Files
postgrest/src/PostgREST/Query.hs
T

272 lines
12 KiB
Haskell

{-# LANGUAGE NamedFieldPuns #-}
{-# LANGUAGE RecordWildCards #-}
module PostgREST.Query
( createQuery
, deleteQuery
, invokeQuery
, openApiQuery
, readQuery
, singleUpsertQuery
, updateQuery
, setPgLocals
, DbHandler
) where
import qualified Data.Aeson as JSON
import qualified Data.Aeson.Key as K
import qualified Data.Aeson.KeyMap as KM
import qualified Data.ByteString.Lazy.Char8 as LBS
import qualified Data.HashMap.Strict as HM
import qualified Data.Set as S
import qualified Data.Text.Encoding as T
import qualified Hasql.Decoders as HD
import qualified Hasql.DynamicStatements.Snippet as SQL (Snippet)
import qualified Hasql.DynamicStatements.Statement as SQL
import qualified Hasql.Transaction as SQL
import qualified PostgREST.Error as Error
import qualified PostgREST.Query.QueryBuilder as QueryBuilder
import qualified PostgREST.Query.Statements as Statements
import qualified PostgREST.RangeQuery as RangeQuery
import qualified PostgREST.SchemaCache as SchemaCache
import qualified PostgREST.SchemaCache.Proc as Proc
import Data.Scientific (FPFormat (..), formatScientific, isInteger)
import PostgREST.ApiRequest (ApiRequest (..),
Target (..))
import PostgREST.ApiRequest.Preferences (PreferCount (..),
PreferParameters (..),
PreferTransaction (..),
shouldCount)
import PostgREST.Config (AppConfig (..),
OpenAPIMode (..))
import PostgREST.Config.PgVersion (PgVersion (..),
pgVersion140)
import PostgREST.Error (Error)
import PostgREST.MediaType (MediaType (..))
import PostgREST.Plan (CallReadPlan (..),
MutateReadPlan (..))
import PostgREST.Plan.MutatePlan (MutatePlan (..))
import PostgREST.Plan.ReadPlan (ReadPlanTree)
import PostgREST.Query.SqlFragment (fromQi, intercalateSnippet,
pgFmtIdentList,
setConfigLocal,
setConfigLocalJson)
import PostgREST.Query.Statements (ResultSet (..))
import PostgREST.SchemaCache (SchemaCache (..))
import PostgREST.SchemaCache.Identifiers (QualifiedIdentifier (..),
Schema)
import PostgREST.SchemaCache.Proc (ProcDescription (..),
ProcsMap)
import PostgREST.SchemaCache.Table (TablesMap)
import Protolude hiding (Handler)
type DbHandler = ExceptT Error SQL.Transaction
readQuery :: ReadPlanTree -> AppConfig -> ApiRequest -> DbHandler ResultSet
readQuery req conf@AppConfig{..} apiReq@ApiRequest{..} = do
let countQuery = QueryBuilder.readPlanToCountQuery req
resultSet <-
lift . SQL.statement mempty $
Statements.prepareRead
(QueryBuilder.readPlanToQuery req)
(if iPreferCount == Just EstimatedCount then
-- LIMIT maxRows + 1 so we can determine below that maxRows was surpassed
QueryBuilder.limitedQuery countQuery ((+ 1) <$> configDbMaxRows)
else
countQuery
)
(shouldCount iPreferCount)
iAcceptMediaType
iBinaryField
configDbPreparedStatements
failNotSingular iAcceptMediaType resultSet
optionalRollback conf apiReq
resultSetWTotal conf apiReq resultSet countQuery
resultSetWTotal :: AppConfig -> ApiRequest -> ResultSet -> SQL.Snippet -> DbHandler ResultSet
resultSetWTotal _ _ rs@RSPlan{} _ = return rs
resultSetWTotal AppConfig{..} ApiRequest{..} rs@RSStandard{rsTableTotal=tableTotal} countQuery =
case iPreferCount of
Just PlannedCount -> do
total <- explain
return rs{rsTableTotal=total}
Just EstimatedCount ->
if tableTotal > (fromIntegral <$> configDbMaxRows) then do
total <- max tableTotal <$> explain
return rs{rsTableTotal=total}
else
return rs
Just ExactCount ->
return rs
Nothing ->
return rs
where
explain =
lift . SQL.statement mempty . Statements.preparePlanRows countQuery $
configDbPreparedStatements
createQuery :: MutateReadPlan -> ApiRequest -> AppConfig -> DbHandler ResultSet
createQuery mrPlan apiReq@ApiRequest{..} conf = do
resultSet <- writeQuery mrPlan apiReq conf
failNotSingular iAcceptMediaType resultSet
optionalRollback conf apiReq
pure resultSet
updateQuery :: MutateReadPlan -> ApiRequest -> AppConfig -> DbHandler ResultSet
updateQuery mrPlan apiReq@ApiRequest{..} conf = do
resultSet <- writeQuery mrPlan apiReq conf
failNotSingular iAcceptMediaType resultSet
failsChangesOffLimits (RangeQuery.rangeLimit iTopLevelRange) resultSet
optionalRollback conf apiReq
pure resultSet
singleUpsertQuery :: MutateReadPlan -> ApiRequest -> AppConfig -> DbHandler ResultSet
singleUpsertQuery mrPlan apiReq conf = do
resultSet <- writeQuery mrPlan apiReq conf
failPut resultSet
optionalRollback conf apiReq
pure resultSet
-- Makes sure the querystring pk matches the payload pk
-- e.g. PUT /items?id=eq.1 { "id" : 1, .. } is accepted,
-- PUT /items?id=eq.14 { "id" : 2, .. } is rejected.
