Trigger a UI refresh when the scanner finds changes.

Closes #1025

scanner/scanner.go

@@ -35,7 +35,8 @@ var (
 )
 
 type FolderScanner interface {
-	Scan(ctx context.Context, lastModifiedSince time.Time, progress chan uint32) error
+	// Scan process finds any changes after `lastModifiedSince` and returns the number of changes found
+	Scan(ctx context.Context, lastModifiedSince time.Time, progress chan uint32) (int64, error)
 }
 
 var isScanning utils.AtomicBool
@@ -89,11 +90,17 @@ func (s *scanner) rescan(ctx context.Context, mediaFolder string, fullRescan boo
 	progress, cancel := s.startProgressTracker(mediaFolder)
 	defer cancel()
 
-	err := folderScanner.Scan(ctx, lastModifiedSince, progress)
+	changeCount, err := folderScanner.Scan(ctx, lastModifiedSince, progress)
 	if err != nil {
 		log.Error("Error importing MediaFolder", "folder", mediaFolder, err)
 	}
 
+	if changeCount > 0 {
+		log.Debug(ctx, "Detected changes in the music folder. Sending refresh event",
+			"folder", mediaFolder, "changeCount", changeCount)
+		s.broker.SendMessage(&events.RefreshResource{})
+	}
+
 	s.updateLastModifiedSince(mediaFolder, start)
 	return err
 }

scanner/tag_scanner.go

@@ -36,15 +36,16 @@ func NewTagScanner(rootFolder string, ds model.DataStore, cacheWarmer core.Cache
 	}
 }
 
-type (
-	counters struct {
-		added     int64
-		updated   int64
-		deleted   int64
-		playlists int64
-	}
-	dirMap map[string]dirStats
-)
+type dirMap map[string]dirStats
+
+type counters struct {
+	added     int64
+	updated   int64
+	deleted   int64
+	playlists int64
+}
+
+func (cnt *counters) total() int64 { return cnt.added + cnt.updated + cnt.deleted }
 
 const (
 	// filesBatchSize used for batching file metadata extraction
@@ -67,13 +68,13 @@ const (
 //      If the playlist is not in the DB, import it, setting sync = true
 //      If the playlist is in the DB and sync == true, import it, or else skip it
 // Delete all empty albums, delete all empty artists, clean-up playlists
-func (s *TagScanner) Scan(ctx context.Context, lastModifiedSince time.Time, progress chan uint32) error {
+func (s *TagScanner) Scan(ctx context.Context, lastModifiedSince time.Time, progress chan uint32) (int64, error) {
 	ctx = s.withAdminUser(ctx)
 	start := time.Now()
 
 	allDBDirs, err := s.getDBDirTree(ctx)
 	if err != nil {
-		return err
+		return 0, err
 	}
 
 	allFSDirs := dirMap{}
@@ -101,19 +102,19 @@ func (s *TagScanner) Scan(ctx context.Context, lastModifiedSince time.Time, prog
 
 	if err := <-walkerError; err != nil {
 		log.Error("Scan was interrupted by error. See errors above", err)
-		return err
+		return 0, err
 	}
 
 	// If the media folder is empty, abort to avoid deleting all data
 	if len(allFSDirs) <= 1 {
 		log.Error(ctx, "Media Folder is empty. Aborting scan.", "folder", s.rootFolder)
-		return nil
+		return 0, nil
 	}
 
 	deletedDirs := s.getDeletedDirs(ctx, allFSDirs, allDBDirs)
 	if len(deletedDirs)+len(changedDirs) == 0 {
 		log.Debug(ctx, "No changes found in Music Folder", "folder", s.rootFolder, "elapsed", time.Since(start))
-		return nil
+		return 0, nil
 	}
 
 	for _, dir := range deletedDirs {
@@ -146,7 +147,7 @@ func (s *TagScanner) Scan(ctx context.Context, lastModifiedSince time.Time, prog
 	log.Info("Finished processing Music Folder", "folder", s.rootFolder, "elapsed", time.Since(start),
 		"added", s.cnt.added, "updated", s.cnt.updated, "deleted", s.cnt.deleted, "playlistsImported", s.cnt.playlists)
 
-	return err
+	return s.cnt.total(), err
 }
 
 func (s *TagScanner) getRootFolderWalker(ctx context.Context) (walkResults, chan error) {

server/events/events.go

@@ -9,16 +9,18 @@ import (
 )
 
 type Event interface {
-	Prepare(Event) string
+	Name(Event) string
+	Data(Event) string
 }
 
