修复 Emby 大海报在剧集图缓存被淘汰后显示占位图

Co-authored-by: Cursor <cursoragent@cursor.com>

internal/service/emby_artwork.go

@@ -32,17 +32,14 @@ func (e *EmbyService) ImageURL(ctx context.Context, id, imageType string) (strin
 		}
 		return backdrop
 	}
-	if strings.HasPrefix(id, embyVirtualSeasonPrefix) {
+	if strings.HasPrefix(id, embyVirtualSeasonPrefix) || strings.HasPrefix(id, embyVirtualSeriesPrefix) {
 		if raw, ok := e.cachedArtworkURL(id, imageType); ok {
 			return raw, nil
 		}
-		return "", nil
-	}
-	if strings.HasPrefix(id, embyVirtualSeriesPrefix) {
-		if raw, ok := e.cachedArtworkURL(id, imageType); ok {
-			return raw, nil
-		}
-		return "", nil
+		// Latest JSON can outlive (or be served after) the in-memory artwork
+		// map. Rebuild from the library instead of handing the client a 1x1
+		// placeholder that it then caches as a successful image.
+		return e.resolveVirtualArtwork(ctx, id, imageType, pick)
 	}
 	m, err := e.repo.Media.FindByID(ctx, id)
 	if err == nil && m != nil {
@@ -71,6 +68,21 @@ func (e *EmbyService) ImageURL(ctx context.Context, id, imageType string) (strin
 	return "", nil
 }
 
+func (e *EmbyService) resolveVirtualArtwork(ctx context.Context, id, imageType string, pick func(primary, backdrop string) string) (string, error) {
+	if strings.HasPrefix(id, embyVirtualSeasonPrefix) {
+		season, ok, err := e.findSeasonGroup(ctx, id, "")
+		if err != nil || !ok {
+			return "", err
+		}
+		return pick(season.Series.PosterURL, season.Series.BackdropURL), nil
+	}
+	series, ok, err := e.findSeriesGroup(ctx, id, "")
+	if err != nil || !ok {
+		return "", err
+	}
+	return pick(series.PosterURL, series.BackdropURL), nil
+}
+
 // imageInfoTypes 是 GET /Items/{Id}/Images 会报告的图片类型。只列 MeBox
 // 真正存储的两类：ImageURL 对 Thumb / Logo / Banner 等其余类型会回退到
 // 主图，若一并列出会让客户端以为存在这些图并去请求，实际拿到的却是主图。

internal/service/emby_compat.go

@@ -117,6 +117,18 @@ const (
 	embyVirtualCacheTTL     = 10 * time.Minute
 	embyVisibilityCacheTTL  = 30 * time.Second
 	embySeriesGroupingLimit = maxMediaSearchLimit
+	// Virtual artwork used to be wiped entirely once the in-memory map crossed
+	// a few thousand entries. A homepage refresh asks Latest for every library
+	// at once, so that wipe dropped the series the client was about to paint.
+	// Caps are sized for that fan-out; overflow evicts the oldest entries only.
+	embyVirtualSeriesCap  = 8000
+	embyVirtualSeasonCap  = 16000
+	embyVirtualArtworkCap = 24000
+	// Clients that already cached the 1x1 placeholder treat a stable tag as
+	// immutable. Virtual ids are the ones that served that placeholder, so
+	// only those tags get a suffix that forces a refetch.
+	embyVirtualPrimaryTagSuffix  = "-p2"
+	embyVirtualBackdropTagSuffix = "-bd2"
 )
 
 var (

internal/service/emby_items_cache.go

@@ -15,7 +15,8 @@ type embyItemsCacheValue struct {
 }
 
 type embyLatestCacheValue struct {
-	Items []map[string]any `json:"items"`
+	Items   []map[string]any          `json:"items"`
+	Artwork map[string]embyArtworkRef `json:"artwork,omitempty"`
 }
 
 func (e *EmbyService) embyItemsCacheKey(kind string, p ItemsParams) string {
@@ -43,7 +44,8 @@ func (e *EmbyService) embyItemsCacheKey(kind string, p ItemsParams) string {
 }
 
