Enable dateField to put a timestamp with a local time zone

hakyll.cabal

@@ -171,6 +171,7 @@ Library
     tagsoup              >= 0.13.1 && < 0.15,
     text                 >= 0.11   && < 1.3,
     time                 >= 1.4    && < 1.7,
+    timerep              >= 2.0    && < 2.1,
     time-locale-compat   >= 0.1    && < 0.2,
     unordered-containers >= 0.2    && < 0.3,
     vector               >= 0.11   && < 0.12,
@@ -265,6 +266,7 @@ Test-suite hakyll-tests
     tagsoup              >= 0.13.1 && < 0.15,
     text                 >= 0.11   && < 1.3,
     time                 >= 1.4    && < 1.7,
+    timerep              >= 2.0    && < 2.1,
     time-locale-compat   >= 0.1    && < 0.2,
     unordered-containers >= 0.2    && < 0.3,
     vector               >= 0.11   && < 0.12,

src/Hakyll/Web/Feed.hs

@@ -19,10 +19,17 @@
 module Hakyll.Web.Feed
     ( FeedConfiguration (..)
     , renderRss
+    , renderRssWith
     , renderAtom
+    , renderAtomWith
     ) where
 
 
+--------------------------------------------------------------------------------
+import           Control.Monad                 ((<=<))
+import           Data.Time.Format              (TimeLocale (..), defaultTimeLocale)
+
+
 --------------------------------------------------------------------------------
 import           Hakyll.Core.Compiler
 import           Hakyll.Core.Compiler.Internal
@@ -106,9 +113,14 @@ renderRss :: FeedConfiguration       -- ^ Feed configuration
           -> Context String          -- ^ Item context
           -> [Item String]           -- ^ Feed items
           -> Compiler (Item String)  -- ^ Resulting feed
-renderRss config context = renderFeed
+renderRss = renderRssWith defaultTimeLocale
+
+-- | This is an extended version of 'renderRss' that allows you to
+-- specify a time locale that is used for parsing the date.
+renderRssWith :: TimeLocale -> FeedConfiguration -> Context String -> [Item String] -> Compiler (Item String)
+renderRssWith locale config context = renderFeed
     "templates/rss.xml" "templates/rss-item.xml" config
-    (makeItemContext "%a, %d %b %Y %H:%M:%S UT" context)
+    (makeItemContext locale RFC822 context)
 
 
 --------------------------------------------------------------------------------
@@ -117,13 +129,18 @@ renderAtom :: FeedConfiguration       -- ^ Feed configuration
            -> Context String          -- ^ Item context
            -> [Item String]           -- ^ Feed items
            -> Compiler (Item String)  -- ^ Resulting feed
-renderAtom config context = renderFeed
+renderAtom = renderAtomWith defaultTimeLocale
+
+-- | This is an extended version of 'renderAtom' that allows you to
+-- specify a time locale that is used for parsing the date.
+renderAtomWith :: TimeLocale -> FeedConfiguration -> Context String -> [Item String] -> Compiler (Item String)
+renderAtomWith locale config context = renderFeed
     "templates/atom.xml" "templates/atom-item.xml" config
-    (makeItemContext "%Y-%m-%dT%H:%M:%SZ" context)
+    (makeItemContext locale RFC3339 context)
 
 
 --------------------------------------------------------------------------------
 -- | Copies @$updated$@ from @$published$@ if it is not already set.
-makeItemContext :: String -> Context a -> Context a
-makeItemContext fmt context = mconcat
-    [dateField "published" fmt, context, dateField "updated" fmt]
+makeItemContext :: TimeLocale -> DateFormat -> Context a -> Context a
+makeItemContext locale fmt context = mconcat
+    [dateFieldWith locale "published" fmt, context, dateFieldWith locale "updated" fmt]

src/Hakyll/Web/Template/Context.hs

@@ -4,6 +4,7 @@
 module Hakyll.Web.Template.Context
     ( ContextField (..)
     , Context (..)
+    , DateFormat (..)
     , field
     , boolField
     , constField
@@ -22,6 +23,7 @@ module Hakyll.Web.Template.Context
     , dateField
     , dateFieldWith
     , getItemUTC
+    , getItemTime
     , getItemModificationTime
     , modificationTimeField
     , modificationTimeFieldWith
@@ -36,9 +38,13 @@ import           Control.Applicative           (Alternative (..))
 import           Control.Monad                 (msum)
 import           Data.List                     (intercalate)
 import           Data.Time.Clock               (UTCTime (..))
-import           Data.Time.Format              (formatTime)
+import           Data.Time.Format              (ParseTime, formatTime)
 import qualified Data.Time.Format              as TF
+import           Data.Time.LocalTime           (ZonedTime (..))
 import           Data.Time.Locale.Compat       (TimeLocale, defaultTimeLocale)
+import           Data.Time.RFC822              (formatTimeRFC822)
+import           Data.Time.RFC3339             (formatTimeRFC3339)
+import           GHC.Exts                      (IsString, fromString)
 import           Hakyll.Core.Compiler
 import           Hakyll.Core.Compiler.Internal
 import           Hakyll.Core.Identifier
@@ -56,6 +62,16 @@ data ContextField
     = StringField String
     | forall a. ListField (Context a) [Item a]
 
