mongodb/Database/MongoDB.hs

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{-
Copyright (C) 2010 Scott R Parish <srp@srparish.net>
Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:
The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-}
module Database.MongoDB
(
-- * Connection
Connection,
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connect, connectOnPort, conClose, disconnect, dropDatabase,
serverInfo, serverShutdown,
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databasesInfo, databaseNames,
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-- * Database
Database, MongoDBCollectionInvalid,
ColCreateOpt(..),
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collectionNames, createCollection, dropCollection,
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renameCollection, runCommand, validateCollection,
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-- * Collection
Collection, FieldSelector, FullCollection,
NumToSkip, NumToReturn, Selector,
QueryOpt(..),
UpdateFlag(..),
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count, countMatching, delete, insert, insertMany, query, remove, update,
-- * Convenience collection operations
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find, findOne, quickFind, quickFind',
-- * Cursor
Cursor,
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allDocs, allDocs', finish, nextDoc,
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-- * Index
Key, Unique,
Direction(..),
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createIndex, dropIndex, dropIndexes, indexInformation,
)
where
import Control.Exception
import Control.Monad
import Data.Binary
import Data.Binary.Get
import Data.Binary.Put
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import Data.Bits
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import Data.ByteString.Internal (c2w)
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
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import qualified Data.Map as Map
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import Data.Maybe
import Data.Typeable
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import Database.MongoDB.BSON as 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.IO.Unsafe
import System.Random
-- | A handle to a database connection
data Connection = Connection { cHandle :: Handle, cRand :: IORef [Int] }
-- | Establish a connection to a MongoDB server
connect :: HostName -> IO Connection
connect = flip connectOnPort $ Network.PortNumber 27017
-- | Establish a connection to a MongoDB server on a non-standard port
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
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return Connection { cHandle = h, cRand = nsRef }
-- | Close database connection
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conClose :: Connection -> IO ()
conClose = hClose . cHandle
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-- | Information about the databases on the server.
databasesInfo :: Connection -> IO BsonDoc
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databasesInfo c =
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runCommand c (s2L "admin") $ toBsonDoc [("listDatabases", toBson (1::Int))]
-- | Return a list of database names on the server.
databaseNames :: Connection -> IO [Database]
databaseNames c = do
info <- databasesInfo c
let (BsonArray dbs) = fromJust $ Map.lookup (s2L "databases") info
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names = mapMaybe (Map.lookup (s2L "name") . fromBson) dbs
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return $ List.map fromBson (names::[BsonValue])
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-- | Alias for 'conClose'
disconnect :: Connection -> IO ()
disconnect = conClose
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-- | Drop a database.
dropDatabase :: Connection -> Database -> IO ()
dropDatabase c db = do
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_ <- runCommand c db $ toBsonDoc [("dropDatabase", toBson (1::Int))]
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return ()
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-- | Get information about the MongoDB server we're connected to.
serverInfo :: Connection -> IO BsonDoc
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serverInfo c =
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runCommand c (s2L "admin") $ toBsonDoc [("buildinfo", toBson (1::Int))]
-- | Shut down the MongoDB server.
--
-- Force a clean exit, flushing and closing all data files.
-- Note that it will wait until all ongoing operations are complete.
serverShutdown :: Connection -> IO BsonDoc
serverShutdown c =
runCommand c (s2L "admin") $ toBsonDoc [("shutdown", toBson (1::Int))]
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-- | Return a list of collections in /Database/.
collectionNames :: Connection -> Database -> IO [FullCollection]
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collectionNames c db = do
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docs <- quickFind' c (L.append db $ s2L ".system.namespaces") empty
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let names = flip List.map docs $ fromBson . fromJust . BSON.lookup "name"
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return $ List.filter (L.notElem $ c2w '$') names
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data ColCreateOpt = CCOSize Int64 -- ^ Desired initial size for the
-- collection (in bytes). must be
-- less than or equal to
-- 10000000000. For capped
-- collections this size is the max
-- size of the collection.
| CCOCapped Bool -- ^ If 'True', this is a capped collection.
| CCOMax Int64 -- ^ Maximum number of objects if capped.
deriving (Show, Eq)
colCreateOptToBson :: ColCreateOpt -> (String, BsonValue)
colCreateOptToBson (CCOSize sz) = ("size", toBson sz)
colCreateOptToBson (CCOCapped b) = ("capped", toBson b)
colCreateOptToBson (CCOMax m) = ("max", toBson m)
-- | Create a new collection in this database.
