diff --git a/code/rest/dashboard_service.go b/code/rest/dashboard_service.go
index 04281bc..473a552 100644
--- a/code/rest/dashboard_service.go
+++ b/code/rest/dashboard_service.go
@@ -57,8 +57,6 @@ func (this *DashboardService) Bootstrap() {
 // handle the dashboard data.
 func (this *DashboardService) Etl() {
 
-	this.logger.Info("ETL dashboard data.")
-
 	startTime := util.FirstSecondOfDay(util.Yesterday())
 	endTime := util.LastSecondOfDay(util.Yesterday())
 	dt := util.ConvertTimeToDateString(startTime)
diff --git a/code/rest/matter_dao.go b/code/rest/matter_dao.go
index 6468b9a..453aba8 100644
--- a/code/rest/matter_dao.go
+++ b/code/rest/matter_dao.go
@@ -7,6 +7,7 @@ import (
 	"github.com/eyebluecn/tank/code/tool/util"
 	"github.com/eyebluecn/tank/code/tool/uuid"
 	"github.com/jinzhu/gorm"
+	"math"
 	"os"
 	"time"
 )
@@ -298,6 +299,31 @@ func (this *MatterDao) Page(page int, pageSize int, puuid string, userUuid strin
 	return pager
 }
 
+//handle matter page by page.
+func (this *MatterDao) PageHandle(puuid string, userUuid string, name string, dir string, fun func(matter *Matter)) {
+
+	//delete share and bridges.
+	pageSize := 1000
+	sortArray := []builder.OrderPair{
+		{
+			Key:   "uuid",
+			Value: DIRECTION_ASC,
+		},
+	}
+	count, _ := this.PlainPage(0, pageSize, puuid, userUuid, name, dir, nil, sortArray)
+	if count > 0 {
+		var totalPages = int(math.Ceil(float64(count) / float64(pageSize)))
+
+		var page int
+		for page = 0; page < totalPages; page++ {
+			_, matters := this.PlainPage(0, pageSize, puuid, userUuid, name, dir, nil, sortArray)
+			for _, matter := range matters {
+				fun(matter)
+			}
+		}
+	}
+}
+
 func (this *MatterDao) Create(matter *Matter) *Matter {
 
 	timeUUID, _ := uuid.NewV4()
diff --git a/code/rest/matter_service.go b/code/rest/matter_service.go
index fdc33f0..74d9df5 100644
--- a/code/rest/matter_service.go
+++ b/code/rest/matter_service.go
@@ -1049,3 +1049,29 @@ func (this *MatterService) adjustPath(matter *Matter, parentMatter *Matter) {
 	}
 
 }
+
+//delete someone's EyeblueTank files according to physics files.
+func (this *MatterService) DeleteByPhysics(user *User) {
+
+	if user == nil {
+		panic(result.BadRequest("user cannot be nil."))
+	}
+
+	//scan user's file.
+	this.matterDao.PageHandle("", user.Uuid, "", "", func(matter *Matter) {
+		this.logger.Info("handle %s", matter.Name)
+	})
+
+}
+
+//scan someone's physics files to EyeblueTank
+func (this *MatterService) Scan(user *User) {
+
+	if user == nil {
+		panic(result.BadRequest("user cannot be nil."))
+	}
+
+	rootDirPath := GetUserMatterRootDir(user.Username)
+	this.logger.Info("scan %s's root dir %s", user.Username, rootDirPath)
+
+}
diff --git a/code/rest/preference_controller.go b/code/rest/preference_controller.go
index f8d273c..e53a04e 100644
--- a/code/rest/preference_controller.go
+++ b/code/rest/preference_controller.go
@@ -5,6 +5,7 @@ import (
 	"github.com/eyebluecn/tank/code/tool/result"
 	"github.com/eyebluecn/tank/code/tool/util"
 	jsoniter "github.com/json-iterator/go"
+	"github.com/robfig/cron/v3"
 	"net/http"
 	"strconv"
 )
@@ -157,7 +158,19 @@ func (this *PreferenceController) EditScanConfig(writer http.ResponseWriter, req
 	//validate the scan config.
 	if scanConfig.Enable {
 		//validate cron.
+		_, err := cron.ParseStandard(scanConfig.Cron)
+		this.PanicError(err)
 
