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postgrest/src/PostgREST/ApiRequest/QueryParams.hs
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Haskell

-- |
-- Module : PostgREST.ApiRequest.QueryParams
-- Description : Parser for PostgREST Query parameters
--
-- This module is in charge of parsing all the querystring values in an url, e.g.
-- the select, id, order in `/projects?select=id,name&id=eq.1&order=id,name.desc`.
{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE TupleSections #-}
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
import qualified Data.Text.Encoding as T
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.Parsec.Prim (parserFail)
import Text.ParserCombinators.Parsec (GenParser, ParseError, Parser,
anyChar, between, char, digit,
eof, errorPos, letter,
lookAhead, many1, noneOf,
notFollowedBy, oneOf,
optionMaybe, sepBy1, string,
try, (<?>))
import PostgREST.RangeQuery (NonnegRange, allRange,
rangeGeq, rangeLimit,
rangeOffset, restrictRange)
import PostgREST.SchemaCache.Identifiers (FieldName)
import PostgREST.ApiRequest.Types (EmbedParam (..), EmbedPath, Field,
Filter (..), FtsOperator (..),
JoinType (..), JsonOperand (..),
JsonOperation (..), JsonPath,
ListVal, LogicOperator (..),
LogicTree (..), OpExpr (..),
Operation (..),
OrderDirection (..),
OrderNulls (..), OrderTerm (..),
QPError (..), SelectItem (..),
SimpleOperator (..), SingleVal,
TrileanVal (..))
import Protolude hiding (try)
-- $setup
-- Setup for doctests
-- >>> import Text.Pretty.Simple (pPrint)
-- >>> deriving instance Show QPError
-- >>> deriving instance Show TrileanVal
-- >>> deriving instance Show FtsOperator
-- >>> deriving instance Show SimpleOperator
-- >>> deriving instance Show Operation
-- >>> deriving instance Show OpExpr
-- >>> deriving instance Show JsonOperand
-- >>> deriving instance Show JsonOperation
-- >>> deriving instance Show Filter
-- >>> deriving instance Show JoinType
-- >>> deriving instance Show SelectItem
-- >>> deriving instance Show OrderDirection
-- >>> deriving instance Show OrderNulls
-- >>> deriving instance Show OrderTerm
data QueryParams =
QueryParams
{ qsCanonical :: ByteString
-- ^ Canonical representation of the query params, sorted alphabetically
, qsParams :: [(Text, Text)]
-- ^ Parameters for RPC calls
, qsRanges :: HM.HashMap Text (Range Integer)
-- ^ Ranges derived from &limit and &offset params
, qsOrder :: [(EmbedPath, [OrderTerm])]
-- ^ &order parameters for each level
, qsLogic :: [(EmbedPath, LogicTree)]
-- ^ &and and &or parameters used for complex boolean logic
, qsColumns :: Maybe (S.Set FieldName)
-- ^ &columns parameter and payload
, qsSelect :: [Tree SelectItem]
-- ^ &select parameter used to shape the response
, qsFilters :: [(EmbedPath, Filter)]
-- ^ Filters on the result from e.g. &id=e.10
, qsFiltersRoot :: [Filter]
-- ^ Subset of the filters that apply on the root table. These are used on UPDATE/DELETE.
, qsFiltersNotRoot :: [(EmbedPath, Filter)]
-- ^ Subset of the filters that do not apply on the root table
, qsFilterFields :: S.Set FieldName
-- ^ Set of fields that filters apply to
, qsOnConflict :: Maybe [FieldName]
-- ^ &on_conflict parameter used to upsert on specific unique keys
}
-- |
-- Parse query parameters from a query string like "id=eq.1&select=name".
