Improve error handling for Xero calls

src/Xero.hs

@@ -2,6 +2,7 @@
 
 module Xero where
 
+import Control.Exception
 import Control.Monad.IO.Class
 import Data.Aeson
 import qualified Data.Bson as B
@@ -15,7 +16,6 @@ import Data.Time.Clock
 import Database.MongoDB
 import GHC.Generics
 import Network.HTTP.Simple
-import Network.HTTP.Simple (getResponseStatus)
 import Network.HTTP.Types.Header
 import Owner
 import Web.JWT
@@ -381,7 +381,13 @@ getXeroInvoice pipe dbName inv address = do
                   let sCode = getResponseStatusCode res
                   case sCode of
                     200 -> do
-                      let invData =
-                            getResponseBody (res :: Response XeroInvResponse)
-                      return $ Just (head $ xir_invs invData)
+                      invData <-
+                        try
+                          (evaluate $
+                           getResponseBody (res :: Response XeroInvResponse)) :: IO (Either JSONException XeroInvResponse)
+                      case invData of
+                        Left ex -> do
+                          putStrLn "Failed to parse JSON from Xero"
+                          return Nothing
+                        Right iData -> return $ Just (head $ xir_invs iData)
                     _ -> return Nothing

src/ZGoBackend.hs

@@ -535,7 +535,8 @@ routes pipe config = do
             if res
               then do
                 resInv <-
-                  liftIO $ getXeroInvoice pipe (c_dbName config) inv oAddress
+                  liftAndCatchIO $
+                  getXeroInvoice pipe (c_dbName config) inv oAddress
                 case resInv of
                   Nothing -> do
                     status noContent204