fix: mixing offset and limit with Range header

src/PostgREST/ApiRequest.hs

@@ -35,8 +35,7 @@ import Data.Either.Combinators (mapBoth)
 import Control.Arrow             ((***))
 import Data.Aeson.Types          (emptyArray, emptyObject)
 import Data.List                 (lookup)
-import Data.Ranged.Ranges        (emptyRange, rangeIntersection,
-                                  rangeIsEmpty)
+import Data.Ranged.Ranges        (rangeIsEmpty)
 import Network.HTTP.Types.Header (RequestHeaders, hCookie)
 import Network.HTTP.Types.URI    (parseSimpleQuery)
 import Network.Wai               (Request (..))
@@ -50,8 +49,6 @@ import PostgREST.Config                  (AppConfig (..),
                                           OpenAPIMode (..))
 import PostgREST.MediaType               (MediaType (..))
 import PostgREST.RangeQuery              (NonnegRange, allRange,
-                                          convertToLimitZeroRange,
-                                          hasLimitZero,
                                           rangeRequested)
 import PostgREST.SchemaCache             (SchemaCache (..))
 import PostgREST.SchemaCache.Identifiers (FieldName,
@@ -111,8 +108,7 @@ data Action
 -}
 data ApiRequest = ApiRequest {
     iAction              :: Action                           -- ^ Action on the resource
-  , iRange               :: HM.HashMap Text NonnegRange      -- ^ Requested range of rows within response
-  , iTopLevelRange       :: NonnegRange                      -- ^ Requested range of rows from the top level
+  , iRange               :: NonnegRange                      -- ^ Requested range of rows from the selected resource
   , iPayload             :: Maybe Payload                    -- ^ Data sent by client and used for mutation actions
   , iPreferences         :: Preferences.Preferences          -- ^ Prefer header values
   , iQueryParams         :: QueryParams.QueryParams
@@ -134,12 +130,11 @@ userApiRequest conf req reqBody sCache = do
   (schema, negotiatedByProfile) <- getSchema conf hdrs method
   act <- getAction resource schema method
   qPrms <- first QueryParamError $ QueryParams.parse (actIsInvokeSafe act) $ rawQueryString req
-  (topLevelRange, ranges) <- getRanges method qPrms hdrs
+  hRange <- getRange method qPrms hdrs
   (payload, columns) <- getPayload reqBody contentMediaType qPrms act
   return $ ApiRequest {
     iAction = act
-  , iRange = ranges
-  , iTopLevelRange = topLevelRange
+  , iRange = hRange
   , iPayload = payload
   , iPreferences = Preferences.fromHeaders (configDbTxAllowOverride conf) (dbTimezones sCache) hdrs
   , iQueryParams = qPrms
@@ -217,24 +212,15 @@ getSchema AppConfig{configDbSchemas} hdrs method = do
     acceptProfile = T.decodeUtf8 <$> lookupHeader "Accept-Profile"
     lookupHeader    = flip lookup hdrs
 
-getRanges :: ByteString -> QueryParams -> RequestHeaders -> Either ApiRequestError (NonnegRange, HM.HashMap Text NonnegRange)
-getRanges method QueryParams{qsOrder,qsRanges} hdrs
-  | isInvalidRange = Left $ InvalidRange (if rangeIsEmpty headerRange then LowerGTUpper else NegativeLimit)
-  | method `elem` ["PATCH", "DELETE"] && not (null qsRanges) && null qsOrder = Left LimitNoOrderError
-  | method == "PUT" && topLevelRange /= allRange = Left PutLimitNotAllowedError
-  | otherwise = Right (topLevelRange, ranges)
+getRange :: ByteString -> QueryParams -> RequestHeaders -> Either ApiRequestError NonnegRange
+getRange method QueryParams{qsOffset,qsLimit} hdrs
+  | rangeIsEmpty headerRange = Left $ InvalidRange LowerGTUpper -- TODO: Change to more appropriate error
+  | method == "PUT" && (isJust qsOffset || isJust qsLimit) = Left PutLimitNotAllowedError
+  | otherwise = Right headerRange
   where
     -- According to the RFC (https://www.rfc-editor.org/rfc/rfc9110.html#name-range),
     -- the Range header must be ignored for all methods other than GET
     headerRange = if method == "GET" then rangeRequested hdrs else allRange
-    limitRange = fromMaybe allRange (HM.lookup "limit" qsRanges)
-    headerAndLimitRange = rangeIntersection headerRange limitRange
-    -- Bypass all the ranges and send only the limit zero range (0 <= x <= -1) if
-    -- limit=0 is present in the query params (not allowed for the Range header)
-    ranges = HM.insert "limit" (convertToLimitZeroRange limitRange headerAndLimitRange) qsRanges
-    -- The only emptyRange allowed is the limit zero range
-    isInvalidRange = topLevelRange == emptyRange && not (hasLimitZero limitRange)
-    topLevelRange = fromMaybe allRange $ HM.lookup "limit" ranges -- if no limit is specified, get all the request rows
 
