diff --git a/src/PostgREST/Middleware.hs b/src/PostgREST/Middleware.hs
index 34533b23e..9232cb88e 100644
--- a/src/PostgREST/Middleware.hs
+++ b/src/PostgREST/Middleware.hs
@@ -33,12 +33,12 @@ runWithClaims conf eClaims app req =
     JWTClaims claims -> do
       -- role claim defaults to anon if not specified in jwt
       let setClaims = claimsToSQL (M.union claims (M.singleton "role" anon))
-      H.sql (mconcat $ setClaims ++ customReqCheck)
+      H.sql $ mconcat setClaims
+      mapM_ H.sql customReqCheck
       app req
   where
     anon = String . toS $ configAnonRole conf
-    customReqCheck = maybeToList $ (\f -> "select " <> toS f <> "();")
-                                 <$> configReqCheck conf
+    customReqCheck = (\f -> "select " <> toS f <> "();") <$> configReqCheck conf
     unauthed message = responseLBS unauthorized401
       [ ctToHeader CTApplicationJSON
       , ( "WWW-Authenticate"
diff --git a/test/Feature/AuthSpec.hs b/test/Feature/AuthSpec.hs
index ceb2b0378..bda4931a4 100644
--- a/test/Feature/AuthSpec.hs
+++ b/test/Feature/AuthSpec.hs
@@ -1,6 +1,7 @@
 module Feature.AuthSpec where
 
 -- {{{ Imports
+import Text.Heredoc
 import Test.Hspec
 import Test.Hspec.Wai
 import Test.Hspec.Wai.JSON
@@ -103,11 +104,6 @@ spec = describe "authorization" $ do
           ]
         }
 
-  it "runs a custom request validation proc" $ do
-    let auth = authHeaderJWT "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJyb2xlIjoiYmFkX3JvbGUifQ.ENAiheEOlskpfoT5byj-gKJkOhHKTvETQu1Zso3c4Ts"
-    request methodGet "/items" [auth] ""
-      `shouldRespondWith` 400
-
   it "should fail when jwt contains no claims" $ do
     let auth = authHeaderJWT "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.e30.lu-rG8aSCiw-aOlN0IxpRGz5r7Jwq7K9r3tuMPUpytI"
     request methodGet "/authors_only" [auth] ""
@@ -124,3 +120,35 @@ spec = describe "authorization" $ do
     _ <- request methodPost "/rpc/problem" [auth] ""
     request methodGet "/authors_only" [auth] ""
       `shouldRespondWith` 200
+
+  describe "custom pre-request proc acting on id claim" $ do
+
+    it "able to switch to postgrest_test_author role (id=1)" $
+      let auth = authHeaderJWT "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpZCI6MX0.mI2HNoOum6xM3sc4oHLxU4yLv-_WV5W1kqBfY_wEvLw" in
+      request methodPost "/rpc/get_current_user" [auth]
+        [json| {} |]
+         `shouldRespondWith` ResponseMatcher {
+            matchBody    = Just [str|"postgrest_test_author"|]
+          , matchStatus = 200
+          , matchHeaders = []
+          }
+
+    it "able to switch to postgrest_test_default_role (id=2)" $
+      let auth = authHeaderJWT "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpZCI6Mn0.W7jLsG-zswM91AJkCvZeIMHrnz7_6ceY2jnscVl3Yhk" in
+      request methodPost "/rpc/get_current_user" [auth]
+        [json| {} |]
+         `shouldRespondWith` ResponseMatcher {
+            matchBody    = Just [str|"postgrest_test_default_role"|]
+          , matchStatus = 200
+          , matchHeaders = []
+          }
+
+    it "raises error (id=3)" $
+      let auth = authHeaderJWT "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpZCI6M30.15Gy8PezQhJIaHYDJVLa-Gmz9T3sJnW66EKAYIsXc7c" in
+      request methodPost "/rpc/get_current_user" [auth]
+        [json| {} |]
+         `shouldRespondWith` ResponseMatcher {
+            matchBody    = Just [str|{"hint":"Please contact administrator","details":null,"code":"P0001","message":"Disabled ID --> 3"}|]
+          , matchStatus = 400
+          , matchHeaders = []
+          }
diff --git a/test/SpecHelper.hs b/test/SpecHelper.hs
index b07ffe225..97675dbc8 100644
--- a/test/SpecHelper.hs
+++ b/test/SpecHelper.hs
@@ -51,7 +51,7 @@ testDbConn = "postgres://postgrest_test_authenticator@localhost:5432/postgrest_t
 
