refactor: APIs returns ghost users when user is deleted (#3373)

#### What type of PR is this?
/kind improvement
/area core
/milestone 2.3.x

#### What this PR does / why we need it:
用户被删除时关联到的用户返回 ghost 用户信息

#### Which issue(s) this PR fixes:

Fixes #3356

#### Special notes for your reviewer:
/cc @halo-dev/sig-halo 
#### Does this PR introduce a user-facing change?
```release-note
用户被删除时关联到的用户返回 ghost 用户信息
```

src/main/java/run/halo/app/content/comment/CommentServiceImpl.java

@@ -15,6 +15,7 @@ import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 import run.halo.app.core.extension.User;
 import run.halo.app.core.extension.content.Comment;
+import run.halo.app.core.extension.service.UserService;
 import run.halo.app.extension.Extension;
 import run.halo.app.extension.ListResult;
 import run.halo.app.extension.ReactiveExtensionClient;
@@ -33,14 +34,16 @@ import run.halo.app.plugin.ExtensionComponentsFinder;
 public class CommentServiceImpl implements CommentService {
 
     private final ReactiveExtensionClient client;
+    private final UserService userService;
     private final ExtensionComponentsFinder extensionComponentsFinder;
 
     private final SystemConfigurableEnvironmentFetcher environmentFetcher;
 
     public CommentServiceImpl(ReactiveExtensionClient client,
-        ExtensionComponentsFinder extensionComponentsFinder,
+        UserService userService, ExtensionComponentsFinder extensionComponentsFinder,
         SystemConfigurableEnvironmentFetcher environmentFetcher) {
         this.client = client;
+        this.userService = userService;
         this.extensionComponentsFinder = extensionComponentsFinder;
         this.environmentFetcher = environmentFetcher;
     }
@@ -153,9 +156,8 @@ public class CommentServiceImpl implements CommentService {
 
     private Mono<OwnerInfo> getCommentOwnerInfo(Comment.CommentOwner owner) {
         if (User.KIND.equals(owner.getKind())) {
-            return client.fetch(User.class, owner.getName())
+            return userService.getUserOrGhost(owner.getName())
-                .map(OwnerInfo::from)
+                .map(OwnerInfo::from);
-                .switchIfEmpty(Mono.just(OwnerInfo.ghostUser()));
         }
         if (Comment.CommentOwner.KIND_EMAIL.equals(owner.getKind())) {
             return Mono.just(OwnerInfo.from(owner));

src/main/java/run/halo/app/content/comment/OwnerInfo.java

@@ -2,7 +2,6 @@ package run.halo.app.content.comment;
 
 import lombok.Builder;
 import lombok.Value;
-import org.apache.commons.lang3.StringUtils;
 import run.halo.app.core.extension.User;
 import run.halo.app.core.extension.content.Comment;
 
@@ -60,18 +59,4 @@ public class OwnerInfo {
             .displayName(user.getSpec().getDisplayName())
             .build();
     }
-
-    /**
-     * Obtain a ghost owner info when user not found.
-     *
-     * @return a ghost user if user not found.
-     */
-    public static OwnerInfo ghostUser() {
-        return OwnerInfo.builder()
-            .kind(User.KIND)
-            .name("ghost")
-            .email(StringUtils.EMPTY)
-            .displayName("Ghost")
-            .build();
-    }
 }

src/main/java/run/halo/app/content/comment/ReplyServiceImpl.java

@@ -5,6 +5,7 @@ import static run.halo.app.extension.router.selector.SelectorUtil.labelAndFieldS
 import java.time.Instant;
 import java.util.function.Function;
 import java.util.function.Predicate;
+import lombok.RequiredArgsConstructor;
 import org.apache.commons.lang3.BooleanUtils;
 import org.springframework.security.core.context.ReactiveSecurityContextHolder;
 import org.springframework.stereotype.Service;
@@ -13,6 +14,7 @@ import reactor.core.publisher.Mono;
 import run.halo.app.core.extension.User;
 import run.halo.app.core.extension.content.Comment;
 import run.halo.app.core.extension.content.Reply;
+import run.halo.app.core.extension.service.UserService;
 import run.halo.app.extension.Extension;
 import run.halo.app.extension.ListResult;
 import run.halo.app.extension.ReactiveExtensionClient;
@@ -26,16 +28,12 @@ import run.halo.app.infra.exception.AccessDeniedException;
  * @since 2.0.0
  */
 @Service
+@RequiredArgsConstructor
 public class ReplyServiceImpl implements ReplyService {
 
     private final ReactiveExtensionClient client;
     private final SystemConfigurableEnvironmentFetcher environmentFetcher;
-
+    private final UserService userService;
-    public ReplyServiceImpl(ReactiveExtensionClient client,
-        SystemConfigurableEnvironmentFetcher environmentFetcher) {
-        this.client = client;
-        this.environmentFetcher = environmentFetcher;
-    }
 
