Add distinct() method to ming.mim.Collection

The new method is implemented as a command on the Database
connection, so that API works, too.

Signed-off-by: Doug Hellmann <doug.hellmann@dreamhost.com>

ming/mim.py

@@ -133,6 +133,10 @@ def command(self, command,
         elif 'mapreduce' in command:
             collection = command.pop('mapreduce')
             return self._handle_mapreduce(collection, **command)
+        elif 'distinct' in command:
+            collection = self._collections[command['distinct']]
+            key = command['key']
+            return list(set(d[key] for d in collection.find()))
         else:
             raise NotImplementedError, repr(command)
 
@@ -409,6 +413,11 @@ def map_reduce(self, map, reduce, out, full_response=False, **kwargs):
         cmd_args.update(kwargs)
         return self.database.command(cmd_args)
 
+    def distinct(self, key):
+        return self.database.command({'distinct': self.name,
+                                      'key': key,
+                                      })
+
 
 class Cursor(object):
 

ming/tests/test_mim.py

@@ -182,5 +182,9 @@ def test_upsert_push(self):
             upsert=True)
         doc = test.find_one()
         self.assertEqual(doc, dict(_id=0, a=5, c=[1]))
-
 
+    def test_distinct(self):
+        for i in range(5):
+            self.bind.db.coll.insert({'_id':str(i), 'a':'A'})
+        result = self.bind.db.coll.distinct('a')
+        self.assertEqual(result, ['A'])