 func (e *EmbyService) embyLatestCacheKey(userID, parentID string, limit int) string {
-	sum := sha256.Sum256([]byte(strings.Join([]string{"latest", userID, parentID, strconv.Itoa(limit)}, "|")))
+	// v2: payload tags for virtual artwork changed so clients drop cached placeholders.
+	sum := sha256.Sum256([]byte(strings.Join([]string{"latest-v2", userID, parentID, strconv.Itoa(limit)}, "|")))
 	return "media:emby:" + hex.EncodeToString(sum[:])
 }
 

internal/service/emby_items_detail.go

@@ -132,15 +132,16 @@ func (e *EmbyService) LatestItems(ctx context.Context, userID, parentID string,
 	cacheKey := e.embyLatestCacheKey(userID, parentID, limit)
 	var cached embyLatestCacheValue
 	if e.cache != nil && e.cache.GetJSON(ctx, cacheKey, &cached) {
+		e.rememberArtworkRefs(cached.Artwork)
 		return cached.Items, nil
 	}
 	q := e.repo.DB.WithContext(ctx).Model(&model.Media{}).Where("deleted_at IS NULL")
 	q = e.applyUserMediaVisibility(ctx, q, userID)
 	if parentID != "" {
 		if episodic, err := e.libraryIsEpisodic(ctx, parentID); err == nil && episodic {
-			out, err := e.latestSeriesItemsForLibrary(ctx, userID, parentID, limit)
+			out, artwork, err := e.latestSeriesItemsForLibrary(ctx, userID, parentID, limit)
 			if err == nil && e.cache != nil {
-				e.cache.SetJSON(ctx, cacheKey, embyLatestCacheValue{Items: out}, time.Duration(e.embyLatestCacheTTLSeconds())*time.Second)
+				e.cache.SetJSON(ctx, cacheKey, embyLatestCacheValue{Items: out, Artwork: artwork}, time.Duration(e.embyLatestCacheTTLSeconds())*time.Second)
 			}
 			return out, err
 		}
@@ -171,7 +172,7 @@ func (e *EmbyService) LatestItems(ctx context.Context, userID, parentID string,
 	return out, nil
 }
 
-func (e *EmbyService) latestSeriesItemsForLibrary(ctx context.Context, userID, libraryID string, limit int) ([]map[string]any, error) {
+func (e *EmbyService) latestSeriesItemsForLibrary(ctx context.Context, userID, libraryID string, limit int) ([]map[string]any, map[string]embyArtworkRef, error) {
 	if limit <= 0 || limit > 100 {
 		limit = 20
 	}
@@ -180,7 +181,7 @@ func (e *EmbyService) latestSeriesItemsForLibrary(ctx context.Context, userID, l
 	q = e.applyUserMediaVisibility(ctx, q, userID)
 	var rows []model.Media
 	if err := q.Order(mediaReleaseOrderSQL(true)).Limit(embySeriesGroupingLimit).Find(&rows).Error; err != nil {
-		return nil, err
+		return nil, nil, err
 	}
 	groups := e.seriesGroupsFromMedia(ctx, rows)
 	sortSeriesGroups(groups, ItemsParams{SortBy: "premieredate", SortOrder: "Descending"})
@@ -191,7 +192,7 @@ func (e *EmbyService) latestSeriesItemsForLibrary(ctx context.Context, userID, l
 	for _, group := range groups {
 		items = append(items, e.seriesPayload(group))
 	}
-	return items, nil
+	return items, e.artworkRefsForSeriesGroups(groups), nil
 }
 
 // ResumeItems 列出有未完成播放进度的媒体。
@@ -519,11 +520,11 @@ func (e *EmbyService) itemPayload(ctx context.Context, m *model.Media, fav bool,
 	if seriesID != "" {
 		if sEntry, ok, _ := e.payloadSeriesEntry(ctx, seriesID); ok {
 			if sEntry.posterURL != "" {
-				item["SeriesPrimaryImageTag"] = seriesID
+				item["SeriesPrimaryImageTag"] = embyVirtualImageTag(seriesID, embyVirtualPrimaryTagSuffix)
 			}
-			if len(backdropTags) == 0 && sEntry.backdropURL != "" {
+			if len(backdropTags) == 0 && (sEntry.backdropURL != "" || sEntry.posterURL != "") {
 				item["ParentBackdropItemId"] = seriesID
-				item["ParentBackdropImageTags"] = []string{seriesID + "-bd"}
+				item["ParentBackdropImageTags"] = []string{embyVirtualImageTag(seriesID, embyVirtualBackdropTagSuffix)}
 			}
 		}
 	}

