{-# LANGUAGE CPP, PackageImports, OverloadedStrings, ScopedTypeVariables #-}
{-# LANGUAGE GeneralizedNewtypeDeriving, MultiParamTypeClasses #-}
{-# LANGUAGE TypeSynonymInstances, FlexibleInstances, FlexibleContexts #-}
{-# LANGUAGE RankNTypes, TypeFamilies #-}
{-# LANGUAGE UndecidableInstances #-} -- FIXME
{-# OPTIONS_GHC -fno-warn-orphans #-}
module Database.Persist.MongoDB
(
-- * using connections
withMongoDBConn
, withMongoDBPool
, createMongoDBPool
, runMongoDBPool
, runMongoDBPoolDef
, ConnectionPool
, Connection
, MongoConf (..)
-- * Key conversion helpers
, keyToOid
, oidToKey
-- * Entity conversion
, entityToFields
, toInsertFields
-- * network type
, HostName
-- * MongoDB driver types
, DB.Action
, DB.AccessMode(..)
, DB.master
, DB.slaveOk
, (DB.=:)
-- * Database.Persist
, module Database.Persist
) where
import Database.Persist
import Database.Persist.EntityDef
import Database.Persist.Store
import Database.Persist.Query.Internal
import qualified Control.Monad.IO.Class as Trans
import Control.Exception (throw, throwIO)
import qualified Database.MongoDB as DB
import Database.MongoDB.Query (Database)
import Control.Applicative (Applicative)
import Network.Socket (HostName)
import Data.Maybe (mapMaybe, fromJust)
import qualified Data.Text as T
import Data.Text (Text)
import qualified Data.Text.Encoding as E
import qualified Data.Serialize as Serialize
import Web.PathPieces (PathPiece (..))
import Data.Conduit
import Control.Monad.Trans.Class (lift)
import Control.Monad.IO.Class (liftIO)
import Data.Aeson (Value (Object, Number), (.:), (.:?), (.!=), FromJSON(..))
import Control.Monad (mzero)
import Control.Monad.Trans.Control (MonadBaseControl)
import qualified Data.Conduit.Pool as Pool
import Data.Time (NominalDiffTime)
import Data.Attoparsec.Number
#ifdef DEBUG
import FileLocation (debug)
#endif
newtype NoOrphanNominalDiffTime = NoOrphanNominalDiffTime NominalDiffTime
deriving (Show, Eq, Num)
instance FromJSON NoOrphanNominalDiffTime where
parseJSON (Number (I x)) = (return . NoOrphanNominalDiffTime . fromInteger) x
parseJSON (Number (D x)) = (return . NoOrphanNominalDiffTime . fromRational . toRational) x
parseJSON _ = fail "couldn't parse diff time"
data Connection = Connection DB.Pipe DB.Database
type ConnectionPool = Pool.Pool Connection
instance PathPiece (Key DB.Action entity) where
toPathPiece (Key pOid@(PersistObjectId _)) = -- T.pack $ show $ Serialize.encode bsonId
let oid = persistObjectIdToDbOid pOid
in T.pack $ show oid
toPathPiece k = throw $ PersistInvalidField $ T.pack $ "Invalid Key (expected PersistObjectId): " ++ show k
fromPathPiece str =
case (reads $ (T.unpack str))::[(DB.ObjectId,String)] of
(parsed,_):[] -> Just $ Key $ PersistObjectId $ Serialize.encode parsed
_ -> Nothing
withMongoDBConn :: (Trans.MonadIO m, Applicative m) =>
Database -> HostName -> Maybe MongoAuth -> NominalDiffTime -> (ConnectionPool -> m b) -> m b
withMongoDBConn dbname hostname mauth connectionIdleTime = withMongoDBPool dbname hostname mauth 1 1 connectionIdleTime
createConnection :: Database -> HostName -> Maybe MongoAuth -> IO Connection
createConnection dbname hostname mAuth = do
pipe <- DB.runIOE $ DB.connect (DB.host hostname)
_ <- case mAuth of
Just (MongoAuth user pass) -> DB.access pipe DB.UnconfirmedWrites dbname (DB.auth user pass)
Nothing -> return undefined
return $ Connection pipe dbname
createMongoDBPool :: (Trans.MonadIO m, Applicative m) => Database -> HostName
-> Maybe MongoAuth