--
-- The canonical representation of the query string has parameters sorted alphabetically:
--
-- >>> qsCanonical <$> parse "a=1&c=3&b=2&d"
-- Right "a=1&b=2&c=3&d="
--
-- 'select' is a reserved parameter that selects the fields to be returned:
--
-- >>> qsSelect <$> parse "select=name,location"
-- Right [Node {rootLabel = SelectField {selField = ("name",[]), selCast = Nothing, selAlias = Nothing}, subForest = []},Node {rootLabel = SelectField {selField = ("location",[]), selCast = Nothing, selAlias = Nothing}, subForest = []}]
--
-- Filters are parameters whose value contains an operator, separated by a '.' from its value:
--
-- >>> qsFilters <$> parse "a.b=eq.0"
-- Right [(["a"],Filter {field = ("b",[]), opExpr = OpExpr False (Op OpEqual "0")})]
--
-- If the operator specified in a filter does not exist, parsing the query string fails:
--
-- >>> qsFilters <$> parse "a.b=noop.0"
-- Left (QPError "\"failed to parse filter (noop.0)\" (line 1, column 6)" "unknown single value operator noop")
parse :: ByteString -> Either QPError QueryParams
parse qs =
QueryParams
canonical
params
ranges
<$> pRequestOrder `traverse` order
<*> pRequestLogicTree `traverse` logic
<*> pRequestColumns columns
<*> pRequestSelect select
<*> pRequestFilter `traverse` filters
<*> (fmap snd <$> (pRequestFilter `traverse` filtersRoot))
<*> pRequestFilter `traverse` filtersNotRoot
<*> pure (S.fromList (fst <$> filters))
<*> sequenceA (pRequestOnConflict <$> onConflict)
where
logic = filter (endingIn ["and", "or"] . fst) nonemptyParams
select = fromMaybe "*" $ lookupParam "select"
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") <$> filter (endingIn ["offset"] . fst) nonemptyParams
lookupParam :: Text -> Maybe Text
lookupParam needle = toS <$> join (L.lookup needle qParams)
nonemptyParams = mapMaybe (\(k, v) -> (k,) <$> v) qParams
qString = HTTP.parseQueryReplacePlus True qs
qParams = [(T.decodeUtf8 k, T.decodeUtf8 <$> v)|(k,v) <- qString]
canonical =
BS.pack $ HTTP.urlEncodeVars
. L.sortOn fst
. map (join (***) BS.unpack . second (fromMaybe mempty))
$ qString
endingIn:: [Text] -> Text -> Bool
endingIn xx key = lastWord `elem` xx
where lastWord = L.last $ T.split (== '.') key
(filters, params) = L.partition isParam filtersAndParams
isParam (k, v) = isEmbedPath k || hasOperator v || hasFtsOperator v
filtersAndParams = filter (isFilterOrParam . fst) nonemptyParams
isFilterOrParam k = not (endingIn reservedEmbeddable k) && notElem k reserved
reserved = ["select", "columns", "on_conflict"]
reservedEmbeddable = ["order", "limit", "offset", "and", "or"]
(filtersNotRoot, filtersRoot) = L.partition isNotRoot filters
isNotRoot = flip T.isInfixOf "." . fst
-- TODO: These checks are redundant to the parsers, should use parsers to differentiate params
hasOperator val =
case T.splitOn "." val of
"not" : _ : _ -> True
"is" : _ -> True
"in" : _ -> True
x : _ -> isJust (operator x) || isJust (ftsOperator x)
_ -> False
hasFtsOperator val =
case T.splitOn "(" val of
x : _ : _ -> isJust $ ftsOperator x
_ -> False
isEmbedPath = T.isInfixOf "."