--
-- Normally collection creation is automatic. This function should
-- only be needed if you want to specify 'ColCreateOpt's on creation.
-- 'MongoDBCollectionInvalid' is thrown if the collection already
-- exists.
createCollection :: Connection -> FullCollection -> [ColCreateOpt] -> IO ()
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createCollection c col opts = do
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(db, col') <- validateCollectionName col
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dbcols <- collectionNames c db
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when (col `List.elem` dbcols) $
throwColInvalid $ "Collection already exists: " ++ show col
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let cmd = ("create", toBson col') : List.map colCreateOptToBson opts
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_ <- runCommand c db $ toBsonDoc cmd
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return ()
-- | Drop a collection.
dropCollection :: Connection -> FullCollection -> IO ()
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dropCollection c col = do
let (db, col') = splitFullCol col
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_ <- runCommand c db $ toBsonDoc [("drop", toBson col')]
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return ()
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-- | Rename a collection--first /FullCollection/ argument is the
-- existing name, the second is the new name. At the moment this command
-- can also be used to move a collection between databases.
renameCollection :: Connection -> FullCollection -> FullCollection -> IO ()
renameCollection c col newName = do
_ <- validateCollectionName col
_ <- runCommand c (s2L "admin") $ toBsonDoc [("renameCollection", toBson col),
("to", toBson newName)]
return ()
-- | Return a string of validation info about the collection.
--
-- Example output (note this probably can/will change with different
-- versions of the server):
--
-- > validate
-- > details: 0x7fe5cc2c1da4 ofs:e7da4
-- > firstExtent:0:24100 ns:test.foo.bar
-- > lastExtent:0:24100 ns:test.foo.bar
-- > # extents:1
-- > datasize?:180 nrecords?:5 lastExtentSize:1024
-- > padding:1
-- > first extent:
-- > loc:0:24100 xnext:null xprev:null
-- > nsdiag:test.foo.bar
-- > size:1024 firstRecord:0:241e4 lastRecord:0:24280
-- > 5 objects found, nobj:5
-- > 260 bytes data w/headers
-- > 180 bytes data wout/headers
-- > deletedList: 0100100000000000000
-- > deleted: n: 4 size: 588
-- > nIndexes:1
-- > test.foo.bar.$_id_ keys:5
validateCollection :: Connection -> FullCollection -> IO String
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validateCollection c col = do
let (db, col') = splitFullCol col
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res <- runCommand c db $ toBsonDoc [("validate", toBson col')]
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return $ fromBson $ fromJust $ BSON.lookup "result" res
splitFullCol :: FullCollection -> (Database, Collection)
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splitFullCol col = (L.takeWhile (c2w '.' /=) col,
L.tail $ L.dropWhile (c2w '.' /=) col)
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-- | Run a database command. Usually this is unneeded as driver wraps
-- all of the commands for you (eg 'createCollection',
-- 'dropCollection', etc).
runCommand :: Connection -> Database -> BsonDoc -> IO BsonDoc
runCommand c db cmd = do
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mres <- findOne c (L.append db $ s2L ".$cmd") cmd
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let res = fromJust mres
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when (1 /= (fromBson $ fromJust $ BSON.lookup "ok" res :: Int)) $
throwOpFailure $ "command \"" ++ show cmd ++ "\" failed: " ++
fromBson (fromJust $ BSON.lookup "errmsg" res)
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return res
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-- | An Iterator 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.
data Cursor = Cursor {
curCon :: Connection,
curID :: IORef Int64,
curNumToRet :: Int32,
curCol :: FullCollection,
curDocBytes :: IORef L.ByteString,
curClosed :: IORef Bool
}
data Opcode
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= OPReply -- 1 Reply to a client request. responseTo is set
| OPMsg -- 1000 generic msg command followed by a string
| OPUpdate -- 2001 update document
| OPInsert -- 2002 insert new document
| OPGetByOid -- 2003 is this used?
