{-# LANGUAGE OverloadedStrings #-}
------------------------------------------------------------------------------
-- | In this module you can find variations of @withDB@ functions.
--
-- Functions from this module are to be used when you have single MongoDB snaplet in your application and your application is an instance of HasMongoDB.
------------------------------------------------------------------------------
module Snap.Snaplet.MongoDB.Functions.S
( eitherWithDB
, eitherWithDB'
, maybeWithDB
, maybeWithDB'
, unsafeWithDB
, unsafeWithDB'
) where
import Control.Monad.Error
import Snap
import Snap.Snaplet.MongoDB.Core
import Database.MongoDB
import System.IO.Pool
------------------------------------------------------------------------------
-- | Database access function.
--
-- Usage:
--
-- > unsafeWithDB $ insert "test-collection" ["some_field" = "something" ]
unsafeWithDB :: (MonadIO m, MonadState app m, HasMongoDB app)
=> Action IO a -- ^ 'Action' you want to perform.
-> m a -- ^ The action's result; in case of failure 'error' is called.
unsafeWithDB action = getMongoAccessMode >>= flip unsafeWithDB' action
------------------------------------------------------------------------------
-- | Database access function.
--
-- Usage:
--
-- > unsafeWithDB' UnconfirmedWrites $ insert "test-collection" ["some_field" = "something" ]
unsafeWithDB' :: (MonadIO m, MonadState app m, HasMongoDB app)
=> AccessMode -- ^ Access mode you want to use when performing the action.
-> Action IO a -- ^ 'Action' you want to perform.
-> m a -- ^ The action's result; in case of failure 'error' is called.
unsafeWithDB' mode action = do
res <- (eitherWithDB' mode action)
either (error . show) return res
------------------------------------------------------------------------------
-- | Database access function.
--
-- Usage:
--
-- > maybeWithDB $ insert "test-collection" ["some_field" = "something" ]
maybeWithDB :: (MonadIO m, MonadState app m, HasMongoDB app)
=> Action IO a -- ^ 'Action' you want to perform.
-> m (Maybe a) -- ^ 'Nothing' in case of failure or 'Just' the result of the action.
maybeWithDB action = getMongoAccessMode >>= flip maybeWithDB' action
------------------------------------------------------------------------------
-- | Database access function.
--
-- Usage:
--
-- > maybeWithDB' UnconfirmedWrites $ insert "test-collection" ["some_field" = "something" ]
maybeWithDB' :: (MonadIO m, MonadState app m, HasMongoDB app)
=> AccessMode -- ^ Access mode you want to use when performing the action.
-> Action IO a -- ^ 'Action' you want to perform.
-> m (Maybe a) -- ^ 'Nothing' in case of failure or 'Just' the result of the action.
maybeWithDB' mode action = do
res <- (eitherWithDB' mode action)
return $ either (const Nothing) Just res
------------------------------------------------------------------------------
-- | Database access function.
--
-- Usage:
--
-- > eitherWithDB $ insert "test-collection" ["some_field" = "something" ]
eitherWithDB :: (MonadIO m, MonadState app m, HasMongoDB app)
=> Action IO a -- ^ 'Action' you want to perform.
-> m (Either Failure a) -- ^ 'Either' 'Failure' or the action's result.
eitherWithDB action = getMongoAccessMode >>= flip eitherWithDB' action
------------------------------------------------------------------------------
-- | Database access function.
--
-- Usage:
--
-- > eitherWithDB' UnconfirmedWrites $ insert "test-collection" ["some_field" = "something" ]
eitherWithDB' :: (MonadIO m, MonadState app m, HasMongoDB app)
=> AccessMode -- ^ Access mode you want to use when performing the action.
-> Action IO a -- ^ 'Action' you want to perform.
-> m (Either Failure a) -- ^ 'Either' 'Failure' or the action's result.
eitherWithDB' mode action = do
(MongoDB pool database _) <- gets getMongoDB
ep <- liftIO $ runErrorT $ aResource pool
case ep of
Left err -> return $ Left $ ConnectionFailure err
Right pip -> liftIO $ access pip mode database action
getMongoAccessMode :: (MonadIO m, MonadState app m, HasMongoDB app) => m AccessMode
getMongoAccessMode = gets getMongoDB >>= return . mongoAccessMode
{-# INLINE getMongoAccessMode #-}