allow put and get to work with compressed blob properties (#175)

google/cloud/ndb/model.py

@@ -251,6 +251,7 @@ class Person(Model):
 import inspect
 import json
 import pickle
+import six
 import zlib
 
 from google.cloud.datastore import entity as ds_entity_module
@@ -2188,15 +2189,13 @@ def _validate(self, value):
         return float(value)
 
 
-class _CompressedValue:
+class _CompressedValue(six.binary_type):
     """A marker object wrapping compressed values.
 
     Args:
         z_val (bytes): A return value of ``zlib.compress``.
     """
 
-    __slots__ = ("z_val",)
-
     def __init__(self, z_val):
         self.z_val = z_val
 
@@ -2355,6 +2354,9 @@ def _from_base_type(self, value):
             indicate that the value didn't need to be unwrapped and
             decompressed.
         """
+        if self._compressed and not isinstance(value, _CompressedValue):
+            value = _CompressedValue(value)
+
         if isinstance(value, _CompressedValue):
             return zlib.decompress(value.z_val)
 

tests/system/test_crud.py

@@ -285,6 +285,36 @@ class SomeKind(ndb.Model):
     dispose_of(key._key)
 
 
+@pytest.mark.usefixtures("client_context")
+def test_compressed_json_property(dispose_of, ds_client):
+    class SomeKind(ndb.Model):
+        foo = ndb.JsonProperty(compressed=True)
+
+    foo = {str(i): i for i in range(500)}
+    entity = SomeKind(foo=foo)
+    key = entity.put()
+
+    retrieved = key.get()
+    assert retrieved.foo == foo
+
+    dispose_of(key._key)
+
+
+@pytest.mark.usefixtures("client_context")
+def test_compressed_blob_property(dispose_of, ds_client):
+    class SomeKind(ndb.Model):
+        foo = ndb.BlobProperty(compressed=True)
+
+    foo = b"abc" * 100
+    entity = SomeKind(foo=foo)
+    key = entity.put()
+
+    retrieved = key.get()
+    assert retrieved.foo == foo
+
+    dispose_of(key._key)
+
+
 @pytest.mark.usefixtures("client_context")
 def test_large_pickle_property(dispose_of, ds_client):
     class SomeKind(ndb.Model):

tests/unit/test_model.py

@@ -1677,6 +1677,16 @@ def test__from_base_type():
 
         assert converted == original
 
+    @staticmethod
+    def test__from_base_type_no_compressed_value():
+        prop = model.BlobProperty(name="blob")
+        original = b"abc" * 10
+        value = zlib.compress(original)
+        prop._compressed = True
+        converted = prop._from_base_type(value)
+
+        assert converted == original
+
     @staticmethod
     def test__from_base_type_no_convert():
         prop = model.BlobProperty(name="blob")