Add rate limiting code

implementations/python/rate_limiting/sliding_window_counter.py

@@ -0,0 +1,39 @@
+import time
+
+class SlidingWindowCounter:
+    def __init__(self, window_size, max_requests):
+        self.window_size = window_size  # Size of the sliding window in seconds
+        self.max_requests = max_requests  # Maximum number of requests per window
+        self.current_window = time.time() // window_size
+        self.request_count = 0
+        self.previous_count = 0
+
+    def allow_request(self):
+        now = time.time()
+        window = now // self.window_size
+
+        # If we've moved to a new window, update the counts
+        if window != self.current_window:
+            self.previous_count = self.request_count
+            self.request_count = 0
+            self.current_window = window
+
+        # Calculate the weighted request count
+        window_elapsed = (now % self.window_size) / self.window_size
+        threshold = self.previous_count * (1 - window_elapsed) + self.request_count
+
+        # Check if we're within the limit
+        if threshold < self.max_requests:
+            self.request_count += 1
+            return True
+        return False
+
+# Usage example
+limiter = SlidingWindowCounter(window_size=60, max_requests=5)  # 5 requests per minute
+
+for _ in range(10):
+    print(limiter.allow_request())  # Will print True for the first 5 requests, then gradually become False
+    time.sleep(0.1)  # Wait a bit between requests
+
+time.sleep(30)  # Wait for half the window to pass
+print(limiter.allow_request())  # Might be True or False depending on the exact timing