feat(social): cache trending hashtags in Redis

veza-backend-api/internal/api/routes_social.go

@@ -10,6 +10,9 @@ import (
 // setupSocialRoutes configure les routes sociales
 func (r *APIRouter) setupSocialRoutes(router *gin.RouterGroup) {
 	socialService := socialcore.NewService(r.db.GormDB, r.logger)
+	if r.config.CacheService != nil {
+		socialService.SetCacheService(r.config.CacheService)
+	}
 	socialHandler := handlers.NewSocialHandler(socialService, r.logger)
 	groupHandler := handlers.NewGroupHandler(socialService, r.logger)
 

veza-backend-api/internal/core/social/service.go

@@ -7,6 +7,8 @@ import (
 	"github.com/google/uuid"
 	"go.uber.org/zap"
 	"gorm.io/gorm"
+
+	"veza-backend-api/internal/services"
 )
 
 // SocialService gère les interactions sociales
@@ -30,8 +32,14 @@ type SocialService interface {
 
 // Service implémente SocialService
 type Service struct {
-	db     *gorm.DB
-	logger *zap.Logger
+	db           *gorm.DB
+	logger       *zap.Logger
+	cacheService *services.CacheService // optional, for trending cache
+}
+
+// SetCacheService définit le service de cache (optionnel, pour trending)
+func (s *Service) SetCacheService(cache *services.CacheService) {
+	s.cacheService = cache
 }
 
 // NewService crée une nouvelle instance du service social

veza-backend-api/internal/core/social/trending_service.go

@@ -5,6 +5,7 @@ import (
 	"regexp"
 	"sort"
 	"strings"
+	"time"
 )
 
 // TrendingTag represents a hashtag with its occurrence count
@@ -16,8 +17,12 @@ type TrendingTag struct {
 // trendingHashtagRegex matches #word patterns in post content
 var trendingHashtagRegex = regexp.MustCompile(`#(\w+)`)
 
+const trendingCacheKey = "trending:hashtags"
+const trendingCacheTTL = 15 * time.Minute
+const trendingCacheLimit = 50
+
 // GetTrendingHashtags extracts hashtags from recent posts and returns them sorted by count.
-// Posts from the last 7 days are considered.
+// Posts from the last 7 days are considered. Uses Redis cache if available (15 min TTL).
 func (s *Service) GetTrendingHashtags(ctx context.Context, limit int) ([]TrendingTag, error) {
 	if limit <= 0 {
 		limit = 10
@@ -26,6 +31,17 @@ func (s *Service) GetTrendingHashtags(ctx context.Context, limit int) ([]Trendin
 		limit = 50
 	}
 
+	// Try cache first (cache stores top 50, we slice to limit)
+	if s.cacheService != nil {
+		var cached []TrendingTag
+		if err := s.cacheService.Get(ctx, trendingCacheKey, &cached); err == nil {
+			if len(cached) >= limit {
+				return cached[:limit], nil
+			}
+			return cached, nil
+		}
+	}
+
 	var posts []Post
 	if err := s.db.WithContext(ctx).
 		Where("created_at > NOW() - INTERVAL '7 days'").
@@ -58,6 +74,15 @@ func (s *Service) GetTrendingHashtags(ctx context.Context, limit int) ([]Trendin
 		return result[i].Tag < result[j].Tag
 	})
 
+	// Cache full result (top 50) for future requests
+	if s.cacheService != nil && len(result) > 0 {
+		toCache := result
+		if len(toCache) > trendingCacheLimit {
+			toCache = toCache[:trendingCacheLimit]
+		}
+		_ = s.cacheService.Set(ctx, trendingCacheKey, toCache, trendingCacheTTL)
+	}
+
 	if len(result) > limit {
 		result = result[:limit]
 	}