Implement sliding window type

halon-extras · Mar 28, 2023 · 7e8ca43 · 7e8ca43
1 parent 56d32d2
commit 7e8ca43
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Showing 2 changed files with 37 additions and 1 deletion.
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -1,6 +1,6 @@
 CMAKE_MINIMUM_REQUIRED(VERSION 3.0)
 
-PROJECT("rate-redis" VERSION 1.0.0)
+PROJECT("rate-redis" VERSION 1.1.0)
 
 IF (EXISTS "${CMAKE_CURRENT_BINARY_DIR}/CPACK_GENERATOR.txt")
 	FILE(STRINGS ${CMAKE_CURRENT_BINARY_DIR}/CPACK_GENERATOR.txt CPACK_GENERATOR)

diff --git a/rate.hsl b/rate.hsl
@@ -29,3 +29,39 @@ function rate($namespace, $entry, $count, $interval) {
     if ($response["error"]) throw Exception($response["error"]);
     return true;
 }
+
+function rate_sliding_window($namespace, $entry, $count, $interval) {
+    $time = time();
+
+    $currentWindow = floor($time / $interval);
+    $response = redisClusterCommand("GET", "$namespace:$entry:$currentWindow");
+    if ($response["error"]) throw Exception($response["error"]);
+    $currentWindowCount = number($response["reply"]);
+
+    if ($count === 0) {
+        return $currentWindowCount;
+    }
+
+    if ($currentWindowCount === 0) {
+        $response = redisClusterCommand("SET", "$namespace:$entry:$currentWindow", "0", "EX", string($interval * 2));
+        if ($response["error"]) throw Exception($response["error"]);
+    }
+
+    if ($currentWindowCount >= $count) {
+        return false;
+    }
+
+    $lastWindow = round(($time - $interval) / $interval);
+    $response = redisClusterCommand("GET", "$namespace:$entry:$lastWindow");
+    if ($response["error"]) throw Exception($response["error"]);
+    $lastWindowCount = number($response["reply"]);
+
+    $elapsedTimePercentage = ($time % $interval) / $interval;
+    if ($lastWindowCount * (1 - $elapsedTimePercentage) + $currentWindowCount >= $count) {
+        return false;
+    }
+
+    $response = redisClusterCommand("INCR", "$namespace:$entry:$currentWindow");
+    if ($response["error"]) throw Exception($response["error"]);
+    return true;
+}