Cache the json DbStructure in AppState

Also adds a test

src/PostgREST/App.hs

@@ -141,11 +141,12 @@ postgrest logLev appState connWorker =
       conf <- AppState.getConfig appState
       maybeDbStructure <- AppState.getDbStructure appState
       pgVer <- AppState.getPgVersion appState
+      jsonDbS <- AppState.getJsonDbS appState
 
       let
         eitherResponse :: IO (Either Error Wai.Response)
         eitherResponse =
-          runExceptT $ postgrestResponse conf maybeDbStructure pgVer (AppState.getPool appState) time req
+          runExceptT $ postgrestResponse conf maybeDbStructure jsonDbS pgVer (AppState.getPool appState) time req
 
       response <- either Error.errorResponseFor identity <$> eitherResponse
 
@@ -159,12 +160,13 @@ postgrest logLev appState connWorker =
 postgrestResponse
   :: AppConfig
   -> Maybe DbStructure
+  -> ByteString
   -> PgVersion
   -> SQL.Pool
   -> UTCTime
   -> Wai.Request
   -> Handler IO Wai.Response
-postgrestResponse conf maybeDbStructure pgVer pool time req = do
+postgrestResponse conf maybeDbStructure jsonDbS pgVer pool time req = do
   body <- lift $ Wai.strictRequestBody req
 
   dbStructure <-
@@ -187,7 +189,7 @@ postgrestResponse conf maybeDbStructure pgVer pool time req = do
 
   runDbHandler pool (txMode apiRequest) jwtClaims .
     Middleware.optionalRollback conf apiRequest $
-      Middleware.runPgLocals conf jwtClaims handleReq apiRequest dbStructure
+      Middleware.runPgLocals conf jwtClaims handleReq apiRequest jsonDbS
 
 runDbHandler :: SQL.Pool -> SQL.Mode -> Auth.JWTClaims -> DbHandler a -> Handler IO a
 runDbHandler pool mode jwtClaims handler = do

src/PostgREST/AppState.hs

@@ -5,6 +5,7 @@ module PostgREST.AppState
   , getConfig
   , getDbStructure
   , getIsWorkerOn
+  , getJsonDbS
   , getMainThreadId
   , getPgVersion
   , getPool
@@ -14,6 +15,7 @@ module PostgREST.AppState
   , putConfig
   , putDbStructure
   , putIsWorkerOn
+  , putJsonDbS
   , putPgVersion
   , releasePool
   , signalListener
@@ -41,6 +43,8 @@ data AppState = AppState
   , statePgVersion    :: IORef PgVersion
   -- | No schema cache at the start. Will be filled in by the connectionWorker
   , stateDbStructure  :: IORef (Maybe DbStructure)
+  -- | Cached DbStructure in json
+  , stateJsonDbS      :: IORef ByteString
   -- | Helper ref to make sure just one connectionWorker can run at a time
   , stateIsWorkerOn   :: IORef Bool
   -- | Binary semaphore used to sync the listener(NOTIFY reload) with the connectionWorker.
@@ -62,6 +66,7 @@ initWithPool newPool conf =
     -- assume we're in a supported version when starting, this will be corrected on a later step
     <$> newIORef minimumPgVersion
     <*> newIORef Nothing
+    <*> newIORef mempty
     <*> newIORef False
     <*> newEmptyMVar
     <*> newIORef conf
@@ -91,6 +96,12 @@ putDbStructure :: AppState -> DbStructure -> IO ()
 putDbStructure appState structure =
   atomicWriteIORef (stateDbStructure appState) $ Just structure
 
+getJsonDbS :: AppState -> IO ByteString
+getJsonDbS = readIORef . stateJsonDbS
+
+putJsonDbS :: AppState -> ByteString -> IO ()
+putJsonDbS appState = atomicWriteIORef (stateJsonDbS appState)
+
 getIsWorkerOn :: AppState -> IO Bool
 getIsWorkerOn = readIORef . stateIsWorkerOn
 

src/PostgREST/Middleware.hs

@@ -40,7 +40,6 @@ import System.IO.Unsafe          (unsafePerformIO)
 import System.Log.FastLogger     (toLogStr)
 