internal/service/emby_series_cache.go

@@ -1,6 +1,7 @@
 package service
 
 import (
+	"sort"
 	"strings"
 	"time"
 )
@@ -37,11 +38,7 @@ func (e *EmbyService) rememberSeriesGroup(group embySeriesGroup) {
 	if e.virtualArtwork == nil {
 		e.virtualArtwork = make(map[string]embyArtworkCacheEntry)
 	}
-	if len(e.virtualSeries) > 2000 || len(e.virtualSeasons) > 5000 || len(e.virtualArtwork) > 7000 {
-		e.virtualSeries = make(map[string]embySeriesCacheEntry)
-		e.virtualSeasons = make(map[string]embySeasonCacheEntry)
-		e.virtualArtwork = make(map[string]embyArtworkCacheEntry)
-	}
+	e.trimVirtualCachesLocked(time.Now())
 	e.virtualSeries[group.ID] = embySeriesCacheEntry{group: group, expiresAt: expiresAt}
 	e.virtualArtwork[group.ID] = embyArtworkCacheEntry{primary: group.PosterURL, backdrop: group.BackdropURL, expiresAt: expiresAt}
 	e.virtualArtwork[group.ID+"-bd"] = embyArtworkCacheEntry{primary: group.PosterURL, backdrop: group.BackdropURL, expiresAt: expiresAt}
@@ -65,6 +62,7 @@ func (e *EmbyService) rememberSeasonGroup(season embySeasonGroup) {
 	if e.virtualArtwork == nil {
 		e.virtualArtwork = make(map[string]embyArtworkCacheEntry)
 	}
+	e.trimVirtualCachesLocked(time.Now())
 	e.virtualSeasons[season.ID] = embySeasonCacheEntry{season: season, expiresAt: expiresAt}
 	e.virtualArtwork[season.ID] = embyArtworkCacheEntry{primary: season.Series.PosterURL, backdrop: season.Series.BackdropURL, expiresAt: expiresAt}
 	e.virtualArtwork[season.ID+"-bd"] = embyArtworkCacheEntry{primary: season.Series.PosterURL, backdrop: season.Series.BackdropURL, expiresAt: expiresAt}
@@ -135,3 +133,123 @@ func (e *EmbyService) cachedArtworkURL(id, imageType string) (string, bool) {
 	}
 	return entry.backdrop, entry.backdrop != ""
 }
+
+// embyArtworkRef is the poster/backdrop pair stored next to a Latest payload
+// so a JSON-cache hit can refill the in-memory artwork map before the client
+// asks for the image.
+type embyArtworkRef struct {
+	Primary  string `json:"primary,omitempty"`
+	Backdrop string `json:"backdrop,omitempty"`
+}
+
+func (e *EmbyService) artworkRefsForSeriesGroups(groups []embySeriesGroup) map[string]embyArtworkRef {
+	if e == nil || len(groups) == 0 {
+		return nil
+	}
+	refs := make(map[string]embyArtworkRef, len(groups)*2)
+	for _, group := range groups {
+		if group.PosterURL == "" && group.BackdropURL == "" {
+			continue
+		}
+		ref := embyArtworkRef{Primary: group.PosterURL, Backdrop: group.BackdropURL}
+		refs[group.ID] = ref
+		for _, season := range e.seasonsForSeries(group) {
+			refs[season.ID] = ref
+		}
+	}
+	if len(refs) == 0 {
+		return nil
+	}
+	return refs
+}
+
+func (e *EmbyService) rememberArtworkRefs(refs map[string]embyArtworkRef) {
