Added renderAtom, feeds now validate.

chungyc · Mar 8, 2010 · 45459c3 · 45459c3
1 parent 64b640f
commit 45459c3
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Showing 7 changed files with 157 additions and 86 deletions.
diff --git a/data/templates/atom-item.xml b/data/templates/atom-item.xml
@@ -0,0 +1,7 @@
+<entry>
+    <title>$title</title>
+    <link href="$absolute/$url" />
+    <id>$absolute/$url</id>
+    <updated>$timestamp</updated>
+    <summary>$description</summary>
+</entry>
diff --git a/data/templates/atom.xml b/data/templates/atom.xml
@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="utf-8"?>
+<feed xmlns="http://www.w3.org/2005/Atom">
+    <title>$title</title>
+    <link href="$absolute/$url" rel="self" />
+    <link href="$absolute" />
+    <!-- We use the link as id. -->
+    <id>$absolute/$url</id>
+    <author>
+        <name>$authorName</name>
+    </author>
+    <updated>$timestamp</updated>
+    $body
+</feed>
diff --git a/data/templates/rss-item.xml b/data/templates/rss-item.xml
@@ -3,4 +3,6 @@
     <link>$absolute/$url</link>
     <description>$description</description>
     <pubDate>$timestamp</pubDate>
+    <!-- We use the link as id. -->
+    <guid>$absolute/$url</guid>
 </item>
diff --git a/data/templates/rss.xml b/data/templates/rss.xml
@@ -1,9 +1,12 @@
 <?xml version="1.0" encoding="utf8"?>
-<rss version="2.0">
+<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom">
     <channel>
         <title>$title</title>
         <link>$absolute</link>
         <description>$description</description>
+        <atom:link href="$absolute/$url" rel="self"
+                   type="application/rss+xml" />
+        <lastBuildDate>$timestamp</lastBuildDate>
         $body
     </channel> 
 </rss>
diff --git a/hakyll.cabal b/hakyll.cabal
@@ -13,7 +13,9 @@ License-File:       LICENSE
 Category:           Text
 Cabal-Version:      >= 1.6
 Data-Dir:           data
-Data-Files:         templates/rss.xml
+Data-Files:         templates/atom.xml
+                    templates/atom-item.xml
+                    templates/rss.xml
                     templates/rss-item.xml
 
 build-type:         Simple
@@ -51,7 +53,7 @@ library
                     Text.Hakyll.Paginate
                     Text.Hakyll.Util
                     Text.Hakyll.Tags
-                    Text.Hakyll.Rss
+                    Text.Hakyll.Feed
                     Text.Hakyll.Internal.Cache
                     Text.Hakyll.Internal.CompressCss
                     Text.Hakyll.Internal.FileType

