fradrive/src/Utils/DB.hs
2021-01-11 14:16:39 +01:00

157 lines
6.5 KiB
Haskell

module Utils.DB where
import ClassyPrelude.Yesod
import qualified Data.List as List
import qualified Data.Map as Map
import qualified Data.Set as Set
import qualified Database.Esqueleto as E
-- import Database.Persist -- currently not needed here
import Utils
import Control.Lens
import Control.Lens.Extras (is)
import Control.Monad.Catch
emptyOrIn :: PersistField typ
=> E.SqlExpr (E.Value typ) -> Set typ -> E.SqlExpr (E.Value Bool)
emptyOrIn criterion testSet
| Set.null testSet = E.val True
| otherwise = criterion `E.in_` E.valList (Set.toList testSet)
entities2map :: PersistEntity record => [Entity record] -> Map (Key record) record
entities2map = foldl' (\m entity -> Map.insert (entityKey entity) (entityVal entity) m) Map.empty
getJustBy :: (PersistRecordBackend record backend, PersistUniqueRead backend, MonadIO m, MonadThrow m, Show (Unique record))
=> Unique record -> ReaderT backend m (Entity record)
getJustBy u = getBy u >>= maybe
(throwM . PersistForeignConstraintUnmet $ tshow u)
return
getKeyBy :: (PersistRecordBackend record backend, PersistUniqueRead backend, MonadIO m)
=> Unique record -> ReaderT backend m (Maybe (Key record))
getKeyBy u = fmap entityKey <$> getBy u -- TODO optimize this, so that DB does not deliver entire record!
getKeyJustBy :: (PersistRecordBackend record backend, PersistUniqueRead backend, MonadIO m, MonadThrow m, Show (Unique record))
=> Unique record -> ReaderT backend m (Key record)
getKeyJustBy u = getKeyBy u >>= maybe
(throwM . PersistForeignConstraintUnmet $ tshow u)
return
getKeyBy404 :: (PersistRecordBackend record backend, PersistUniqueRead backend, MonadHandler m)
=> Unique record -> ReaderT backend m (Key record)
getKeyBy404 u = getKeyBy u >>= maybe notFound return
getEntity404 :: (PersistStoreRead backend, PersistRecordBackend record backend, MonadHandler m)
=> Key record -> ReaderT backend m (Entity record)
getEntity404 k = Entity k <$> get404 k
existsBy :: (PersistRecordBackend record backend, PersistUniqueRead backend, MonadIO m)
=> Unique record -> ReaderT backend m Bool
existsBy = fmap (is _Just) . getKeyBy
existsBy404 :: (PersistRecordBackend record backend, PersistUniqueRead backend, MonadHandler m)
=> Unique record -> ReaderT backend m ()
existsBy404 = bool notFound (return ()) <=< fmap (is _Just) . getKeyBy
existsKey :: (PersistRecordBackend record backend, PersistQueryRead backend, MonadIO m)
=> Key record -> ReaderT backend m Bool
existsKey = exists . pure . (persistIdField ==.)
-- -- Available in persistent since 2.11.0.0
-- exists :: (PersistRecordBackend record backend, PersistQueryRead backend, MonadIO m)
-- => [Filter record] -> ReaderT backend m Bool
-- exists = fmap (not . null) . flip selectKeysList [LimitTo 1]
exists404 :: (PersistRecordBackend record backend, PersistQueryRead backend, MonadHandler m)
=> [Filter record] -> ReaderT backend m ()
exists404 = bool (return ()) notFound <=< fmap null . flip selectKeysList [LimitTo 1]
existsKey404 :: (PersistRecordBackend record backend, PersistQueryRead backend, MonadHandler m)
=> Key record -> ReaderT backend m ()
existsKey404 = bool notFound (return ()) <=< existsKey
updateBy :: (PersistUniqueRead backend, PersistStoreWrite backend, MonadIO m, PersistRecordBackend record backend )
=> Unique record -> [Update record] -> ReaderT backend m ()
updateBy uniq updates = do
key <- getKeyBy uniq
for_ key $ flip update updates
updateGetEntity :: (PersistStoreWrite backend, MonadIO m, PersistRecordBackend record backend) => Key record -> [Update record] -> ReaderT backend m (Entity record)
updateGetEntity k = fmap (Entity k) . updateGet k
-- | Like 'myReplaceUnique' or 'replaceUnique' but with reversed result: returns 'Nothing' if the replacement was not possible,
-- and 'Just key' for the successfully replaced record
uniqueReplace :: ( MonadIO m
, Eq (Unique record)
, PersistRecordBackend record backend
, PersistUniqueWrite backend
)
=> Key record -> record -> ReaderT backend m (Maybe (Key record))
uniqueReplace key datumNew = flipMaybe key <$> myReplaceUnique key datumNew
-- | Identical to 'Database.Persist.Class', except for the better type signature (original requires Eq record which is not needed anyway)
myReplaceUnique :: ( MonadIO m
, Eq (Unique record)
, PersistRecordBackend record backend
, PersistUniqueWrite backend
)
=> Key record -> record -> ReaderT backend m (Maybe (Unique record))
myReplaceUnique key datumNew = getJust key >>= replaceOriginal
where
uniqueKeysNew = persistUniqueKeys datumNew
replaceOriginal original = do
conflict <- checkUniqueKeys changedKeys
case conflict of
Nothing -> replace key datumNew >> return Nothing
(Just conflictingKey) -> return $ Just conflictingKey
where
changedKeys = uniqueKeysNew List.\\ uniqueKeysOriginal
uniqueKeysOriginal = persistUniqueKeys original
replaceEntity :: ( MonadIO m
, PersistRecordBackend record backend
, PersistStoreWrite backend
)
=> Entity record -> ReaderT backend m ()
replaceEntity Entity{..} = replace entityKey entityVal
checkUniqueKeys :: ( MonadIO m
, PersistUniqueRead backend
, PersistRecordBackend record backend
)
=> [Unique record] -> ReaderT backend m (Maybe (Unique record))
checkUniqueKeys [] = return Nothing
checkUniqueKeys (x:xs) = do
y <- getBy x
case y of
Nothing -> checkUniqueKeys xs
Just _ -> return (Just x)
put :: ( MonadIO m
, PersistUniqueWrite backend
, PersistRecordBackend record backend
)
=> record -> ReaderT backend m (Key record)
-- ^ `insert`, but remove all records with matching uniqueness constraints first
put v = do
forM_ (persistUniqueKeys v) deleteBy
insert v
selectMaybe :: forall record backend m.
( MonadIO m
, PersistQueryRead backend
, PersistRecordBackend record backend
)
=> [Filter record] -> [SelectOpt record]
-> ReaderT backend m (Maybe (Entity record))
selectMaybe fltrs opts = listToMaybe <$> selectList fltrs (LimitTo 1 : opts')
where opts' = filter (not . isLimit) opts
isLimit = \case
LimitTo _ -> True
_other -> False