[article] 문서의 현재 편집자 조회 API 추가

src/main/kotlin/io/github/wntopia/gikipedia/server/domain/article/controller/ArticleController.kt

@@ -4,13 +4,15 @@ import io.github.wntopia.gikipedia.server.domain.article.dto.request.CreateArtic
 import io.github.wntopia.gikipedia.server.domain.article.dto.request.LookupArticleTitlesReqDto
 import io.github.wntopia.gikipedia.server.domain.article.dto.request.UpdateArticleImageReqDto
 import io.github.wntopia.gikipedia.server.domain.article.dto.request.UpdateArticleReqDto
+import io.github.wntopia.gikipedia.server.domain.article.dto.response.ArticleEditorsResDto
 import io.github.wntopia.gikipedia.server.domain.article.dto.response.ArticleResDto
 import io.github.wntopia.gikipedia.server.domain.article.dto.response.LookupArticleTitlesResDto
 import io.github.wntopia.gikipedia.server.domain.article.dto.response.PopularArticleResDto
 import io.github.wntopia.gikipedia.server.domain.article.dto.response.RecentChangeResDto
 import io.github.wntopia.gikipedia.server.domain.article.service.CreateArticleService
 import io.github.wntopia.gikipedia.server.domain.article.service.LookupArticleTitlesService
 import io.github.wntopia.gikipedia.server.domain.article.service.QueryArticleByTitleService
+import io.github.wntopia.gikipedia.server.domain.article.service.QueryArticleEditorsService
 import io.github.wntopia.gikipedia.server.domain.article.service.QueryArticleService
 import io.github.wntopia.gikipedia.server.domain.article.service.QueryPopularArticlesService
 import io.github.wntopia.gikipedia.server.domain.article.service.QueryRecentChangesService
@@ -60,6 +62,7 @@ class ArticleController(
     private val queryRecentChangesService: QueryRecentChangesService,
     private val queryPopularArticlesService: QueryPopularArticlesService,
     private val trackArticleViewService: TrackArticleViewService,
+    private val queryArticleEditorsService: QueryArticleEditorsService,
 ) {
     @Operation(
         summary = "문서 생성",
@@ -208,6 +211,20 @@ class ArticleController(
         @Parameter(hidden = true) request: HttpServletRequest,
     ): ArticleResDto = withViewCount(queryArticleService.execute(articleId), request)
 
+    @Operation(
+        summary = "문서 현재 편집자 조회",
+        description =
+            "지금 실시간 공동편집 room에 접속해 있는 편집자를 반환한다. 읽기 화면의 \"○○ 편집 중\" 표시에 쓴다. " +
+                "편집 중인 사람이 없거나 공동편집 room이 없는 문서(존재하지 않는 문서 포함)는 오류 없이 " +
+                "`editing=false`의 빈 결과를 반환한다. 로그인 없이 호출할 수 있다. 읽기 전용 구독은 제공하지 않으므로 " +
+                "표시가 필요한 동안 10~30초 간격으로 폴링하면 된다.",
+    )
+    @ApiResponses(value = [ApiResponse(responseCode = "200", description = "조회 성공")])
+    @GetMapping("/{articleId}/editors")
+    fun editors(
+        @Parameter(description = "문서 ID", example = "1") @PathVariable articleId: Long,
+    ): ArticleEditorsResDto = queryArticleEditorsService.execute(articleId)
+
     @Operation(
         summary = "문서 수정",
         description =

src/main/kotlin/io/github/wntopia/gikipedia/server/domain/article/dto/response/ArticleEditorsResDto.kt

@@ -0,0 +1,19 @@
+package io.github.wntopia.gikipedia.server.domain.article.dto.response
+
+import io.swagger.v3.oas.annotations.media.Schema
+
+data class ArticleEditorsResDto(
+    @field:Schema(description = "지금 이 문서를 편집 중인 사람이 있는지 여부")
+    val editing: Boolean,
+    @field:Schema(description = "편집 중인 사용자 수 (같은 사용자의 여러 탭은 한 명으로 센다)", example = "2")
+    val editorCount: Int,
+    @field:Schema(
+        description = "편집 중인 사용자 이름 (학번 제외). \"○○ 외 N명\"은 첫 이름과 editorCount - 1로 만든다.",
+        example = "[\"이서연\", \"홍길동\"]",
+    )
+    val editorNames: List<String>,
+) {
+    companion object {
+        val EMPTY = ArticleEditorsResDto(false, 0, emptyList())
+    }
+}

src/main/kotlin/io/github/wntopia/gikipedia/server/domain/article/service/QueryArticleEditorsService.kt