+		//validate scope.
+		if scanConfig.Scope == SCAN_SCOPE_CUSTOM {
+			if len(scanConfig.Usernames) == 0 {
+				panic(result.BadRequest("scope cannot be null"))
+			}
+		} else if scanConfig.Scope == SCAN_SCOPE_ALL {
+
+		} else {
+			panic(result.BadRequest("cannot recognize scope %s", scanConfig.Scope))
+		}
 	}
 
 	preference = this.preferenceService.Save(preference)
diff --git a/code/rest/preference_model.go b/code/rest/preference_model.go
index 9b6ced6..ec66310 100644
--- a/code/rest/preference_model.go
+++ b/code/rest/preference_model.go
@@ -37,7 +37,7 @@ const (
 type ScanConfig struct {
 	//whether enable the scan task.
 	Enable bool `json:"enable"`
-	//when to process the task.
+	//when to process the task. five fields. @every 1s
 	Cron string `json:"cron"`
 	//username
 	Usernames []string `json:"usernames"`
diff --git a/code/rest/share_service.go b/code/rest/share_service.go
index 7a7a7c9..54e0074 100644
--- a/code/rest/share_service.go
+++ b/code/rest/share_service.go
@@ -118,17 +118,20 @@ func (this *ShareService) DeleteSharesByUser(request *http.Request, currentUser
 	pageSize := 100
 	var sortArray []builder.OrderPair
 	count, _ := this.shareDao.PlainPage(0, pageSize, currentUser.Uuid, sortArray)
-	var totalPages = int(math.Ceil(float64(count) / float64(pageSize)))
+	if count > 0 {
+		var totalPages = int(math.Ceil(float64(count) / float64(pageSize)))
 
-	var page int
-	for page = 0; page < totalPages; page++ {
-		_, shares := this.shareDao.PlainPage(0, pageSize, currentUser.Uuid, sortArray)
-		for _, share := range shares {
-			this.bridgeDao.DeleteByShareUuid(share.Uuid)
+		var page int
+		for page = 0; page < totalPages; page++ {
+			_, shares := this.shareDao.PlainPage(0, pageSize, currentUser.Uuid, sortArray)
+			for _, share := range shares {
+				this.bridgeDao.DeleteByShareUuid(share.Uuid)
 
-			//delete this share
-			this.shareDao.Delete(share)
+				//delete this share
+				this.shareDao.Delete(share)
+			}
 		}
+
 	}
 
 }
diff --git a/code/rest/user_controller.go b/code/rest/user_controller.go
index 9af71c9..765b107 100644
--- a/code/rest/user_controller.go
+++ b/code/rest/user_controller.go
@@ -16,6 +16,7 @@ type UserController struct {
 	BaseController
 	preferenceService *PreferenceService
 	userService       *UserService
+	matterService     *MatterService
 }
 
 func (this *UserController) Init() {
@@ -31,6 +32,11 @@ func (this *UserController) Init() {
 		this.userService = b
 	}
 
+	b = core.CONTEXT.GetBean(this.matterService)
+	if b, ok := b.(*MatterService); ok {
+		this.matterService = b
+	}
+
 }
 
 func (this *UserController) RegisterRoutes() map[string]func(writer http.ResponseWriter, request *http.Request) {
@@ -50,6 +56,7 @@ func (this *UserController) RegisterRoutes() map[string]func(writer http.Respons
 	routeMap["/api/user/page"] = this.Wrap(this.Page, USER_ROLE_ADMINISTRATOR)
 	routeMap["/api/user/toggle/status"] = this.Wrap(this.ToggleStatus, USER_ROLE_ADMINISTRATOR)
 	routeMap["/api/user/transfiguration"] = this.Wrap(this.Transfiguration, USER_ROLE_ADMINISTRATOR)
+	routeMap["/api/user/scan"] = this.Wrap(this.Scan, USER_ROLE_ADMINISTRATOR)
 	routeMap["/api/user/delete"] = this.Wrap(this.Delete, USER_ROLE_ADMINISTRATOR)
 
 	return routeMap
@@ -432,6 +439,16 @@ func (this *UserController) Transfiguration(writer http.ResponseWriter, request
 	return this.Success(session.Uuid)
 }
 
+//scan user's physics files. create index into EyeblueTank
+func (this *UserController) Scan(writer http.ResponseWriter, request *http.Request) *result.WebResult {
+
+	uuid := request.FormValue("uuid")
+	currentUser := this.userDao.CheckByUuid(uuid)
+	this.matterService.Scan(currentUser)
+
+	return this.Success("OK")
+}
+
 func (this *UserController) Delete(writer http.ResponseWriter, request *http.Request) *result.WebResult {
 
 	uuid := request.FormValue("uuid")