[FIX] IsTex API with Maybe parameters

src/ISTEX.hs

@@ -48,7 +48,7 @@ getMetadataScroll q scroll scrollId page = do
     case eRes of
       Left err -> pure $ Left err
       Right res@(ScrollResponse { .. }) -> do
-        eDocs <- getMetadataScroll q scroll (Just _scroll_scrollId) (page + 1)
+        eDocs <- getMetadataScroll q scroll _scroll_scrollId (page + 1)
         case eDocs of
           Left err -> pure $ Left err
           Right docs -> pure $ Right $ _scroll_documents <> docs
@@ -68,7 +68,7 @@ getMetadataScrollProgress q scroll scrollId progress errorHandler = do
                               , _scroll_nextScrollURI
                               , _scroll_scrollId }) -> do
       progress res
-      getMetadataScrollProgress q scroll (Just _scroll_scrollId) progress errorHandler
+      getMetadataScrollProgress q scroll _scroll_scrollId progress errorHandler
 
 type Query = Text
 

src/ISTEX/Client.hs

@@ -91,17 +91,18 @@ instance Monoid Documents where
 
 data ScrollResponse = ScrollResponse
   { _scroll_documents           :: Documents
-  , _scroll_noMoreScrollResults :: Bool
-  , _scroll_nextScrollURI       :: T.Text
-  , _scroll_scrollId            :: T.Text }
+  , _scroll_noMoreScrollResults :: Maybe Bool
+  , _scroll_nextScrollURI       :: Maybe T.Text
+  , _scroll_scrollId            :: Maybe T.Text }
 L.makeLenses ''ScrollResponse
+
 instance FromJSON ScrollResponse where
   parseJSON (Object o) = do
     _documents_total            <- o .: "total"
     _documents_hits             <- o .: "hits"
-    _scroll_noMoreScrollResults <- o .: "noMoreScrollResults"
-    _scroll_nextScrollURI <- o .: "nextScrollURI"
-    _scroll_scrollId <- o .: "scrollId"
+    _scroll_noMoreScrollResults <- o .:? "noMoreScrollResults"
+    _scroll_nextScrollURI       <- o .:? "nextScrollURI"
+    _scroll_scrollId            <- o .:? "scrollId"
     pure $ ScrollResponse { _scroll_documents = Documents { .. }
                           , .. }