[rest] Fix GET /rest/persistence/items?serviceid=... returns null entries

When querying Items from InMemory, I noticed that the return is an array of null values.
This was caused by a silent serialization failure, where Gson serialized anonymous implementations of PersistenceItemInfo to null due to missing fields.
Serialization was error-prone in general, as the serialization results depended on the field names of PersistenceItemInfo implementations from the persistence services.

This PR fixes that issue by introducing a proper DTO and mapping to that.
It also adds unit tests.

Signed-off-by: Florian Hotze <dev@florianhotze.com>

Author: florian-h05

bundles/org.openhab.core.io.rest.core/src/main/java/org/openhab/core/io/rest/core/internal/persistence/PersistenceResource.java

@@ -17,7 +17,6 @@
 import java.time.LocalDateTime;
 import java.time.ZonedDateTime;
 import java.util.ArrayList;
-import java.util.Date;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Locale;
@@ -70,6 +69,7 @@
 import org.openhab.core.persistence.PersistenceServiceRegistry;
 import org.openhab.core.persistence.QueryablePersistenceService;
 import org.openhab.core.persistence.dto.ItemHistoryDTO;
+import org.openhab.core.persistence.dto.PersistenceItemInfoDTO;
 import org.openhab.core.persistence.dto.PersistenceServiceConfigurationDTO;
 import org.openhab.core.persistence.dto.PersistenceServiceDTO;
 import org.openhab.core.persistence.dto.PersistenceStrategyDTO;
@@ -620,6 +620,18 @@ private List<PersistenceServiceDTO> getPersistenceServiceList(Locale locale) {
         return dtoList;
     }
 
+    protected Set<PersistenceItemInfoDTO> getServiceItemList(QueryablePersistenceService service,
+            Map<String, String> aliases) {
+        return service.getItemInfo().stream().map(info -> {
+            String alias = aliases.get(info.getName());
+            if (alias != null) {
+                return new PersistenceItemInfoDTO(info, alias);
+            } else {
+                return new PersistenceItemInfoDTO(info);
+            }
+        }).collect(Collectors.toSet());
+    }
+
     private Response getServiceItemList(@Nullable String serviceId) {
         // If serviceId is null, then use the default service
         PersistenceService service;
@@ -647,35 +659,7 @@ private Response getServiceItemList(@Nullable String serviceId) {
 
         PersistenceServiceConfiguration config = persistenceServiceConfigurationRegistry.get(effectiveServiceId);
         Map<String, String> aliases = config != null ? config.getAliases() : Map.of();
-        Set<PersistenceItemInfo> itemInfo = qService.getItemInfo().stream().map(info -> {
-            String alias = aliases.get(info.getName());
-            if (alias != null) {
-                return new PersistenceItemInfo() {
-
-                    @Override
-                    public String getName() {
-                        return alias;
-                    }
-
-                    @Override
-                    public @Nullable Integer getCount() {
-                        return info.getCount();
-                    }
-
-                    @Override
-                    public @Nullable Date getEarliest() {
-                        return info.getEarliest();
-                    }
-
-                    @Override
-                    public @Nullable Date getLatest() {
-                        return info.getLatest();
-                    }
-                };
-            } else {
-                return info;
-            }
-        }).collect(Collectors.toSet());
+        Set<PersistenceItemInfoDTO> itemInfo = getServiceItemList(qService, aliases);
         return JSONResponse.createResponse(Status.OK, itemInfo, "");
     }
 

bundles/org.openhab.core.io.rest.core/src/test/java/org/openhab/core/io/rest/core/internal/persistence/PersistenceResourceTest.java

@@ -23,11 +23,15 @@
 import java.time.ZoneId;
 import java.time.ZonedDateTime;
 import java.util.ArrayList;
+import java.util.Date;
 import java.util.List;
+import java.util.Map;
+import java.util.Set;
 
 import javax.ws.rs.core.HttpHeaders;
 
 import org.eclipse.jdt.annotation.NonNullByDefault;
+import org.eclipse.jdt.annotation.Nullable;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
@@ -46,9 +50,11 @@
 import org.openhab.core.library.types.OnOffType;
 import org.openhab.core.persistence.HistoricItem;
 import org.openhab.core.persistence.ModifiablePersistenceService;
+import org.openhab.core.persistence.PersistenceItemInfo;
 import org.openhab.core.persistence.PersistenceServiceRegistry;
 import org.openhab.core.persistence.dto.ItemHistoryDTO;
 import org.openhab.core.persistence.dto.ItemHistoryDTO.HistoryDataBean;
+import org.openhab.core.persistence.dto.PersistenceItemInfoDTO;
 import org.openhab.core.persistence.internal.PersistenceManagerImpl;
 import org.openhab.core.persistence.registry.ManagedPersistenceServiceConfigurationProvider;
 import org.openhab.core.persistence.registry.PersistenceServiceConfigurationRegistry;
@@ -67,6 +73,7 @@
 public class PersistenceResourceTest {
 