-type baseEvent struct {
-	Name string `json:"name"`
-}
+type baseEvent struct{}
 
-func (e *baseEvent) Prepare(evt Event) string {
+func (e *baseEvent) Name(evt Event) string {
 	str := strings.TrimPrefix(reflect.TypeOf(evt).String(), "*events.")
-	e.Name = str[:0] + string(unicode.ToLower(rune(str[0]))) + str[1:]
+	return str[:0] + string(unicode.ToLower(rune(str[0]))) + str[1:]
+}
+
+func (e *baseEvent) Data(evt Event) string {
 	data, _ := json.Marshal(evt)
 	return string(data)
 }
@@ -35,6 +37,11 @@ type KeepAlive struct {
 	TS int64 `json:"ts"`
 }
 
+type RefreshResource struct {
+	baseEvent
+	Resource string `json:"resource"`
+}
+
 type ServerStart struct {
 	baseEvent
 	StartTime time.Time `json:"startTime"`

server/events/events_test.go

@@ -8,8 +8,10 @@ import (
 var _ = Describe("Event", func() {
 	It("marshals Event to JSON", func() {
 		testEvent := TestEvent{Test: "some data"}
-		json := testEvent.Prepare(&testEvent)
-		Expect(json).To(Equal(`{"name":"testEvent","Test":"some data"}`))
+		data := testEvent.Data(&testEvent)
+		Expect(data).To(Equal(`{"Test":"some data"}`))
+		name := testEvent.Name(&testEvent)
+		Expect(name).To(Equal("testEvent"))
 	})
 })
 

server/events/sse.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"io"
 	"net/http"
+	"sync/atomic"
 	"time"
 
 	"code.cloudfoundry.org/go-diodes"
@@ -26,12 +27,15 @@ const (
 )
 
 var (
+	eventId         uint32
 	errWriteTimeOut = errors.New("write timeout")
 )
 
 type (
 	message struct {
-		Data string
+		ID    uint32
+		Event string
+		Data  string
 	}
 	messageChan chan message
 	clientsChan chan client
@@ -81,7 +85,9 @@ func (b *broker) SendMessage(evt Event) {
 
 func (b *broker) prepareMessage(event Event) message {
 	msg := message{}
-	msg.Data = event.Prepare(event)
+	msg.ID = atomic.AddUint32(&eventId, 1)
+	msg.Data = event.Data(event)
+	msg.Event = event.Name(event)
 	return msg
 }
 
@@ -90,7 +96,7 @@ func writeEvent(w io.Writer, event message, timeout time.Duration) (err error) {
 	flusher, _ := w.(http.Flusher)
 	complete := make(chan struct{}, 1)
 	go func() {
-		_, err = fmt.Fprintf(w, "data: %s\n\n", event.Data)
+		_, err = fmt.Fprintf(w, "id: %d\nevent: %s\ndata: %s\n\n", event.ID, event.Event, event.Data)
 		// Flush the data immediately instead of buffering it for later.
 		flusher.Flush()
 		complete <- struct{}{}

ui/src/actions/serverEvents.js

@@ -1,5 +1,6 @@
 export const EVENT_SCAN_STATUS = 'scanStatus'
 export const EVENT_SERVER_START = 'serverStart'
+export const EVENT_REFRESH_RESOURCE = 'refreshResource'
 
 export const processEvent = (type, data) => {
   return {

ui/src/album/AlbumList.js

@@ -18,6 +18,7 @@ import {
   QuickFilter,
   Title,
   useAlbumsPerPage,
+  useResourceRefresh,
   useSetToggleableFields,
 } from '../common'
 import AlbumListActions from './AlbumListActions'
@@ -71,6 +72,7 @@ const AlbumList = (props) => {
   const albumView = useSelector((state) => state.albumView)
   const [perPage, perPageOptions] = useAlbumsPerPage(width)
   const location = useLocation()
+  useResourceRefresh('album')
 
   const albumListType = location.pathname
     .replace(/^\/album/, '')

ui/src/artist/ArtistList.js

@@ -20,6 +20,7 @@ import {
   ArtistSimpleList,
   RatingField,
   useSelectedFields,
+  useResourceRefresh,
 } from '../common'
 import config from '../config'
 import ArtistListActions from './ArtistListActions'
@@ -66,6 +67,7 @@ const ArtistListView = ({ hasShow, hasEdit, hasList, width, ...rest }) => {
   const handleArtistLink = useGetHandleArtistClick(width)
   const history = useHistory()
   const isXsmall = useMediaQuery((theme) => theme.breakpoints.down('xs'))
+  useResourceRefresh('artist')
 
   const toggleableFields = useMemo(() => {
     return {

ui/src/common/index.js

@@ -23,6 +23,7 @@ export * from './Title'
 export * from './SongBulkActions'
 export * from './useAlbumsPerPage'
 export * from './useInterval'
+export * from './useResourceRefresh'
 export * from './useToggleLove'
 export * from './useTraceUpdate'
 export * from './Writable'