-> Int -- ^ pool size (number of stripes)
-> Int -- ^ stripe size (number of connections per stripe)
-> NominalDiffTime -- ^ time a connection is left idle before closing
-> m ConnectionPool
createMongoDBPool dbname hostname mAuth connectionPoolSize stripeSize connectionIdleTime = do
Trans.liftIO $ Pool.createPool
(createConnection dbname hostname mAuth)
(\(Connection pipe _) -> DB.close pipe)
connectionPoolSize
connectionIdleTime
stripeSize
withMongoDBPool :: (Trans.MonadIO m, Applicative m) =>
Database -> HostName -> Maybe MongoAuth -> Int -> Int -> NominalDiffTime -> (ConnectionPool -> m b) -> m b
withMongoDBPool dbname hostname mauth poolStripes stripeConnections connectionIdleTime connectionReader = do
pool <- createMongoDBPool dbname hostname mauth poolStripes stripeConnections connectionIdleTime
connectionReader pool
runMongoDBPool :: (Trans.MonadIO m, MonadBaseControl IO m) => DB.AccessMode -> DB.Action m a -> ConnectionPool -> m a
runMongoDBPool accessMode action pool =
Pool.withResource pool $ \(Connection pipe db) -> do
res <- DB.access pipe accessMode db action
either (Trans.liftIO . throwIO . PersistMongoDBError . T.pack . show) return res
runMongoDBPoolDef :: (Trans.MonadIO m, MonadBaseControl IO m) => DB.Action m a -> ConnectionPool -> m a
runMongoDBPoolDef = runMongoDBPool (DB.ConfirmWrites ["j" DB.=: True])
value :: DB.Field -> DB.Value
value (_ DB.:= val) = val
rightPersistVals :: (PersistEntity val) => EntityDef -> [DB.Field] -> val
rightPersistVals ent vals = case wrapFromPersistValues ent vals of
Left e -> error $ T.unpack e
Right v -> v
filterByKey :: (PersistEntity val) => Key DB.Action val -> DB.Document
filterByKey k = [_id DB.=: keyToOid k]
queryByKey :: (PersistEntity val) => Key DB.Action val -> EntityDef -> DB.Query
queryByKey k entity = (DB.select (filterByKey k) (unDBName $ entityDB entity))
selectByKey :: (PersistEntity val) => Key DB.Action val -> EntityDef -> DB.Selection
selectByKey k entity = (DB.select (filterByKey k) (unDBName $ entityDB entity))
updateFields :: (PersistEntity val) => [Update val] -> [DB.Field]
updateFields upds = map updateToMongoField upds
updateToMongoField :: (PersistEntity val) => Update val -> DB.Field
updateToMongoField (Update field v up) =
opName DB.:= DB.Doc [( (unDBName $ fieldDB $ persistFieldDef field) DB.:= opValue)]
where
(opName, opValue) =
case (up, toPersistValue v) of
(Assign, PersistNull) -> ("$unset", DB.Int64 1)
(Assign,a) -> ("$set", DB.val a)
(Add, a) -> ("$inc", DB.val a)
(Subtract, PersistInt64 i) -> ("$inc", DB.Int64 (-i))
(Subtract, _) -> error "expected PersistInt64 for a subtraction"
(Multiply, _) -> throw $ PersistMongoDBUnsupported "multiply not supported"
(Divide, _) -> throw $ PersistMongoDBUnsupported "divide not supported"
uniqSelector :: forall val. (PersistEntity val) => Unique val DB.Action -> [DB.Field]
uniqSelector uniq = zipWith (DB.:=)
(map (unDBName . snd) $ persistUniqueToFieldNames uniq)
(map DB.val (persistUniqueToValues uniq))
pairFromDocument :: (PersistEntity val, PersistEntityBackend val ~ DB.Action)
=> EntityDef
-> [DB.Field]
-> Either String (Entity val)
pairFromDocument ent document = pairFromPersistValues document
where
pairFromPersistValues (x:xs) =
case wrapFromPersistValues ent xs of
Left e -> Left $ T.unpack e
Right xs' -> Right (Entity (oidToKey . fromJust . DB.cast' . value $ x) xs')
pairFromPersistValues _ = Left "error in fromPersistValues'"
-- | convert a PersistEntity into document fields.
