initial MongoDB.hs: can insert and delete

Database/MongoDB.hs

@@ -0,0 +1,146 @@
+module Database.MongoDB
+    (
+     connect, connectOnPort,
+     delete,
+     remove,
+     insert,
+     insertMany,
+     query
+    )
+where
+import Control.Monad
+import Data.Binary
+import Data.Binary.Put
+import Data.ByteString.Char8
+import qualified Data.ByteString.Lazy as L
+import qualified Data.ByteString.Lazy.UTF8 as L8
+import Data.Int
+import Data.IORef
+import qualified Data.List as List
+import Database.MongoDB.BSON
+import Database.MongoDB.Util
+import qualified Network
+import Network.Socket hiding (connect, send, sendTo, recv, recvFrom)
+import Prelude hiding (getContents)
+import System.IO
+import System.Random
+
+data Connection = Connection { cHandle :: Handle, cRand :: IORef [Int] }
+
+connect :: HostName -> IO Connection
+connect = flip connectOnPort $ Network.PortNumber 27017
+
+connectOnPort :: HostName -> Network.PortID -> IO Connection
+connectOnPort host port = do
+  h <- Network.connectTo host port
+  hSetBuffering h NoBuffering
+  r <- newStdGen
+  let ns = randomRs (fromIntegral (minBound :: Int32),
+                     fromIntegral (maxBound :: Int32)) r
+  nsRef <- newIORef ns
+  return $ Connection { cHandle = h, cRand = nsRef }
+
+data Opcode
+    = OP_REPLY          -- 1     Reply to a client request. responseTo is set
+    | OP_MSG            -- 1000	 generic msg command followed by a string
+    | OP_UPDATE         -- 2001  update document
+    | OP_INSERT	        -- 2002	 insert new document
+    | OP_GET_BY_OID	-- 2003	 is this used?
+    | OP_QUERY	        -- 2004	 query a collection
+    | OP_GET_MORE	-- 2005	 Get more data from a query. See Cursors
+    | OP_DELETE	        -- 2006	 Delete documents
+    | OP_KILL_CURSORS	-- 2007	 Tell database client is done with a cursor
+    deriving (Show, Eq)
+
+fromOpcode OP_REPLY        =    1
+fromOpcode OP_MSG          = 1000
+fromOpcode OP_UPDATE       = 2001
+fromOpcode OP_INSERT       = 2002
+fromOpcode OP_GET_BY_OID   = 2003
+fromOpcode OP_QUERY        = 2004
+fromOpcode OP_GET_MORE     = 2005
+fromOpcode OP_DELETE       = 2006
+fromOpcode OP_KILL_CURSORS = 2007
+
+toOpcode    1 = OP_REPLY
+toOpcode 1000 = OP_MSG
+toOpcode 2001 = OP_UPDATE
+toOpcode 2002 = OP_INSERT
+toOpcode 2003 = OP_GET_BY_OID
+toOpcode 2004 = OP_QUERY
+toOpcode 2005 = OP_GET_MORE
+toOpcode 2006 = OP_DELETE
+toOpcode 2007 = OP_KILL_CURSORS
+
+type Collection = String
+type Selector = BSONObject
+type FieldSelector = BSONObject
+type RequestID = Int32
+type NumToSkip = Int32
+type NumToReturn = Int32
+
+delete :: Connection -> Collection -> Selector -> IO RequestID
+delete c col sel = do
+  let body = runPut $ do
+                     putI32 0
+                     putCol col
+                     putI32 0
+                     put sel
+  (reqId, msg) <- packMsg c OP_DELETE body
+  L.hPut (cHandle c) msg
+  return reqId
+
+remove = delete
+
+insert :: Connection -> Collection -> BSONObject -> IO RequestID
+insert c col doc = do
+  let body = runPut $ do
+                     putI32 0
+                     putCol col
+                     put doc
+  (reqId, msg) <- packMsg c OP_INSERT body
+  L.hPut (cHandle c) msg
+  return reqId
+
+insertMany :: Connection -> Collection -> [BSONObject] -> IO RequestID
+insertMany c col docs = do
+  let body = runPut $ do
+               putI32 0
+               putCol col
+               forM_ docs put
+  (reqId, msg) <- packMsg c OP_INSERT body
+  L.hPut (cHandle c) msg
+  return reqId
+
+query :: Connection -> Collection -> NumToSkip -> NumToReturn -> Selector ->
+         Maybe FieldSelector -> IO RequestID
+query c col skip ret sel fsel = do
+  let body = runPut $ do
+               putI32 0 -- TODO opts
+               putCol col
+               putI32 skip
+               putI32 ret
+               put sel
+               put fsel
+  (reqId, msg) <- packMsg c OP_QUERY body
+  L.hPut (cHandle c) msg
+  return reqId
+
+
+putCol col = putByteString (pack col) >> putNull
+
+packMsg :: Connection -> Opcode -> L.ByteString -> IO (RequestID, L.ByteString)
+packMsg c op body = do
+  reqId <- randNum c
+  let msg = runPut $ do
+                      putI32 $ fromIntegral $ L.length body + 16
+                      putI32 reqId
+                      putI32 0
+                      putI32 $ fromOpcode op
+                      putLazyByteString body
+  return (reqId, msg)
+
+randNum :: Connection -> IO Int32
+randNum Connection { cRand = nsRef } = atomicModifyIORef nsRef $ \ns ->
+                                       (List.tail ns,
+                                        fromIntegral $ List.head ns)

mongoDB.cabal

@@ -6,8 +6,11 @@ Build-Depends:       base,
 		     bytestring,
 		     containers,
 		     data-binary-ieee754,
+		     network,
+		     random,
 		     time,
 		     utf8-string
 Build-Type:          Simple
-Exposed-modules:     Database.MongoDB.BSON
+Exposed-modules:     Database.MongoDB,
+		     Database.MongoDB.BSON
 Other-modules:       Database.MongoDB.Util