expanded fields: add a non-resolvable system record

* introduce a base ghost schema
* closes zenodo/zenodo-rdm#284

invenio_records_resources/references/registry.py

@@ -10,7 +10,7 @@
 
 from abc import ABC, abstractmethod
 
-from invenio_access.permissions import system_process
+from invenio_access.permissions import system_identity, system_user_id
 
 
 class ResolverRegistryBase(ABC):
@@ -101,7 +101,7 @@ def reference_entity(cls, entity, raise_=False):
     @classmethod
     def reference_identity(cls, identity, raise_=False):
         """Create a reference dict for the user behind the given identity."""
-        if system_process in identity.provides:
-            return None
+        if identity == system_identity:
+            return {"user": str(system_user_id)}
 
         return {"user": str(identity.id)}

invenio_records_resources/services/records/results.py

@@ -10,10 +10,12 @@
 """Service results."""
 from abc import ABC, abstractmethod
 
+from invenio_access.permissions import system_user_id
 from invenio_records.dictutils import dict_lookup, dict_merge, dict_set
 
 from ...pagination import Pagination
 from ..base import ServiceItemResult, ServiceListResult
+from .schema import BaseGhostSchema
 
 
 class RecordItem(ServiceItemResult):
@@ -277,6 +279,14 @@ def ghost_record(self, value):
         """
         raise NotImplementedError()
 
+    @abstractmethod
+    def system_record(self):
+        """Return the representation of a system user.
+
+        This is used for the user with id = 'system'.
+        """
+        raise NotImplementedError()
+
     def has(self, service, value):
         """Return true if field has given value for given service."""
         try:
@@ -292,10 +302,12 @@ def add_service_value(self, service, value):
 
     def add_dereferenced_record(self, service, value, resolved_rec):
         """Save the dereferenced record."""
+        # mark the record as a "ghost" or "system" record i.e not resolvable
         if resolved_rec is None:
-            resolved_rec = self.ghost_record({"id": value})
-            # mark the record as a "ghost" record i.e not resolvable
-            resolved_rec["is_ghost"] = True
+            if value == system_user_id:
+                resolved_rec = self.system_record()
+            else:
+                resolved_rec = self.ghost_record({"id": value})
         self._service_values[service][value] = resolved_rec
 
     def get_dereferenced_record(self, service, value):
@@ -389,7 +401,7 @@ def _add_dereferenced_record(service, value, resolved_rec):
             if ghost_values:
                 for value in ghost_values:
                     # set dereferenced record to None. That will trigger eventually
-                    # the field.ghost_recor() to be called
+                    # the field.ghost_record() to be called
                     _add_dereferenced_record(service, value, None)
 
     def resolve(self, identity, hits):

invenio_records_resources/services/records/schema.py

@@ -42,6 +42,12 @@ def clean(self, data, **kwargs):
         return data
 
 
+class BaseGhostSchema(Schema):
+    """Base ghost schema."""
+
+    is_ghost = fields.Constant(True, dump_only=True)
+
+
 class ServiceSchemaWrapper:
     """Schema wrapper that enhances load/dump of wrapped schema.
 

tests/services/test_results_expand.py

@@ -49,6 +49,10 @@ def ghost_record(self, value):
         """Override default."""
         return {}
 
+    def system_record(self):
+        """Override default."""
+        raise NotImplementedError()
+
     def get_value_service(self, value):
         """Override default."""
         if value.get("user"):
@@ -75,6 +79,10 @@ def ghost_record(self, value):
         """Override default."""
         return {}
 
+    def system_record(self):
+        """Override default."""
+        raise NotImplementedError()
+
     def get_value_service(self, value):
         """Override default."""
         return value, mocked_simple_service
@@ -93,6 +101,10 @@ def ghost_record(self, value):
         """Override default."""
         return {}
 
+    def system_record(self):
+        """Override default."""
+        raise NotImplementedError()
+
     def get_value_service(self, value):
         """Override default."""
         return value, mocked_other_service