Added the possibility of retrieving query cache with a timestamp

api.go

@@ -59,7 +59,14 @@ func StartAPIServer(config *Config,
 	})
 
 	router.GET("/questioncache", func(c *gin.Context) {
-		c.IndentedJSON(http.StatusOK, gin.H{"length": questionCache.Length(), "items": questionCache.Backend})
+		highWater, err := strconv.ParseInt(c.DefaultQuery("highWater", "-1"), 10, 64)
+		if err != nil {
+			highWater = -1
+		}
+		c.IndentedJSON(http.StatusOK, gin.H{
+			"length": questionCache.Length(),
+			"items":  questionCache.GetOlder(highWater),
+		})
 	})
 
 	router.GET("/questioncache/length", func(c *gin.Context) {

cache.go

@@ -302,3 +302,15 @@ func (c *MemoryQuestionCache) Length() int {
 	defer c.mu.RUnlock()
 	return len(c.Backend)
 }
+
+// GetOlder eturns a slice of the entries older than `time`
+func (c *MemoryQuestionCache) GetOlder(time int64) []QuestionCacheEntry {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+	for i, e := range c.Backend {
+		if e.Date > time {
+			return c.Backend[i:]
+		}
+	}
+	return []QuestionCacheEntry{}
+}

cache_test.go

@@ -283,3 +283,28 @@ func TestExpirationRace(t *testing.T) {
 		go cache.Set(testDomain, m, true)
 	}
 }
+
+func addToCache(cache *MemoryQuestionCache, time int64) {
+	cache.Add(QuestionCacheEntry{
+		Date:    time,
+		Remote:  fmt.Sprintf("%d", time),
+		Blocked: true,
+		Query:   Question{},
+	})
+}
+
+func TestQuestionCacheGetFromTimestamp(t *testing.T) {
+	memCache := makeQuestionCache(100)
+	for i := 0; i < 100; i++ {
+		addToCache(memCache, int64(i))
+	}
+
+	entries := memCache.GetOlder(50)
+	assert.Len(t, entries, 49)
+	entries = memCache.GetOlder(0)
+	assert.Len(t, entries, 99)
+	entries = memCache.GetOlder(-1)
+	assert.Len(t, entries, 100)
+	entries = memCache.GetOlder(200)
+	assert.Len(t, entries, 0)
+}

config.go

@@ -78,7 +78,7 @@ apidebug = false
 bind = "0.0.0.0:53"
 
 # address to bind to for the API server
-api = "127.0.0.1:18080"
+api = "127.0.0.1:8080"
 
 # ipv4 address to forward blocked queries to
 nullroute = "0.0.0.0"

main.go

@@ -69,8 +69,7 @@ func main() {
 	// BlockCache contains all blocked domains
 	blockCache := &MemoryBlockCache{Backend: make(map[string]bool)}
 	// QuestionCache contains all queries to the dns server
-	questionCache := &MemoryQuestionCache{Backend: make([]QuestionCacheEntry, 0), Maxcount: 1000}
-	questionCache.Maxcount = config.QuestionCacheCap
+	questionCache := makeQuestionCache(config.QuestionCacheCap)
 
 	reloadChan := make(chan bool)
 

utils.go

@@ -0,0 +1,12 @@
+package main
+
+func makeCache() MemoryCache {
+	return MemoryCache{
+		Backend:  make(map[string]*Mesg, 0),
+		Maxcount: 0,
+	}
+}
+
+func makeQuestionCache(maxCount int) *MemoryQuestionCache {
+	return &MemoryQuestionCache{Backend: make([]QuestionCacheEntry, 0), Maxcount: maxCount}
+}