Add demoteHeaders, refactor a bit

1 files changed, 52 insertions, 0 deletions

diff --git a/src/Hakyll/Web/Html/RelativizeUrls.hs b/src/Hakyll/Web/Html/RelativizeUrls.hs
new file mode 100644
index 0000000..33b0c2c
--- /dev/null
+++ b/src/Hakyll/Web/Html/RelativizeUrls.hs
@@ -0,0 +1,52 @@
+--------------------------------------------------------------------------------
+-- | This module exposes a function which can relativize URL's on a webpage.
+--
+-- This means that one can deploy the resulting site on
+-- @http:\/\/example.com\/@, but also on @http:\/\/example.com\/some-folder\/@
+-- without having to change anything (simply copy over the files).
+--
+-- To use it, you should use absolute URL's from the site root everywhere. For
+-- example, use
+--
+-- > <img src="/images/lolcat.png" alt="Funny zomgroflcopter" />
+--
+-- in a blogpost. When running this through the relativize URL's module, this
+-- will result in (suppose your blogpost is located at @\/posts\/foo.html@:
+--
+-- > <img src="../images/lolcat.png" alt="Funny zomgroflcopter" />
+module Hakyll.Web.Html.RelativizeUrls
+    ( relativizeUrls
+    , relativizeUrlsWith
+    ) where
+
+
+--------------------------------------------------------------------------------
+import           Data.List            (isPrefixOf)
+
+
+--------------------------------------------------------------------------------
+import           Hakyll.Core.Compiler
+import           Hakyll.Core.Item
+import           Hakyll.Web.Html
+
+
+--------------------------------------------------------------------------------
+-- | Compiler form of 'relativizeUrls' which automatically picks the right root
+-- path
+relativizeUrls :: Item String -> Compiler (Item String)
+relativizeUrls item = do
+    route <- getRoute $ itemIdentifier item
+    return $ case route of
+        Nothing -> item
+        Just r  -> fmap (relativizeUrlsWith $ toSiteRoot r) item
+
+
+--------------------------------------------------------------------------------
+-- | Relativize URL's in HTML
+relativizeUrlsWith :: String  -- ^ Path to the site root
+                   -> String  -- ^ HTML to relativize
+                   -> String  -- ^ Resulting HTML
+relativizeUrlsWith root = withUrls rel
+  where
+    isRel x = "/" `isPrefixOf` x && not ("//" `isPrefixOf` x)
+    rel x   = if isRel x then root ++ x else x