From aeaa7095cf91ed8470e2604c8c81c86dec1ce59e Mon Sep 17 00:00:00 2001
From: Michael Stephens <me@mikej.st>
Date: Thu, 17 Jun 2010 17:52:43 -0400
Subject: [PATCH] added UniqueID filter

---
 saucebrush/filters.py | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/saucebrush/filters.py b/saucebrush/filters.py
index 93de546..94c5c4a 100644
--- a/saucebrush/filters.py
+++ b/saucebrush/filters.py
@@ -339,6 +339,27 @@ class Unique(ConditionalFilter):
         else:
             return False
 
+class UniqueID(ConditionalFilter):
+    """ Filter that ensures that all records through have a unique ID.
+
+        Takes the name of an ID field, or multiple field names in the case
+        of a composite ID.
+    """
+
+    def __init__(self, field='id', *args):
+        super(UniqueID, self).__init__()
+        self._seen = set()
+        self._id_fields = [field]
+        self._id_fields.extend(args)
+
+    def test_record(self, record):
+        id_hash = hash(repr([record[key] for key in self._id_fields]))
+        if id_hash not in self._seen:
+            self._seen.add(id_hash)
+            return True
+        else:
+            return False
+
 class UnicodeFilter(Filter):
     """ Convert all str elements in the record to Unicode.
     """