 getPayload :: RequestBody -> MediaType -> QueryParams.QueryParams -> Action -> Either ApiRequestError (Maybe Payload, S.Set FieldName)
 getPayload reqBody contentMediaType QueryParams{qsColumns} action = do

src/PostgREST/ApiRequest/QueryParams.hs

@@ -9,11 +9,9 @@
 module PostgREST.ApiRequest.QueryParams
   ( parse
   , QueryParams(..)
-  , pRequestRange
   ) where
 
 import qualified Data.ByteString.Char8         as BS
-import qualified Data.HashMap.Strict           as HM
 import qualified Data.List                     as L
 import qualified Data.Set                      as S
 import qualified Data.Text                     as T
@@ -22,42 +20,43 @@ import qualified Network.HTTP.Base             as HTTP
 import qualified Network.HTTP.Types.URI        as HTTP
 import qualified Text.ParserCombinators.Parsec as P
 
-import Control.Arrow                 ((***))
-import Data.Either.Combinators       (mapLeft)
-import Data.List                     (init, last)
-import Data.Ranged.Boundaries        (Boundary (..))
-import Data.Ranged.Ranges            (Range (..))
-import Data.Tree                     (Tree (..))
-import Text.Parsec.Error             (errorMessages,
-                                      showErrorMessages)
-import Text.ParserCombinators.Parsec (GenParser, ParseError, Parser,
-                                      anyChar, between, char, choice,
-                                      digit, eof, errorPos, letter,
-                                      lookAhead, many1, noneOf,
-                                      notFollowedBy, oneOf,
-                                      optionMaybe, sepBy, sepBy1,
-                                      string, try, (<?>))
-
-import PostgREST.RangeQuery              (NonnegRange, allRange,
-                                          rangeGeq, rangeLimit,
-                                          rangeOffset, restrictRange)
+import Control.Arrow                     ((***))
+import Data.Either.Combinators           (mapLeft)
+import Data.Functor                      ((<&>))
+import Data.List                         (init, last)
+import Data.Tree                         (Tree (..))
+import PostgREST.ApiRequest.Types        (AggregateFunction (..),
+                                          EmbedParam (..), EmbedPath,
+                                          Field, Filter (..),
+                                          FtsOperator (..), Hint,
+                                          JoinType (..),
+                                          JsonOperand (..),
+                                          JsonOperation (..),
+                                          JsonPath, ListVal,
+                                          LogicOperator (..),
+                                          LogicTree (..), OpExpr (..),
+                                          OpQuantifier (..),
+                                          Operation (..),
+                                          OrderDirection (..),
+                                          OrderNulls (..),
+                                          OrderTerm (..),
+                                          QPError (..),
+                                          QuantOperator (..),
+                                          SelectItem (..),
+                                          SimpleOperator (..),
+                                          SingleVal, TrileanVal (..))
 import PostgREST.SchemaCache.Identifiers (FieldName)
-
-import PostgREST.ApiRequest.Types (AggregateFunction (..),
-                                   EmbedParam (..), EmbedPath, Field,
-                                   Filter (..), FtsOperator (..),
-                                   Hint, JoinType (..),
-                                   JsonOperand (..),
-                                   JsonOperation (..), JsonPath,
-                                   ListVal, LogicOperator (..),
-                                   LogicTree (..), OpExpr (..),
-                                   OpQuantifier (..), Operation (..),
-                                   OrderDirection (..),
-                                   OrderNulls (..), OrderTerm (..),
-                                   QPError (..), QuantOperator (..),
-                                   SelectItem (..),
-                                   SimpleOperator (..), SingleVal,
-                                   TrileanVal (..))
+import Text.Parsec.Error                 (errorMessages,
+                                          showErrorMessages)
+import Text.ParserCombinators.Parsec     (GenParser, ParseError,
+                                          Parser, anyChar, between,
+                                          char, choice, digit, eof,
+                                          errorPos, letter, lookAhead,
+                                          many1, noneOf,
+                                          notFollowedBy, oneOf,
+                                          optionMaybe, sepBy, sepBy1,
+                                          string, try, (<?>))
+import Text.Read                         (read)
 
 import Protolude hiding (Sum, try)
 