-- for inserts only: nulls are ignored so they will be unset in the document.
-- 'entityToFields' includes nulls
toInsertFields :: forall val. (PersistEntity val) => val -> [DB.Field]
toInsertFields record = zipFilter (entityFields entity) (toPersistFields record)
where
zipFilter [] _ = []
zipFilter _ [] = []
zipFilter (e:efields) (p:pfields) = let pv = toPersistValue p in
if pv == PersistNull then zipFilter efields pfields
else (toLabel e DB.:= DB.val pv):zipFilter efields pfields
entity = entityDef record
-- | convert a PersistEntity into document fields.
-- unlike 'toInsertFields', nulls are included.
entityToFields :: forall val. (PersistEntity val) => val -> [DB.Field]
entityToFields record = zipIt (entityFields entity) (toPersistFields record)
where
zipIt [] _ = []
zipIt _ [] = []
zipIt (e:efields) (p:pfields) =
let pv = toPersistValue p
in (toLabel e DB.:= DB.val pv):zipIt efields pfields
entity = entityDef record
toLabel :: FieldDef -> Text
toLabel = unDBName . fieldDB
saveWithKey :: forall m record keyEntity. -- (Applicative m, Functor m, MonadBaseControl IO m,
(PersistEntity keyEntity, PersistEntity record)
=> (record -> [DB.Field])
-> (DB.Collection -> DB.Document -> DB.Action m () )
-> Key DB.Action keyEntity
-> record
-> DB.Action m ()
saveWithKey entToFields dbSave key record =
dbSave (unDBName $ entityDB entity) ((keyToMongoIdField key):(entToFields record))
where
entity = entityDef record
instance (Applicative m, Functor m, Trans.MonadIO m, MonadBaseControl IO m) => PersistStore DB.Action m where
insert record = do
DB.ObjId oid <- DB.insert (unDBName $ entityDB entity) (toInsertFields record)
return $ oidToKey oid
where
entity = entityDef record
insertKey k record = saveWithKey toInsertFields DB.insert_ k record
repsert k record = saveWithKey entityToFields DB.save k record
replace k record = do
DB.replace (selectByKey k t) (toInsertFields record)
return ()
where
t = entityDef record
delete k =
DB.deleteOne DB.Select {
DB.coll = (unDBName $ entityDB t)
, DB.selector = filterByKey k
}
where
t = entityDef $ dummyFromKey k
get k = do
d <- DB.findOne (queryByKey k t)
case d of
Nothing -> return Nothing
Just doc -> do
return $ Just $ rightPersistVals t (tail doc)
where
t = entityDef $ dummyFromKey k
instance MonadThrow m => MonadThrow (DB.Action m) where
monadThrow = lift . monadThrow
instance (Applicative m, Functor m, Trans.MonadIO m, MonadBaseControl IO m) => PersistUnique DB.Action m where
getBy uniq = do
mdocument <- DB.findOne $
(DB.select (uniqSelector uniq) (unDBName $ entityDB t))
case mdocument of
Nothing -> return Nothing
Just document -> case pairFromDocument t document of
Left s -> Trans.liftIO . throwIO $ PersistMarshalError $ T.pack s
Right e -> return $ Just e
where
t = entityDef $ dummyFromUnique uniq
deleteBy uniq =
DB.delete DB.Select {
DB.coll = unDBName $ entityDB t
, DB.selector = uniqSelector uniq
}
where
t = entityDef $ dummyFromUnique uniq
_id :: T.Text
_id = "_id"
keyToMongoIdField :: PersistEntity val => Key DB.Action val -> DB.Field
