Add db-extra-search-path config (#1218)

For adding schemas to the search_path, solves issues related to extensions created in the public schema.

src/PostgREST/Config.hs

@@ -39,7 +39,7 @@ import           Data.Scientific              (floatingOrInteger)
 import           Data.String                  (String)
 import           Data.Text                    (dropAround,
                                                intercalate, lines,
-                                               strip, take)
+                                               strip, take, splitOn)
 import           Data.Text.Encoding           (encodeUtf8)
 import           Data.Text.IO                 (hPutStrLn)
 import           Data.Version                 (versionBranch)
@@ -78,6 +78,7 @@ data AppConfig = AppConfig {
   , configQuiet             :: Bool
   , configSettings          :: [(Text, Text)]
   , configRoleClaimKey      :: Either ApiRequestError JSPath
+  , configExtraSearchPath   :: [Text]
   }
 
 defaultCorsPolicy :: CorsResourcePolicy
@@ -140,6 +141,7 @@ readOptions = do
           <*> pure False
           <*> (fmap (fmap coerceText) <$> C.subassocs "app.settings")
           <*> (maybe (Right [JSPKey "role"]) parseRoleClaimKey <$> C.key "role-claim-key")
+          <*> (maybe ["public"] splitExtraSearchPath <$> C.key "db-extra-search-path")
 
   case mAppConf of
     Nothing -> do
@@ -176,6 +178,10 @@ readOptions = do
     parseRoleClaimKey (String s) = pRoleClaimKey s
     parseRoleClaimKey v = pRoleClaimKey $ show v
 
+    splitExtraSearchPath :: Value -> [Text]
+    splitExtraSearchPath (String s) = strip <$> splitOn "," s
+    splitExtraSearchPath _ = []
+
     opts = info (helper <*> pathParser) $
              fullDesc
              <> progDesc (
@@ -199,7 +205,7 @@ readOptions = do
     exampleCfg :: Doc
     exampleCfg = vsep . map (text . toS) . lines $
       [str|db-uri = "postgres://user:pass@localhost:5432/dbname"
-          |db-schema = "public"
+          |db-schema = "public" # this schema gets added to the search_path of every request
           |db-anon-role = "postgres"
           |db-pool = 10
           |
@@ -223,6 +229,9 @@ readOptions = do
           |
           |## jspath to the role claim key
           |# role-claim-key = ".role"
+          |
+          |## extra schemas to add to the search_path of every request
+          |# db-extra-search-path = "extensions, util"
           |]
 
 pathParser :: Parser FilePath

src/PostgREST/Middleware.hs

@@ -19,7 +19,7 @@ import           PostgREST.ApiRequest          (ApiRequest(..))
 import           PostgREST.Auth                (JWTAttempt(..))
 import           PostgREST.Config              (AppConfig (..), corsPolicy)
 import           PostgREST.Error               (simpleError)
-import           PostgREST.QueryBuilder        (pgFmtLit, unquoted, pgFmtSetLocal)
+import           PostgREST.QueryBuilder        (unquoted, pgFmtSetLocal, pgFmtSetLocalSearchPath)
 
 import           Protolude
 
@@ -32,7 +32,7 @@ runWithClaims conf eClaims app req =
     JWTInvalid e -> return $ unauthed $ show e
     JWTMissingSecret -> return $ simpleError status500 [] "Server lacks JWT secret"
     JWTClaims claims -> do
-      H.sql $ toS.mconcat $ setSchemaSql ++ setRoleSql ++ claimsSql ++ headersSql ++ cookiesSql ++ appSettingsSql
+      H.sql $ toS . mconcat $ setSearchPathSql : setRoleSql ++ claimsSql ++ headersSql ++ cookiesSql ++ appSettingsSql
       mapM_ H.sql customReqCheck
       app req
       where
@@ -40,9 +40,9 @@ runWithClaims conf eClaims app req =
         cookiesSql = pgFmtSetLocal "request.cookie." <$> iCookies req
         claimsSql = pgFmtSetLocal "request.jwt.claim." <$> [(c,unquoted v) | (c,v) <- M.toList claimsWithRole]
         appSettingsSql = pgFmtSetLocal mempty <$> configSettings conf
-        setRoleSql = maybeToList $
-          (\r -> "set local role " <> r <> ";") . toS . pgFmtLit . unquoted <$> M.lookup "role" claimsWithRole
-        setSchemaSql = ["set local schema " <> pgFmtLit (configSchema conf) <> ";"] :: [Text]
+        setRoleSql = maybeToList $ (\x ->
+          pgFmtSetLocal mempty ("role", unquoted x)) <$> M.lookup "role" claimsWithRole
+        setSearchPathSql = pgFmtSetLocalSearchPath $ configSchema conf : configExtraSearchPath conf
         -- role claim defaults to anon if not specified in jwt
         claimsWithRole = M.union claims (M.singleton "role" anon)
         anon = JSON.String . toS $ configAnonRole conf

src/PostgREST/QueryBuilder.hs

@@ -24,6 +24,7 @@ module PostgREST.QueryBuilder (
   , unquoted
   , ResultsWithCount
   , pgFmtSetLocal
+  , pgFmtSetLocalSearchPath
   ) where
 
 import qualified Hasql.Statement         as H
@@ -470,7 +471,11 @@ pgFmtAs _ _ (Just alias) = " AS " <> pgFmtIdent alias
 
 pgFmtSetLocal :: Text -> (Text, Text) -> SqlFragment
 pgFmtSetLocal prefix (k, v) =
-  "set local " <> pgFmtIdent (prefix <> k) <> " = " <> pgFmtLit v <> ";"
+  "SET LOCAL " <> pgFmtIdent (prefix <> k) <> " = " <> pgFmtLit v <> ";"
+
+pgFmtSetLocalSearchPath :: [Text] -> SqlFragment
+pgFmtSetLocalSearchPath vals =
+  "SET LOCAL search_path = " <> intercalate ", " (pgFmtLit <$> vals) <> ";"
 
 trimNullChars :: Text -> Text
 trimNullChars = T.takeWhile (/= '\x0')