     @Override
     public Mono<Reply> create(String commentName, Reply reply) {
@@ -132,9 +130,8 @@ public class ReplyServiceImpl implements ReplyService {
     private Mono<OwnerInfo> getOwnerInfo(Reply reply) {
         Comment.CommentOwner owner = reply.getSpec().getOwner();
         if (User.KIND.equals(owner.getKind())) {
-            return client.fetch(User.class, owner.getName())
+            return userService.getUserOrGhost(owner.getName())
-                .map(OwnerInfo::from)
+                .map(OwnerInfo::from);
-                .switchIfEmpty(Mono.just(OwnerInfo.ghostUser()));
         }
         if (Comment.CommentOwner.KIND_EMAIL.equals(owner.getKind())) {
             return Mono.just(OwnerInfo.from(owner));

src/main/java/run/halo/app/content/impl/PostServiceImpl.java

@@ -28,10 +28,10 @@ import run.halo.app.content.PostRequest;
 import run.halo.app.content.PostService;
 import run.halo.app.content.PostSorter;
 import run.halo.app.content.Stats;
-import run.halo.app.core.extension.User;
 import run.halo.app.core.extension.content.Category;
 import run.halo.app.core.extension.content.Post;
 import run.halo.app.core.extension.content.Tag;
+import run.halo.app.core.extension.service.UserService;
 import run.halo.app.extension.ListResult;
 import run.halo.app.extension.ReactiveExtensionClient;
 import run.halo.app.extension.Ref;
@@ -51,11 +51,14 @@ import run.halo.app.metrics.MeterUtils;
 public class PostServiceImpl extends AbstractContentService implements PostService {
     private final ReactiveExtensionClient client;
     private final CounterService counterService;
+    private final UserService userService;
 
-    public PostServiceImpl(ReactiveExtensionClient client, CounterService counterService) {
+    public PostServiceImpl(ReactiveExtensionClient client, CounterService counterService,
+        UserService userService) {
         super(client);
         this.client = client;
         this.counterService = counterService;
+        this.userService = userService;
     }
 
     @Override
@@ -191,7 +194,7 @@ public class PostServiceImpl extends AbstractContentService implements PostServi
     }
 
     private Mono<ListedPost> setOwner(String ownerName, ListedPost post) {
-        return client.fetch(User.class, ownerName)
+        return userService.getUserOrGhost(ownerName)
             .map(user -> {
                 Contributor contributor = new Contributor();
                 contributor.setName(user.getMetadata().getName());
@@ -224,8 +227,7 @@ public class PostServiceImpl extends AbstractContentService implements PostServi
             return Flux.empty();
         }
         return Flux.fromIterable(usernames)
-            .flatMap(username -> client.fetch(User.class, username)
+            .flatMap(userService::getUserOrGhost)
-                .switchIfEmpty(Mono.defer(() -> client.fetch(User.class, "ghost"))))
             .map(user -> {
                 Contributor contributor = new Contributor();
                 contributor.setName(user.getMetadata().getName());

src/main/java/run/halo/app/content/impl/SinglePageServiceImpl.java

@@ -28,9 +28,9 @@ import run.halo.app.content.SinglePageRequest;
 import run.halo.app.content.SinglePageService;
 import run.halo.app.content.SinglePageSorter;
 import run.halo.app.content.Stats;
-import run.halo.app.core.extension.User;
 import run.halo.app.core.extension.content.Post;
 import run.halo.app.core.extension.content.SinglePage;
+import run.halo.app.core.extension.service.UserService;
 import run.halo.app.extension.ListResult;
 import run.halo.app.extension.ReactiveExtensionClient;
 import run.halo.app.extension.Ref;
@@ -51,11 +51,14 @@ public class SinglePageServiceImpl extends AbstractContentService implements Sin
 
     private final ReactiveExtensionClient client;
     private final CounterService counterService;
+    private final UserService userService;
 