+	if e == nil || len(refs) == 0 {
+		return
+	}
+	expiresAt := time.Now().Add(embyVirtualCacheTTL)
+	e.virtualMu.Lock()
+	defer e.virtualMu.Unlock()
+	if e.virtualArtwork == nil {
+		e.virtualArtwork = make(map[string]embyArtworkCacheEntry, len(refs))
+	}
+	e.trimVirtualArtworkLocked(time.Now())
+	for id, ref := range refs {
+		if strings.TrimSpace(id) == "" || (ref.Primary == "" && ref.Backdrop == "") {
+			continue
+		}
+		e.virtualArtwork[id] = embyArtworkCacheEntry{primary: ref.Primary, backdrop: ref.Backdrop, expiresAt: expiresAt}
+	}
+}
+
+func (e *EmbyService) trimVirtualCachesLocked(now time.Time) {
+	e.trimVirtualSeriesLocked(now)
+	e.trimVirtualSeasonsLocked(now)
+	e.trimVirtualArtworkLocked(now)
+}
+
+func (e *EmbyService) trimVirtualSeriesLocked(now time.Time) {
+	for id, entry := range e.virtualSeries {
+		if now.After(entry.expiresAt) {
+			delete(e.virtualSeries, id)
+		}
+	}
+	evictOldest(e.virtualSeries, embyVirtualSeriesCap, func(entry embySeriesCacheEntry) time.Time {
+		return entry.expiresAt
+	})
+}
+
+func (e *EmbyService) trimVirtualSeasonsLocked(now time.Time) {
+	for id, entry := range e.virtualSeasons {
+		if now.After(entry.expiresAt) {
+			delete(e.virtualSeasons, id)
+		}
+	}
+	evictOldest(e.virtualSeasons, embyVirtualSeasonCap, func(entry embySeasonCacheEntry) time.Time {
+		return entry.expiresAt
+	})
+}
+
+func (e *EmbyService) trimVirtualArtworkLocked(now time.Time) {
+	for id, entry := range e.virtualArtwork {
+		if now.After(entry.expiresAt) {
+			delete(e.virtualArtwork, id)
+		}
+	}
+	evictOldest(e.virtualArtwork, embyVirtualArtworkCap, func(entry embyArtworkCacheEntry) time.Time {
+		return entry.expiresAt
+	})
+}
+
+// evictOldest drops the soonest-expiring entries until the map is under cap.
+// It must not replace the map: a homepage refresh remembers many series at
+// once, and wiping the whole cache made the just-advertised backdrops 404
+// into a 1x1 placeholder.
+func evictOldest[T any](items map[string]T, cap int, expiresAt func(T) time.Time) {
+	excess := len(items) - cap
+	if cap <= 0 || excess <= 0 {
+		return
+	}
+	type pair struct {
+		id string
+		at time.Time
+	}
+	ordered := make([]pair, 0, len(items))
+	for id, entry := range items {
+		ordered = append(ordered, pair{id: id, at: expiresAt(entry)})
+	}
+	sort.Slice(ordered, func(i, j int) bool { return ordered[i].at.Before(ordered[j].at) })
+	if excess > len(ordered) {
+		excess = len(ordered)
+	}
+	for i := 0; i < excess; i++ {
+		delete(items, ordered[i].id)
+	}
+}
+
+func embyVirtualImageTag(id, suffix string) string {
+	if strings.HasPrefix(id, embyVirtualSeriesPrefix) || strings.HasPrefix(id, embyVirtualSeasonPrefix) {
+		return id + suffix
+	}
+	return id
+}