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]
operator :: Text -> Maybe SimpleOperator
operator = \case
"eq" -> Just OpEqual
"gte" -> Just OpGreaterThanEqual
"gt" -> Just OpGreaterThan
"lte" -> Just OpLessThanEqual
"lt" -> Just OpLessThan
"neq" -> Just OpNotEqual
"like" -> Just OpLike
"ilike" -> Just OpILike
"cs" -> Just OpContains
"cd" -> Just OpContained
"ov" -> Just OpOverlap
"sl" -> Just OpStrictlyLeft
"sr" -> Just OpStrictlyRight
"nxr" -> Just OpNotExtendsRight
"nxl" -> Just OpNotExtendsLeft
"adj" -> Just OpAdjacent
"match" -> Just OpMatch
"imatch" -> Just OpIMatch
_ -> Nothing
ftsOperator :: Text -> Maybe FtsOperator
ftsOperator = \case
"fts" -> Just FilterFts
"plfts" -> Just FilterFtsPlain
"phfts" -> Just FilterFtsPhrase
"wfts" -> Just FilterFtsWebsearch
_ -> Nothing
-- PARSERS
pRequestSelect :: Text -> Either QPError [Tree SelectItem]
pRequestSelect selStr =
mapError $ P.parse pFieldForest ("failed to parse select parameter (" <> toS selStr <> ")") (toS selStr)
pRequestOnConflict :: Text -> Either QPError [FieldName]
pRequestOnConflict oncStr =
mapError $ P.parse pColumns ("failed to parse on_conflict parameter (" <> toS oncStr <> ")") (toS oncStr)
pRequestFilter :: (Text, Text) -> Either QPError (EmbedPath, Filter)
pRequestFilter (k, v) = mapError $ (,) <$> path <*> (Filter <$> fld <*> oper)
where
treePath = P.parse pTreePath ("failed to parse tree path (" ++ toS k ++ ")") $ toS k
oper = P.parse (pOpExpr pSingleVal) ("failed to parse filter (" ++ toS v ++ ")") $ toS v
path = fst <$> treePath
fld = snd <$> treePath
pRequestOrder :: (Text, Text) -> Either QPError (EmbedPath, [OrderTerm])
pRequestOrder (k, v) = mapError $ (,) <$> path <*> ord'
where
treePath = P.parse pTreePath ("failed to parse tree path (" ++ toS k ++ ")") $ toS k
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
pRequestLogicTree :: (Text, Text) -> Either QPError (EmbedPath, LogicTree)
pRequestLogicTree (k, v) = mapError $ (,) <$> embedPath <*> logicTree
where
path = P.parse pLogicPath ("failed to parse logic path (" ++ toS k ++ ")") $ toS k
embedPath = fst <$> path
logicTree = do
op <- snd <$> path
-- Concat op and v to make pLogicTree argument regular,
-- in the form of "?and=and(.. , ..)" instead of "?and=(.. , ..)"
P.parse pLogicTree ("failed to parse logic tree (" ++ toS v ++ ")") $ toS (op <> v)
pRequestColumns :: Maybe Text -> Either QPError (Maybe (S.Set FieldName))
pRequestColumns colStr =
case colStr of
Just str ->
mapError $ Just . S.fromList <$> P.parse pColumns ("failed to parse columns parameter (" <> toS str <> ")") (toS str)
_ -> Right Nothing
ws :: Parser Text
ws = toS <$> many (oneOf " \t")
lexeme :: Parser a -> Parser a
lexeme p = ws *> p <* ws
pTreePath :: Parser (EmbedPath, Field)
pTreePath = do
p <- pFieldName `sepBy1` pDelimiter
jp <- P.option [] pJsonPath
return (init p, (last p, jp))
-- |
-- Parse select= into a Forest of SelectItems
--
-- >>> P.parse pFieldForest "" "id"
-- Right [Node {rootLabel = SelectField {selField = ("id",[]), selCast = Nothing, selAlias = Nothing}, subForest = []}]
--
-- >>> P.parse pFieldForest "" "client(id)"
-- Right [Node {rootLabel = SelectRelation {selRelation = "client", selAlias = Nothing, selHint = Nothing, selJoinType = Nothing}, subForest = [Node {rootLabel = SelectField {selField = ("id",[]), selCast = Nothing, selAlias = Nothing}, subForest = []}]}]