@@ -0,0 +1,7 @@
+package io.github.wntopia.gikipedia.server.domain.article.service
+
+import io.github.wntopia.gikipedia.server.domain.article.dto.response.ArticleEditorsResDto
+
+interface QueryArticleEditorsService {
+    fun execute(articleId: Long): ArticleEditorsResDto
+}

src/main/kotlin/io/github/wntopia/gikipedia/server/domain/article/service/impl/QueryArticleEditorsServiceImpl.kt

@@ -0,0 +1,23 @@
+package io.github.wntopia.gikipedia.server.domain.article.service.impl
+
+import io.github.wntopia.gikipedia.server.domain.article.dto.response.ArticleEditorsResDto
+import io.github.wntopia.gikipedia.server.domain.article.service.QueryArticleEditorsService
+import io.github.wntopia.gikipedia.server.domain.collaboration.service.CollaborationRoomRegistry
+import org.springframework.stereotype.Service
+
+/** 활성 공동편집 room의 현재 참여자 기준. room이 없거나 비어 있으면(마지막 편집자가 나갔으면) 빈 결과다. */
+@Service
+class QueryArticleEditorsServiceImpl(
+    private val collaborationRoomRegistry: CollaborationRoomRegistry,
+) : QueryArticleEditorsService {
+    override fun execute(articleId: Long): ArticleEditorsResDto {
+        val editors = collaborationRoomRegistry.findIfActive(articleId)?.currentEditors().orEmpty()
+        if (editors.isEmpty()) return ArticleEditorsResDto.EMPTY
+
+        return ArticleEditorsResDto(
+            editing = true,
+            editorCount = editors.size,
+            editorNames = editors.map { it.name ?: it.label },
+        )
+    }
+}

src/main/kotlin/io/github/wntopia/gikipedia/server/domain/collaboration/model/CollaborationRoom.kt

@@ -19,6 +19,7 @@ class CollaborationRoom(
     private val objectMapper: ObjectMapper,
 ) {
     private val sessions = LinkedHashMap<String, WebSocketSession>()
+    private val editorsBySessionId = LinkedHashMap<String, EditorIdentity>()
 
     /** 가장 최근 `sync` 또는 `save` 메시지가 실어온 plain text — 안전망 저장의 원천. */
     var lastKnownPlainText: String? = null
@@ -31,14 +32,23 @@ class CollaborationRoom(
     private var pendingLeaveSafetyNet: ScheduledFuture<*>? = null
 
     @Synchronized
-    fun join(session: WebSocketSession) {
+    fun join(
+        session: WebSocketSession,
+        editor: EditorIdentity? = null,
+    ) {
         sessions[session.id] = session
+        editor?.let { editorsBySessionId[session.id] = it }
     }
 
+    /** 지금 room에 접속해 있는 편집자들. 같은 사용자가 여러 탭으로 들어와 있어도 한 번만 나온다. */
+    @Synchronized
+    fun currentEditors(): List<EditorIdentity> = editorsBySessionId.values.distinctBy { it.userId ?: it.label }
+
     /** @return 이 호출로 인해 room이 비게 됐는지 여부 */
     @Synchronized
     fun leave(sessionId: String): Boolean {
         sessions.remove(sessionId)
+        editorsBySessionId.remove(sessionId)
         return sessions.isEmpty()
     }
 

src/main/kotlin/io/github/wntopia/gikipedia/server/domain/collaboration/service/CollaborationRoomRegistry.kt

@@ -1,6 +1,7 @@
 package io.github.wntopia.gikipedia.server.domain.collaboration.service
 
 import io.github.wntopia.gikipedia.server.domain.collaboration.model.CollaborationRoom
+import io.github.wntopia.gikipedia.server.global.security.session.EditorIdentity
 import org.springframework.stereotype.Component
 import org.springframework.web.socket.WebSocketSession
 import tools.jackson.databind.ObjectMapper
@@ -27,11 +28,12 @@ class CollaborationRoomRegistry(
     fun joinOrCreate(
         articleId: Long,
         session: WebSocketSession,
+        editor: EditorIdentity? = null,
     ): CollaborationRoom =
         rooms.compute(articleId) { _, existing ->
             val room = existing ?: CollaborationRoom(articleId, objectMapper)
             room.cancelPendingSafetyNet()
-            room.join(session)
+            room.join(session, editor)
             room
         }!!
 