-- If this condition is not satisfied then nothing is inserted,
-- check the WHERE for INSERT in QueryBuilder.hs to see how it's done
failPut :: ResultSet -> DbHandler ()
failPut RSPlan{} = pure ()
failPut RSStandard{rsQueryTotal=queryTotal} =
when (queryTotal /= 1) $ do
lift SQL.condemn
throwError Error.PutMatchingPkError
deleteQuery :: MutateReadPlan -> ApiRequest -> AppConfig -> DbHandler ResultSet
deleteQuery mrPlan apiReq@ApiRequest{..} conf = do
resultSet <- writeQuery mrPlan apiReq conf
failNotSingular iAcceptMediaType resultSet
failsChangesOffLimits (RangeQuery.rangeLimit iTopLevelRange) resultSet
optionalRollback conf apiReq
pure resultSet
invokeQuery :: ProcDescription -> CallReadPlan -> ApiRequest -> AppConfig -> DbHandler ResultSet
invokeQuery proc CallReadPlan{crReadPlan, crCallPlan} apiReq@ApiRequest{..} conf@AppConfig{..} = do
resultSet <-
lift . SQL.statement mempty $
Statements.prepareCall
(Proc.procReturnsScalar proc)
(Proc.procReturnsSingle proc)
(QueryBuilder.callPlanToQuery crCallPlan)
(QueryBuilder.readPlanToQuery crReadPlan)
(QueryBuilder.readPlanToCountQuery crReadPlan)
(shouldCount iPreferCount)
iAcceptMediaType
(iPreferParameters == Just MultipleObjects)
iBinaryField
configDbPreparedStatements
optionalRollback conf apiReq
failNotSingular iAcceptMediaType resultSet
pure resultSet
openApiQuery :: SchemaCache -> PgVersion -> AppConfig -> Schema -> DbHandler (Maybe (TablesMap, ProcsMap, Maybe Text))
openApiQuery sCache pgVer AppConfig{..} tSchema =
lift $ case configOpenApiMode of
OAFollowPriv -> do
tableAccess <- SQL.statement [tSchema] (SchemaCache.accessibleTables pgVer configDbPreparedStatements)
Just <$> ((,,)
(HM.filterWithKey (\qi _ -> S.member qi tableAccess) $ SchemaCache.dbTables sCache)
<$> SQL.statement tSchema (SchemaCache.accessibleProcs pgVer configDbPreparedStatements)
<*> SQL.statement tSchema (SchemaCache.schemaDescription configDbPreparedStatements))
OAIgnorePriv ->
Just <$> ((,,)
(HM.filterWithKey (\(QualifiedIdentifier sch _) _ -> sch == tSchema) $ SchemaCache.dbTables sCache)
(HM.filterWithKey (\(QualifiedIdentifier sch _) _ -> sch == tSchema) $ SchemaCache.dbProcs sCache)
<$> SQL.statement tSchema (SchemaCache.schemaDescription configDbPreparedStatements))
OADisabled ->
pure Nothing
writeQuery :: MutateReadPlan -> ApiRequest -> AppConfig -> DbHandler ResultSet
writeQuery MutateReadPlan{mrReadPlan, mrMutatePlan} apiReq conf =
let
(isInsert, pkCols) = case mrMutatePlan of {Insert{insPkCols} -> (True, insPkCols); _ -> (False, mempty);}
in
lift . SQL.statement mempty $
Statements.prepareWrite
(QueryBuilder.readPlanToQuery mrReadPlan)
(QueryBuilder.mutatePlanToQuery mrMutatePlan)
isInsert
(iAcceptMediaType apiReq)
(iPreferRepresentation apiReq)
pkCols
(configDbPreparedStatements conf)
-- |
-- Fail a response if a single JSON object was requested and not exactly one
-- was found.
