From 378bc42393b71f5ea2cf220dbcd3f1ff71781c8e Mon Sep 17 00:00:00 2001
From: "Scott R. Parish" <sparish@peak6.com>
Date: Mon, 18 Jan 2010 15:03:13 -0600
Subject: [PATCH] collectionNames

---
 Database/MongoDB.hs | 19 +++++++++++++++++--
 TODO                |  1 -
 2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/Database/MongoDB.hs b/Database/MongoDB.hs
index 5ec9636..51721dd 100644
--- a/Database/MongoDB.hs
+++ b/Database/MongoDB.hs
@@ -28,7 +28,10 @@ module Database.MongoDB
      -- * Connection
      Connection,
      connect, connectOnPort, conClose, disconnect,
-     -- * Basic database operations
+     -- * Database operations
+     Database,
+     collectionNames,
+     -- * Collection operations
      Collection, FieldSelector, NumToSkip, NumToReturn, Selector,
      QueryOpt(..),
      UpdateFlag(..),
@@ -52,8 +55,9 @@ import qualified Data.ByteString.Lazy.UTF8 as L8
 import Data.Int
 import Data.IORef
 import qualified Data.List as List
+import Data.Maybe
 import Data.Typeable
-import Database.MongoDB.BSON
+import Database.MongoDB.BSON as BSON
 import Database.MongoDB.Util
 import qualified Network
 import Network.Socket hiding (connect, send, sendTo, recv, recvFrom)
@@ -88,6 +92,14 @@ conClose = hClose . cHandle
 disconnect :: Connection -> IO ()
 disconnect = conClose
 
+-- | Return a list of collections in /Database/.
+collectionNames :: Connection -> Database -> IO [Collection]
+collectionNames c db = do
+  docs <- quickFind' c (db ++ ".system.namespaces") $ toBsonDoc []
+  let names = flip List.map docs $ \doc ->
+              fromBson $ fromJust $ BSON.lookup (L8.fromString "name") doc
+  return $ List.filter (not . List.elem '$') names
+
 -- | An Itertaor over the results of a query. Use 'nextDoc' to get each
 -- successive result document, or 'allDocs' or 'allDocs'' to get lazy or
 -- strict lists of results.
@@ -146,6 +158,9 @@ toOpcode 2006 = OP_DELETE
 toOpcode 2007 = OP_KILL_CURSORS
 toOpcode n = throw $ MongoDBInternalError $ "Got unexpected Opcode: " ++ show n
 
+-- | The name of a database.
+type Database = String
+
 -- | The full collection name. The full collection name is the
 -- concatenation of the database name with the collection name, using
 -- a @.@ for the concatenation. For example, for the database @foo@
diff --git a/TODO b/TODO
index 6012d7d..ead6d5f 100644
--- a/TODO
+++ b/TODO
@@ -23,7 +23,6 @@ MongoDB
   - pair mode connection
   - operations on database objects
     * getName
-    * getCollectionNames
     * getCollection
     * dropCollection
     * executeCommand