internal/service/emby_series_hierarchy_test.go

@@ -296,6 +296,71 @@ func TestEmbyVirtualSeriesArtworkUsesListCache(t *testing.T) {
 	}
 }
 
+func TestEmbyVirtualSeriesArtworkRebuildsAfterMemoryDrop(t *testing.T) {
+	svc := newTestEmbyService(t)
+	svc.cache = NewRuntimeCacheService(nil, nil)
+	lib := model.Library{Name: "番剧", Path: `/media/anime`, Type: "anime", Enabled: true}
+	if err := svc.repo.Library.Create(t.Context(), &lib); err != nil {
+		t.Fatalf("create library: %v", err)
+	}
+	media := model.Media{
+		Base:        model.Base{ID: "ep-hero"},
+		LibraryID:   lib.ID,
+		Title:       "树海之魔",
+		Path:        `/media/anime/树海之魔/Season 01/树海之魔 - S01E01.mkv`,
+		PosterURL:   `/poster.jpg`,
+		BackdropURL: `/backdrop.jpg`,
+		SeasonNum:   1,
+		EpisodeNum:  1,
+	}
+	if err := svc.repo.DB.Create(&media).Error; err != nil {
+		t.Fatalf("create media: %v", err)
+	}
+
+	items, err := svc.LatestItems(t.Context(), "", lib.ID, 5)
+	if err != nil {
+		t.Fatalf("latest items: %v", err)
+	}
+	if len(items) != 1 {
+		t.Fatalf("latest len = %d, want 1", len(items))
+	}
+	seriesID, _ := items[0]["Id"].(string)
+	tags, _ := items[0]["BackdropImageTags"].([]string)
+	if seriesID == "" || len(tags) != 1 || tags[0] != seriesID+embyVirtualBackdropTagSuffix {
+		t.Fatalf("hero item should advertise a cache-busted backdrop tag, got id=%q tags=%#v", seriesID, items[0]["BackdropImageTags"])
+	}
+
+	svc.virtualMu.Lock()
+	svc.virtualArtwork = nil
+	svc.virtualSeries = nil
+	svc.virtualSeasons = nil
+	svc.virtualMu.Unlock()
+
+	backdrop, err := svc.ImageURL(t.Context(), seriesID, "Backdrop")
+	if err != nil {
+		t.Fatalf("backdrop after memory drop: %v", err)
+	}
+	if backdrop != "/backdrop.jpg" {
+		t.Fatalf("backdrop = %q, want rebuilt backdrop", backdrop)
+	}
+
+	svc.virtualMu.Lock()
+	svc.virtualArtwork = nil
+	svc.virtualMu.Unlock()
+	if _, err := svc.LatestItems(t.Context(), "", lib.ID, 5); err != nil {
+		t.Fatalf("cached latest: %v", err)
+	}
+	cancelled, cancel := context.WithCancel(t.Context())
+	cancel()
+	backdrop, err = svc.ImageURL(cancelled, seriesID, "Backdrop")
+	if err != nil {
+		t.Fatalf("backdrop from rewarmed cache: %v", err)
+	}
+	if backdrop != "/backdrop.jpg" {
+		t.Fatalf("rewarmed backdrop = %q, want cached backdrop", backdrop)
+	}
+}
+
 func TestEmbyCloudAnimeUsesSeriesNameFromChineseSeasonFolder(t *testing.T) {
 	svc := newTestEmbyService(t)
 	lib := model.Library{Name: "OpenList · 国漫", Path: `cloud://openlist/国漫`, Type: "anime", Enabled: true}
@@ -429,13 +494,13 @@ func TestInferSeriesNameFromPath(t *testing.T) {
 			want: "间谍过家家",
 		},
 	}
-			for _, tc := range tests {
-				got := inferSeriesNameFromPath(tc.path)
-				if got != tc.want {
-					t.Errorf("inferSeriesNameFromPath(%q) = %q, want %q", tc.path, got, tc.want)
-				}
-			}
+	for _, tc := range tests {
+		got := inferSeriesNameFromPath(tc.path)
+		if got != tc.want {
+			t.Errorf("inferSeriesNameFromPath(%q) = %q, want %q", tc.path, got, tc.want)
 		}
+	}
+}
 
 func TestEmbySeriesSortByDateLastMediaAdded(t *testing.T) {
 	svc := newTestEmbyService(t)