-    public SinglePageServiceImpl(ReactiveExtensionClient client, CounterService counterService) {
+    public SinglePageServiceImpl(ReactiveExtensionClient client, CounterService counterService,
+        UserService userService) {
         super(client);
         this.client = client;
         this.counterService = counterService;
+        this.userService = userService;
     }
 
     @Override
@@ -242,7 +245,7 @@ public class SinglePageServiceImpl extends AbstractContentService implements Sin
     }
 
     private Mono<ListedSinglePage> setOwner(String ownerName, ListedSinglePage page) {
-        return client.fetch(User.class, ownerName)
+        return userService.getUserOrGhost(ownerName)
             .map(user -> {
                 Contributor contributor = new Contributor();
                 contributor.setName(user.getMetadata().getName());
@@ -273,7 +276,7 @@ public class SinglePageServiceImpl extends AbstractContentService implements Sin
             return Flux.empty();
         }
         return Flux.fromIterable(usernames)
-            .flatMap(username -> client.fetch(User.class, username))
+            .flatMap(userService::getUserOrGhost)
             .map(user -> {
                 Contributor contributor = new Contributor();
                 contributor.setName(user.getMetadata().getName());

src/main/java/run/halo/app/core/extension/service/UserService.java

@@ -10,6 +10,8 @@ public interface UserService {
 
     Mono<User> getUser(String username);
 
+    Mono<User> getUserOrGhost(String username);
+
     Mono<User> updatePassword(String username, String newPassword);
 
     Mono<User> updateWithRawPassword(String username, String rawPassword);

src/main/java/run/halo/app/core/extension/service/UserServiceImpl.java

@@ -19,6 +19,7 @@ import run.halo.app.extension.ReactiveExtensionClient;
 
 @Service
 public class UserServiceImpl implements UserService {
+    public static final String GHOST_USER_NAME = "ghost";
 
     private final ReactiveExtensionClient client;
 
@@ -34,6 +35,12 @@ public class UserServiceImpl implements UserService {
         return client.get(User.class, username);
     }
 
+    @Override
+    public Mono<User> getUserOrGhost(String username) {
+        return client.fetch(User.class, username)
+            .switchIfEmpty(Mono.defer(() -> client.get(User.class, GHOST_USER_NAME)));
+    }
+
     @Override
     public Mono<User> updatePassword(String username, String newPassword) {
         return getUser(username)

src/main/java/run/halo/app/theme/finders/impl/CommentFinderImpl.java

@@ -5,6 +5,7 @@ import java.util.Comparator;
 import java.util.List;
 import java.util.function.Function;
 import java.util.function.Predicate;
+import lombok.RequiredArgsConstructor;
 import org.apache.commons.lang3.BooleanUtils;
 import org.apache.commons.lang3.ObjectUtils;
 import org.apache.commons.lang3.StringUtils;
@@ -16,9 +17,9 @@ import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 import run.halo.app.content.comment.OwnerInfo;
 import run.halo.app.content.comment.ReplyService;
-import run.halo.app.core.extension.User;
 import run.halo.app.core.extension.content.Comment;
 import run.halo.app.core.extension.content.Reply;
+import run.halo.app.core.extension.service.UserService;
 import run.halo.app.extension.ListResult;
 import run.halo.app.extension.ReactiveExtensionClient;
 import run.halo.app.extension.Ref;
@@ -35,13 +36,11 @@ import run.halo.app.theme.finders.vo.ReplyVo;
  * @since 2.0.0
  */
 @Finder("commentFinder")
+@RequiredArgsConstructor
 public class CommentFinderImpl implements CommentFinder {
 
     private final ReactiveExtensionClient client;
-
+    private final UserService userService;
-    public CommentFinderImpl(ReactiveExtensionClient client) {
-        this.client = client;
-    }
 