keyToMongoIdField k = _id DB.:= (DB.ObjId $ keyToOid k)
findAndModifyOne :: (Applicative m, Trans.MonadIO m)
=> DB.Collection
-> DB.ObjectId -- ^ _id for query
-> [DB.Field] -- ^ updates
-> DB.Action m (Either String DB.Document)
findAndModifyOne coll objectId updates = do
result <- DB.runCommand [
"findAndModify" DB.:= DB.String coll,
"new" DB.:= DB.Bool True, -- return updated document, not original document
"query" DB.:= DB.Doc [_id DB.:= DB.ObjId objectId],
"update" DB.:= DB.Doc updates
]
return $ case DB.lookup "err" (DB.at "lastErrorObject" result) result of
Just e -> Left e
Nothing -> case DB.lookup "value" result of
Nothing -> Left "no value field"
Just doc -> Right doc
instance (Applicative m, Functor m, Trans.MonadIO m, MonadBaseControl IO m) => PersistQuery DB.Action m where
update _ [] = return ()
update key upds =
DB.modify
(DB.Select [keyToMongoIdField key] (unDBName $ entityDB t))
$ updateFields upds
where
t = entityDef $ dummyFromKey key
updateGet key upds = do
result <- findAndModifyOne (unDBName $ entityDB t)
(keyToOid key) (updateFields upds)
case result of
Left e -> err e
Right doc -> return $ (rightPersistVals t) $ tail doc
where
err msg = Trans.liftIO $ throwIO $ KeyNotFound $ show key ++ msg
t = entityDef $ dummyFromKey key
updateWhere _ [] = return ()
updateWhere filts upds =
DB.modify DB.Select {
DB.coll = (unDBName $ entityDB t)
, DB.selector = filtersToSelector filts
} $ updateFields upds
where
t = entityDef $ dummyFromFilts filts
deleteWhere filts = do
DB.delete DB.Select {
DB.coll = (unDBName $ entityDB t)
, DB.selector = filtersToSelector filts
}
where
t = entityDef $ dummyFromFilts filts
count filts = do
i <- DB.count query
return $ fromIntegral i
where
query = DB.select (filtersToSelector filts) (unDBName $ entityDB t)
t = entityDef $ dummyFromFilts filts
selectSource filts opts = do
cursor <- lift $ lift $ DB.find $ makeQuery filts opts
pull cursor
where
pull cursor = do
mdoc <- lift $ lift $ DB.next cursor
case mdoc of
Nothing -> return ()
Just doc ->
case pairFromDocument t doc of
Left s -> liftIO $ throwIO $ PersistMarshalError $ T.pack s
Right row -> do
yield row
pull cursor
t = entityDef $ dummyFromFilts filts
selectFirst filts opts = do
doc <- DB.findOne $ makeQuery filts opts
case doc of
Nothing -> return Nothing
Just document -> case pairFromDocument t document of
Left s -> Trans.liftIO . throwIO $ PersistMarshalError $ T.pack s
Right row -> return $ Just row
where
t = entityDef $ dummyFromFilts filts
selectKeys filts opts = do
cursor <- lift $ lift $ DB.find $ (makeQuery filts opts) {
DB.project = [_id DB.=: (1 :: Int)]
}
pull cursor
where
pull cursor = do
mdoc <- lift $ lift $ DB.next cursor
case mdoc of
Nothing -> return ()
Just [_ DB.:= DB.ObjId oid] -> do
yield $ oidToKey oid
pull cursor
Just y -> liftIO $ throwIO $ PersistMarshalError $ T.pack $ "Unexpected in selectKeys: " ++ show y
orderClause :: PersistEntity val => SelectOpt val -> DB.Field
orderClause o = case o of
Asc f -> fieldName f DB.=: ( 1 :: Int)
Desc f -> fieldName f DB.=: (-1 :: Int)
_ -> error "orderClause: expected Asc or Desc"
