book: add cache for asset-rates

asset.py

@@ -0,0 +1,48 @@
+# -*- coding: utf-8 -*-
+# This file is part of the cashbook-module from m-ds.de for Tryton.
+# The COPYRIGHT file at the top level of this repository contains the
+# full copyright notices and license terms.
+
+from trytond.pool import Pool, PoolMeta
+CACHEKEY_ASSETRATE = 'assetrate-%s'
+
+
+class AssetRate(metaclass=PoolMeta):
+    __name__ = 'investment.rate'
+
+    @classmethod
+    def create(cls, vlist):
+        """ update cache-value
+        """
+        MemCache = Pool().get('cashbook.memcache')
+
+        records = super(AssetRate, cls).create(vlist)
+        for rate in records:
+            MemCache.record_update(CACHEKEY_ASSETRATE % rate.asset.id, rate)
+        return records
+
+    @classmethod
+    def write(cls, *args):
+        """ update cache-value
+        """
+        MemCache = Pool().get('cashbook.memcache')
+
+        super(AssetRate, cls).write(*args)
+
+        actions = iter(args)
+        for rates, values in zip(actions, actions):
+            for rate in rates:
+                MemCache.record_update(CACHEKEY_ASSETRATE % rate.asset.id, rate)
+
+    @classmethod
+    def delete(cls, records):
+        """ set cache to None
+        """
+        MemCache = Pool().get('cashbook.memcache')
+
+        for record in records:
+            MemCache.record_update(CACHEKEY_ASSETRATE % record.asset.id, None)
+        super(AssetRate, cls).delete(records)
+
+# end
+