src/main/kotlin/io/github/wntopia/gikipedia/server/domain/collaboration/websocket/ArticleCollaborationWebSocketHandler.kt

@@ -63,9 +63,10 @@ class ArticleCollaborationWebSocketHandler(
                     return
                 }
 
-        editorsBySessionId[session.id] = authenticationReader.getEditor(session.attributes)
+        val editor = authenticationReader.getEditor(session.attributes)
+        editorsBySessionId[session.id] = editor
         val decoratedSession = ConcurrentWebSocketSessionDecorator(session, SEND_TIME_LIMIT_MS, BUFFER_SIZE_LIMIT_BYTES)
-        val room = collaborationRoomRegistry.joinOrCreate(articleId, decoratedSession)
+        val room = collaborationRoomRegistry.joinOrCreate(articleId, decoratedSession, editor)
         room.sendTo(session.id, bootstrap)
     }
 

src/main/kotlin/io/github/wntopia/gikipedia/server/global/security/session/AuthenticationReader.kt

@@ -28,7 +28,7 @@ class AuthenticationReader {
 
     private fun editorOf(userInfo: DataGsmUserInfoResDto?): EditorIdentity {
         val student = userInfo?.student ?: throw ExpectedException("인증이 필요합니다.", HttpStatus.UNAUTHORIZED)
-        return EditorIdentity(userInfo.id, "${student.studentNumber ?: "?"} ${student.name ?: "?"}")
+        return EditorIdentity(userInfo.id, "${student.studentNumber ?: "?"} ${student.name ?: "?"}", student.name)
     }
 
     /** 로그인한 사용자의 DataGSM 계정 id. 로그인하지 않았거나 계정 id가 없으면 401. */

src/main/kotlin/io/github/wntopia/gikipedia/server/global/security/session/EditorIdentity.kt

@@ -7,4 +7,6 @@ package io.github.wntopia.gikipedia.server.global.security.session
 data class EditorIdentity(
     val userId: Long?,
     val label: String,
+    /** 화면에 "○○ 편집 중"으로 보여줄 이름(학번 제외). 알 수 없으면 null. */
+    val name: String? = null,
 )

src/test/kotlin/io/github/wntopia/gikipedia/server/domain/article/service/impl/QueryArticleEditorsServiceImplTest.kt

@@ -0,0 +1,59 @@
+package io.github.wntopia.gikipedia.server.domain.article.service.impl
+
+import io.github.wntopia.gikipedia.server.domain.collaboration.service.CollaborationRoomRegistry
+import io.github.wntopia.gikipedia.server.global.security.session.EditorIdentity
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.DisplayName
+import org.junit.jupiter.api.Test
+import org.mockito.kotlin.mock
+import org.mockito.kotlin.whenever
+import org.springframework.web.socket.WebSocketSession
+import tools.jackson.module.kotlin.jacksonObjectMapper
+
+class QueryArticleEditorsServiceImplTest {
+    private val registry = CollaborationRoomRegistry(jacksonObjectMapper())
+    private val service = QueryArticleEditorsServiceImpl(registry)
+
+    private fun fakeSession(id: String) = mock<WebSocketSession>().also { whenever(it.id).thenReturn(id) }
+
+    @Test
+    @DisplayName("누군가 편집 중이면 편집자 이름과 인원 수를 반환한다")
+    fun returnsEditorsWhileEditing() {
+        registry.joinOrCreate(1L, fakeSession("a"), EditorIdentity(1L, "2412 홍길동", "홍길동"))
+        registry.joinOrCreate(1L, fakeSession("b"), EditorIdentity(2L, "2413 김철수", "김철수"))
+
+        val result = service.execute(1L)
+
+        assertThat(result.editing).isTrue()
+        assertThat(result.editorCount).isEqualTo(2)
+        assertThat(result.editorNames).containsExactly("홍길동", "김철수")
+    }
+
+    @Test
+    @DisplayName("이름을 모르면 라벨로 대신한다")
+    fun fallsBackToLabel() {
+        registry.joinOrCreate(1L, fakeSession("a"), EditorIdentity(1L, "2412 홍길동"))
+
+        assertThat(service.execute(1L).editorNames).containsExactly("2412 홍길동")
+    }
+
+    @Test
+    @DisplayName("마지막 편집자가 나가면 결과가 비어 있다")
+    fun emptyAfterLastEditorLeaves() {
+        val room = registry.joinOrCreate(1L, fakeSession("a"), EditorIdentity(1L, "2412 홍길동", "홍길동"))
+        room.leave("a")
+
+        val result = service.execute(1L)
+
+        assertThat(result.editing).isFalse()
+        assertThat(result.editorCount).isEqualTo(0)
+        assertThat(result.editorNames).isEmpty()
+    }
+
+    @Test
+    @DisplayName("활성 room이 없는 문서도 오류 없이 빈 결과를 반환한다")
+    fun emptyWhenNoRoom() {
+        assertThat(service.execute(404L).editing).isFalse()
+        assertThat(service.execute(404L).editorNames).isEmpty()
+    }
+}