| OPQuery -- 2004 query a collection
| OPGetMore -- 2005 Get more data from a query. See Cursors
| OPDelete -- 2006 Delete documents
| OPKillCursors -- 2007 Tell database client is done with a cursor
deriving (Show, Eq)
data MongoDBInternalError = MongoDBInternalError String
deriving (Eq, Show, Read)
mongoDBInternalError :: TyCon
mongoDBInternalError = mkTyCon "Database.MongoDB.MongoDBInternalError"
instance Typeable MongoDBInternalError where
typeOf _ = mkTyConApp mongoDBInternalError []
instance Exception MongoDBInternalError
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data MongoDBCollectionInvalid = MongoDBCollectionInvalid String
deriving (Eq, Show, Read)
mongoDBCollectionInvalid :: TyCon
mongoDBCollectionInvalid = mkTyCon "Database.MongoDB.MongoDBcollectionInvalid"
instance Typeable MongoDBCollectionInvalid where
typeOf _ = mkTyConApp mongoDBCollectionInvalid []
instance Exception MongoDBCollectionInvalid
throwColInvalid :: String -> a
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throwColInvalid = throw . MongoDBCollectionInvalid
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data MongoDBOperationFailure = MongoDBOperationFailure String
deriving (Eq, Show, Read)
mongoDBOperationFailure :: TyCon
mongoDBOperationFailure = mkTyCon "Database.MongoDB.MongoDBoperationFailure"
instance Typeable MongoDBOperationFailure where
typeOf _ = mkTyConApp mongoDBOperationFailure []
instance Exception MongoDBOperationFailure
throwOpFailure :: String -> a
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throwOpFailure = throw . MongoDBOperationFailure
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fromOpcode :: Opcode -> Int32
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fromOpcode OPReply = 1
fromOpcode OPMsg = 1000
fromOpcode OPUpdate = 2001
fromOpcode OPInsert = 2002
fromOpcode OPGetByOid = 2003
fromOpcode OPQuery = 2004
fromOpcode OPGetMore = 2005
fromOpcode OPDelete = 2006
fromOpcode OPKillCursors = 2007
toOpcode :: Int32 -> Opcode
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toOpcode 1 = OPReply
toOpcode 1000 = OPMsg
toOpcode 2001 = OPUpdate
toOpcode 2002 = OPInsert
toOpcode 2003 = OPGetByOid
toOpcode 2004 = OPQuery
toOpcode 2005 = OPGetMore
toOpcode 2006 = OPDelete
toOpcode 2007 = OPKillCursors
toOpcode n = throw $ MongoDBInternalError $ "Got unexpected Opcode: " ++ show n
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-- | The name of a database.
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type Database = L8.ByteString
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-- | 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@
-- and the collection @bar@, the full collection name is @foo.bar@.
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type FullCollection = L8.ByteString
-- | The same as 'FullCollection' but without the 'Database' prefix.
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type Collection = L8.ByteString
-- | A 'BsonDoc' representing restrictions for a query much like the
-- /where/ part of an SQL query.
type Selector = BsonDoc
-- | A list of field names that limits the fields in the returned
-- documents. The list can contains zero or more elements, each of
-- which is the name of a field that should be returned. An empty list
-- means that no limiting is done and all fields are returned.
type FieldSelector = [L8.ByteString]
type RequestID = Int32
-- | Sets the number of documents to omit - starting from the first
-- document in the resulting dataset - when returning the result of
-- the query.
type NumToSkip = Int32
-- | This controls how many documents are returned at a time. The
-- cursor works by requesting /NumToReturn/ documents, which are then
-- immediately all transfered over the network; these are held locally
-- until the those /NumToReturn/ are all consumed and then the network
-- will be hit again for the next /NumToReturn/ documents.
--
-- If the value @0@ is given, the database will choose the number of
-- documents to return.
--
-- Otherwise choosing a good value is very dependant on the document size
-- and the way the cursor is being used.
type NumToReturn = Int32
-- | Options that control the behavior of a 'query' operation.
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data QueryOpt = QOTailableCursor
| QOSlaveOK
| QOOpLogReplay
| QONoCursorTimeout
deriving (Show)
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fromQueryOpts :: [QueryOpt] -> Int32
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fromQueryOpts opts = List.foldl (.|.) 0 $ fmap toVal opts
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where toVal QOTailableCursor = 2
toVal QOSlaveOK = 4
toVal QOOpLogReplay = 8
toVal QONoCursorTimeout = 16
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-- | Options that effect the behavior of a 'update' operation.