diff --git a/src/Text/Hakyll/Feed.hs b/src/Text/Hakyll/Feed.hs
@@ -0,0 +1,127 @@
+-- | A Module that allows easy rendering of RSS feeds. If you use this module,
+--   you must make sure you set the `absoluteUrl` field in the main Hakyll
+--   configuration.
+module Text.Hakyll.Feed
+    ( FeedConfiguration (..)
+    , renderRss
+    , renderRssWith
+    , renderAtom
+    , renderAtomWith
+    ) where
+
+import Control.Arrow ((>>>), second)
+import Control.Monad.Reader (liftIO)
+import Data.Maybe (fromMaybe)
+import qualified Data.Map as M
+
+import Text.Hakyll.Context (ContextManipulation, renderDate)
+import Text.Hakyll.Hakyll (Hakyll)
+import Text.Hakyll.Render (render, renderChain)
+import Text.Hakyll.Renderables (createListingWith)
+import Text.Hakyll.RenderAction
+
+import Paths_hakyll
+
+-- | This is a data structure to keep the configuration of a feed.
+data FeedConfiguration = FeedConfiguration
+    { -- | Url of the feed (relative to site root). For example, @rss.xml@.
+      feedUrl         :: String
+    , -- | Title of the feed.
+      feedTitle       :: String
+    , -- | Description of the feed.
+      feedDescription :: String
+    , -- | Name of the feed author.
+      feedAuthorName  :: String
+    }
+
+-- | This is an auxiliary function to create a listing that is, in fact, a feed.
+--   The items should be sorted on date.
+createFeedWith :: ContextManipulation -- ^ Manipulation to apply on the items.
+               -> FeedConfiguration   -- ^ Feed configuration.
+               -> [Renderable]        -- ^ Items to include.
+               -> FilePath            -- ^ Feed template.
+               -> FilePath            -- ^ Item template.
+               -> Renderable
+createFeedWith manipulation configuration renderables template itemTemplate =
+    listing >>> render template
+  where
+    listing = createListingWith manipulation (feedUrl configuration)
+                                [itemTemplate] renderables additional
+
+    additional = map (second $ Left . ($ configuration))
+        [ ("title", feedTitle)
+        , ("description", feedDescription)
+        , ("authorName", feedAuthorName)
+        ] ++ updated
+
+    -- Take the first timestamp, which should be the most recent.
+    updated = let action = createRenderAction $
+                                return . fromMaybe "foo" . M.lookup "timestamp"
+                  manip = createManipulationAction manipulation
+                  toTuple r = ("timestamp", Right $ r >>> manip >>> action)
+              in map toTuple $ take 1 renderables
+
+
+-- | Abstract function to render any feed.
+renderFeedWith :: ContextManipulation -- ^ Manipulation to apply on the items.
+               -> FeedConfiguration   -- ^ Feed configuration.
+               -> [Renderable]        -- ^ Items to include in the feed.
+               -> FilePath            -- ^ Feed template.
+               -> FilePath            -- ^ Item template.
+               -> Hakyll ()
+renderFeedWith manipulation configuration renderables template itemTemplate = do
+    template' <- liftIO $ getDataFileName template
+    itemTemplate' <- liftIO $ getDataFileName itemTemplate
+    let renderFeedWith' = createFeedWith manipulation configuration
+                                         renderables template' itemTemplate'
+    renderChain [] renderFeedWith'
+
+-- | Render an RSS feed with a number of items.
+--
+--   Note that the @Renderable@s should have the following fields:
+--
+--   - @$title@: Title of the item.
+--
+--   - @$description@: Description to appear in the feed.
+--
+--   - @$url@: URL to the item - this is usually set automatically.
+--
+renderRss :: FeedConfiguration -- ^ Feed configuration.
+          -> [Renderable]     -- ^ Items to include in the feed.
+          -> Hakyll ()
+renderRss = renderRssWith id
+
+-- | Render an RSS feed with a number of items. This function allows you to
+--   specify a @ContextManipulation@ which will be applied on every
+--   @Renderable@. Note that the given @Renderable@s should be sorted so the
+--   most recent one is first.
+renderRssWith :: ContextManipulation -- ^ Manipulation to apply on the items.
+              -> FeedConfiguration   -- ^ Feed configuration.
+              -> [Renderable]        -- ^ Items to include in the feed.
+              -> Hakyll ()
+renderRssWith manipulation configuration renderables =
+    renderFeedWith manipulation' configuration renderables
+                   "templates/rss.xml" "templates/rss-item.xml"
+  where
+    manipulation' = manipulation . renderRssDate
+
+renderRssDate :: ContextManipulation
+renderRssDate = renderDate "timestamp" "%a, %d %b %Y %H:%M:%S UT" "No date found."
+
+renderAtom :: FeedConfiguration
+           -> [Renderable]
+           -> Hakyll ()
+renderAtom = renderAtomWith id
+
+renderAtomWith :: ContextManipulation -- ^ Manipulation to apply on the items.
+               -> FeedConfiguration   -- ^ Feed configuration.
+               -> [Renderable]        -- ^ Items to include in the feed.
+               -> Hakyll ()
+renderAtomWith manipulation configuration renderables =
+    renderFeedWith manipulation' configuration renderables
+                   "templates/atom.xml" "templates/atom-item.xml"
+  where
+    manipulation' = manipulation . renderAtomDate
+
+renderAtomDate :: ContextManipulation
+renderAtomDate = renderDate "timestamp" "%Y-%m-%dT%H:%M:%SZ" "No date found."
diff --git a/src/Text/Hakyll/Rss.hs b/src/Text/Hakyll/Rss.hs