     @Override
     public Mono<CommentVo> getByName(String name) {
@@ -107,9 +106,8 @@ public class CommentFinderImpl implements CommentFinder {
         if (Comment.CommentOwner.KIND_EMAIL.equals(owner.getKind())) {
             return Mono.just(OwnerInfo.from(owner));
         }
-        return client.fetch(User.class, owner.getName())
+        return userService.getUserOrGhost(owner.getName())
-            .map(OwnerInfo::from)
+            .map(OwnerInfo::from);
-            .defaultIfEmpty(OwnerInfo.ghostUser());
     }
 
     private Mono<Predicate<Comment>> fixedCommentPredicate(Ref ref) {

src/main/java/run/halo/app/theme/finders/impl/ContributorFinderImpl.java

@@ -1,10 +1,10 @@
 package run.halo.app.theme.finders.impl;
 
 import java.util.List;
+import lombok.RequiredArgsConstructor;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
-import run.halo.app.core.extension.User;
+import run.halo.app.core.extension.service.UserService;
-import run.halo.app.extension.ReactiveExtensionClient;
 import run.halo.app.theme.finders.ContributorFinder;
 import run.halo.app.theme.finders.Finder;
 import run.halo.app.theme.finders.vo.ContributorVo;
@@ -16,17 +16,14 @@ import run.halo.app.theme.finders.vo.ContributorVo;
  * @since 2.0.0
  */
 @Finder("contributorFinder")
+@RequiredArgsConstructor
 public class ContributorFinderImpl implements ContributorFinder {
 
-    private final ReactiveExtensionClient client;
+    private final UserService userService;
-
-    public ContributorFinderImpl(ReactiveExtensionClient client) {
-        this.client = client;
-    }
 
     @Override
     public Mono<ContributorVo> getContributor(String name) {
-        return client.fetch(User.class, name)
+        return userService.getUserOrGhost(name)
             .map(ContributorVo::from);
     }
 

src/test/java/run/halo/app/content/comment/CommentServiceImplTest.java

@@ -31,6 +31,7 @@ import run.halo.app.content.TestPost;
 import run.halo.app.core.extension.User;
 import run.halo.app.core.extension.content.Comment;
 import run.halo.app.core.extension.content.Post;
+import run.halo.app.core.extension.service.UserService;
 import run.halo.app.extension.ListResult;
 import run.halo.app.extension.Metadata;
 import run.halo.app.extension.ReactiveExtensionClient;
@@ -55,6 +56,9 @@ class CommentServiceImplTest {
     @Mock
     private ReactiveExtensionClient client;
 
+    @Mock
+    private UserService userService;
+
     @Mock
     private ExtensionComponentsFinder extensionComponentsFinder;
 
@@ -70,15 +74,10 @@ class CommentServiceImplTest {
         when(client.list(eq(Comment.class), any(), any(), anyInt(), anyInt()))
             .thenReturn(Mono.just(comments));
 
-        User user = new User();
+        when(userService.getUserOrGhost(eq("A-owner")))
-        user.setMetadata(new Metadata());
+                .thenReturn(Mono.just(createUser("A-owner")));
-        user.getMetadata().setName("B-owner");
+        when(userService.getUserOrGhost(eq("B-owner")))
-        user.setSpec(new User.UserSpec());
+                .thenReturn(Mono.just(createUser("B-owner")));
-        user.getSpec().setAvatar("B-avatar");
-        user.getSpec().setDisplayName("B-displayName");
-        user.getSpec().setEmail("B-email");
-        when(client.fetch(eq(User.class), eq("B-owner")))
-            .thenReturn(Mono.just(user));
         when(client.fetch(eq(User.class), eq("C-owner")))
             .thenReturn(Mono.empty());
 
@@ -90,8 +89,26 @@ class CommentServiceImplTest {
         when(postCommentSubject.get(eq("fake-post"))).thenReturn(Mono.just(post()));
     }
 
+    private static User createUser(String name) {
+        User user = new User();
+        user.setMetadata(new Metadata());
+        user.getMetadata().setName(name);
+        user.setSpec(new User.UserSpec());
+        user.getSpec().setAvatar(name + "-avatar");
+        user.getSpec().setDisplayName(name + "-displayName");
+        user.getSpec().setEmail(name + "-email");
+        return user;
+    }
+
     @Test
     void listComment() {
+        when(userService.getUserOrGhost(any()))
+            .thenReturn(Mono.just(ghostUser()));
+        when(userService.getUserOrGhost("A-owner"))
+            .thenReturn(Mono.just(createUser("A-owner")));
+        when(userService.getUserOrGhost("B-owner"))
+            .thenReturn(Mono.just(createUser("B-owner")));
+
         Mono<ListResult<ListedComment>> listResultMono =
             commentService.listComment(new CommentQuery(new LinkedMultiValueMap<>()));
         StepVerifier.create(listResultMono)
@@ -118,6 +135,8 @@ class CommentServiceImplTest {
 