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data UpdateFlag = UFUpsert
| UFMultiupdate
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deriving (Show, Enum)
fromUpdateFlags :: [UpdateFlag] -> Int32
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fromUpdateFlags flags = List.foldl (.|.) 0 $
flip fmap flags $ (1 `shiftL`) . fromEnum
-- | Return the number of documents in /FullCollection/.
count :: Connection -> FullCollection -> IO Int64
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count c col = countMatching c col empty
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-- | Return the number of documents in /FullCollection/ matching /Selector/
countMatching :: Connection -> FullCollection -> Selector -> IO Int64
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countMatching c col sel = do
let (db, col') = splitFullCol col
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res <- runCommand c db $ toBsonDoc [("count", toBson col'),
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("query", toBson sel)]
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return $ fromBson $ fromJust $ BSON.lookup "n" res
-- | Delete documents matching /Selector/ from the given /FullCollection/.
delete :: Connection -> FullCollection -> Selector -> IO RequestID
delete c col sel = do
let body = runPut $ do
putI32 0
putCol col
putI32 0
putBsonDoc sel
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(reqID, msg) <- packMsg c OPDelete body
L.hPut (cHandle c) msg
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return reqID
-- | An alias for 'delete'.
remove :: Connection -> FullCollection -> Selector -> IO RequestID
remove = delete
-- | Insert a single document into /FullCollection/.
insert :: Connection -> FullCollection -> BsonDoc -> IO RequestID
insert c col doc = do
let body = runPut $ do
putI32 0
putCol col
putBsonDoc doc
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(reqID, msg) <- packMsg c OPInsert body
L.hPut (cHandle c) msg
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return reqID
-- | Insert a list of documents into /FullCollection/.
insertMany :: Connection -> FullCollection -> [BsonDoc] -> IO RequestID
insertMany c col docs = do
let body = runPut $ do
putI32 0
putCol col
forM_ docs putBsonDoc
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(reqID, msg) <- packMsg c OPInsert body
L.hPut (cHandle c) msg
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return reqID
-- | Open a cursor to find documents. If you need full functionality,
-- see 'query'
find :: Connection -> FullCollection -> Selector -> IO Cursor
find c col sel = query c col [] 0 0 sel []
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-- | Query, but only return the first result, if any.
findOne :: Connection -> FullCollection -> Selector -> IO (Maybe BsonDoc)
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findOne c col sel = do
cur <- query c col [] 0 (-1) sel []
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nextDoc cur
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-- | Perform a query and return the result as a lazy list. Be sure to
-- understand the comments about using the lazy list given for
-- 'allDocs'.
quickFind :: Connection -> FullCollection -> Selector -> IO [BsonDoc]
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quickFind c col sel = find c col sel >>= allDocs
-- | Perform a query and return the result as a strict list.
quickFind' :: Connection -> FullCollection -> Selector -> IO [BsonDoc]
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quickFind' c col sel = find c col sel >>= allDocs'
-- | Open a cursor to find documents in /FullCollection/ that match
-- /Selector/. See the documentation for each argument's type for
-- information about how it effects the query.
query :: Connection -> FullCollection -> [QueryOpt] ->
NumToSkip -> NumToReturn -> Selector -> FieldSelector -> IO Cursor
query c col opts nskip ret sel fsel = do
let h = cHandle c
let body = runPut $ do
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putI32 $ fromQueryOpts opts
putCol col
putI32 nskip
putI32 ret
putBsonDoc sel
case fsel of
[] -> putNothing
_ -> putBsonDoc $ toBsonDoc $ List.zip fsel $
repeat $ BsonInt32 1
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(reqID, msg) <- packMsg c OPQuery body
L.hPut h msg
hdr <- getHeader h
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assert (OPReply == hOp hdr) $ return ()
assert (hRespTo hdr == reqID) $ return ()
reply <- getReply h
assert (rRespFlags reply == 0) $ return ()
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docBytes <- L.hGet h (fromIntegral $ hMsgLen hdr - 16 - 20) >>= newIORef
closed <- newIORef False
cid <- newIORef $ rCursorID reply
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return Cursor {
curCon = c,
curID = cid,
curNumToRet = ret,
curCol = col,
curDocBytes = docBytes,
curClosed = closed
}
-- | Update documents with /BsonDoc/ in /FullCollection/ that match /Selector/.
