Molodetz blogrol volgens DPP-template

molodetz/cache.py

@@ -0,0 +1,54 @@
+# retoor <retoor@molodetz.nl>
+import threading
+import time
+
+
+class TTLCache:
+    def __init__(self, ttl=60, max_size=1000):
+        self.ttl = ttl
+        self.max_size = max_size
+        self._data = {}
+        self._lock = threading.Lock()
+
+    def get(self, key, default=None):
+        if self.ttl <= 0:
+            return default
+        with self._lock:
+            item = self._data.get(key)
+            if item is None:
+                return default
+            expires, value = item
+            if expires < time.monotonic():
+                self._data.pop(key, None)
+                return default
+            return value
+
+    def set(self, key, value):
+        if self.ttl <= 0:
+            return
+        with self._lock:
+            if len(self._data) >= self.max_size:
+                self._evict()
+            self._data[key] = (time.monotonic() + self.ttl, value)
+
+    def pop(self, key):
+        with self._lock:
+            self._data.pop(key, None)
+
+    def clear(self):
+        with self._lock:
+            self._data.clear()
+
+    def __contains__(self, key):
+        return self.get(key, _MISSING) is not _MISSING
+
+    def _evict(self):
+        now = time.monotonic()
+        expired = [k for k, (exp, _) in self._data.items() if exp < now]
+        for key in expired:
+            self._data.pop(key, None)
+        while len(self._data) >= self.max_size:
+            self._data.pop(next(iter(self._data)))
+
+
+_MISSING = object()