ui/src/common/useResourceRefresh.js

@@ -0,0 +1,23 @@
+import { useSelector } from 'react-redux'
+import { useState } from 'react'
+import { useRefresh } from 'react-admin'
+
+export const useResourceRefresh = (...resources) => {
+  const [lastTime, setLastTime] = useState(Date.now())
+  const refreshData = useSelector(
+    (state) => state.activity?.refresh || { lastTime }
+  )
+  const refresh = useRefresh()
+
+  const resource = refreshData.resource
+  if (refreshData.lastTime > lastTime) {
+    if (
+      resource === '' ||
+      resources.length === 0 ||
+      resources.includes(resource)
+    ) {
+      refresh()
+    }
+    setLastTime(refreshData.lastTime)
+  }
+}

ui/src/eventStream.js

@@ -52,17 +52,15 @@ const setDispatch = (dispatchFunc) => {
   dispatch = dispatchFunc
 }
 
-const eventHandler = throttle(
-  (event) => {
-    const data = JSON.parse(event.data)
-    if (data.name !== 'keepAlive') {
-      dispatch(processEvent(data.name, data))
-    }
-    setTimeout(defaultIntervalCheck) // Reset timeout on every received message
-  },
-  100,
-  { trailing: true }
-)
+const eventHandler = (event) => {
+  const data = JSON.parse(event.data)
+  if (event.type !== 'keepAlive') {
+    dispatch(processEvent(event.type, data))
+  }
+  setTimeout(defaultIntervalCheck) // Reset timeout on every received message
+}
+
+const throttledEventHandler = throttle(eventHandler, 100, { trailing: true })
 
 const startEventStream = async () => {
   setTimeout(currentIntervalCheck)
@@ -72,7 +70,10 @@ const startEventStream = async () => {
   }
   return getEventStream()
     .then((newStream) => {
-      newStream.onmessage = eventHandler
+      newStream.addEventListener('serverStart', eventHandler)
+      newStream.addEventListener('scanStatus', throttledEventHandler)
+      newStream.addEventListener('refreshResource', eventHandler)
+      newStream.addEventListener('keepAlive', eventHandler)
       newStream.onerror = (e) => {
         console.log('EventStream error', e)
         setTimeout(reconnectIntervalCheck)

ui/src/playlist/PlaylistList.js

@@ -18,6 +18,7 @@ import {
   Writable,
   isWritable,
   useSelectedFields,
+  useResourceRefresh,
 } from '../common'
 import PlaylistListActions from './PlaylistListActions'
 
@@ -66,6 +67,7 @@ const TogglePublicInput = ({ permissions, resource, record = {}, source }) => {
 const PlaylistList = ({ permissions, ...props }) => {
   const isXsmall = useMediaQuery((theme) => theme.breakpoints.down('xs'))
   const isDesktop = useMediaQuery((theme) => theme.breakpoints.up('md'))
+  useResourceRefresh('playlist')
 
   const toggleableFields = useMemo(() => {
     return {

ui/src/reducers/activityReducer.js

@@ -1,4 +1,8 @@
-import { EVENT_SCAN_STATUS, EVENT_SERVER_START } from '../actions'
+import {
+  EVENT_REFRESH_RESOURCE,
+  EVENT_SCAN_STATUS,
+  EVENT_SERVER_START,
+} from '../actions'
 
 const defaultState = {
   scanStatus: { scanning: false, folderCount: 0, count: 0 },
@@ -21,6 +25,14 @@ export const activityReducer = (
           startTime: data.startTime && Date.parse(data.startTime),
         },
       }
+    case EVENT_REFRESH_RESOURCE:
+      return {
+        ...previousState,
+        refresh: {
+          lastTime: Date.now(),
+          resource: data.resource,
+        },
+      }
     default:
       return previousState
   }

ui/src/song/SongList.js

@@ -18,6 +18,7 @@ import {
   SongTitleField,
   SongSimpleList,
   RatingField,
+  useResourceRefresh,
 } from '../common'
 import { useDispatch } from 'react-redux'
 import { makeStyles } from '@material-ui/core/styles'
@@ -71,6 +72,7 @@ const SongList = (props) => {
   const dispatch = useDispatch()
   const isXsmall = useMediaQuery((theme) => theme.breakpoints.down('xs'))
   const isDesktop = useMediaQuery((theme) => theme.breakpoints.up('md'))
+  useResourceRefresh('song')
 
   const handleRowClick = (id, basePath, record) => {
     dispatch(setTrack(record))