--
-- >>> P.parse pFieldForest "" "*,client(*,nested(*))"
-- Right [Node {rootLabel = SelectField {selField = ("*",[]), selCast = Nothing, selAlias = Nothing}, subForest = []},Node {rootLabel = SelectRelation {selRelation = "client", selAlias = Nothing, selHint = Nothing, selJoinType = Nothing}, subForest = [Node {rootLabel = SelectField {selField = ("*",[]), selCast = Nothing, selAlias = Nothing}, subForest = []},Node {rootLabel = SelectRelation {selRelation = "nested", selAlias = Nothing, selHint = Nothing, selJoinType = Nothing}, subForest = [Node {rootLabel = SelectField {selField = ("*",[]), selCast = Nothing, selAlias = Nothing}, subForest = []}]}]}]
--
-- >>> P.parse pFieldForest "" "id,clients(name[])"
-- Left (line 1, column 16):
-- unexpected '['
-- expecting letter, digit, "-", "!", "(", "->>", "->", "::", ")", "," or end of input
pFieldForest :: Parser [Tree SelectItem]
pFieldForest = pFieldTree `sepBy1` lexeme (char ',')
where
pFieldTree :: Parser (Tree SelectItem)
pFieldTree = try (Node <$> pRelationSelect <*> between (char '(') (char ')') pFieldForest) <|>
Node <$> pFieldSelect <*> pure []
pStar :: Parser Text
pStar = string "*" $> "*"
-- |
-- Parse field names
--
-- >>> P.parse pFieldName "" "identifier"
-- Right "identifier"
--
-- >>> P.parse pFieldName "" "identifier with spaces"
-- Right "identifier with spaces"
--
-- >>> P.parse pFieldName "" "identifier-with-dashes"
-- Right "identifier-with-dashes"
--
-- >>> P.parse pFieldName "" "123"
-- Right "123"
--
-- >>> P.parse pFieldName "" "_"
-- Right "_"
--
-- >>> P.parse pFieldName "" "$"
-- Right "$"
--
-- >>> P.parse pFieldName "" ":"
-- Left (line 1, column 1):
-- unexpected ":"
-- expecting field name (* or [a..z0..9_$])
--
-- >>> P.parse pFieldName "" "\":\""
-- Right ":"
--
-- >>> P.parse pFieldName "" " no leading or trailing spaces "
-- Right "no leading or trailing spaces"
--
-- >>> P.parse pFieldName "" "\" leading and trailing spaces \""
-- Right " leading and trailing spaces "
pFieldName :: Parser Text
pFieldName =
pQuotedValue <|>
T.intercalate "-" . map toS <$> (pIdentifier `sepBy1` dash) <?>
"field name (* or [a..z0..9_$])"
where
isDash :: GenParser Char st ()
isDash = try ( char '-' >> notFollowedBy (char '>') )
dash :: Parser Char
dash = isDash $> '-'
-- |
-- Parse json operators in select, order and filters
--
-- >>> P.parse pJsonPath "" "->text"
-- Right [JArrow {jOp = JKey {jVal = "text"}}]
--
-- >>> P.parse pJsonPath "" "->1"
-- Right [JArrow {jOp = JIdx {jVal = "+1"}}]
--
-- >>> P.parse pJsonPath "" "->>text"
-- Right [J2Arrow {jOp = JKey {jVal = "text"}}]
--
-- >>> P.parse pJsonPath "" "->>1"
-- Right [J2Arrow {jOp = JIdx {jVal = "+1"}}]
--
-- >>> P.parse pJsonPath "" "->0,other"
-- Right [JArrow {jOp = JIdx {jVal = "+0"}}]
--
-- >>> P.parse pJsonPath "" "->0.desc"
-- Right [JArrow {jOp = JIdx {jVal = "+0"}}]
pJsonPath :: Parser JsonPath
pJsonPath = many pJsonOperation
where
pJsonOperation :: Parser JsonOperation
pJsonOperation = pJsonArrow <*> pJsonOperand
pJsonArrow =
try (string "->>" $> J2Arrow) <|>
try (string "->" $> JArrow)
pJsonOperand =
let pJKey = JKey . toS <$> pFieldName
pJIdx = JIdx . toS <$> ((:) <$> P.option '+' (char '-') <*> many1 digit) <* pEnd
pEnd = try (void $ lookAhead (string "->")) <|>
try (void $ lookAhead (string "::")) <|>
