services: Add support for nested links (#564)

Co-authored-by: Alex Ioannidis <a.ioannidis@cern.ch>

invenio_records_resources/factories/factory.py

@@ -208,6 +208,7 @@ def create_service_class(self):
                 "self": RecordLink("{+api}" + route + "/{id}"),
             },
             "links_search": pagination_links("{+api}" + route + "{?args*}"),
+            "nested_links_item": None,
         }
         if self.service_components:
             config_cls_attributes.update({"components": self.service_components})

invenio_records_resources/services/__init__.py

@@ -8,8 +8,14 @@
 
 """High-level API for wokring with records, files, pids and search."""
 
-
-from .base import ConditionalLink, Link, LinksTemplate, Service, ServiceConfig
+from .base import (
+    ConditionalLink,
+    Link,
+    LinksTemplate,
+    NestedLinks,
+    Service,
+    ServiceConfig,
+)
 from .files import FileLink, FileService, FileServiceConfig
 from .records import (
     RecordIndexerMixin,
@@ -37,4 +43,5 @@
     "ServiceConfig",
     "ServiceSchemaWrapper",
     "RecordIndexerMixin",
+    "NestedLinks",
 )

invenio_records_resources/services/base/__init__.py

@@ -10,7 +10,7 @@
 """Base Service API."""
 
 from .config import ServiceConfig
-from .links import ConditionalLink, Link, LinksTemplate
+from .links import ConditionalLink, Link, LinksTemplate, NestedLinks
 from .results import ServiceItemResult, ServiceListResult
 from .service import Service
 
@@ -22,4 +22,5 @@
     "ServiceConfig",
     "ServiceItemResult",
     "ServiceListResult",
+    "NestedLinks",
 )

invenio_records_resources/services/base/links.py

@@ -8,9 +8,11 @@
 
 """Utility for rendering URI template links."""
 
+import operator
 from copy import deepcopy
 
 from flask import current_app
+from invenio_records.dictutils import dict_lookup
 from uritemplate import URITemplate
 from werkzeug.datastructures import MultiDict
 
@@ -145,3 +147,51 @@ def expand(self, obj, ctx):
             return self._if_link.expand(obj, ctx)
         else:
             return self._else_link.expand(obj, ctx)
+
+
+class NestedLinks:
+    """Base class for generating nested links."""
+
+    def __init__(
+        self,
+        links,
+        key=None,
+        load_key=None,
+        dump_key=None,
+        context_func=None,
+    ):
+        """Initialize NestedLinkGenerator."""
+        self.links = links
+        self.load_key = load_key or key
+        self.dump_key = dump_key or key
+        assert self.load_key and self.dump_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)
+
+    def expand(self, identity, record, data):
+        """Update data with links in each object inside the dictionary."""
+        try:
+            record_data = operator.attrgetter(self.load_key)(record)
+        except AttributeError:
+            return
+        try:
+            output_data = dict_lookup(data, self.dump_key)
+        except KeyError:
+            return
+
+        if isinstance(record_data, (tuple, list)):
+            items_iter = enumerate(record_data)
+        elif isinstance(record_data, dict):
+            items_iter = record_data.items()
+        else:
+            return
+
+        for key, value in items_iter:
+            context = self.context(identity, record, key, value)
+            links = LinksTemplate(self.links, context=context).expand(identity, value)
+            output_data[key]["links"] = links

invenio_records_resources/services/records/results.py

@@ -8,14 +8,14 @@
 # details.
 
 """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):
@@ -31,6 +31,7 @@ def __init__(
         schema=None,
         expandable_fields=None,
         expand=False,
+        nested_links_item=None,
     ):
         """Constructor."""
         self._errors = errors
@@ -41,6 +42,7 @@ def __init__(
         self._schema = schema or service.schema
         self._fields_resolver = FieldsResolver(expandable_fields)
         self._expand = expand
+        self._nested_links_item = nested_links_item
         self._data = None
 
     @property
@@ -78,6 +80,10 @@ def data(self):
         if self._links_tpl:
             self._data["links"] = self.links
 
+        if self._nested_links_item:
+            for link in self._nested_links_item:
+                link.expand(self._identity, self._record, self._data)
+
         if self._expand and self._fields_resolver:
             self._fields_resolver.resolve(self._identity, [self._data])
             fields = self._fields_resolver.expand(self._identity, self._data)
@@ -135,6 +141,7 @@ def __init__(
         params=None,
         links_tpl=None,
         links_item_tpl=None,
+        nested_links_item=None,
         schema=None,
         expandable_fields=None,
         expand=False,
@@ -153,6 +160,7 @@ def __init__(
         self._params = params
         self._links_tpl = links_tpl
         self._links_item_tpl = links_item_tpl
+        self._nested_links_item = nested_links_item
         self._fields_resolver = FieldsResolver(expandable_fields)
         self._expand = expand
 
@@ -201,6 +209,9 @@ def hits(self):
                 projection["links"] = self._links_item_tpl.expand(
                     self._identity, record
                 )
+            if self._nested_links_item:
+                for link in self._nested_links_item:
+                    link.expand(self._identity, record, projection)
 
             yield projection
 

invenio_records_resources/services/records/service.py

@@ -365,6 +365,7 @@ def _create(
             identity,
             record,
             links_tpl=self.links_item_tpl,
+            nested_links_item=getattr(self.config, "nested_links_item", None),
             errors=errors,
             expandable_fields=self.expandable_fields,
             expand=expand,
@@ -387,6 +388,7 @@ def read(self, identity, id_, expand=False, action="read"):
             record,
             links_tpl=self.links_item_tpl,
             expandable_fields=self.expandable_fields,
+            nested_links_item=getattr(self.config, "nested_links_item", None),
             expand=expand,
         )
 
@@ -490,6 +492,7 @@ def update(self, identity, id_, data, revision_id=None, uow=None, expand=False):
             identity,
             record,
             links_tpl=self.links_item_tpl,
+            nested_links_item=getattr(self.config, "nested_links_item", None),
             expandable_fields=self.expandable_fields,
             expand=expand,
         )

tests/mock_module/config.py

@@ -76,6 +76,7 @@ class ServiceConfig(RecordServiceConfig):
     }
 
     links_search = pagination_links("{+api}/mocks{?args*}")
+    nested_links_item = None
 
 
 class ServiceWithFilesConfig(ServiceConfig):