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128 lines
3.8 KiB
Haskell
128 lines
3.8 KiB
Haskell
module Hasura.RQL.DML.Count
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( CountQueryP1(..)
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, validateCountQWith
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, validateCountQ
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, runCount
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, countQToTx
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) where
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import Hasura.Prelude
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import qualified Data.ByteString.Builder as BB
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import qualified Data.Sequence as DS
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import Data.Aeson
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import Instances.TH.Lift ()
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import qualified Database.PG.Query as Q
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import qualified Hasura.Backends.Postgres.SQL.DML as S
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import Hasura.Backends.Postgres.SQL.Types
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import Hasura.EncJSON
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import Hasura.RQL.DML.Internal
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import Hasura.RQL.GBoolExp
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import Hasura.RQL.Types
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import Hasura.SQL.Types
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data CountQueryP1
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= CountQueryP1
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{ cqp1Table :: !QualifiedTable
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, cqp1Where :: !(AnnBoolExpSQL 'Postgres, Maybe (AnnBoolExpSQL 'Postgres))
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, cqp1Distinct :: !(Maybe [PGCol])
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} deriving (Eq)
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mkSQLCount
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:: CountQueryP1 -> S.Select
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mkSQLCount (CountQueryP1 tn (permFltr, mWc) mDistCols) =
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S.mkSelect
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{ S.selExtr = [S.Extractor S.countStar Nothing]
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, S.selFrom = Just $ S.FromExp
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[S.mkSelFromExp False innerSel $ TableName "r"]
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}
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where
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finalWC =
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toSQLBoolExp (S.QualTable tn) $
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maybe permFltr (andAnnBoolExps permFltr) mWc
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innerSel = partSel
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{ S.selFrom = Just $ S.mkSimpleFromExp tn
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, S.selWhere = S.WhereFrag <$> Just finalWC
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}
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partSel = case mDistCols of
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Just distCols ->
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let extrs = flip map distCols $ \c -> S.Extractor (S.mkSIdenExp c) Nothing
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in S.mkSelect
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{ S.selDistinct = Just S.DistinctSimple
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, S.selExtr = extrs
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}
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Nothing -> S.mkSelect
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{ S.selExtr = [S.Extractor (S.SEStar Nothing) Nothing] }
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-- SELECT count(*) FROM (SELECT DISTINCT c1, .. cn FROM .. WHERE ..) r;
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-- SELECT count(*) FROM (SELECT * FROM .. WHERE ..) r;
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validateCountQWith
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:: (UserInfoM m, QErrM m, CacheRM m)
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=> SessVarBldr 'Postgres m
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-> (PGColumnType -> Value -> m S.SQLExp)
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-> CountQuery
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-> m CountQueryP1
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validateCountQWith sessVarBldr prepValBldr (CountQuery qt mDistCols mWhere) = do
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tableInfo <- askTabInfo qt
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-- Check if select is allowed
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selPerm <- modifyErr (<> selNecessaryMsg) $
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askSelPermInfo tableInfo
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let colInfoMap = _tciFieldInfoMap $ _tiCoreInfo tableInfo
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forM_ mDistCols $ \distCols -> do
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let distColAsrns = [ checkSelOnCol selPerm
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, assertPGCol colInfoMap relInDistColsErr]
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withPathK "distinct" $ verifyAsrns distColAsrns distCols
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-- convert the where clause
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annSQLBoolExp <- forM mWhere $ \be ->
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withPathK "where" $
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convBoolExp colInfoMap selPerm be sessVarBldr prepValBldr
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resolvedSelFltr <- convAnnBoolExpPartialSQL sessVarBldr $
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spiFilter selPerm
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return $ CountQueryP1
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qt
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(resolvedSelFltr, annSQLBoolExp)
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mDistCols
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where
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selNecessaryMsg =
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"; \"count\" is only allowed if the role "
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<> "has \"select\" permissions on the table"
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relInDistColsErr =
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"Relationships can't be used in \"distinct\"."
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validateCountQ
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:: (QErrM m, UserInfoM m, CacheRM m)
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=> CountQuery -> m (CountQueryP1, DS.Seq Q.PrepArg)
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validateCountQ =
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runDMLP1T . validateCountQWith sessVarFromCurrentSetting binRHSBuilder
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countQToTx
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:: (QErrM m, MonadTx m)
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=> (CountQueryP1, DS.Seq Q.PrepArg) -> m EncJSON
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countQToTx (u, p) = do
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qRes <- liftTx $ Q.rawQE dmlTxErrorHandler
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(Q.fromBuilder countSQL) (toList p) True
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return $ encJFromBuilder $ encodeCount qRes
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where
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countSQL = toSQL $ mkSQLCount u
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encodeCount (Q.SingleRow (Identity c)) =
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BB.byteString "{\"count\":" <> BB.intDec c <> BB.char7 '}'
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runCount
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:: (QErrM m, UserInfoM m, CacheRM m, MonadTx m)
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=> CountQuery -> m EncJSON
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runCount q =
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validateCountQ q >>= countQToTx
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