From 128f10deb8e06a0137f06165aa3b6166564ac28d Mon Sep 17 00:00:00 2001
From: Simonas Kazlauskas <git@kazlauskas.me>
Date: Mon, 1 Apr 2013 15:10:46 +0300
Subject: [PATCH] Properly implement protocol skipping in checker

Network.HTTP can only check if http:// and https:// links resolve,
however there is much more scheme names than just `mail:`, `http://` and
`https://`.
They would be handed off to internal URI checker and would fail.
---
 src/Hakyll/Check.hs | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/Hakyll/Check.hs b/src/Hakyll/Check.hs
index 5c05aa5..10e7df0 100644
--- a/src/Hakyll/Check.hs
+++ b/src/Hakyll/Check.hs
@@ -137,15 +137,23 @@ checkFile filePath = do
 --------------------------------------------------------------------------------
 checkUrl :: FilePath -> String -> Checker ()
 checkUrl filePath url
-    | isExternal url             = checkExternalUrl url
-    | "mailto:" `isPrefixOf` url = ok url
-    | otherwise                  = checkInternalUrl filePath url
-
+    | isExternal url  = checkExternalUrl url
+    | hasProtocol url = skip "Unknown protocol, skipping"
+    | otherwise       = checkInternalUrl filePath url
+  where
+    hasProtocol = all (`elem` validProtoChars) . takeWhile (/= ':')
+    validProtoChars = ['A'..'Z'] ++ ['a'..'z'] ++ ['0'..'9'] ++ "+-."
 
 --------------------------------------------------------------------------------
 ok :: String -> Checker ()
 ok _ = tell $ mempty {checkerOk = 1}
 
+--------------------------------------------------------------------------------
+skip :: String -> Checker ()
+skip reason = do
+    logger <- checkerLogger <$> ask
+    Logger.debug logger $ reason
+    tell $ mempty {checkerOk = 1}
 
 --------------------------------------------------------------------------------
 faulty :: String -> Checker ()