diff --git a/CHANGELOG.md b/CHANGELOG.md index 7228e0afc..bb9034f01 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -8,6 +8,7 @@ All notable changes to this project will be documented in this file. From versio - Log error when `db-schemas` config contains schema `pg_catalog` or `information_schema` by @taimoorzaeem in #4359 - Add a `HINT` when the LISTEN channel stops working due to a PostgreSQL bug by @laurenceisla in #4581 +- Add string slicing operator for `jwt-role-claim-key` by @taimoorzaeem in #4599 ## [14.3] - 2026-01-03 diff --git a/docs/references/auth.rst b/docs/references/auth.rst index 4970dd39a..30551abeb 100644 --- a/docs/references/auth.rst +++ b/docs/references/auth.rst @@ -234,6 +234,17 @@ The DSL follows the `JSONPath `_ expres - ``==^`` selects the first array element that ends with the right operand - ``*==`` selects the first array element that contains the right operand +The selected role value can also be sliced using the slice operator ``[a:b]``. It is similar to `slice operator in python `_. Negative index values are also supported. The syntax is as: + +- ``[a:b]`` take slice from index ``a`` up to ``b`` +- ``[a:]`` take slice from index ``a`` to end +- ``[:b]`` take slice from start to index ``b`` +- ``[:]`` select everything, no slicing + +.. important:: + + Make sure that you are not taking a slice where the start index comes after the end index like ``[11:2]``. The result of this would be empty string and so no role would get selected. + Usage examples: .. code:: bash @@ -255,6 +266,11 @@ Usage examples: jwt-role-claim-key = ".postgrest.roles[?(@ ==^ \"hor\")]" jwt-role-claim-key = ".postgrest.roles[?(@ *== \"utho\")]" + # {"postgrest":{"wlcg": ["/groupa", "/groupb/"]}} + # skip the "/" character using slice operator + jwt-role-claim-key = ".postgrest.wlcg[0][1:]" + jwt-role-claim-key = ".postgrest.wlcg[1][1:-1]" + .. note:: The string comparison operators are implemented as a custom extension to the JSPath and does not strictly follow the `RFC 9535 `_. diff --git a/src/PostgREST/Config/JSPath.hs b/src/PostgREST/Config/JSPath.hs index e28e5c366..8116a2d21 100644 --- a/src/PostgREST/Config/JSPath.hs +++ b/src/PostgREST/Config/JSPath.hs @@ -29,9 +29,10 @@ type JSPath = [JSPathExp] -- NOTE: We only accept one JSPFilter expr (at the end of input) -- | jspath expression data JSPathExp - = JSPKey Text -- .property or ."property-dash" - | JSPIdx Int -- [0] - | JSPFilter FilterExp -- [?(@ == "match")] + = JSPKey Text -- .property or ."property-dash" + | JSPIdx Int -- [0] + | JSPSlice (Maybe Int) (Maybe Int) -- [0:5] or [0:] or [:5] or [:] + | JSPFilter FilterExp -- [?(@ == "match")] data FilterExp = EqualsCond Text @@ -44,6 +45,7 @@ dumpJSPath :: JSPathExp -> Text -- TODO: this needs to be quoted properly for special chars dumpJSPath (JSPKey k) = "." <> show k dumpJSPath (JSPIdx i) = "[" <> show i <> "]" +dumpJSPath (JSPSlice s e) = "[" <> maybe "" show s <> ":" <> maybe "" show e <> "]" dumpJSPath (JSPFilter cond) = "[?(@" <> expr <> ")]" where expr = @@ -59,12 +61,25 @@ walkJSPath :: Maybe JSON.Value -> JSPath -> Maybe JSON.Value walkJSPath x [] = x walkJSPath (Just (JSON.Object o)) (JSPKey key:rest) = walkJSPath (KM.lookup (K.fromText key) o) rest walkJSPath (Just (JSON.Array ar)) (JSPIdx idx:rest) = walkJSPath (ar V.!? idx) rest -walkJSPath (Just (JSON.Array ar)) [JSPFilter jspFilter] = case jspFilter of - EqualsCond txt -> findFirstMatch (==) txt ar - NotEqualsCond txt -> findFirstMatch (/=) txt ar - StartsWithCond txt -> findFirstMatch T.isPrefixOf txt ar - EndsWithCond txt -> findFirstMatch T.isSuffixOf txt ar - ContainsCond txt -> findFirstMatch T.isInfixOf txt ar +walkJSPath (Just (JSON.String str)) (JSPSlice start end:rest) = + let + len = T.length str + + norm :: Maybe Int -> Maybe Int -- Normalize negative indices to positive + norm = fmap (\i -> max 0 $ min len $ if i < 0 then len + i else i) + + s = fromMaybe 0 $ norm start -- normalized start index + e = fromMaybe len $ norm end -- normalized end index + slicedString = if s >= e then T.empty else T.take (e-s) $ T.drop s str + in + walkJSPath (Just $ JSON.String slicedString) rest + +walkJSPath (Just (JSON.Array ar)) (JSPFilter jspFilter:rest) = case jspFilter of + EqualsCond txt -> walkJSPath (findFirstMatch (==) txt ar) rest + NotEqualsCond txt -> walkJSPath (findFirstMatch (/=) txt ar) rest + StartsWithCond txt -> walkJSPath (findFirstMatch T.isPrefixOf txt ar) rest + EndsWithCond txt -> walkJSPath (findFirstMatch T.isSuffixOf txt ar) rest + ContainsCond txt -> walkJSPath (findFirstMatch T.isInfixOf txt ar) rest where findFirstMatch matchWith pattern = find (\case JSON.String txt -> pattern `matchWith` txt @@ -80,7 +95,7 @@ pJSPath :: P.Parser JSPath pJSPath = P.many1 pJSPathExp <* P.eof pJSPathExp :: P.Parser JSPathExp -pJSPathExp = pJSPKey <|> pJSPFilter <|> pJSPIdx +pJSPathExp = P.try pJSPKey <|> P.try pJSPFilter <|> P.try pJSPIdx <|> pJSPSlice pJSPKey :: P.Parser JSPathExp pJSPKey = do @@ -95,13 +110,25 @@ pJSPIdx = do P.char ']' return (JSPIdx num) "pJSPIdx: JSPath array index" +pJSPSlice :: P.Parser JSPathExp +pJSPSlice = do + P.char '[' + startSign <- P.optionMaybe $ P.char '-' + startIndex <- P.optionMaybe (read <$> P.many1 P.digit) + P.char ':' + endSign <- P.optionMaybe $ P.char '-' + endIndex <- P.optionMaybe (read <$> P.many1 P.digit) + P.char ']' + let start' = if isJust startSign then ((-1) *) <$> startIndex else startIndex + end' = if isJust endSign then ((-1) *) <$> endIndex else endIndex + return (JSPSlice start' end') "pJSPSlice: JSPath string slice" + pJSPFilter :: P.Parser JSPathExp pJSPFilter = do P.try $ P.string "[?(" condition <- pFilterConditionParser P.char ')' P.char ']' - P.eof -- this should be the last jspath expression return (JSPFilter condition) "pJSPFilter: JSPath filter exp" pFilterConditionParser :: P.Parser FilterExp diff --git a/test/io/fixtures/fixtures.yaml b/test/io/fixtures/fixtures.yaml index 640a584b4..50fe14cdc 100644 --- a/test/io/fixtures/fixtures.yaml +++ b/test/io/fixtures/fixtures.yaml @@ -194,6 +194,44 @@ roleclaims: roles: - obj_key: obj_value expected_status: 401 # fails because it compares an object with a string + - key: '.realm_access.roles[0][7:]' + data: + realm_access: + roles: + - prefix_postgrest_test_author + expected_status: 200 # passes because it removes the "prefix_" part using slice + - key: '.realm_access.roles[0][:-7]' + data: + realm_access: + roles: + - postgrest_test_author_suffix + expected_status: 200 # passes because it removes the "_suffix" part using slice + - key: '.realm_access.roles[0][7:-7]' + data: + realm_access: + roles: + - prefix_postgrest_test_author_suffix + expected_status: 200 # passes because it removes the "prefix_" and "_suffix" part using slice + - key: '.realm_access.roles[0][:]' + data: + realm_access: + roles: + - postgrest_test_author + expected_status: 200 # passes because nothing gets sliced + - key: '.realm_access.roles[?(@ *== "_test_")][7:]' + data: + realm_access: + roles: + - other + - prefix_postgrest_test_author + expected_status: 200 # passes on both comparison operators and slicing + - key: '.realm_access.roles[?(@ *== "_test_")][200:]' + data: + realm_access: + roles: + - other + - prefix_postgrest_test_author + expected_status: 401 # fails due to slicing results in empty string jwtaudroleclaims: - key: '.aud'