implement icon cache expiry, cleanup code and upgrade deps

internal/api/v1/favicon/cache.go

@@ -0,0 +1,133 @@
+package favicon
+
+import (
+	"encoding/json"
+	"sync"
+	"time"
+
+	"github.com/yusing/go-proxy/internal/common"
+	"github.com/yusing/go-proxy/internal/logging"
+	route "github.com/yusing/go-proxy/internal/route/types"
+	"github.com/yusing/go-proxy/internal/task"
+	"github.com/yusing/go-proxy/internal/utils"
+)
+
+type cacheEntry struct {
+	Icon       []byte    `json:"icon"`
+	LastAccess time.Time `json:"lastAccess"`
+}
+
+// cache key can be absolute url or route name.
+var (
+	iconCache   = make(map[string]*cacheEntry)
+	iconCacheMu sync.RWMutex
+)
+
+const (
+	iconCacheTTL    = 24 * time.Hour
+	cleanUpInterval = time.Hour
+)
+
+func InitIconCache() {
+	err := utils.LoadJSONIfExist(common.IconCachePath, &iconCache)
+	if err != nil {
+		logging.Error().Err(err).Msg("failed to load icon cache")
+	} else {
+		logging.Info().Msgf("icon cache loaded (%d icons)", len(iconCache))
+	}
+
+	go func() {
+		cleanupTicker := time.NewTicker(cleanUpInterval)
+		defer cleanupTicker.Stop()
+		for {
+			select {
+			case <-task.RootContextCanceled():
+				return
+			case <-cleanupTicker.C:
+				pruneExpiredIconCache()
+			}
+		}
+	}()
+
+	task.OnProgramExit("save_favicon_cache", func() {
+		iconCacheMu.Lock()
+		defer iconCacheMu.Unlock()
+
+		if len(iconCache) == 0 {
+			return
+		}
+
+		if err := utils.SaveJSON(common.IconCachePath, &iconCache, 0o644); err != nil {
+			logging.Error().Err(err).Msg("failed to save icon cache")
+		}
+	})
+}
+
+func pruneExpiredIconCache() {
+	iconCacheMu.Lock()
+	defer iconCacheMu.Unlock()
+
+	nPruned := 0
+	for key, icon := range iconCache {
+		if icon.IsExpired() {
+			delete(iconCache, key)
+			nPruned++
+		}
+	}
+	logging.Info().Int("pruned", nPruned).Msg("pruned expired icon cache")
+}
+
+func routeKey(r route.HTTPRoute) string {
+	return r.RawEntry().Provider + ":" + r.TargetName()
+}
+
+func PruneRouteIconCache(route route.HTTPRoute) {
+	iconCacheMu.Lock()
+	defer iconCacheMu.Unlock()
+	delete(iconCache, routeKey(route))
+}
+
+func loadIconCache(key string) *fetchResult {
+	iconCacheMu.RLock()
+	defer iconCacheMu.RUnlock()
+
+	icon, ok := iconCache[key]
+	if ok && icon != nil {
+		logging.Debug().
+			Str("key", key).
+			Msg("icon found in cache")
+		icon.LastAccess = time.Now()
+		return &fetchResult{icon: icon.Icon}
+	}
+	return nil
+}
+
+func storeIconCache(key string, icon []byte) {
+	iconCacheMu.Lock()
+	defer iconCacheMu.Unlock()
+	iconCache[key] = &cacheEntry{Icon: icon, LastAccess: time.Now()}
+}
+
+func (e *cacheEntry) IsExpired() bool {
+	return time.Since(e.LastAccess) > iconCacheTTL
+}
+
+func (e *cacheEntry) UnmarshalJSON(data []byte) error {
+	attempt := struct {
+		Icon       []byte    `json:"icon"`
+		LastAccess time.Time `json:"lastAccess"`
+	}{}
+	err := json.Unmarshal(data, &attempt)
+	if err == nil {
+		e.Icon = attempt.Icon
+		e.LastAccess = attempt.LastAccess
+		return nil
+	}
+	// fallback to bytes
+	err = json.Unmarshal(data, &e.Icon)
+	if err == nil {
+		e.LastAccess = time.Now()
+		return nil
+	}
+	return err
+}