makeQuery :: PersistEntity val => [Filter val] -> [SelectOpt val] -> DB.Query
makeQuery filts opts =
(DB.select (filtersToSelector filts) (unDBName $ entityDB t)) {
DB.limit = fromIntegral limit
, DB.skip = fromIntegral offset
, DB.sort = orders
}
where
t = entityDef $ dummyFromFilts filts
(limit, offset, orders') = limitOffsetOrder opts
orders = map orderClause orders'
filtersToSelector :: PersistEntity val => [Filter val] -> DB.Document
filtersToSelector filts =
#ifdef DEBUG
debug $
#endif
if null filts then [] else concatMap filterToDocument filts
multiFilter :: forall val. PersistEntity val => String -> [Filter val] -> [DB.Field]
multiFilter multi fs = [T.pack multi DB.:= DB.Array (map (DB.Doc . filterToDocument) fs)]
filterToDocument :: PersistEntity val => Filter val -> DB.Document
filterToDocument f =
case f of
Filter field v filt -> return $ case filt of
Eq -> fieldName field DB.:= toValue v
_ -> fieldName field DB.=: [(showFilter filt) DB.:= toValue v]
FilterOr [] -> -- Michael decided to follow Haskell's semantics, which seems reasonable to me.
-- in Haskell an empty or is a False
-- Perhaps there is a less hacky way of creating a query that always returns false?
["$not" DB.=: ["$exists" DB.=: _id]]
FilterOr fs -> multiFilter "$or" fs
-- $and is usually unecessary but makes query construction easier in special cases
FilterAnd [] -> []
FilterAnd fs -> multiFilter "$and" fs
where
toValue :: forall a. PersistField a => Either a [a] -> DB.Value
toValue val =
case val of
Left v -> DB.val $ toPersistValue v
Right vs -> DB.val $ map toPersistValue vs
showFilter Ne = "$ne"
showFilter Gt = "$gt"
showFilter Lt = "$lt"
showFilter Ge = "$gte"
showFilter Le = "$lte"
showFilter In = "$in"
showFilter NotIn = "$nin"
showFilter Eq = error "EQ filter not expected"
showFilter (BackendSpecificFilter bsf) = throw $ PersistMongoDBError $ T.pack $ "did not expect BackendSpecificFilter " ++ T.unpack bsf
fieldName :: forall v typ. (PersistEntity v) => EntityField v typ -> DB.Label
fieldName = idfix . unDBName . fieldDB . persistFieldDef
where idfix f = if f == "id" then _id else f
wrapFromPersistValues :: (PersistEntity val) => EntityDef -> [DB.Field] -> Either T.Text val
wrapFromPersistValues e doc = fromPersistValues reorder
where
castDoc = mapFromDoc doc
castColumns = map (unDBName . fieldDB) $ (entityFields e)
-- we have an alist of fields that need to be the same order as entityColumns
--
-- this naive lookup is O(n^2)
-- reorder = map (fromJust . (flip Prelude.lookup $ castDoc)) castColumns
--
-- this is O(n * log(n))
-- reorder = map (\c -> (M.fromList castDoc) M.! c) castColumns
--
-- and finally, this is O(n * log(n))
-- * do an alist lookup for each column
-- * but once we found an item in the alist use a new alist without that item for future lookups
-- * so for the last query there is only one item left
--
-- TODO: the above should be re-thought now that we are no longer inserting null: searching for a null column will look at every returned field before giving up
reorder :: [PersistValue]
