slapos.recipe.request: Add requestoptional.serialised

It is combination of requestoptional and serialised.

setup.py

@@ -163,6 +163,8 @@ setup(name=name,
           'request.serialised = slapos.recipe.request:RequestJSONEncoded',
           'request.edge = slapos.recipe.request:RequestEdge',
           'requestoptional = slapos.recipe.request:RequestOptional',
+          'requestoptional.serialised = '
+          'slapos.recipe.request:RequestOptionalJSONEncoded',
           're6stnet.registry = slapos.recipe.re6stnet:Recipe',
           'reverseproxy.nginx = slapos.recipe.reverse_proxy_nginx:Recipe',
           'seleniumrunner = slapos.recipe.seleniumrunner:Recipe',

slapos/recipe/request.py

@@ -280,6 +280,11 @@ class RequestJSONEncoded(JSONCodec, Recipe):
   """
   pass
 
+class RequestOptionalJSONEncoded(JSONCodec, RequestOptional):
+  """
+  Like RequestOptional, but serialised with JSONCodec.
+  """
+  pass
 
 
 CONNECTION_PARAMETER_STRING = 'connection-'

slapos/test/recipe/test_request.py

@@ -112,3 +112,10 @@ class RequestJSONEncodedTest(RecipeTestMixin, unittest.TestCase):
   raises = True
   called_partition_parameter_kw = {'_': '{}'}
 
+
+class RequestOptionalJSONEncodedTest(RecipeTestMixin, unittest.TestCase):
+  recipe = request.RequestOptionalJSONEncoded
+  return_value_empty = "{}"
+  return_value = '{"anything": "done"}'
+  raises = False
+  called_partition_parameter_kw = {'_': '{}'}