     private static final String PERSISTENCE_SERVICE_ID = "TestServiceID";
+    private static final String ITEM_NAME = "Test";
 
     private @NonNullByDefault({}) PersistenceResource pResource;
     private @NonNullByDefault({}) List<HistoricItem> items;
@@ -110,12 +117,33 @@ public State getState() {
 
                 @Override
                 public String getName() {
-                    return "Test";
+                    return ITEM_NAME;
                 }
             });
         }
 
         when(pServiceMock.query(any(), any())).thenReturn(items);
+        when(pServiceMock.getItemInfo()).thenReturn(Set.of(new PersistenceItemInfo() {
+            @Override
+            public String getName() {
+                return ITEM_NAME;
+            }
+
+            @Override
+            public @Nullable Integer getCount() {
+                return 5;
+            }
+
+            @Override
+            public @Nullable Date getEarliest() {
+                return null;
+            }
+
+            @Override
+            public @Nullable Date getLatest() {
+                return null;
+            }
+        }));
 
         when(persistenceServiceRegistryMock.get(PERSISTENCE_SERVICE_ID)).thenReturn(pServiceMock);
         when(timeZoneProviderMock.getTimeZone()).thenReturn(ZoneId.systemDefault());
@@ -183,6 +211,28 @@ public void testGetPersistenceItemDataWithItemStateUndefined() throws ItemNotFou
         assertThat(dto.data, hasSize(5));
     }
 
+    @Test
+    public void testGetPersistenceServiceItems() {
+        Set<PersistenceItemInfoDTO> info = pResource.getServiceItemList(pServiceMock, Map.of());
+
+        assertEquals(1, info.size());
+        PersistenceItemInfoDTO dto = info.iterator().next();
+        assertEquals(ITEM_NAME, dto.name);
+        assertEquals(5, dto.count);
+        assertNull(dto.earliest);
+        assertNull(dto.latest);
+    }
+
+    @Test
+    public void testGetPersistenceServiceItemsWithAlias() {
+        final String alias = "TestAlias";
+        Set<PersistenceItemInfoDTO> info = pResource.getServiceItemList(pServiceMock, Map.of(ITEM_NAME, alias));
+
+        assertEquals(1, info.size());
+        PersistenceItemInfoDTO dto = info.iterator().next();
+        assertEquals(alias, dto.name);
+    }
+
     @Test
     public void testGetPersistenceItemDataWithItemStateNull() throws ItemNotFoundException {
         when(itemRegistryMock.getItem("testItem")).thenReturn(itemMock);

bundles/org.openhab.core.persistence/src/main/java/org/openhab/core/persistence/dto/PersistenceItemInfoDTO.java

@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2010-2026 Contributors to the openHAB project
+ *
+ * See the NOTICE file(s) distributed with this work for additional
+ * information.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
+package org.openhab.core.persistence.dto;
+
+import java.util.Date;
+
+import org.eclipse.jdt.annotation.NonNullByDefault;
+import org.eclipse.jdt.annotation.Nullable;
+import org.openhab.core.persistence.PersistenceItemInfo;
+
+import io.swagger.v3.oas.annotations.media.Schema;
+
+/**
+ * The {@link PersistenceItemInfoDTO} is used for transferring {@link org.openhab.core.persistence.PersistenceItemInfo}
+ * data.
+ *
+ * @author Florian Hotze - Initial contribution
+ */
+@Schema(name = "PersistenceItemInfo")
+@NonNullByDefault
+public class PersistenceItemInfoDTO {
+    public @NonNullByDefault({}) String name;
+    public @Nullable Integer count;
+    public @Nullable Date earliest;
+    public @Nullable Date latest;
+
+    // do not remove - needed by GSON
+    public PersistenceItemInfoDTO() {
+    }
+
+    public PersistenceItemInfoDTO(PersistenceItemInfo info) {
+        this(info, info.getName());
+    }
+
+    public PersistenceItemInfoDTO(PersistenceItemInfo info, String alias) {
+        this.name = alias;
+        this.count = info.getCount();
+        this.earliest = info.getEarliest();
+        this.latest = info.getLatest();
+    }
+}