feat: add onlyUpdateCache option

cache.go

@@ -80,9 +80,11 @@ func cache(
 			respCache := &ResponseCache{}
 			err := cacheStore.Get(cacheKey, &respCache)
 			if err == nil {
-				replyWithCache(c, cfg, respCache)
-				cfg.hitCacheCallback(c)
-				return
+				if !cfg.onlyUpdateCache {
+					replyWithCache(c, cfg, respCache)
+					cfg.hitCacheCallback(c)
+					return
+				}
 			}
 
 			if err != persist.ErrCacheMiss {

cache_test.go

@@ -221,6 +221,24 @@ func TestCacheByRequestURIIgnoreOrder(t *testing.T) {
 	assert.NotEqual(t, w3.Body, w1.Body)
 }
 
+func TestCacheByRequestURIOnlyUpdateCache(t *testing.T) {
+	memoryStore := persist.NewMemoryStore(1 * time.Minute)
+	cacheURIMiddleware := CacheByRequestURI(memoryStore, 3*time.Second)
+
+	w1 := mockHttpRequest(cacheURIMiddleware, "/cache?uid=u1", true)
+	w2 := mockHttpRequest(cacheURIMiddleware, "/cache?uid=u1", true)
+	assert.Equal(t, w1.Body, w2.Body)
+
+	cacheURIMiddlewareOnlyUpdateCache := CacheByRequestURI(memoryStore, 3*time.Second, OnlyUpdateCache())
+
+	w3 := mockHttpRequest(cacheURIMiddlewareOnlyUpdateCache, "/cache?uid=u1", true)
+	w4 := mockHttpRequest(cacheURIMiddlewareOnlyUpdateCache, "/cache?uid=u1", true)
+	assert.NotEqual(t, w3.Body, w4.Body)
+
+	w5 := mockHttpRequest(cacheURIMiddleware, "/cache?uid=u1", true)
+	assert.Equal(t, w5.Body, w4.Body)
+}
+
 const prefixKey = "#prefix#"
 
 func TestPrefixKey(t *testing.T) {

option.go

@@ -24,6 +24,7 @@ type Config struct {
 	prefixKey        string
 	withoutHeader    bool
 	discardHeaders   []string
+	onlyUpdateCache  bool
 }
 
 func newConfigByOpts(opts ...Option) *Config {
@@ -148,6 +149,12 @@ func IgnoreQueryOrder() Option {
 	}
 }
 
+func OnlyUpdateCache() Option {
+	return func(c *Config) {
+		c.onlyUpdateCache = true
+	}
+}
+
 // WithPrefixKey will prefix the key
 func WithPrefixKey(prefix string) Option {
 	return func(c *Config) {