use memcached as the cache backend

evelink/cache/memcached.py

@@ -0,0 +1,36 @@
+import pickle
+import time
+import memcache
+
+from evelink import api
+
+class MemcachedCache(api.APICache):
+    """An implementation of APICache using memcached."""
+
+    def __init__(self, serverList, prefix='el_'):
+        """
+        serverList could be ['127.0.0.1:11211']
+        prefix allows multiple applications to share the same memcached instance if necessary
+        """
+        super(MemcachedCache, self).__init__()
+        self.mc = memcache.Client(serverList, debug=0)
+        self.prefix = prefix
+
+
+    def get(self, key):
+        prefix_key = self.prefix + key
+        result = self.mc.get(prefix_key)
+        if not result:
+            return None
+        value, expiration = result
+        if expiration < time.time():
+            self.mc.delete(prefix_key)
+            return None
+        return value
+
+    def put(self, key, value, duration):
+        prefix_key = self.prefix + key
+        expiration = time.time() + duration
+        res = self.mc.set(prefix_key, (value, expiration), time=duration)
+        return res
+