Python-side evaluation of MongoDB filter documents.

marrow/mongo/evaluate.py

@@ -0,0 +1,39 @@
+# encoding: utf-8
+
+
+
+
+
+
+def matches(data, query):
+	pass
+
+
+def filter(records, query):
+	for record in records:
+		if matches(record, query):
+			yield record
+
+
+def project(data, query):
+	"""MongoDB-style record projection."""
+	include = {'_id'} if '_id' in data else set()
+	exclude = set()
+
+	for field in query:
+		if field not in data:
+			continue
+
+		if query[field]:
+			include.add(field)
+			continue
+
+		exclude.add(field)
+
+		if field in include:
+			include.remove(field)
+
+	if exclude and exclude != {'_id'}:
+		return data.__class__({i: data[i] for i in data if i not in exclude})
+
+	return data.__class__({i: data[i] for i in include})