add basic ARCHITECTURE.md (#2503)

* refactor: move ApiRequest a top-level module
* refactor: rename DbStructure to SchemaCache
* refactor: GucHeader inside Response
* refactor: admin app to Workers

src/PostgREST/Response/GucHeader.hs

@@ -0,0 +1,30 @@
+module PostgREST.Response.GucHeader
+  ( GucHeader
+  , unwrapGucHeader
+  ) where
+
+import qualified Data.Aeson           as JSON
+import qualified Data.Aeson.Key       as K
+import qualified Data.Aeson.KeyMap    as KM
+import qualified Data.CaseInsensitive as CI
+
+import Network.HTTP.Types.Header (Header)
+
+import Protolude
+
+
+{-|
+  Custom guc header, it's obtained by parsing the json in a:
+  `SET LOCAL "response.headers" = '[{"Set-Cookie": ".."}]'
+-}
+newtype GucHeader = GucHeader (CI.CI ByteString, ByteString)
+
+instance JSON.FromJSON GucHeader where
+  parseJSON (JSON.Object o) =
+    case KM.toList o of
+      [(k, JSON.String s)] -> pure $ GucHeader (CI.mk $ toUtf8 $ K.toText k, toUtf8 s)
+      _ -> mzero
+  parseJSON _ = mzero
+
+unwrapGucHeader :: GucHeader -> Header
+unwrapGucHeader (GucHeader (k, v)) = (k, v)

src/PostgREST/Response/OpenAPI.hs

@@ -26,14 +26,14 @@ import Data.Swagger
 
 import PostgREST.Config                   (AppConfig (..), Proxy (..),
                                            isMalformedProxyUri, toURI)
-import PostgREST.DbStructure              (DbStructure (..))
-import PostgREST.DbStructure.Identifiers  (QualifiedIdentifier (..))
-import PostgREST.DbStructure.Proc         (ProcDescription (..),
+import PostgREST.SchemaCache              (SchemaCache (..))
+import PostgREST.SchemaCache.Identifiers  (QualifiedIdentifier (..))
+import PostgREST.SchemaCache.Proc         (ProcDescription (..),
                                            ProcParam (..))
-import PostgREST.DbStructure.Relationship (Cardinality (..),
+import PostgREST.SchemaCache.Relationship (Cardinality (..),
                                            Relationship (..),
                                            RelationshipsMap)
-import PostgREST.DbStructure.Table        (Column (..), Table (..),
+import PostgREST.SchemaCache.Table        (Column (..), Table (..),
                                            TablesMap)
 import PostgREST.Version                  (docsVersion, prettyVersion)
 
@@ -41,11 +41,11 @@ import PostgREST.MediaType
 
 import Protolude hiding (Proxy, get)
 
-encode :: AppConfig -> DbStructure -> TablesMap -> HM.HashMap k [ProcDescription] -> Maybe Text -> LBS.ByteString
-encode conf dbStructure tables procs schemaDescription =
+encode :: AppConfig -> SchemaCache -> TablesMap -> HM.HashMap k [ProcDescription] -> Maybe Text -> LBS.ByteString
+encode conf sCache tables procs schemaDescription =
   JSON.encode $
     postgrestSpec
-      (dbRelationships dbStructure)
+      (dbRelationships sCache)
       (concat $ HM.elems procs)
       (snd <$> HM.toList tables)
       (proxyUri conf)