 import PostgREST.Config             (AppConfig (..), LogLevel (..))
-import PostgREST.DbStructure        (DbStructure)
 import PostgREST.Error              (Error, errorResponseFor)
 import PostgREST.GucHeader          (addHeadersIfNotIncluded)
 import PostgREST.Query.SqlFragment  (fromQi, intercalateSnippet,
@@ -55,8 +54,8 @@ import Protolude.Conv (toS)
 -- | Runs local(transaction scoped) GUCs for every request, plus the pre-request function
 runPgLocals :: AppConfig   -> M.HashMap Text JSON.Value ->
                (ApiRequest -> ExceptT Error H.Transaction Wai.Response) ->
-               ApiRequest  -> DbStructure -> ExceptT Error H.Transaction Wai.Response
-runPgLocals conf claims app req dbs = do
+               ApiRequest  -> ByteString -> ExceptT Error H.Transaction Wai.Response
+runPgLocals conf claims app req jsonDbS = do
   lift $ H.statement mempty $ H.dynamicallyParameterized
     ("select " <> intercalateSnippet ", " (searchPathSql : roleSql ++ claimsSql ++ [methodSql, pathSql] ++ headersSql ++ cookiesSql ++ appSettingsSql ++ specSql))
     HD.noResult (configDbPreparedStatements conf)
@@ -78,7 +77,7 @@ runPgLocals conf claims app req dbs = do
       setConfigLocal mempty ("search_path", toS schemas)
     preReqSql = (\f -> "select " <> fromQi f <> "();") <$> configDbPreRequest conf
     specSql = case iTarget req of
-      TargetProc{tpIsRootSpec=True} -> [setConfigLocal mempty ("request.spec", toS $ JSON.encode dbs)]
+      TargetProc{tpIsRootSpec=True} -> [setConfigLocal mempty ("request.spec", jsonDbS)]
       _                             -> mempty
     -- | Do a pg set_config(setting, value, true) call. This is equivalent to a SET LOCAL.
     setConfigLocal :: ByteString -> (ByteString, ByteString) -> H.Snippet

src/PostgREST/Workers.hs

@@ -7,6 +7,7 @@ module PostgREST.Workers
   , listener
   ) where
 
+import qualified Data.Aeson                 as JSON
 import qualified Data.ByteString            as BS
 import qualified Hasql.Connection           as C
 import qualified Hasql.Notifications        as N
@@ -172,6 +173,8 @@ loadSchemaCache appState = do
 
     Right dbStructure -> do
       AppState.putDbStructure appState dbStructure
+      when (isJust configDbRootSpec) $
+        AppState.putJsonDbS appState $ toS $ JSON.encode dbStructure
       putStrLn ("Schema cache loaded" :: Text)
       return SCLoaded
 

test/Feature/RootSpec.hs

@@ -26,5 +26,9 @@ spec =
     it "accepts application/json" $
       request methodGet "/"
         [("Accept", "application/json")] "" `shouldRespondWith`
-        [json| [{"table": "items"}, {"table": "subitems"}] |]
+        [json| {
+            "tableName": "orders_view", "tableSchema": "test",
+            "tableDeletable": true, "tableUpdatable": true,
+            "tableInsertable": true, "tableDescription": null
+          } |]
         { matchHeaders = [matchContentTypeJson] }

test/Main.hs

@@ -1,5 +1,6 @@
 module Main where
 
+import qualified Data.Aeson                 as JSON
 import qualified Hasql.Pool                 as P
 import qualified Hasql.Transaction.Sessions as HT
 
@@ -68,19 +69,25 @@ main = do
   let
     -- For tests that run with the same refDbStructure
     app cfg = do
-      appState <- AppState.initWithPool pool $ cfg testDbConn
+      let config = cfg testDbConn
+      appState <- AppState.initWithPool pool config
       AppState.putPgVersion appState actualPgVersion
       AppState.putDbStructure appState baseDbStructure
+      when (isJust $ configDbRootSpec config) $
+        AppState.putJsonDbS appState $ toS $ JSON.encode baseDbStructure
       return ((), postgrest LogCrit appState $ pure ())
 
     -- For tests that run with a different DbStructure(depends on configSchemas)
     appDbs cfg = do
+      let config = cfg testDbConn
       customDbStructure <-
         loadDbStructure pool
-          (configDbSchemas $ cfg testDbConn)
-          (configDbExtraSearchPath $ cfg testDbConn)
-      appState <- AppState.initWithPool pool $ cfg testDbConn
+          (configDbSchemas config)
+          (configDbExtraSearchPath config)
+      appState <- AppState.initWithPool pool config
       AppState.putDbStructure appState customDbStructure
+      when (isJust $ configDbRootSpec config) $
+        AppState.putJsonDbS appState $ toS $ JSON.encode baseDbStructure
       return ((), postgrest LogCrit appState $ pure ())
 
   let withApp              = app testCfg

test/fixtures/schema.sql

@@ -1713,9 +1713,9 @@ returns integer as $$
   select a + b;
 $$ language sql;
 
-create function root() returns jsonb as $_$
+create or replace function root() returns json as $_$
 declare
-openapi jsonb = $$
+openapi json = $$
   {
     "swagger": "2.0",
     "info":{
@@ -1724,22 +1724,12 @@ openapi jsonb = $$
     }
   }
 $$;
-simple jsonb = $$
-  [
-    {
-      "table":"items"
-    },
-    {
-      "table":"subitems"
-    }
-  ]
-$$;
 begin
 case current_setting('request.header.accept', true)
   when 'application/openapi+json' then
     return openapi;
   when 'application/json' then
-    return simple;
+    return (current_setting('request.spec', true)::json)->'dbRelationships'->0->'relTable';
   else
     return openapi;
   end case;