119 lines
5.4 KiB
Haskell
119 lines
5.4 KiB
Haskell
module Utils.DB where
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import ClassyPrelude.Yesod
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import qualified Data.List as List
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import Data.Map (Map)
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import qualified Data.Map as Map
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import Data.Set (Set)
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import qualified Data.Set as Set
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import qualified Database.Esqueleto as E
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-- import Database.Persist -- currently not needed here
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import Utils
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import Control.Lens
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import Control.Lens.Extras (is)
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import Control.Monad.Catch
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emptyOrIn :: PersistField typ
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=> E.SqlExpr (E.Value typ) -> Set typ -> E.SqlExpr (E.Value Bool)
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emptyOrIn criterion testSet
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| Set.null testSet = E.val True
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| otherwise = criterion `E.in_` E.valList (Set.toList testSet)
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entities2map :: PersistEntity record => [Entity record] -> Map (Key record) record
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entities2map = foldl' (\m entity -> Map.insert (entityKey entity) (entityVal entity) m) Map.empty
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getJustBy :: (PersistEntityBackend record ~ BaseBackend backend, PersistEntity record, PersistUniqueRead backend, MonadIO m, MonadThrow m, Show (Unique record))
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=> Unique record -> ReaderT backend m (Entity record)
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getJustBy u = getBy u >>= maybe
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(throwM . PersistForeignConstraintUnmet $ tshow u)
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return
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getKeyBy :: (PersistEntityBackend record ~ BaseBackend backend, PersistEntity record, PersistUniqueRead backend, MonadIO m)
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=> Unique record -> ReaderT backend m (Maybe (Key record))
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getKeyBy u = fmap entityKey <$> getBy u -- TODO optimize this, so that DB does not deliver entire record!
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getKeyJustBy :: (PersistEntityBackend record ~ BaseBackend backend, PersistEntity record, PersistUniqueRead backend, MonadIO m, MonadThrow m, Show (Unique record))
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=> Unique record -> ReaderT backend m (Key record)
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getKeyJustBy u = getKeyBy u >>= maybe
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(throwM . PersistForeignConstraintUnmet $ tshow u)
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return
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getKeyBy404 :: (PersistEntityBackend record ~ BaseBackend backend, PersistEntity record, PersistUniqueRead backend, MonadHandler m)
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=> Unique record -> ReaderT backend m (Key record)
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getKeyBy404 u = getKeyBy u >>= maybe notFound return
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getEntity404 :: (PersistStoreRead backend, PersistRecordBackend val backend, MonadHandler m)
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=> Key val -> ReaderT backend m (Entity val)
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getEntity404 k = Entity <$> pure k <*> get404 k
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existsBy :: (PersistEntityBackend record ~ BaseBackend backend, PersistEntity record, PersistUniqueRead backend, MonadIO m)
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=> Unique record -> ReaderT backend m Bool
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existsBy = fmap (is _Just) . getKeyBy
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existsBy404 :: (PersistEntityBackend record ~ BaseBackend backend, PersistEntity record, PersistUniqueRead backend, MonadHandler m)
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=> Unique record -> ReaderT backend m ()
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existsBy404 = bool notFound (return ()) <=< fmap (is _Just) . getKeyBy
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existsKey :: (PersistEntityBackend record ~ BaseBackend backend, PersistEntity record, PersistStoreRead backend, MonadIO m)
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=> Key record -> ReaderT backend m Bool
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existsKey = fmap isJust . get -- TODO optimize, so that DB does not deliver entire record
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exists :: (PersistEntityBackend record ~ BaseBackend backend, PersistEntity record, PersistQueryRead backend, MonadIO m)
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=> [Filter record] -> ReaderT backend m Bool
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exists = fmap (not . null) . flip selectKeysList [LimitTo 1]
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exists404 :: (PersistEntityBackend record ~ BaseBackend backend, PersistEntity record, PersistQueryRead backend, MonadHandler m)
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=> [Filter record] -> ReaderT backend m ()
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exists404 = bool (return ()) notFound <=< fmap null . flip selectKeysList [LimitTo 1]
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updateBy :: (PersistUniqueRead backend, PersistStoreWrite backend, MonadIO m, PersistRecordBackend record backend )
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=> Unique record -> [Update record] -> ReaderT backend m ()
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updateBy uniq updates = do
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key <- getKeyBy uniq
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for_ key $ flip update updates
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-- | Like 'myReplaceUnique' or 'replaceUnique' but with reversed result: returns 'Nothing' if the replacement was not possible,
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-- and 'Just key' for the successfully replaced record
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uniqueReplace :: ( MonadIO m
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, Eq (Unique record)
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, PersistRecordBackend record backend
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, PersistUniqueWrite backend
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)
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=> Key record -> record -> ReaderT backend m (Maybe (Key record))
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uniqueReplace key datumNew = flipMaybe key <$> myReplaceUnique key datumNew
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-- | Identical to 'Database.Persist.Class', except for the better type signature (original requires Eq record which is not needed anyway)
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myReplaceUnique :: ( MonadIO m
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, Eq (Unique record)
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, PersistRecordBackend record backend
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, PersistUniqueWrite backend
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)
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=> Key record -> record -> ReaderT backend m (Maybe (Unique record))
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myReplaceUnique key datumNew = getJust key >>= replaceOriginal
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where
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uniqueKeysNew = persistUniqueKeys datumNew
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replaceOriginal original = do
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conflict <- checkUniqueKeys changedKeys
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case conflict of
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Nothing -> replace key datumNew >> return Nothing
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(Just conflictingKey) -> return $ Just conflictingKey
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where
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changedKeys = uniqueKeysNew List.\\ uniqueKeysOriginal
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uniqueKeysOriginal = persistUniqueKeys original
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checkUniqueKeys :: ( MonadIO m
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, PersistUniqueRead backend
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, PersistRecordBackend record backend
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)
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=> [Unique record] -> ReaderT backend m (Maybe (Unique record))
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checkUniqueKeys [] = return Nothing
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checkUniqueKeys (x:xs) = do
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y <- getBy x
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case y of
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Nothing -> checkUniqueKeys xs
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Just _ -> return (Just x)
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