src/test/kotlin/io/github/wntopia/gikipedia/server/domain/collaboration/model/CollaborationRoomTest.kt

@@ -1,5 +1,7 @@
 package io.github.wntopia.gikipedia.server.domain.collaboration.model
 
+import io.github.wntopia.gikipedia.server.global.security.session.EditorIdentity
+import org.assertj.core.api.Assertions.assertThat
 import org.assertj.core.api.Assertions.assertThatCode
 import org.junit.jupiter.api.DisplayName
 import org.junit.jupiter.api.Test
@@ -75,4 +77,31 @@ class CollaborationRoomTest {
 
         verify(closed, never()).sendMessage(any())
     }
+
+    @Test
+    @DisplayName("접속한 편집자가 현재 편집자로 나오고, 나가면 빠진다")
+    fun tracksCurrentEditors() {
+        room.join(fakeSession("a"), EditorIdentity(1L, "2412 홍길동", "홍길동"))
+        room.join(fakeSession("b"), EditorIdentity(2L, "2413 김철수", "김철수"))
+
+        assertThat(room.currentEditors().map { it.name }).containsExactly("홍길동", "김철수")
+
+        room.leave("a")
+        assertThat(room.currentEditors().map { it.name }).containsExactly("김철수")
+
+        room.leave("b")
+        assertThat(room.currentEditors()).isEmpty()
+    }
+
+    @Test
+    @DisplayName("같은 사용자가 여러 탭으로 접속해도 한 명으로 센다")
+    fun countsSameUserOnce() {
+        val editor = EditorIdentity(1L, "2412 홍길동", "홍길동")
+        room.join(fakeSession("a"), editor)
+        room.join(fakeSession("b"), editor)
+
+        assertThat(room.currentEditors()).hasSize(1)
+        assertThat(room.leave("a")).isFalse()
+        assertThat(room.currentEditors()).hasSize(1)
+    }
 }

src/test/kotlin/io/github/wntopia/gikipedia/server/domain/collaboration/websocket/ArticleCollaborationWebSocketHandlerTest.kt

@@ -261,4 +261,18 @@ class ArticleCollaborationWebSocketHandlerTest {
         assertThat(messagesSentTo(session)).anyMatch { it.type == CollaborationMessage.TYPE_ERROR }
         verify(session, org.mockito.kotlin.never()).close(any<CloseStatus>())
     }
+
+    @Test
+    @DisplayName("접속하면 room의 현재 편집자에 나오고, 나가면 비어 있다")
+    fun exposesCurrentEditorsWhileConnected() {
+        whenever(taskScheduler.schedule(any<Runnable>(), any<Instant>())).thenReturn(mock<ScheduledFuture<*>>())
+        val session = fakeSession("a", 1L, "2412 홍길동")
+
+        handler.afterConnectionEstablished(session)
+        val room = requireNotNull(collaborationRoomRegistry.findIfActive(1L))
+        assertThat(room.currentEditors().map { it.label }).containsExactly("2412 홍길동")
+
+        handler.afterConnectionClosed(session, CloseStatus.NORMAL)
+        assertThat(room.currentEditors()).isEmpty()
+    }
 }