Refactor caching logic and add support for a new feature

redis/client.go

@@ -16,6 +16,7 @@ type contextKey string
 const redisKey contextKey = "redisClient"
 
 const CacheKey = "top-wallpaper:latestImage"
+const NsfwCacheKey = "top-wallpaper-nsfw:latestImage"
 
 type Cache interface {
 	Get(key string) (string, error)
@@ -92,6 +93,14 @@ func (r *Redis) Set(key string, value string, expiration time.Duration) error {
 	return nil
 }
 
+func (*Redis) GetCacheKey(nsfw bool) string {
+	if nsfw {
+		return NsfwCacheKey
+	}
+
+	return CacheKey
+}
+
 func (r *Redis) Close() error {
 	if r.client == nil {
 		return nil