优化

internal/service/emby_payload_ctx.go

@@ -0,0 +1,175 @@
+package service
+
+import (
+	"context"
+	"errors"
+	"strings"
+	"sync"
+
+	"gorm.io/gorm"
+
+	"github.com/truewhile/MeBox/internal/model"
+)
+
+// 请求级 payload 构建缓存：/Items 列表为每行构建 payload 时，
+// mediaShouldBeEpisode 需要库类型、剧集 payload 需要 series 标题。
+// 一次页面请求内这些值高度重复（同一库、同一部剧），挂在 ctx 上的
+// 小缓存可以把每条目 2-3 次 DB 查询降为整个请求各 1 次预取。
+
+type embyPayloadCacheKey struct{}
+
+type embyLibraryTypeEntry struct {
+	typ   string
+	found bool // 库不存在时 found=false，调用方可退回计数启发式
+}
+
+type embyPayloadCache struct {
+	mu       sync.Mutex
+	libTypes map[string]embyLibraryTypeEntry
+	series   map[string]string // series_id -> title（"" 表示不存在/无标题）
+}
+
+func (c *embyPayloadCache) libraryType(id string) (embyLibraryTypeEntry, bool) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	entry, ok := c.libTypes[id]
+	return entry, ok
+}
+
+func (c *embyPayloadCache) setLibraryType(id string, entry embyLibraryTypeEntry) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	c.libTypes[id] = entry
+}
+
+func (c *embyPayloadCache) seriesTitle(id string) (string, bool) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	title, ok := c.series[id]
+	return title, ok
+}
+
+func (c *embyPayloadCache) setSeriesTitle(id, title string) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	c.series[id] = title
+}
+
+// withPayloadCache attaches a fresh request-scoped cache if none exists yet.
+func (e *EmbyService) withPayloadCache(ctx context.Context) context.Context {
+	if e == nil || e.repo == nil {
+		return ctx
+	}
+	if ctx.Value(embyPayloadCacheKey{}) != nil {
+		return ctx
+	}
+	return context.WithValue(ctx, embyPayloadCacheKey{}, &embyPayloadCache{
+		libTypes: map[string]embyLibraryTypeEntry{},
+		series:   map[string]string{},
+	})
+}
+
+// prefetchPayloadCache warms the cache for the given media rows with two bulk
+// queries (library types, series titles) instead of per-item lookups.
+func (e *EmbyService) prefetchPayloadCache(ctx context.Context, rows []model.Media) {
+	cache, ok := ctx.Value(embyPayloadCacheKey{}).(*embyPayloadCache)
+	if !ok || len(rows) == 0 {
+		return
+	}
+	libIDs := make([]string, 0, 8)
+	seriesIDs := make([]string, 0, 8)
+	seenLib := map[string]struct{}{}
+	seenSeries := map[string]struct{}{}
+	for i := range rows {
+		row := &rows[i]
+		if id := strings.TrimSpace(row.LibraryID); id != "" {
+			if _, done := seenLib[id]; !done {
+				// 已在缓存中的库不必再查。
+				if _, hit := cache.libraryType(id); !hit {
+					seenLib[id] = struct{}{}
+					libIDs = append(libIDs, id)
+				}
+			}
+		}
+		if id := strings.TrimSpace(row.SeriesID); id != "" {
+			if _, done := seenSeries[id]; !done {
+				if _, hit := cache.seriesTitle(id); !hit {
+					seenSeries[id] = struct{}{}
+					seriesIDs = append(seriesIDs, id)
+				}
+			}
+		}
+	}
+	if len(libIDs) > 0 {
+		var libs []model.Library
+		if err := e.repo.DB.WithContext(ctx).Select("id, type").Where("id IN ?", libIDs).Find(&libs).Error; err == nil {
+			found := map[string]string{}
+			for _, lib := range libs {
+				found[lib.ID] = lib.Type
+			}
+			for _, id := range libIDs {
+				typ, ok := found[id]
+				cache.setLibraryType(id, embyLibraryTypeEntry{typ: typ, found: ok})
+			}
+		}
+	}
+	if len(seriesIDs) > 0 {
+		var series []model.Series
+		if err := e.repo.DB.WithContext(ctx).Select("id, title").Where("id IN ?", seriesIDs).Find(&series).Error; err == nil {
+			for _, s := range series {
+				cache.setSeriesTitle(s.ID, s.Title)
+			}
+		}
+	}
+}
+
+// payloadLibraryType resolves a library type through the request cache,
+// falling back to a direct lookup when no cache is attached. found=false
+// means the library row does not exist (soft-deleted or orphaned id).
+func (e *EmbyService) payloadLibraryType(ctx context.Context, libraryID string) (typ string, found bool, err error) {
+	if cache, ok := ctx.Value(embyPayloadCacheKey{}).(*embyPayloadCache); ok {
+		if entry, hit := cache.libraryType(libraryID); hit {
+			return entry.typ, entry.found, nil
+		}
+		var lib model.Library
+		if dbErr := e.repo.DB.WithContext(ctx).Select("id, type").Where("id = ?", libraryID).First(&lib).Error; dbErr != nil {
+			cache.setLibraryType(libraryID, embyLibraryTypeEntry{})
+			return "", false, nil
+		}
+		cache.setLibraryType(lib.ID, embyLibraryTypeEntry{typ: lib.Type, found: true})
+		return lib.Type, true, nil
+	}
+	var lib model.Library
+	if err = e.repo.DB.WithContext(ctx).Select("id, type").Where("id = ?", libraryID).First(&lib).Error; err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			return "", false, nil
+		}
+		return "", false, err
+	}
+	return lib.Type, true, nil
+}
+
+// payloadSeriesTitle resolves a series title through the request cache,
+// falling back to a direct lookup when no cache is attached.
+func (e *EmbyService) payloadSeriesTitle(ctx context.Context, seriesID string) (string, bool, error) {
+	if cache, ok := ctx.Value(embyPayloadCacheKey{}).(*embyPayloadCache); ok {
+		if title, hit := cache.seriesTitle(seriesID); hit {
+			return title, true, nil
+		}
+		var s model.Series
+		if err := e.repo.DB.WithContext(ctx).Select("id, title").Where("id = ?", seriesID).First(&s).Error; err != nil {
+			cache.setSeriesTitle(seriesID, "")
+			return "", true, nil
+		}
+		cache.setSeriesTitle(s.ID, s.Title)
+		return s.Title, true, nil
+	}
+	series, err := e.repo.Series.FindByID(ctx, seriesID)
+	if err != nil {
+		return "", false, err
+	}
+	if series == nil {
+		return "", false, nil
+	}
+	return series.Title, true, nil
+}