Refs. #30. Create a base engine class ``pyzor.engines.common.BaseEngi…

…ne``.

Add a base class for engines with stubs for all methods that require
implementation for a pyzord server engine.

The ``whitelist`` and ``report`` methods are exceptions to this, as
noted in the documentation.

pyzor/engines/common.py

@@ -5,7 +5,7 @@
 
 from collections import namedtuple
 
-__all__ = ["DBHandle", "DatabaseError", "Record"]
+__all__ = ["DBHandle", "DatabaseError", "Record", "BaseEngine"]
 
 DBHandle = namedtuple("DBHandle", ["single_threaded", "multi_threaded",
                                    "multi_processing", "prefork"])
@@ -51,3 +51,59 @@ def r_update(self):
     def wl_update(self):
         self.wl_updated = datetime.datetime.now()
 
+
+class BaseEngine(object):
+    """Base class for Pyzor engines."""
+    absolute_source = True
+    handles_one_step = False
+
+    def __iter__(self):
+        """Iterate over all keys"""
+        raise NotImplementedError()
+
+    def iteritems(self):
+        """Iterate over pairs of (key, record)."""
+        raise NotImplementedError()
+
+    def items(self):
+        """Return a list of (key, record)."""
+        raise NotImplementedError()
+
+    def __getitem__(self, key):
+        """Get the record for this corresponding key."""
+        raise NotImplementedError()
+
+    def __setitem__(self, key, value):
+        """Set the record for this corresponding key. 'value' should be a
+        instance of the ``Record`` class.
+        """
+        raise NotImplementedError()
+
+    def __delitem__(self, key):
+        """Remove the corresponding record from the database."""
+        raise NotImplementedError()
+
+    def report(self, keys):
+        """Report the corresponding key as spam, incrementing the report count.
+
+        Engines that implement don't implement this method should have
+        handles_one_step set to False.
+        """
+        raise NotImplementedError()
+
+    def whitelist(self, keys):
+        """Report the corresponding key as ham, incrementing the whitelist
+        count.
+
+        Engines that implement don't implement this method should have
+        handles_one_step set to False.
+        """
+
+        raise NotImplementedError()
+
+    @classmethod
+    def get_prefork_connections(cls, fn, mode, max_age=None):
+        """Yields an unlimited number of partial functions that return a new
+        engine instance, suitable for using toghether with the Pre-Fork server.
+        """
+        raise NotImplementedError()

pyzor/engines/gdbm_.py

@@ -15,7 +15,7 @@
 import datetime
 import threading
 
-from pyzor.engines.common import Record, DBHandle
+from pyzor.engines.common import Record, DBHandle, BaseEngine
 
 
 def _dt_decode(datetime_str):
@@ -28,7 +28,7 @@ def _dt_decode(datetime_str):
         return datetime.datetime.strptime(datetime_str, "%Y-%m-%d %H:%M:%S")
 
 
-class GdbmDBHandle(object):
+class GdbmDBHandle(BaseEngine):
     absolute_source = True
     handles_one_step = False
 

pyzor/engines/mysql.py

@@ -22,7 +22,7 @@
 from pyzor.engines.common import *
 
 
-class MySQLDBHandle(object):
+class MySQLDBHandle(BaseEngine):
     absolute_source = False
     handles_one_step = True
     # The table must already exist, and have this schema:

pyzor/engines/redis_.py

@@ -37,7 +37,7 @@ def wrapped_f(self, *args, **kwargs):
     return wrapped_f
 
 
-class RedisDBHandle(object):
+class RedisDBHandle(BaseEngine):
     absolute_source = False
     handles_one_step = False