move: 后端

backend/internal/video/video_service.go

@@ -0,0 +1,168 @@
+package video
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"strings"
+	"time"
+
+	rediscache "feedsystem_video_go/internal/redis"
+)
+
+type VideoService struct {
+	repo     *VideoRepository
+	cache    *rediscache.Client
+	cacheTTL time.Duration
+}
+
+func NewVideoService(repo *VideoRepository, cache *rediscache.Client) *VideoService {
+	return &VideoService{repo: repo, cache: cache, cacheTTL: 5 * time.Minute}
+}
+
+func (vs *VideoService) Publish(ctx context.Context, video *Video) error {
+	if video == nil {
+		return errors.New("video is nil")
+	}
+	video.Title = strings.TrimSpace(video.Title)
+	video.PlayURL = strings.TrimSpace(video.PlayURL)
+	video.CoverURL = strings.TrimSpace(video.CoverURL)
+
+	if video.Title == "" {
+		return errors.New("title is required")
+	}
+	if video.PlayURL == "" {
+		return errors.New("play url is required")
+	}
+	if video.CoverURL == "" {
+		return errors.New("cover url is required")
+	}
+	if err := vs.repo.CreateVideo(ctx, video); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (vs *VideoService) Delete(ctx context.Context, id uint, authorID uint) error {
+	video, err := vs.repo.GetByID(ctx, id)
+	if err != nil {
+		return err
+	}
+	if video == nil {
+		return errors.New("video not found")
+	}
+	if video.AuthorID != authorID {
+		return errors.New("unauthorized")
+	}
+	if err := vs.repo.DeleteVideo(ctx, id); err != nil {
+		return err
+	}
+	if vs.cache != nil {
+		cacheKey := fmt.Sprintf("video:detail:id=%d", id)
+		_ = vs.cache.Del(context.Background(), cacheKey)
+	}
+	return nil
+}
+
+func (vs *VideoService) ListByAuthorID(ctx context.Context, authorID uint) ([]Video, error) {
+	videos, err := vs.repo.ListByAuthorID(ctx, int64(authorID))
+	if err != nil {
+		return nil, err
+	}
+	return videos, nil
+}
+
+func (vs *VideoService) GetDetail(ctx context.Context, id uint) (*Video, error) {
+	cacheKey := fmt.Sprintf("video:detail:id=%d", id)
+
+	getCached := func() (*Video, bool) {
+		opCtx, cancel := context.WithTimeout(ctx, 50*time.Millisecond)
+		defer cancel()
+
+		b, err := vs.cache.GetBytes(opCtx, cacheKey)
+		if err != nil {
+			return nil, false
+		}
+		var cached Video
+		if err := json.Unmarshal(b, &cached); err != nil {
+			return nil, false
+		}
+		return &cached, true
+	}
+
+	setCached := func(video *Video) {
+		b, err := json.Marshal(video)
+		if err != nil {
+			return
+		}
+		opCtx, cancel := context.WithTimeout(ctx, 50*time.Millisecond)
+		defer cancel()
+		_ = vs.cache.SetBytes(opCtx, cacheKey, b, vs.cacheTTL)
+	}
+
+	if vs.cache != nil {
+		if v, ok := getCached(); ok {
+			return v, nil
+		}
+
+		opCtx, cancel := context.WithTimeout(ctx, 50*time.Millisecond)
+		b, err := vs.cache.GetBytes(opCtx, cacheKey)
+		cancel()
+		if err == nil {
+			var cached Video
+			if err := json.Unmarshal(b, &cached); err == nil {
+				return &cached, nil
+			}
+		} else if rediscache.IsMiss(err) {
+			lockKey := "lock:" + cacheKey
+
+			lockCtx, lockCancel := context.WithTimeout(ctx, 50*time.Millisecond)
+			token, locked, lockErr := vs.cache.Lock(lockCtx, lockKey, 2*time.Second)
+			lockCancel()
+
+			if lockErr == nil && locked {
+				defer func() { _ = vs.cache.Unlock(context.Background(), lockKey, token) }()
+
+				if v, ok := getCached(); ok {
+					return v, nil
+				}
+
+				video, err := vs.repo.GetByID(ctx, id)
+				if err != nil {
+					return nil, err
+				}
+				setCached(video)
+				return video, nil
+			}
+
+			// 没拿到锁：等待别人回填缓存
+			for i := 0; i < 5; i++ {
+				select {
+				case <-ctx.Done():
+					return nil, ctx.Err()
+				case <-time.After(20 * time.Millisecond):
+				}
+				if v, ok := getCached(); ok {
+					return v, nil
+				}
+			}
+		}
+	}
+
+	video, err := vs.repo.GetByID(ctx, id)
+	if err != nil {
+		return nil, err
+	}
+	if vs.cache != nil {
+		setCached(video)
+	}
+	return video, nil
+}
+
+func (vs *VideoService) UpdateLikesCount(ctx context.Context, id uint, likesCount int64) error {
+	if err := vs.repo.UpdateLikesCount(ctx, id, likesCount); err != nil {
+		return err
+	}
+	return nil
+}