try (void $ lookAhead (string ".")) <|>
try (void $ lookAhead (string ",")) <|>
try eof in
try pJIdx <|> try pJKey
pField :: Parser Field
pField = lexeme $ (,) <$> pFieldName <*> P.option [] pJsonPath
aliasSeparator :: Parser ()
aliasSeparator = char ':' >> notFollowedBy (char ':')
-- |
-- Parse regular fields in select
--
-- >>> P.parse pRelationSelect "" "rel(*)"
-- Right (SelectRelation {selRelation = "rel", selAlias = Nothing, selHint = Nothing, selJoinType = Nothing})
--
-- >>> P.parse pRelationSelect "" "alias:rel(*)"
-- Right (SelectRelation {selRelation = "rel", selAlias = Just "alias", selHint = Nothing, selJoinType = Nothing})
--
-- >>> P.parse pRelationSelect "" "rel!hint(*)"
-- Right (SelectRelation {selRelation = "rel", selAlias = Nothing, selHint = Just "hint", selJoinType = Nothing})
--
-- >>> P.parse pRelationSelect "" "rel!inner(*)"
-- Right (SelectRelation {selRelation = "rel", selAlias = Nothing, selHint = Nothing, selJoinType = Just JTInner})
--
-- >>> P.parse pRelationSelect "" "rel!hint!inner(*)"
-- Right (SelectRelation {selRelation = "rel", selAlias = Nothing, selHint = Just "hint", selJoinType = Just JTInner})
--
-- >>> P.parse pRelationSelect "" "alias:rel!inner!hint(*)"
-- Right (SelectRelation {selRelation = "rel", selAlias = Just "alias", selHint = Just "hint", selJoinType = Just JTInner})
--
-- >>> P.parse pRelationSelect "" "rel->jsonpath(*)"
-- Left (line 1, column 6):
-- unexpected '>'
--
-- >>> P.parse pRelationSelect "" "rel->jsonpath!hint(*)"
-- Left (line 1, column 6):
-- unexpected '>'
pRelationSelect :: Parser SelectItem
pRelationSelect = lexeme $ try ( do
alias <- optionMaybe ( try(pFieldName <* aliasSeparator) )
name <- pFieldName
prm1 <- optionMaybe pEmbedParam
prm2 <- optionMaybe pEmbedParam
try (void $ lookAhead (string "("))
return $ SelectRelation name alias (embedParamHint prm1 <|> embedParamHint prm2) (embedParamJoin prm1 <|> embedParamJoin prm2)
)
where
pEmbedParam :: Parser EmbedParam
pEmbedParam =
char '!' *> (
try (string "left" $> EPJoinType JTLeft) <|>
try (string "inner" $> EPJoinType JTInner) <|>
try (EPHint <$> pFieldName))
embedParamHint prm = case prm of
Just (EPHint hint) -> Just hint
_ -> Nothing
embedParamJoin prm = case prm of
Just (EPJoinType jt) -> Just jt
_ -> Nothing
-- |
-- Parse regular fields in select
--
-- >>> P.parse pFieldSelect "" "name"
-- Right (SelectField {selField = ("name",[]), selCast = Nothing, selAlias = Nothing})
--
-- >>> P.parse pFieldSelect "" "name->jsonpath"
-- Right (SelectField {selField = ("name",[JArrow {jOp = JKey {jVal = "jsonpath"}}]), selCast = Nothing, selAlias = Nothing})
--
-- >>> P.parse pFieldSelect "" "name::cast"
-- Right (SelectField {selField = ("name",[]), selCast = Just "cast", selAlias = Nothing})
--
-- >>> P.parse pFieldSelect "" "alias:name"
-- Right (SelectField {selField = ("name",[]), selCast = Nothing, selAlias = Just "alias"})
--
-- >>> P.parse pFieldSelect "" "alias:name->jsonpath::cast"
-- Right (SelectField {selField = ("name",[JArrow {jOp = JKey {jVal = "jsonpath"}}]), selCast = Just "cast", selAlias = Just "alias"})
--
-- >>> P.parse pFieldSelect "" "*"
-- Right (SelectField {selField = ("*",[]), selCast = Nothing, selAlias = Nothing})
--
-- >>> P.parse pFieldSelect "" "name!hint"
-- Left (line 1, column 5):
-- unexpected '!'
