services: add nested links context function

invenio_records_resources/services/base/links.py

@@ -12,7 +12,7 @@
 from copy import deepcopy
 
 from flask import current_app
-from invenio_records.dictutils import dict_lookup, dict_set
+from invenio_records.dictutils import dict_lookup
 from uritemplate import URITemplate
 from werkzeug.datastructures import MultiDict
 
@@ -97,20 +97,37 @@ def expand(self, identity, obj):
 class NestedLinkGeneratorBase:
     """Base class for generating nested links."""
 
-    def __init__(self, tpl, key):
+    def __init__(self, links, key, context_func=None):
         """Initialize NestedLinkGenerator."""
-        self.tpl = tpl
+        self.links = links
         self.key = key
+        self.context_func = context_func
+
+    def context(self, identity, record, key, value):
+        """Get the context for the links."""
+        if not self.context_func:
+            return {}
+        return self.context_func(identity, record, key, value)
 
 
 class NestedDictLinkGenerator(NestedLinkGeneratorBase):
     """Nested link generator for nested dictionaries."""
 
     def update(self, identity, data, record):
         """Update data with links in each object inside the dictionary."""
-        for key, rf in operator.attrgetter(self.key)(record).items():
-            links = LinksTemplate(self.tpl, context={"id": rf.id}).expand(identity, rf)
-            dict_lookup(data, self.key)[key]["links"] = links
+        try:
+            nested_data = operator.attrgetter(self.key)(record)
+            if not isinstance(nested_data, dict):
+                return
+            for key, value in nested_data.items():
+                context = self.context(identity, record, key, value)
+                links = LinksTemplate(self.links, context=context).expand(
+                    identity,
+                    value,
+                )
+                dict_lookup(data, self.key)[key]["links"] = links
+        except AttributeError:
+            pass
 
 
 class Link:

invenio_records_resources/services/records/service.py

@@ -383,7 +383,7 @@ def read(self, identity, id_, expand=False, action="read"):
             record,
             links_tpl=self.links_item_tpl,
             expandable_fields=self.expandable_fields,
-            nested_links=self.config.nested_links,
+            nested_links=getattr(self.config, "nested_links", None),
             expand=expand,
         )