set up way to request lockUser to unlock task

app/org/maproulette/framework/controller/TaskController.scala

@@ -7,7 +7,12 @@ package org.maproulette.framework.controller
 import akka.util.ByteString
 import javax.inject.Inject
 import org.maproulette.data.ActionManager
-import org.maproulette.framework.service.{ServiceManager, TaskService, TaskClusterService}
+import org.maproulette.framework.service.{
+  ServiceManager,
+  TaskService,
+  TaskClusterService,
+  NotificationService
+}
 import org.maproulette.framework.psql.Paging
 import org.maproulette.framework.model.User
 import org.maproulette.framework.mixins.TaskJSONMixin
@@ -33,7 +38,8 @@ class TaskController @Inject() (
     taskClusterService: TaskClusterService,
     components: ControllerComponents,
     val taskDAL: TaskDAL,
-    val serviceManager: ServiceManager
+    val serviceManager: ServiceManager,
+    val notificationService: NotificationService
 ) extends AbstractController(components)
     with MapRouletteController
     with TaskJSONMixin {
@@ -240,4 +246,38 @@ class TaskController @Inject() (
         }
       }
     }
+
+  /**
+    * Request that a task be unlocked by sending a notification to the user who has it locked
+    *
+    * @param taskId The id of the task that is locked
+    * @return 200 OK with success message, or error status
+    */
+  def requestTaskUnlock(taskId: Long): Action[AnyContent] = Action.async { implicit request =>
+    this.sessionManager.authenticatedRequest { implicit user =>
+      val task = taskDAL.retrieveById(taskId)
+
+      task match {
+        case Some(t) => {
+          val lockerId = taskDAL.lockItem(user, t)
+          if (lockerId != user.id) {
+            this.serviceManager.user.retrieve(lockerId) match {
+              case Some(lockUser) =>
+                this.serviceManager.notification
+                  .createTaskUnlockRequestNotification(user, lockUser, t)
+                Ok(Json.obj("message" -> "Unlock request notification has been sent successfully"))
+              case None =>
+                throw new IllegalAccessException(s"Your notification request encountered an error")
+            }
+          } else {
+            throw new IllegalAccessException(s"Your notification request encountered an error")
+          }
+        }
+        case None =>
+          throw new NotFoundException(
+            s"Task with $taskId not found, unable to process unlock notification request."
+          )
+      }
+    }
+  }
 }

app/org/maproulette/framework/model/UserNotification.scala

@@ -80,6 +80,8 @@ object UserNotification extends CommonField {
   val NOTIFICATION_TYPE_REVISION_COUNT_NAME             = "Revision Count"
   val NOTIFICATION_TYPE_CHALLENGE_COMMENT               = 14
   val NOTIFICATION_TYPE_CHALLENGE_COMMENT_NAME          = "Challenge Comment"
+  val NOTIFICATION_TYPE_CHALLENGE_UNLOCK_REQUESTED      = 15
+  val NOTIFICATION_TYPE_CHALLENGE_UNLOCK_REQUESTED_NAME = "Challenge Unlock Requested"
 
   val notificationTypeMap = Map(
     NOTIFICATION_TYPE_SYSTEM                     -> NOTIFICATION_TYPE_SYSTEM_NAME,
@@ -94,7 +96,8 @@ object UserNotification extends CommonField {
     NOTIFICATION_TYPE_TEAM                       -> NOTIFICATION_TYPE_TEAM_NAME,
     NOTIFICATION_TYPE_FOLLOW                     -> NOTIFICATION_TYPE_FOLLOW_NAME,
     NOTIFICATION_TYPE_MAPPER_CHALLENGE_COMPLETED -> NOTIFICATION_TYPE_MAPPER_CHALLENGE_COMPLETED_NAME,
-    NOTIFICATION_TYPE_CHALLENGE_COMMENT          -> NOTIFICATION_TYPE_CHALLENGE_COMMENT_NAME
+    NOTIFICATION_TYPE_CHALLENGE_COMMENT          -> NOTIFICATION_TYPE_CHALLENGE_COMMENT_NAME,
+    NOTIFICATION_TYPE_CHALLENGE_UNLOCK_REQUESTED -> NOTIFICATION_TYPE_CHALLENGE_UNLOCK_REQUESTED_NAME
   )
 
   val NOTIFICATION_IGNORE          = 0 // ignore notification

app/org/maproulette/framework/service/NotificationService.scala

@@ -487,6 +487,8 @@ class NotificationService @Inject() (
       case UserNotification.NOTIFICATION_TYPE_FOLLOW => subscriptions.follow
       case UserNotification.NOTIFICATION_TYPE_CHALLENGE_COMMENT =>
         UserNotification.NOTIFICATION_EMAIL_IMMEDIATE
+      case UserNotification.NOTIFICATION_TYPE_CHALLENGE_UNLOCK_REQUESTED =>
+        UserNotification.NOTIFICATION_EMAIL_IMMEDIATE
       case _ => throw new InvalidException("Invalid notification type")
     }
 
@@ -580,4 +582,30 @@ class NotificationService @Inject() (
     permission.hasSuperAccess(user)
     this.repository.usersWithTasksToBeReviewed()
   }
+
+  /**
+    * Create new notification requesting that a task be unlocked
+    *
+    * @param fromUser  The user requesting the unlock
+    * @param lockedByUser  The user receiving the request
+    * @param task The challenge that needs to be unlocked
+    */
+  def createTaskUnlockRequestNotification(
+      fromUser: User,
+      lockedByUser: User,
+      task: Task
+  ): Unit = {
+    val fromUserName = Some(fromUser.osmProfile.displayName)
+    this.addNotification(
+      UserNotification(
+        -1,
+        userId = lockedByUser.id,
+        notificationType = UserNotification.NOTIFICATION_TYPE_CHALLENGE_UNLOCK_REQUESTED,
+        fromUsername = fromUserName,
+        taskId = Some(task.id),
+        description = Some(s"${fromUserName} is requesting you to unlock a task")
+      ),
+      User.superUser
+    )
+  }
 }

conf/v2_route/task.api

@@ -915,4 +915,25 @@ GET     /tasks/box/:left/:bottom/:right/:top        @org.maproulette.framework.c
 #   '200':
 #     description: Success
 ###
+# tags: [ Task ]
+# summary: Request task unlock
+# description: Sends a notification to the user who has locked a task requesting them to unlock it
+# responses:
+#   '200':
+#     description: Ok with a standard message
+#     content:
+#       application/json:
+#         schema:
+#           $ref: '#/components/schemas/org.maproulette.exception.StatusMessage'
+#   '401':
+#     description: The user is not authorized to make this request
+#   '404':
+#     description: The task or user was not found
+# parameters:
+#   - name: taskId
+#     in: path
+#     description: The id of the task that is locked
+###
+PUT     /task/:taskId/unlock/request                @org.maproulette.framework.controller.TaskController.requestTaskUnlock(taskId:Long)
+###
 GET     /taskCluster                                @org.maproulette.framework.controller.TaskController.getTaskClusters(points:Int ?= 100)