Storyden

package node_cache import ( "context" "time" "go.uber.org/fx" "github.com/Southclaws/storyden/app/resources/cachecontrol" "github.com/Southclaws/storyden/internal/infrastructure/cache" "github.com/Southclaws/storyden/internal/infrastructure/pubsub" ) const ( cachePrefix = "node:last-modified:" cacheTTL = time.Hour * 6 storeTimeFmt = time.RFC3339Nano ) type Cache struct { store cache.Store clock func() time.Time } func New( ctx context.Context, lc fx.Lifecycle, store cache.Store, bus *pubsub.Bus, ) *Cache { c := &Cache{ store: store, clock: time.Now, } register := func(hook fx.Hook) { lc.Append(hook) } register(fx.StartHook(func(hctx context.Context) error { return c.subscribe(ctx, bus) })) return c } func (c *Cache) IsNotModified(ctx context.Context, cq cachecontrol.Query, key string) bool { return cq.NotModified(func() *time.Time { return c.lastModified(ctx, key) }) } func (c *Cache) LastModified(ctx context.Context, key string) *time.Time { return c.lastModified(ctx, key) } func (c *Cache) Store(ctx context.Context, key string, ts time.Time) error { return c.storeTimestamp(ctx, key, ts) } func (c *Cache) cacheKey(key string) string { return cachePrefix + key } func (c *Cache) lastModified(ctx context.Context, key string) *time.Time { if ts, ok := c.cached(ctx, key); ok { return ts } return nil } func (c *Cache) cached(ctx context.Context, key string) (*time.Time, bool) { val, err := c.store.Get(ctx, c.cacheKey(key)) if err != nil { return nil, false } ts, err := time.Parse(storeTimeFmt, val) if err != nil { _ = c.store.Delete(ctx, c.cacheKey(key)) return nil, false } return &ts, true } func (c *Cache) storeTimestamp(ctx context.Context, key string, ts time.Time) error { return c.store.Set(ctx, c.cacheKey(key), ts.UTC().Format(storeTimeFmt), cacheTTL) } func (c *Cache) Invalidate(ctx context.Context, key string) error { now := c.clock().UTC() if ts, ok := c.cached(ctx, key); ok { nowTrunc := now.Truncate(time.Second) tsTrunc := ts.Truncate(time.Second) if !nowTrunc.After(tsTrunc) { now = tsTrunc.Add(time.Second) } } return c.storeTimestamp(ctx, key, now) } func (c *Cache) delete(ctx context.Context, key string) error { return c.store.Delete(ctx, c.cacheKey(key)) }