internal/service/emby_series_payload.go

@@ -5,28 +5,28 @@ func (e *EmbyService) seriesPayload(group embySeriesGroup) map[string]any {
 	imageTags := map[string]string{}
 	backdropTags := []string{}
 	if group.PosterURL != "" {
-		imageTags["Primary"] = group.ID
+		imageTags["Primary"] = embyVirtualImageTag(group.ID, embyVirtualPrimaryTagSuffix)
 	}
-	if group.BackdropURL != "" {
-		backdropTags = append(backdropTags, group.ID+"-bd")
+	if group.BackdropURL != "" || group.PosterURL != "" {
+		backdropTags = append(backdropTags, embyVirtualImageTag(group.ID, embyVirtualBackdropTagSuffix))
 	}
-		lastMediaAdded := group.DateLastMediaAdded
-		if lastMediaAdded.IsZero() {
-			lastMediaAdded = group.CreatedAt
-		}
-		item := map[string]any{
-			"Id":                 group.ID,
-			"Name":               group.Name,
-			"ServerId":           embyServerID,
-			"Type":               "Series",
-			"MediaType":          "Video",
-			"IsFolder":           true,
-			"ParentId":           group.LibraryID,
-			"ProductionYear":     group.Year,
-			"Overview":           group.Overview,
-			"CommunityRating":    group.Rating,
-			"RecursiveItemCount": len(group.Episodes),
-			"ChildCount":         len(e.seasonsForSeries(group)),
+	lastMediaAdded := group.DateLastMediaAdded
+	if lastMediaAdded.IsZero() {
+		lastMediaAdded = group.CreatedAt
+	}
+	item := map[string]any{
+		"Id":                 group.ID,
+		"Name":               group.Name,
+		"ServerId":           embyServerID,
+		"Type":               "Series",
+		"MediaType":          "Video",
+		"IsFolder":           true,
+		"ParentId":           group.LibraryID,
+		"ProductionYear":     group.Year,
+		"Overview":           group.Overview,
+		"CommunityRating":    group.Rating,
+		"RecursiveItemCount": len(group.Episodes),
+		"ChildCount":         len(e.seasonsForSeries(group)),
 		"DateCreated":        group.CreatedAt,
 		"DateLastMediaAdded": lastMediaAdded,
 		"ImageTags":          imageTags,
@@ -39,7 +39,7 @@ func (e *EmbyService) seriesPayload(group embySeriesGroup) map[string]any {
 		"UserData": emptyUserData(),
 	}
 	if group.PosterURL != "" {
-		item["PrimaryImageTag"] = group.ID
+		item["PrimaryImageTag"] = embyVirtualImageTag(group.ID, embyVirtualPrimaryTagSuffix)
 	}
 	if premiered, ok := embyPremiereDate(group.ReleaseDate); ok {
 		item["PremiereDate"] = premiered
@@ -52,10 +52,10 @@ func (e *EmbyService) seasonPayload(season embySeasonGroup) map[string]any {
 	imageTags := map[string]string{}
 	backdropTags := []string{}
 	if season.Series.PosterURL != "" {
-		imageTags["Primary"] = season.ID
+		imageTags["Primary"] = embyVirtualImageTag(season.ID, embyVirtualPrimaryTagSuffix)
 	}
-	if season.Series.BackdropURL != "" {
-		backdropTags = append(backdropTags, season.ID+"-bd")
+	if season.Series.BackdropURL != "" || season.Series.PosterURL != "" {
+		backdropTags = append(backdropTags, embyVirtualImageTag(season.ID, embyVirtualBackdropTagSuffix))
 	}
 	item := map[string]any{
 		"Id":                season.ID,
@@ -75,12 +75,12 @@ func (e *EmbyService) seasonPayload(season embySeasonGroup) map[string]any {
 		"UserData":          emptyUserData(),
 	}
 	if season.Series.PosterURL != "" {
-		item["PrimaryImageTag"] = season.ID
-		item["SeriesPrimaryImageTag"] = season.Series.ID
+		item["PrimaryImageTag"] = embyVirtualImageTag(season.ID, embyVirtualPrimaryTagSuffix)
+		item["SeriesPrimaryImageTag"] = embyVirtualImageTag(season.Series.ID, embyVirtualPrimaryTagSuffix)
 	}
-	if season.Series.BackdropURL != "" {
+	if season.Series.BackdropURL != "" || season.Series.PosterURL != "" {
 		item["ParentBackdropItemId"] = season.Series.ID
-		item["ParentBackdropImageTags"] = []string{season.Series.ID + "-bd"}
+		item["ParentBackdropImageTags"] = []string{embyVirtualImageTag(season.Series.ID, embyVirtualBackdropTagSuffix)}
 	}
 	return item
 }