Correct order Id handling

src/Order.hs

@@ -12,6 +12,7 @@ import Data.Time.Clock
 import Database.MongoDB
 import GHC.Generics
 import Test.QuickCheck
+import WooCommerce (WooToken(w_id))
 
 -- | Type to represent a ZGo order
 data ZGoOrder = ZGoOrder
@@ -72,7 +73,7 @@ instance ToJSON ZGoOrder where
 instance FromJSON ZGoOrder where
   parseJSON =
     withObject "Order" $ \obj -> do
-      i <- obj .:? "_id"
+      i <- obj .: "_id"
       a <- obj .: "address"
       s <- obj .: "session"
       ts <- obj .: "timestamp"
@@ -86,7 +87,24 @@ instance FromJSON ZGoOrder where
       eI <- obj .: "externalInvoice"
       sC <- obj .: "shortCode"
       tk <- obj .: "token"
-      pure $ ZGoOrder (read =<< i) a s ts c cur p t tZ l pd eI sC tk
+      pure $
+        ZGoOrder
+          (if not (null i)
+             then Just (read i :: ObjectId)
+             else Nothing)
+          a
+          s
+          ts
+          c
+          cur
+          p
+          t
+          tZ
+          l
+          pd
+          eI
+          sC
+          tk
 
 instance Val ZGoOrder where
   val (ZGoOrder i a s ts c cur p t tZ l pd eI sC tk) =