Move AddrCache to Milter package.

Milter/cache.py

@@ -0,0 +1,108 @@
+# Email address list with expiration
+#
+# This class acts like a map.  Entries with a value of None are persistent,
+# but disappear after a time limit.  This is useful for automatic whitelists
+# and blacklists with expiration.  The persistent store is a simple ascii
+# file with sender and timestamp on each line.  Entries can be appended
+# to the store, and will be picked up the next time it is loaded.
+#
+# Entries with other values are not persistent.  This is used to hold failed
+# CBV results.
+#
+# $Log$
+
+# Author: Stuart D. Gathman <stuart@bmsi.com>
+# Copyright 2001,2002,2003,2004,2005 Business Management Systems, Inc.
+# This code is under the GNU General Public License.  See COPYING for details.
+
+import time
+
+class AddrCache(object):
+  time_format = '%Y%b%d %H:%M:%S %Z'
+
+  def __init__(self,renew=7,fname=None):
+    self.age = renew
+    self.cache = {}
+    self.fname = fname
+
+  def load(self,fname,age=0):
+    "Load address cache from persistent store."
+    if not age:
+      age = self.age
+    self.fname = fname
+    cache = {}
+    self.cache = cache
+    now = time.time()
+    try:
+      too_old = now - age*24*60*60	# max age in days
+      for ln in open(self.fname):
+	try:
+	  rcpt,ts = ln.strip().split(None,1)
+	  l = time.strptime(ts,AddrCache.time_format)
+	  t = time.mktime(l)
+	  if t > too_old:
+	    cache[rcpt.lower()] = (t,None)
+	except:
+	  cache[ln.strip().lower()] = (now,None)
+    except IOError: pass
+
+  def has_key(self,sender):
+    "True if sender is cached and has not expired."
+    try:
+      lsender = sender.lower()
+      ts,res = self.cache[lsender]
+      too_old = time.time() - self.age*24*60*60	# max age in days
+      if not ts or ts > too_old:
+        return True
+      del self.cache[lsender]
+      try:
+	user,host = sender.split('@',1)
+	return self.has_key(host)
+      except ValueError:
+        pass
+    except KeyError:
+      try:
+	user,host = sender.split('@',1)
+	return self.has_key(host)
+      except ValueError:
+        pass
+    return False
+
+  def __getitem__(self,sender):
+    try:
+      lsender = sender.lower()
+      ts,res = self.cache[lsender]
+      too_old = time.time() - self.age*24*60*60	# max age in days
+      if not ts or ts > too_old:
+	return res
+      del self.cache[lsender]
+      raise KeyError, sender
+    except KeyError,x:
+      try:
+	user,host = sender.split('@',1)
+	return self.__getitem__(host)
+      except ValueError:
+        raise x
+
+  def addperm(self,sender,res=None):
+    "Add a permanent sender."
+    lsender = sender.lower()
+    if self.has_key(lsender):
+      ts,res = self.cache[lsender]
+      if not ts: return		# already permanent
+    self.cache[lsender] = (None,res)
+    if not res:
+      print >>open(self.fname,'a'),sender
+    
+  def __setitem__(self,sender,res):
+    lsender = sender.lower()
+    now = time.time()
+    cached = self.has_key(sender)
+    if not cached:
+      self.cache[lsender] = (now,res)
+      if not res and self.fname:
+	s = time.strftime(AddrCache.time_format,time.localtime(now))
+	print >>open(self.fname,'a'),sender,s # log refreshed senders
+
+  def __len__(self):
+    return len(self.cache)