+--------------------------------------------------------------------------------
+-- | Date format: RFC822 for RSS, RFC3339 for Atom, or custom format string
+data DateFormat
+    = RFC822
+    | RFC3339
+    | DateFormat String
+
+instance IsString DateFormat where
+    fromString = DateFormat
+
 
 --------------------------------------------------------------------------------
 -- | The 'Context' monoid. Please note that the order in which you
@@ -239,6 +255,8 @@ titleField = mapContext takeBaseName . pathField
 --
 --   * @2010-09-06 00:01:00+0000@
 --
+--   * @2010-09-06 00:01:00 +0000@
+--
 --   * @2010-09-06 00:01:00@
 --
 --   * @September 06, 2010 00:01 AM@
@@ -259,7 +277,7 @@ titleField = mapContext takeBaseName . pathField
 -- In case of multiple matches, the rightmost one is used.
 
 dateField :: String     -- ^ Key in which the rendered date should be placed
-          -> String     -- ^ Format to use on the date
+          -> DateFormat -- ^ Format to use on the date
           -> Context a  -- ^ Resulting context
 dateField = dateFieldWith defaultTimeLocale
 
@@ -270,11 +288,14 @@ dateField = dateFieldWith defaultTimeLocale
 -- details, see 'dateField'.
 dateFieldWith :: TimeLocale  -- ^ Output time locale
               -> String      -- ^ Destination key
-              -> String      -- ^ Format to use on the date
+              -> DateFormat  -- ^ Format to use on the date
               -> Context a   -- ^ Resulting context
 dateFieldWith locale key format = field key $ \i -> do
-    time <- getItemUTC locale $ itemIdentifier i
-    return $ formatTime locale format time
+    time <- getItemTime locale $ itemIdentifier i :: Compiler ZonedTime
+    return $ case format of
+                 RFC822         -> formatTimeRFC822 time
+                 RFC3339        -> formatTimeRFC3339 time
+                 DateFormat str -> formatTime locale str time
 
 
 --------------------------------------------------------------------------------
@@ -285,7 +306,14 @@ getItemUTC :: MonadMetadata m
            => TimeLocale        -- ^ Output time locale
            -> Identifier        -- ^ Input page
            -> m UTCTime         -- ^ Parsed UTCTime
-getItemUTC locale id' = do
+getItemUTC = getItemTime
+
+-- | General version of `getItemUTC` that returns an instance of `ParseTime`
+getItemTime :: (MonadMetadata m, ParseTime t)
+            => TimeLocale        -- ^ Output time locale
+            -> Identifier        -- ^ Input page
+            -> m t               -- ^ Parsed time
+getItemTime locale id' = do
     metadata <- getMetadata id'
     let tryField k fmt = lookupString k metadata >>= parseTime' fmt
         paths          = splitDirectories $ toFilePath id'
@@ -295,13 +323,14 @@ getItemUTC locale id' = do
         [tryField "date"      fmt | fmt <- formats] ++
         [parseTime' "%Y-%m-%d" $ intercalate "-" $ take 3 $ splitAll "-" fnCand | fnCand <- reverse paths]
   where
-    empty'     = fail $ "Hakyll.Web.Template.Context.getItemUTC: " ++
+    empty'     = fail $ "Hakyll.Web.Template.Context.getItemTime: " ++
         "could not parse time for " ++ show id'
     parseTime' = parseTimeM True locale
     formats    =
         [ "%a, %d %b %Y %H:%M:%S %Z"
         , "%Y-%m-%dT%H:%M:%S%Z"
         , "%Y-%m-%d %H:%M:%S%Z"
+        , "%Y-%m-%d %H:%M:%S %Z"
         , "%Y-%m-%d"
         , "%B %e, %Y %l:%M %p"
         , "%B %e, %Y"
@@ -371,7 +400,7 @@ missingField = Context $ \k _ i -> fail $
     "Missing field $" ++ k ++ "$ in context for item " ++
     show (itemIdentifier i)
 
-parseTimeM :: Bool -> TimeLocale -> String -> String -> Maybe UTCTime
+parseTimeM :: ParseTime t => Bool -> TimeLocale -> String -> String -> Maybe t
 #if MIN_VERSION_time(1,5,0)
 parseTimeM = TF.parseTimeM
 #else

tests/Hakyll/Web/Template/Context/Tests.hs

@@ -12,6 +12,8 @@ import           Test.HUnit                     (Assertion, (@=?))
 
 
 --------------------------------------------------------------------------------
+import           Data.Time.Format              (TimeLocale (..), defaultTimeLocale)
+import           Data.Time.LocalTime           (TimeZone (..))
 import           Hakyll.Core.Compiler
 import           Hakyll.Core.Identifier
 import           Hakyll.Core.Provider
@@ -42,6 +44,12 @@ testDateField = do
             dateField "date" "%B %e, %Y"
     date2 @=? "August 26, 2010"
 
+    let jst = defaultTimeLocale { knownTimeZones = [TimeZone (9 * 60) False "JST"] }
+    date3 <- testContextDone store provider
+        "posts/2016-08-02-localtime.md" "date" $
+            dateFieldWith jst "date" "%Y-%m-%d %H:%M:%S %z"
+    "2016-08-02 23:01:03 +0900" @=? date3
+
     cleanTestEnv
 
 

tests/data/posts/2016-08-02-localtime.md

@@ -0,0 +1,3 @@
+---
+published: 2016-08-02 23:01:03 JST
+---