 testCfg :: AppConfig
 testCfg =
-  AppConfig testDbConn "postgrest_test_anonymous" Nothing "test" "localhost" 3000 (Just "safe") 10 Nothing (Just "test.block_bad_role") True
+  AppConfig testDbConn "postgrest_test_anonymous" Nothing "test" "localhost" 3000 (Just "safe") 10 Nothing (Just "test.switch_role") True
 
 testCfgNoJWT :: AppConfig
 testCfgNoJWT =
diff --git a/test/fixtures/database.sql b/test/fixtures/database.sql
index c80120bd8..a31b4aa2b 100644
--- a/test/fixtures/database.sql
+++ b/test/fixtures/database.sql
@@ -2,3 +2,5 @@ DROP DATABASE IF EXISTS postgrest_test;
 DROP ROLE IF EXISTS postgrest_test;
 CREATE USER postgrest_test createdb createrole;
 CREATE DATABASE postgrest_test OWNER postgrest_test;
+
+ALTER DATABASE postgrest_test SET postgrest.claims.id = '-1';
diff --git a/test/fixtures/privileges.sql b/test/fixtures/privileges.sql
index fa590df9f..3a94812af 100644
--- a/test/fixtures/privileges.sql
+++ b/test/fixtures/privileges.sql
@@ -4,7 +4,7 @@ GRANT USAGE ON SCHEMA
     , test
     , jwt
     , "تست"
-TO postgrest_test_anonymous, bad_role;
+TO postgrest_test_anonymous;
 
 -- Schema test objects
 SET search_path = test, "تست", pg_catalog;
diff --git a/test/fixtures/roles.sql b/test/fixtures/roles.sql
index aa507c87d..a146a8fc8 100644
--- a/test/fixtures/roles.sql
+++ b/test/fixtures/roles.sql
@@ -1,8 +1,7 @@
-DROP ROLE IF EXISTS postgrest_test_authenticator, postgrest_test_anonymous, postgrest_test_default_role, postgrest_test_author, bad_role;
+DROP ROLE IF EXISTS postgrest_test_authenticator, postgrest_test_anonymous, postgrest_test_default_role, postgrest_test_author;
 CREATE ROLE postgrest_test_authenticator WITH login noinherit;
 CREATE ROLE postgrest_test_anonymous;
 CREATE ROLE postgrest_test_default_role;
 CREATE ROLE postgrest_test_author;
-CREATE ROLE bad_role;
 
-GRANT postgrest_test_anonymous, postgrest_test_default_role, postgrest_test_author, bad_role TO postgrest_test_authenticator;
+GRANT postgrest_test_anonymous, postgrest_test_default_role, postgrest_test_author TO postgrest_test_authenticator;
diff --git a/test/fixtures/schema.sql b/test/fixtures/schema.sql
index 56d8f6d8e..96e0c2b6f 100755
--- a/test/fixtures/schema.sql
+++ b/test/fixtures/schema.sql
@@ -237,15 +237,32 @@ SELECT jwt.sign(
   ) r;
 $$;
 
-create function block_bad_role() returns void
-language plpgsql as $$
+
+CREATE OR REPLACE FUNCTION switch_role() RETURNS void
+  LANGUAGE plpgsql
+  AS $$
+declare
+  user_id text;
 begin
-  if current_role = 'bad_role' then
-    raise invalid_password using message = 'role is not allowed';
+  user_id = current_setting('postgrest.claims.id')::text;
+  if user_id = '1'::text then
+    execute 'set local role postgrest_test_author';
+  elseif user_id = '2'::text then
+    execute 'set local role postgrest_test_default_role';
+  elseif user_id = '3'::text then
+    RAISE EXCEPTION 'Disabled ID --> %', user_id USING HINT = 'Please contact administrator';
+  /* else */
+  /*   execute 'set local role postgrest_test_anonymous'; */
   end if;
 end
 $$;
 
+CREATE FUNCTION get_current_user() RETURNS text
+  LANGUAGE sql
+  AS $$
+SELECT current_user::text;
+$$;
+
 --
 -- Name: reveal_big_jwt(); Type: FUNCTION; Schema: test; Owner: -
 --