Prevent duplicate call to stored procs

Reuse a CTE for results of call

test/Feature/QuerySpec.hs

@@ -422,6 +422,12 @@ spec = do
       it "GET with 405 on known procs" $
         get "/rpc/sayhello" `shouldRespondWith` 405
 
+    it "executes the proc exactly once per request" $ do
+      post "/rpc/callcounter" [json| {} |] `shouldRespondWith`
+        [json| [{"callcounter":1}] |]
+      post "/rpc/callcounter" [json| {} |] `shouldRespondWith`
+        [json| [{"callcounter":2}] |]
+
   describe "weird requests" $ do
     it "can query as normal" $ do
       get "/Escap3e;" `shouldRespondWith`

test/fixtures/privileges.sql

@@ -43,6 +43,7 @@ GRANT INSERT ON TABLE insertonly TO postgrest_test_anonymous;
 GRANT USAGE ON SEQUENCE
       auto_incrementing_pk_id_seq
     , items_id_seq
+    , callcounter_count
 TO postgrest_test_anonymous;
 
 -- Privileges for non anonymous users

test/fixtures/schema.sql

@@ -261,6 +261,18 @@ CREATE FUNCTION sayhello(name text) RETURNS text
 $_$;
 
 
+--
+-- Name: callcounter(); Type: FUNCTION; Schema: test; Owner: -
+--
+
+CREATE SEQUENCE callcounter_count START 1;
+
+CREATE FUNCTION callcounter() RETURNS bigint
+    LANGUAGE sql
+    AS $_$
+    SELECT nextval('test.callcounter_count');
+$_$;
+
 --
 -- Name: test_empty_rowset(); Type: FUNCTION; Schema: test; Owner: -
 --