update :: Connection -> FullCollection ->
[UpdateFlag] -> Selector -> BsonDoc -> IO RequestID
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update c col flags sel obj = do
let body = runPut $ do
putI32 0
putCol col
putI32 $ fromUpdateFlags flags
putBsonDoc sel
putBsonDoc obj
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(reqID, msg) <- packMsg c OPUpdate body
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L.hPut (cHandle c) msg
return reqID
data Hdr = Hdr {
hMsgLen :: Int32,
-- hReqID :: Int32,
hRespTo :: Int32,
hOp :: Opcode
} deriving (Show)
data Reply = Reply {
rRespFlags :: Int32,
rCursorID :: Int64
-- rStartFrom :: Int32,
-- rNumReturned :: Int32
} deriving (Show)
getHeader :: Handle -> IO Hdr
getHeader h = do
hdrBytes <- L.hGet h 16
return $ flip runGet hdrBytes $ do
msgLen <- getI32
skip 4 -- reqID <- getI32
respTo <- getI32
op <- getI32
return $ Hdr msgLen respTo $ toOpcode op
getReply :: Handle -> IO Reply
getReply h = do
replyBytes <- L.hGet h 20
return $ flip runGet replyBytes $ do
respFlags <- getI32
cursorID <- getI64
skip 4 -- startFrom <- getI32
skip 4 -- numReturned <- getI32
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return $ Reply respFlags cursorID
-- | Return one document or Nothing if there are no more.
-- Automatically closes the cursor when last document is read
nextDoc :: Cursor -> IO (Maybe BsonDoc)
nextDoc cur = do
closed <- readIORef $ curClosed cur
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if closed
then return Nothing
else do
docBytes <- readIORef $ curDocBytes cur
cid <- readIORef $ curID cur
case L.length docBytes of
0 -> if cid == 0
then writeIORef (curClosed cur) True >> return Nothing
else getMore cur
_ -> do
let (doc, docBytes') = getFirstDoc docBytes
writeIORef (curDocBytes cur) docBytes'
return $ Just doc
-- | Return a lazy list of all (of the rest) of the documents in the
-- cursor. This works much like hGetContents--it will lazily read the
-- cursor data out of the database as the list is used. The cursor is
-- automatically closed when the list has been fully read.
--
-- If you manually finish the cursor before consuming off this list
-- you won't get all the original documents in the cursor.
--
-- If you don't consume to the end of the list, you must manually
-- close the cursor or you will leak the cursor, which may also leak
-- on the database side.
allDocs :: Cursor -> IO [BsonDoc]
allDocs cur = unsafeInterleaveIO $ do
doc <- nextDoc cur
case doc of
Nothing -> return []
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Just d -> liftM (d :) (allDocs cur)
-- | Returns a strict list of all (of the rest) of the documents in
-- the cursor. This means that all of the documents will immediately
-- be read out of the database and loaded into memory.
allDocs' :: Cursor -> IO [BsonDoc]
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allDocs' cur = do
doc <- nextDoc cur
case doc of
Nothing -> return []
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Just d -> liftM (d :) (allDocs' cur)
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getFirstDoc :: L.ByteString -> (BsonDoc, L.ByteString)
getFirstDoc docBytes = flip runGet docBytes $ do
doc <- getBsonDoc
docBytes' <- getRemainingLazyByteString
return (doc, docBytes')
getMore :: Cursor -> IO (Maybe BsonDoc)
getMore cur = do
let h = cHandle $ curCon cur
cid <- readIORef $ curID cur
let body = runPut $ do
putI32 0
putCol $ curCol cur
putI32 $ curNumToRet cur
putI64 cid
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(reqID, msg) <- packMsg (curCon cur) OPGetMore body
L.hPut h msg
hdr <- getHeader h
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assert (OPReply == hOp hdr) $ return ()
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assert (hRespTo hdr == reqID) $ return ()
reply <- getReply h
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assert (rRespFlags reply == 0) $ return ()
case rCursorID reply of
0 -> writeIORef (curID cur) 0
ncid -> assert (ncid == cid) $ return ()
docBytes <- (L.hGet h $ fromIntegral $ hMsgLen hdr - 16 - 20)
case L.length docBytes of
0 -> writeIORef (curClosed cur) True >> return Nothing
_ -> do
let (doc, docBytes') = getFirstDoc docBytes
writeIORef (curDocBytes cur) docBytes'
return $ Just doc
-- | Manually close a cursor -- usually not needed if you use
-- 'allDocs', 'allDocs'', or 'nextDoc'.
