X-Git-Url: http://www.average.org/gitweb/?p=pdns-pipe-nmc.git;a=blobdiff_plain;f=NmcDom.hs;h=f2ad26f3f1e6ec793e2229633c622c3b85287408;hp=b975522095ef4416ab79741f621c381ae250e1fa;hb=531dbfc03d955178e596a7cd9b87fca8bc23918e;hpb=35cea210f8d3a22afd24848441b5d34702d83239

diff --git a/NmcDom.hs b/NmcDom.hs
index b975522..f2ad26f 100644
--- a/NmcDom.hs
+++ b/NmcDom.hs
@@ -3,6 +3,7 @@
 module NmcDom   ( NmcDom(..)
                 , emptyNmcDom
                 , descendNmc
+                , queryDom
                 ) where
 
 import Data.ByteString.Lazy (ByteString)
@@ -158,3 +159,16 @@ mergeNmc sub dom = dom  { domService = choose domService
     choose field = case field dom of
       Nothing -> field sub
       Just x  -> Just x
+
+-- | Perform query and return error string or parsed domain object
+queryDom ::
+  (ByteString -> IO (Either String ByteString)) -- ^ query operation action
+  -> ByteString                                 -- ^ key
+  -> IO (Either String NmcDom)                  -- ^ error string or domain
+queryDom queryOp key = do
+  l <- queryOp key
+  case l of
+    Left estr -> return $ Left estr
+    Right str -> case decode str :: Maybe NmcDom of
+      Nothing  -> return $ Left $ "Unparseable value: " ++ (show str)
+      Just dom -> return $ Right dom