@@ -67,8 +66,10 @@ data QueryParams =
     -- ^ Canonical representation of the query params, sorted alphabetically
     , qsParams         :: [(Text, Text)]
     -- ^ Parameters for RPC calls
-    , qsRanges         :: HM.HashMap Text (Range Integer)
-    -- ^ Ranges derived from &limit and &offset params
+    , qsOffset         :: Maybe Integer
+    -- ^ &offset parameter
+    , qsLimit          :: Maybe Integer
+    -- ^ &limit parameter
     , qsOrder          :: [(EmbedPath, [OrderTerm])]
     -- ^ &order parameters for each level
     , qsLogic          :: [(EmbedPath, LogicTree)]
@@ -115,6 +116,8 @@ parse :: Bool -> ByteString -> Either QPError QueryParams
 parse isRpcRead qs = do
   rOrd                      <- pRequestOrder `traverse` order
   rLogic                    <- pRequestLogicTree `traverse` logic
+  rOffset                   <- pRequestOffset `traverse` offset
+  rLimit                    <- pRequestLimit `traverse` limit
   rCols                     <- pRequestColumns columns
   rSel                      <- pRequestSelect select
   (rFlts, params)           <- L.partition hasOp <$> pRequestFilter isRpcRead `traverse` filters
@@ -125,7 +128,7 @@ parse isRpcRead qs = do
       params'               = mapMaybe (\case {(_, Filter (fld, _) (NoOpExpr v)) -> Just (fld,v); _ -> Nothing}) params
       rFltsRoot'            = snd <$> rFltsRoot
 
-  return $ QueryParams canonical params' ranges rOrd rLogic rCols rSel rFlts rFltsRoot' rFltsNotRoot rFltsFields rOnConflict
+  return $ QueryParams canonical params' rOffset rLimit rOrd rLogic rCols rSel rFlts rFltsRoot' rFltsNotRoot rFltsFields rOnConflict
   where
     hasRootFilter, hasOp :: (EmbedPath, Filter) -> Bool
     hasRootFilter ([], _) = True
@@ -138,9 +141,8 @@ parse isRpcRead qs = do
     onConflict = lookupParam "on_conflict"
     columns = lookupParam "columns"
     order = filter (endingIn ["order"] . fst) nonemptyParams
-    limits = filter (endingIn ["limit"] . fst) nonemptyParams
-    -- Replace .offset ending with .limit to be able to match those params later in a map
-    offsets = first (replaceLast "limit") <$> filter (endingIn ["offset"] . fst) nonemptyParams
+    offset = lookupParam "offset"
+    limit = lookupParam "limit"
     lookupParam :: Text -> Maybe Text
     lookupParam needle = toS <$> join (L.lookup needle qParams)
     nonemptyParams = mapMaybe (\(k, v) -> (k,) <$> v) qParams
@@ -164,21 +166,6 @@ parse isRpcRead qs = do
     reserved = ["select", "columns", "on_conflict"]
     reservedEmbeddable = ["order", "limit", "offset", "and", "or"]
 
-    replaceLast x s = T.intercalate "." $ L.init (T.split (=='.') s) <> [x]
-
-    ranges :: HM.HashMap Text (Range Integer)
-    ranges = HM.unionWith f limitParams offsetParams
-      where
-        f rl ro = Range (BoundaryBelow o) (BoundaryAbove $ o + l - 1)
-          where
-            l = fromMaybe 0 $ rangeLimit rl
-            o = rangeOffset ro
-
-        limitParams =
-          HM.fromList [(k, restrictRange (readMaybe v) allRange) | (k,v) <- limits]
-
-        offsetParams =
-          HM.fromList [(k, maybe allRange rangeGeq (readMaybe v)) | (k,v) <- offsets]
 
 simpleOperator :: Parser SimpleOperator
 simpleOperator =
@@ -243,11 +230,11 @@ pRequestOrder (k, v) = mapError $ (,) <$> path <*> ord'
     path = fst <$> treePath
     ord' = P.parse pOrder ("failed to parse order (" ++ toS v ++ ")") $ toS v
 
