From 2aaeb4711b0e38993a9a242664abc5639f3d1da4 Mon Sep 17 00:00:00 2001
From: Artyom <yom@artyom.me>
Date: Fri, 8 Apr 2016 23:40:09 +0300
Subject: [PATCH] Throw an error when the IP couldn't be parsed

---
 src/Main.hs | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/Main.hs b/src/Main.hs
index 49822b6..da3629b 100644
--- a/src/Main.hs
+++ b/src/Main.hs
@@ -129,7 +129,11 @@ addEdit ed = do
                                  (Spock.header "X-Forwarded-For")
   ip <- case mbForwardedFor of
     Nothing -> sockAddrToIP . Wai.remoteHost <$> Spock.request
-    Just ff -> return (read (T.unpack ip))
+    Just ff -> case readMaybe (T.unpack ip) of
+      Nothing -> error ("couldn't read Forwarded-For address: " ++
+                        show ip ++ " (full header: " ++
+                        show ff ++ ")")
+      Just i  -> return i
       where
         addr = T.strip . snd . T.breakOnEnd "," $ ff
         ip -- [IPv6]:port