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finish :: Cursor -> IO ()
finish cur = do
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let h = cHandle $ curCon cur
cid <- readIORef $ curID cur
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unless (cid == 0) $ do
let body = runPut $ do
putI32 0
putI32 1
putI64 cid
(_reqID, msg) <- packMsg (curCon cur) OPKillCursors body
L.hPut h msg
writeIORef (curClosed cur) True
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return ()
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-- | The field key to index on.
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type Key = L8.ByteString
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-- | Direction to index.
data Direction = Ascending
| Descending
deriving (Show, Eq)
fromDirection :: Direction -> Int
fromDirection Ascending = 1
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fromDirection Descending = - 1
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-- | Should this index guarantee uniqueness?
type Unique = Bool
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-- | Create a new index on /FullCollection/ on the list of /Key/ /
-- /Direction/ pairs.
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createIndex :: Connection -> FullCollection ->
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[(Key, Direction)] -> Unique -> IO L8.ByteString
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createIndex c col keys uniq = do
let (db, _col') = splitFullCol col
name = indexName keys
keysDoc = flip fmap keys $
\(k, d) -> (k, toBson $ fromDirection d :: BsonValue)
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_ <- insert c (L.append db $ s2L ".system.indexes") $
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toBsonDoc [("name", toBson name),
("ns", toBson col),
("key", toBson keysDoc),
("unique", toBson uniq)]
return name
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-- | Drop the specified index on the given /FullCollection/.
dropIndex :: Connection -> FullCollection -> [(Key, Direction)] -> IO ()
dropIndex c col keys = do
let (db, col') = splitFullCol col
name = indexName keys
_ <- runCommand c db $ toBsonDoc [("deleteIndexes", toBson col'),
("index", toBson name)]
return ()
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-- | Drop all indexes on /FullCollection/.
dropIndexes :: Connection -> FullCollection -> IO ()
dropIndexes c col = do
let (db, col') = splitFullCol col
_ <- runCommand c db $ toBsonDoc [("deleteIndexes", toBson col'),
("index", toBson "*")]
return ()
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-- | Return a BsonDoc describing the existing indexes on /FullCollection/.
--
-- With the current server versions (1.2) this will return documents
-- such as:
--
-- > {"key": {"lastname": -1, "firstname": 1},
-- > "name": "lastname_-1_firstname_1",
-- > "ns": "mydb.people",
-- > "unique": true}
--
-- Which is a single key that indexes on @lastname@ (descending) and
-- then @firstname@ (ascending) on the collection @people@ of the
-- database @mydb@ with a uniqueness requirement.
indexInformation :: Connection -> FullCollection -> IO [BsonDoc]
indexInformation c col = do
let (db, _col') = splitFullCol col
quickFind' c (L.append db $ s2L ".system.indexes") $
toBsonDoc [("ns", toBson col)]
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indexName :: [(Key, Direction)] -> L8.ByteString
indexName = L.intercalate (s2L "_") . List.map partName
where partName (k, Ascending) = L.append k $ s2L "_1"
partName (k, Descending) = L.append k $ s2L "_-1"
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putCol :: Collection -> Put
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putCol col = putLazyByteString col >> putNull
packMsg :: Connection -> Opcode -> L.ByteString -> IO (RequestID, L.ByteString)
packMsg c op body = do
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reqID <- randNum c
let msg = runPut $ do
putI32 $ fromIntegral $ L.length body + 16
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putI32 reqID
putI32 0
putI32 $ fromOpcode op
putLazyByteString body
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return (reqID, msg)
randNum :: Connection -> IO Int32
randNum Connection { cRand = nsRef } = atomicModifyIORef nsRef $ \ns ->
(List.tail ns,
fromIntegral $ List.head ns)
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s2L :: String -> L8.ByteString
s2L = L8.fromString
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validateCollectionName :: FullCollection -> IO (Database, Collection)
validateCollectionName col = do
let (db, col') = splitFullCol col
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when (s2L ".." `List.elem` L.group col) $
throwColInvalid $ "Collection can't contain \"..\": " ++ show col
when (c2w '$' `L.elem` col &&
not (s2L "oplog.$mail" `L.isPrefixOf` col' ||
s2L "$cmd" `L.isPrefixOf` col')) $
throwColInvalid $ "Collection can't contain '$': " ++ show col
when (L.head col == c2w '.' || L.last col == c2w '.') $
throwColInvalid $ "Collection can't start or end with '.': " ++ show col
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return (db, col')