reorder = match castColumns castDoc []
where
match :: [T.Text] -> [(T.Text, PersistValue)] -> [PersistValue] -> [PersistValue]
-- when there are no more Persistent castColumns we are done
--
-- allow extra mongoDB fields that persistent does not know about
-- another application may use fields we don't care about
-- our own application may set extra fields with the raw driver
-- TODO: instead use a projection to avoid network overhead
match [] _ values = values
match (c:cs) fields values =
let (found, unused) = matchOne fields []
in match cs unused (values ++ [snd found])
where
matchOne (f:fs) tried =
if c == fst f then (f, tried ++ fs) else matchOne fs (f:tried)
-- a Nothing will not be inserted into the document as a null
-- so if we don't find our column it is a
-- this keeps the document size down
matchOne [] tried = ((c, PersistNull), tried)
mapFromDoc :: DB.Document -> [(Text, PersistValue)]
mapFromDoc = Prelude.map (\f -> ( (DB.label f), (fromJust . DB.cast') (DB.value f) ) )
oidToPersistValue :: DB.ObjectId -> PersistValue
oidToPersistValue = PersistObjectId . Serialize.encode
oidToKey :: (PersistEntity val) => DB.ObjectId -> Key DB.Action val
oidToKey = Key . oidToPersistValue
persistObjectIdToDbOid :: PersistValue -> DB.ObjectId
persistObjectIdToDbOid (PersistObjectId k) = case Serialize.decode k of
Left msg -> throw $ PersistError $ T.pack $ "error decoding " ++ (show k) ++ ": " ++ msg
Right o -> o
persistObjectIdToDbOid _ = throw $ PersistInvalidField "expected PersistObjectId"
keyToOid :: (PersistEntity val) => Key DB.Action val -> DB.ObjectId
keyToOid (Key k) = persistObjectIdToDbOid k
instance DB.Val PersistValue where
val (PersistInt64 x) = DB.Int64 x
val (PersistText x) = DB.String x
val (PersistDouble x) = DB.Float x
val (PersistBool x) = DB.Bool x
val (PersistUTCTime x) = DB.UTC x
val (PersistZonedTime (ZT x)) = DB.String $ T.pack $ show x
val (PersistNull) = DB.Null
val (PersistList l) = DB.Array $ map DB.val l
val (PersistMap m) = DB.Doc $ map (\(k, v)-> (DB.=:) k v) m
val (PersistByteString x) = DB.Bin (DB.Binary x)
val x@(PersistObjectId _) = DB.ObjId $ persistObjectIdToDbOid x
val (PersistDay _) = throw $ PersistMongoDBUnsupported "only PersistUTCTime currently implemented"
val (PersistTimeOfDay _) = throw $ PersistMongoDBUnsupported "only PersistUTCTime currently implemented"
cast' (DB.Float x) = Just (PersistDouble x)
cast' (DB.Int32 x) = Just $ PersistInt64 $ fromIntegral x
cast' (DB.Int64 x) = Just $ PersistInt64 x
cast' (DB.String x) = Just $ PersistText x
cast' (DB.Bool x) = Just $ PersistBool x
cast' (DB.UTC d) = Just $ PersistUTCTime d
cast' DB.Null = Just $ PersistNull
cast' (DB.Bin (DB.Binary b)) = Just $ PersistByteString b
cast' (DB.Fun (DB.Function f)) = Just $ PersistByteString f
cast' (DB.Uuid (DB.UUID uid)) = Just $ PersistByteString uid
cast' (DB.Md5 (DB.MD5 md5)) = Just $ PersistByteString md5
cast' (DB.UserDef (DB.UserDefined bs)) = Just $ PersistByteString bs
cast' (DB.RegEx (DB.Regex us1 us2)) = Just $ PersistByteString $ E.encodeUtf8 $ T.append us1 us2
