    """
+    Deserialize a stream or string of JSON data.
+    """
+    if not isinstance(stream_or_string, (bytes, six.string_types)):
+        stream_or_string = stream_or_string.read()
+    if isinstance(stream_or_string, bytes):
+        stream_or_string = stream_or_string.decode('utf-8')
+    try:
+        objects = json.loads(stream_or_string)
+        for obj in objects:
+            Model = _get_model(obj['model'])
+            if isinstance(obj['pk'], (tuple, list)):
+                o = Model.objects.get_by_natural_key(*obj['pk'])
+                obj['pk'] = o.pk
+        for obj in PythonDeserializer(objects, **options):
+            yield obj
+    except GeneratorExit:
+        raise
+    except Exception as e:
+        # Map to deserializer error
+        six.reraise(DeserializationError, DeserializationError(e), sys.exc_info()[2])