-pRequestRange :: (Text, NonnegRange) -> Either QPError (EmbedPath, NonnegRange)
-pRequestRange (k, v) = mapError $ (,) <$> path <*> pure v
-  where
-    treePath = P.parse pTreePath ("failed to parse tree path (" ++ toS k ++ ")") $ toS k
-    path = fst <$> treePath
+pRequestOffset :: Text -> Either QPError Integer
+pRequestOffset offs = mapError $ P.parse pInt ("failed to parse offset parameter (" <> toS offs <> ")") (toS offs)
+
+pRequestLimit :: Text -> Either QPError Integer
+pRequestLimit lim = mapError $ P.parse pInt ("failed to parse limit parameter (" <> toS lim <> ")") (toS lim)
 
 pRequestLogicTree :: (Text, Text) -> Either QPError (EmbedPath, LogicTree)
 pRequestLogicTree (k, v) = mapError $ (,) <$> embedPath <*> logicTree
@@ -842,6 +829,18 @@ pLogicPath = do
       notOp = "not." <> op
   return (filter (/= "not") (init path), if "not" `elem` path then notOp else op)
 
+pInt :: Parser Integer
+pInt = pPosInt <|> pNegInt
+  where
+    pPosInt :: Parser Integer
+    pPosInt = many1 digit <&> read
+
+    pNegInt :: Parser Integer
+    pNegInt = do
+      _ <- char '-'
+      n <- many1 digit
+      return ((-1) * read n)
+
 pColumns :: Parser [FieldName]
 pColumns = pFieldName `sepBy1` lexeme (char ',')
 

src/PostgREST/ApiRequest/Types.hs

@@ -78,7 +78,6 @@ data ApiRequestError
   | InvalidPreferences [ByteString]
   | InvalidRange RangeError
   | InvalidRpcMethod ByteString
-  | LimitNoOrderError
   | NotFound
   | NoRelBetween Text Text (Maybe Text) Text RelationshipsMap
   | NoRpc Text Text [Text] Bool MediaType Bool [QualifiedIdentifier] [Routine]
@@ -108,8 +107,7 @@ data RaiseError
   | NoDetail
   deriving Show
 data RangeError
-  = NegativeLimit
-  | LowerGTUpper
+  = LowerGTUpper
   | OutOfBounds Text Text
   deriving Show
 

src/PostgREST/Error.hs

@@ -84,7 +84,6 @@ instance PgrstError ApiRequestError where
   status UnacceptableFilter{}        = HTTP.status400
   status UnacceptableSchema{}        = HTTP.status406
   status UnsupportedMethod{}         = HTTP.status405
-  status LimitNoOrderError           = HTTP.status400
   status ColumnNotFound{}            = HTTP.status400
   status GucHeadersError             = HTTP.status500
   status GucStatusError              = HTTP.status500
@@ -118,7 +117,6 @@ instance JSON.ToJSON ApiRequestError where
     ApiRequestErrorCode03
     "Requested range not satisfiable"
     (Just $ case rangeError of
-       NegativeLimit           -> "Limit should be greater than or equal to zero."
        LowerGTUpper            -> "The lower boundary must be lower than or equal to the upper boundary in the Range header."
        OutOfBounds lower total -> JSON.String $ "An offset of " <> lower <> " was requested, but there are only " <> total <> " rows.")
     Nothing
@@ -140,9 +138,6 @@ instance JSON.ToJSON ApiRequestError where
     Nothing
     (Just $ JSON.String $ "Verify that '" <> resource <> "' is included in the 'select' query parameter.")
 
-  toJSON LimitNoOrderError = toJsonPgrstError
-    ApiRequestErrorCode09 "A 'limit' was applied without an explicit 'order'" Nothing (Just "Apply an 'order' using unique column(s)")
-
   toJSON (OffLimitsChangesError n maxs) = toJsonPgrstError
     ApiRequestErrorCode10
     "The maximum number of rows allowed to change was surpassed"