cast' (DB.Doc doc) = Just $ PersistMap $ mapFromDoc doc
cast' (DB.Array xs) = Just $ PersistList $ mapMaybe DB.cast' xs
cast' (DB.ObjId x) = Just $ oidToPersistValue x
cast' (DB.JavaScr _) = throw $ PersistMongoDBUnsupported "cast operation not supported for javascript"
cast' (DB.Sym _) = throw $ PersistMongoDBUnsupported "cast operation not supported for sym"
cast' (DB.Stamp _) = throw $ PersistMongoDBUnsupported "cast operation not supported for stamp"
cast' (DB.MinMax _) = throw $ PersistMongoDBUnsupported "cast operation not supported for minmax"
instance Serialize.Serialize DB.ObjectId where
put (DB.Oid w1 w2) = do Serialize.put w1
Serialize.put w2
get = do w1 <- Serialize.get
w2 <- Serialize.get
return (DB.Oid w1 w2)
dummyFromKey :: Key DB.Action v -> v
dummyFromKey _ = error "dummyFromKey"
dummyFromUnique :: Unique v DB.Action -> v
dummyFromUnique _ = error "dummyFromUnique"
dummyFromFilts :: [Filter v] -> v
dummyFromFilts _ = error "dummyFromFilts"
data MongoAuth = MongoAuth DB.Username DB.Password
-- | Information required to connect to a mongo database
data MongoConf = MongoConf
{ mgDatabase :: Text
, mgHost :: Text
, mgAuth :: Maybe MongoAuth
, mgAccessMode :: DB.AccessMode
, mgPoolStripes :: Int
, mgStripeConnections :: Int
, mgConnectionIdleTime :: NominalDiffTime
}
instance PersistConfig MongoConf where
type PersistConfigBackend MongoConf = DB.Action
type PersistConfigPool MongoConf = ConnectionPool
createPoolConfig c =
createMongoDBPool
(mgDatabase c) (T.unpack (mgHost c))
(mgAuth c)
(mgPoolStripes c) (mgStripeConnections c) (mgConnectionIdleTime c)
runPool c = runMongoDBPool (mgAccessMode c)
loadConfig (Object o) = do
db <- o .: "database"
host <- o .:? "host" .!= "127.0.0.1"
poolStripes <- o .:? "poolstripes" .!= 1
stripeConnections <- o .: "connections"
(NoOrphanNominalDiffTime connectionIdleTime) <- o .:? "connectionIdleTime" .!= 20
mUser <- o .:? "user"
mPass <- o .:? "password"
accessString <- o .:? "accessMode" .!= "ConfirmWrites"
mPoolSize <- o .:? "poolsize"
case mPoolSize of
Nothing -> return ()
Just (_::Int) -> fail "specified deprecated poolsize attribute. Please specify a connections. You can also specify a pools attribute which defaults to 1. Total connections opened to the db are connections * pools"
accessMode <- case accessString of
"ReadStaleOk" -> return DB.ReadStaleOk
"UnconfirmedWrites" -> return DB.UnconfirmedWrites
"ConfirmWrites" -> return $ DB.ConfirmWrites ["j" DB.=: True]
badAccess -> fail $ "unknown accessMode: " ++ (T.unpack badAccess)
return $ MongoConf {
mgDatabase = db
, mgHost = host
, mgAuth =
(case (mUser, mPass) of
(Just user, Just pass) -> Just (MongoAuth user pass)
_ -> Nothing
)
, mgPoolStripes = poolStripes
, mgStripeConnections = stripeConnections
, mgAccessMode = accessMode
, mgConnectionIdleTime = connectionIdleTime
}
where
{-
safeRead :: String -> T.Text -> MEither String Int
safeRead name t = case reads s of
(i, _):_ -> MRight i
[] -> MLeft $ concat ["Invalid value for ", name, ": ", s]
where
s = T.unpack t
-}
loadConfig _ = mzero