         ArgumentCaptor<Comment> captor = ArgumentCaptor.forClass(Comment.class);
 
+        when(client.fetch(eq(User.class), eq("B-owner")))
+                .thenReturn(Mono.just(createUser("B-owner")));
         Comment commentToCreate = commentRequest.toComment();
         commentToCreate.getMetadata().setName("fake");
         Mono<Comment> commentMono = commentService.create(commentToCreate);
@@ -136,7 +155,7 @@ class CommentServiceImplTest {
                         "owner": {
                             "kind": "User",
                             "name": "B-owner",
-                            "displayName": "B-displayName"
+                            "displayName": "B-owner-displayName"
                         },
                         "priority": 0,
                         "top": false,
@@ -239,6 +258,16 @@ class CommentServiceImplTest {
         return commentSetting;
     }
 
+    User ghostUser() {
+        User user = new User();
+        user.setMetadata(new Metadata());
+        user.getMetadata().setName("ghost");
+        user.setSpec(new User.UserSpec());
+        user.getSpec().setDisplayName("Ghost");
+        user.getSpec().setEmail("");
+        return user;
+    }
+
     private String expectListResultJson() {
         return """
             {
@@ -318,9 +347,9 @@ class CommentServiceImplTest {
                         "owner": {
                             "kind": "User",
                             "name": "B-owner",
-                            "displayName": "B-displayName",
+                            "displayName": "B-owner-displayName",
-                            "avatar": "B-avatar",
+                            "avatar": "B-owner-avatar",
-                            "email": "B-email"
+                            "email": "B-owner-email"
                         },
                         "subject": {
                             "spec": {

src/test/java/run/halo/app/theme/finders/impl/CommentFinderImplTest.java

@@ -10,6 +10,7 @@ import java.util.List;
 import java.util.function.Predicate;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
+import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Nested;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
@@ -24,6 +25,7 @@ import run.halo.app.core.extension.User;
 import run.halo.app.core.extension.content.Comment;
 import run.halo.app.core.extension.content.Post;
 import run.halo.app.core.extension.content.Reply;
+import run.halo.app.core.extension.service.UserService;
 import run.halo.app.extension.GroupVersionKind;
 import run.halo.app.extension.ListResult;
 import run.halo.app.extension.Metadata;
@@ -43,10 +45,20 @@ class CommentFinderImplTest {
 
     @Mock
     private ReactiveExtensionClient client;
+    @Mock
+    private UserService userService;
 
     @InjectMocks
     private CommentFinderImpl commentFinder;
 
+    @BeforeEach
+    void setUp() {
+        User ghost = createUser();
+        ghost.getMetadata().setName("ghost");
+        when(userService.getUserOrGhost(eq("ghost"))).thenReturn(Mono.just(ghost));
+        when(userService.getUserOrGhost(eq("fake-user"))).thenReturn(Mono.just(createUser()));
+    }
+
     @Nested
     class ListCommentTest {
         @Test
@@ -211,6 +223,7 @@ class CommentFinderImplTest {
                 return Mono.just(new ListResult<>(1, 10, comments.size(), comments));
             });
 
+            extractedUser();
             when(client.fetch(eq(User.class), any())).thenReturn(Mono.just(createUser()));
         }
 
@@ -340,6 +353,7 @@ class CommentFinderImplTest {
                 return Mono.just(new ListResult<>(1, 10, replies.size(), replies));
             });
 
+            extractedUser();
             when(client.fetch(eq(User.class), any())).thenReturn(Mono.just(createUser()));
         }
 
@@ -362,6 +376,18 @@ class CommentFinderImplTest {
         }
     }
 
+    private void extractedUser() {
+        User another = createUser();
+        another.getMetadata().setName("another");
+        when(userService.getUserOrGhost(eq("another"))).thenReturn(Mono.just(another));
+
+        User ghost = createUser();
+        ghost.getMetadata().setName("ghost");
+        when(userService.getUserOrGhost(eq("ghost"))).thenReturn(Mono.just(ghost));
+        when(userService.getUserOrGhost(eq("fake-user"))).thenReturn(Mono.just(createUser()));
+        when(userService.getUserOrGhost(any())).thenReturn(Mono.just(ghost));
+    }
+
     User createUser() {
         User user = new User();
         user.setMetadata(new Metadata());