-- expecting letter, digit, "-", "->>", "->", "::", ")", "," or end of input
--
-- >>> P.parse pFieldSelect "" "*!hint"
-- Left (line 1, column 2):
-- unexpected '!'
-- expecting ")", "," or end of input
--
-- >>> P.parse pFieldSelect "" "name::"
-- Left (line 1, column 7):
-- unexpected end of input
-- expecting letter or digit
pFieldSelect :: Parser SelectItem
pFieldSelect = lexeme $
try (
do
alias <- optionMaybe ( try(pFieldName <* aliasSeparator) )
fld <- pField
cast' <- optionMaybe (string "::" *> pIdentifier)
pEnd
return $ SelectField fld (toS <$> cast') alias
)
<|> do
s <- pStar
pEnd
return $ SelectField (s, []) Nothing Nothing
where
pEnd = try (void $ lookAhead (string ")")) <|>
try (void $ lookAhead (string ",")) <|>
try eof
-- |
-- Parse operator expression used in horizontal filtering
--
-- >>> P.parse (pOpExpr pSingleVal) "" "fts().value"
-- Left (line 1, column 7):
-- unknown single value operator fts()
pOpExpr :: Parser SingleVal -> Parser OpExpr
pOpExpr pSVal = try ( string "not" *> pDelimiter *> (OpExpr True <$> pOperation)) <|> OpExpr False <$> pOperation
where
pOperation :: Parser Operation
pOperation = pIn <|> pIs <|> try pFts <|> pOp <?> "operator (eq, gt, ...)"
pIn = In <$> (try (string "in" *> pDelimiter) *> pListVal)
pIs = Is <$> (try (string "is" *> pDelimiter) *> pTriVal)
pOp = do
opStr <- try (P.manyTill anyChar (try pDelimiter))
op <- parseMaybe ("unknown single value operator " <> opStr) . operator $ toS opStr
Op op <$> pSVal
pTriVal = try (ciString "null" $> TriNull)
<|> try (ciString "unknown" $> TriUnknown)
<|> try (ciString "true" $> TriTrue)
<|> try (ciString "false" $> TriFalse)
<?> "null or trilean value (unknown, true, false)"
pFts = do
opStr <- try (P.many (noneOf ".("))
op <- parseMaybe ("unknown fts operator " <> opStr) . ftsOperator $ toS opStr
lang <- optionMaybe $ try (between (char '(') (char ')') pIdentifier)
pDelimiter >> Fts op (toS <$> lang) <$> pSVal
parseMaybe :: [Char] -> Maybe a -> Parser a
parseMaybe err Nothing = parserFail err
parseMaybe _ (Just x) = pure x
-- case insensitive char and string
ciChar :: Char -> GenParser Char state Char
ciChar c = char c <|> char (toUpper c)
ciString :: [Char] -> GenParser Char state [Char]
ciString = traverse ciChar
pSingleVal :: Parser SingleVal
pSingleVal = toS <$> many anyChar
pListVal :: Parser ListVal
pListVal = lexeme (char '(') *> pListElement `sepBy1` char ',' <* lexeme (char ')')
pListElement :: Parser Text
pListElement = try (pQuotedValue <* notFollowedBy (noneOf ",)")) <|> (toS <$> many (noneOf ",)"))
pQuotedValue :: Parser Text
pQuotedValue = toS <$> (char '"' *> many pCharsOrSlashed <* char '"')
where
pCharsOrSlashed = noneOf "\\\"" <|> (char '\\' *> anyChar)
pDelimiter :: Parser Char
pDelimiter = char '.' <?> "delimiter (.)"
