FIX 'host' not found

src/Gargantext/Core/Text/Corpus/Parsers/JSON/Istex.hs

@@ -40,7 +40,9 @@ toDoc la (ISTEX.Document i t a ab d s) = do
                            , _hd_title     = t
                            , _hd_authors = Just $ foldl' (\x y -> if x == "" then y else x <> ", " <> y) "" (map ISTEX._author_name a)
                            , _hd_institutes = Just $ foldl' (\x y -> if x == "" then y else x <> ", " <> y) "" (concatMap ISTEX._author_affiliations a)
-                           , _hd_source = Just $ foldl' (\x y -> if x == "" then y else x <> ", " <> y) "" (ISTEX._source_title s)
+                           , _hd_source = case s of 
+                              Just n -> Just $ foldl' (\x y -> if x == "" then y else x <> ", " <> y) "" (ISTEX._source_title n)
+                              Nothing -> Nothing
                            , _hd_abstract = ab
                            , _hd_publication_date = fmap (T.pack . show) utctime
                            , _hd_publication_year = pub_year