failNotSingular :: MediaType -> ResultSet -> DbHandler ()
failNotSingular _ RSPlan{} = pure ()
failNotSingular mediaType RSStandard{rsQueryTotal=queryTotal} =
when (mediaType == MTSingularJSON && queryTotal /= 1) $ do
lift SQL.condemn
throwError $ Error.singularityError queryTotal
failsChangesOffLimits :: Maybe Integer -> ResultSet -> DbHandler ()
failsChangesOffLimits _ RSPlan{} = pure ()
failsChangesOffLimits Nothing _ = pure ()
failsChangesOffLimits (Just maxChanges) RSStandard{rsQueryTotal=queryTotal} =
when (queryTotal > fromIntegral maxChanges) $ do
lift SQL.condemn
throwError $ Error.OffLimitsChangesError queryTotal maxChanges
-- | Set a transaction to roll back if requested
optionalRollback :: AppConfig -> ApiRequest -> DbHandler ()
optionalRollback AppConfig{..} ApiRequest{..} = do
lift $ when (shouldRollback || (configDbTxRollbackAll && not shouldCommit)) $ do
SQL.sql "SET CONSTRAINTS ALL IMMEDIATE"
SQL.condemn
where
shouldCommit =
configDbTxAllowOverride && iPreferTransaction == Just Commit
shouldRollback =
configDbTxAllowOverride && iPreferTransaction == Just Rollback
-- | Runs local(transaction scoped) GUCs for every request, plus the pre-request function
setPgLocals :: AppConfig -> KM.KeyMap JSON.Value -> Text ->
ApiRequest -> ByteString -> PgVersion -> DbHandler ()
setPgLocals conf claims role req jsonDbS actualPgVersion = do
lift $ SQL.statement mempty $ SQL.dynamicallyParameterized
("select " <> intercalateSnippet ", " (searchPathSql : roleSql ++ claimsSql ++ [methodSql, pathSql] ++ headersSql ++ cookiesSql ++ appSettingsSql ++ specSql))
HD.noResult (configDbPreparedStatements conf)
lift $ traverse_ SQL.sql preReqSql
where
methodSql = setConfigLocal mempty ("request.method", iMethod req)
pathSql = setConfigLocal mempty ("request.path", iPath req)
headersSql = if usesLegacyGucs
then setConfigLocal "request.header." <$> iHeaders req
else setConfigLocalJson "request.headers" (iHeaders req)
cookiesSql = if usesLegacyGucs
then setConfigLocal "request.cookie." <$> iCookies req
else setConfigLocalJson "request.cookies" (iCookies req)
claimsSql = if usesLegacyGucs
then setConfigLocal "request.jwt.claim." <$> [(toUtf8 $ K.toText c, toUtf8 $ unquoted v) | (c,v) <- KM.toList claims]
else [setConfigLocal mempty ("request.jwt.claims", LBS.toStrict $ JSON.encode claims)]
roleSql = [setConfigLocal mempty ("role", toUtf8 role)]
appSettingsSql = setConfigLocal mempty <$> (join bimap toUtf8 <$> configAppSettings conf)
searchPathSql =
let schemas = pgFmtIdentList (iSchema req : configDbExtraSearchPath conf) in
setConfigLocal mempty ("search_path", schemas)
preReqSql = (\f -> "select " <> fromQi f <> "();") <$> configDbPreRequest conf
specSql = case iTarget req of
TargetProc{tpIsRootSpec=True} -> [setConfigLocal mempty ("request.spec", jsonDbS)]
_ -> mempty
usesLegacyGucs = configDbUseLegacyGucs conf && actualPgVersion < pgVersion140
unquoted :: JSON.Value -> Text
unquoted (JSON.String t) = t
unquoted (JSON.Number n) =
toS $ formatScientific Fixed (if isInteger n then Just 0 else Nothing) n
unquoted (JSON.Bool b) = show b
unquoted v = T.decodeUtf8 . LBS.toStrict $ JSON.encode v