REST API: paginate project task list

CHANGELOG.md

@@ -12,6 +12,7 @@ For upgrade instructions, please check the [migration guide](MIGRATIONS.md).
 ### Added
 
 - Added the possibility to disable that the current layout is saved automatically when changing it. Instead, the layout can be saved explicitly. [#3620](https://github.com/scalableminds/webknossos/pull/3620)
+- Added pagination to the REST API route `GET /projects/:name/tasks` (new optional parameters `limit` and `pageNumber`). [#3659](https://github.com/scalableminds/webknossos/pull/3659)
 - Added the possibility to open the version restore view for read-only tracings. Older versions can be previewed and be downloaded as NML. [#3660](https://github.com/scalableminds/webknossos/pull/3660)
 
 ### Changed

app/controllers/ProjectController.scala

@@ -119,16 +119,18 @@ class ProjectController @Inject()(projectService: ProjectService,
       Ok(js)
     }
 
-  def tasksForProject(projectName: String) = sil.SecuredAction.async { implicit request =>
-    for {
-      project <- projectDAO.findOneByName(projectName) ?~> Messages("project.notFound", projectName)
-      _ <- Fox.assertTrue(userService.isTeamManagerOrAdminOf(request.identity, project._team)) ?~> "notAllowed"
-      tasks <- taskDAO.findAllByProject(project._id)(GlobalAccessContext)
-      js <- Fox.serialCombined(tasks)(task => taskService.publicWrites(task))
-    } yield {
-      Ok(Json.toJson(js))
+  def tasksForProject(projectName: String, limit: Option[Int] = None, pageNumber: Option[Int] = None) =
+    sil.SecuredAction.async { implicit request =>
+      for {
+        project <- projectDAO.findOneByName(projectName) ?~> Messages("project.notFound", projectName)
+        _ <- Fox.assertTrue(userService.isTeamManagerOrAdminOf(request.identity, project._team)) ?~> "notAllowed"
+        tasks <- taskDAO.findAllByProject(project._id, limit.getOrElse(Int.MaxValue), pageNumber.getOrElse(0))(
+          GlobalAccessContext)
+        js <- Fox.serialCombined(tasks)(task => taskService.publicWrites(task))
+      } yield {
+        Ok(Json.toJson(js))
+      }
     }
-  }
 
   def incrementEachTasksInstances(projectName: String, delta: Option[Long]) = sil.SecuredAction.async {
     implicit request =>

app/models/task/Task.scala

@@ -156,12 +156,13 @@ class TaskDAO @Inject()(sqlClient: SQLClient, projectDAO: ProjectDAO)(implicit e
       parsed <- Fox.combined(r.toList.map(parse))
     } yield parsed
 
-  def findAllByProject(projectId: ObjectId)(implicit ctx: DBAccessContext): Fox[List[Task]] =
+  def findAllByProject(projectId: ObjectId, limit: Int, pageNumber: Int)(
+      implicit ctx: DBAccessContext): Fox[List[Task]] =
     for {
       accessQuery <- readAccessQuery
       r <- run(
-        sql"select #${columns} from #${existingCollectionName} where _project = ${projectId.id} and #${accessQuery}"
-          .as[TasksRow])
+        sql"""select #${columns} from #${existingCollectionName} where _project = ${projectId.id} and #${accessQuery}
+              order by _id desc limit ${limit} offset ${pageNumber * limit}""".as[TasksRow])
       parsed <- Fox.combined(r.toList.map(parse))
     } yield parsed
 

conf/webknossos.latest.routes

@@ -147,7 +147,7 @@ POST          /projects
 GET           /projects/:name                                                   controllers.ProjectController.read(name: String)
 DELETE        /projects/:name                                                   controllers.ProjectController.delete(name: String)
 PUT           /projects/:name                                                   controllers.ProjectController.update(name: String)
-GET           /projects/:name/tasks                                             controllers.ProjectController.tasksForProject(name: String)
+GET           /projects/:name/tasks                                             controllers.ProjectController.tasksForProject(name: String, limit: Option[Int], pageNumber: Option[Int])
 PATCH         /projects/:name/incrementEachTasksInstances                       controllers.ProjectController.incrementEachTasksInstances(name: String, delta: Option[Long])
 PATCH         /projects/:name/pause                                             controllers.ProjectController.pause(name: String)
 PATCH         /projects/:name/resume                                            controllers.ProjectController.resume(name: String)

docs/rest_api.md

@@ -524,10 +524,16 @@ List all tasks of a project
 
 #### Expects
  - In the url: `:name` name of a project
+ - Optional GET parameter `limit=[INT]`
+   - return only the first x results (defaults to infinity)
+ - Optional GET parameter `pageNumber=[INT]`
+   - return the results starting at offset `limit` * `pageNumber` (defaults to 0)
 
 #### Returns
  - JSON list of objects containing task information
 
+#### Note
+ - For smoother backwards compatibility, the limit defaults to infinity. However, to ease server load and improve response time, we suggest using a limit of 1000
 
 
 ---