-- |
-- Parses the elements in the order query parameter
--
-- >>> P.parse pOrder "" "name.desc.nullsfirst"
-- Right [OrderTerm {otTerm = ("name",[]), otDirection = Just OrderDesc, otNullOrder = Just OrderNullsFirst}]
--
-- >>> P.parse pOrder "" "json_col->key.asc.nullslast"
-- Right [OrderTerm {otTerm = ("json_col",[JArrow {jOp = JKey {jVal = "key"}}]), otDirection = Just OrderAsc, otNullOrder = Just OrderNullsLast}]
pOrder :: Parser [OrderTerm]
pOrder = lexeme pOrderTerm `sepBy1` char ','
where
pOrderTerm :: Parser OrderTerm
pOrderTerm = do
fld <- pField
dir <- optionMaybe pOrdDir
nls <- optionMaybe pNulls <* pEnd <|>
pEnd $> Nothing
return $ OrderTerm fld dir nls
pNulls :: Parser OrderNulls
pNulls = try (pDelimiter *> string "nullsfirst" $> OrderNullsFirst) <|>
try (pDelimiter *> string "nullslast" $> OrderNullsLast)
pOrdDir :: Parser OrderDirection
pOrdDir = try (pDelimiter *> string "asc" $> OrderAsc) <|>
try (pDelimiter *> string "desc" $> OrderDesc)
pEnd = try (void $ lookAhead (char ',')) <|> try eof
pLogicTree :: Parser LogicTree
pLogicTree = Stmnt <$> try pLogicFilter
<|> Expr <$> pNot <*> pLogicOp <*> (lexeme (char '(') *> pLogicTree `sepBy1` lexeme (char ',') <* lexeme (char ')'))
where
pLogicFilter :: Parser Filter
pLogicFilter = Filter <$> pField <* pDelimiter <*> pOpExpr pLogicSingleVal
pNot :: Parser Bool
pNot = try (string "not" *> pDelimiter $> True)
<|> pure False
<?> "negation operator (not)"
pLogicOp :: Parser LogicOperator
pLogicOp = try (string "and" $> And)
<|> string "or" $> Or
<?> "logic operator (and, or)"
pLogicSingleVal :: Parser SingleVal
pLogicSingleVal = try (pQuotedValue <* notFollowedBy (noneOf ",)")) <|> try pPgArray <|> (toS <$> many (noneOf ",)"))
where
pPgArray :: Parser Text
pPgArray = do
a <- string "{"
b <- many (noneOf "{}")
c <- string "}"
pure (toS $ a ++ b ++ c)
pLogicPath :: Parser (EmbedPath, Text)
pLogicPath = do
path <- pFieldName `sepBy1` pDelimiter
let op = last path
notOp = "not." <> op
return (filter (/= "not") (init path), if "not" `elem` path then notOp else op)
pColumns :: Parser [FieldName]
pColumns = pFieldName `sepBy1` lexeme (char ',')
pIdentifier :: Parser Text
pIdentifier = T.strip . toS <$> many1 pIdentifierChar
pIdentifierChar :: Parser Char
pIdentifierChar = letter <|> digit <|> oneOf "_ $"
mapError :: Either ParseError a -> Either QPError a
mapError = mapLeft translateError
where
translateError e =
QPError message details
where
message = show $ errorPos e
details = T.strip $ T.replace "\n" " " $ toS
$ showErrorMessages "or" "unknown parse error" "expecting" "unexpected" "end of input" (errorMessages e)