Exodus to GHC 6.8.1

[Lucu.git] / Network / HTTP / Lucu / RFC1123DateTime.hs

diff --git a/Network/HTTP/Lucu/RFC1123DateTime.hs b/Network/HTTP/Lucu/RFC1123DateTime.hs
index ad683a9b490478e35bad9dfcc552de544212f2e2..f86b2b1111dd206e965eff7f59edd87569c52cc4 100644 (file)
--- a/Network/HTTP/Lucu/RFC1123DateTime.hs
+++ b/Network/HTTP/Lucu/RFC1123DateTime.hs
@@ -1,3 +1,6 @@
+-- |This module parses and prints RFC 1123 Date and Time string.
+-- 
+-- In general you don't have to use this module directly.
 module Network.HTTP.Lucu.RFC1123DateTime
     ( formatRFC1123DateTime
     , formatHTTPDateTime
@@ -6,47 +9,85 @@ module Network.HTTP.Lucu.RFC1123DateTime
     where
 
 import           Control.Monad
-import qualified Data.ByteString.Lazy.Char8 as B
-import           Data.ByteString.Lazy.Char8 (ByteString)
+import           Data.Time
+import           Data.Time.Calendar.WeekDate
+import qualified Data.ByteString.Lazy as Lazy (ByteString)
+import           Network.HTTP.Lucu.Format
 import           Network.HTTP.Lucu.Parser
-import           System.Time
-import           System.Locale
-import           Text.Printf
+import           Prelude hiding (min)
 
-month = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"]
-week  = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"]
 
-formatRFC1123DateTime :: CalendarTime -> String
-formatRFC1123DateTime time
-    = printf "%s, %02d %s %04d %02d:%02d:%02d %s"
-      (week     !! fromEnum (ctWDay  time))
-      (ctDay    time)
-      (month    !! fromEnum (ctMonth time))
-      (ctYear   time)
-      (ctHour   time)
-      (ctMin    time)
-      (ctSec    time)
-      (ctTZName time)
+monthStr :: [String]
+monthStr =  ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"]
 
+weekStr :: [String]
+weekStr =  ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"]
 
-formatHTTPDateTime :: ClockTime -> String
-formatHTTPDateTime = formatRFC1123DateTime . (\cal -> cal { ctTZName = "GMT" }) . toUTCTime
+-- |Format a 'System.Time.CalendarTime' to RFC 1123 Date and Time
+-- string.
+formatRFC1123DateTime :: ZonedTime -> String
+formatRFC1123DateTime zonedTime
+    = let localTime          = zonedTimeToLocalTime zonedTime
+          timeZone           = zonedTimeZone zonedTime
+          (year, month, day) = toGregorian (localDay localTime)
+          (_, _, week)       = toWeekDate (localDay localTime)
+          timeOfDay          = localTimeOfDay localTime
+      in
+        id       (weekStr !! (week - 1))
+        ++ ", " ++
+        fmtDec 2 day
+        ++ " "  ++
+        id       (monthStr !! (month - 1))
+        ++ " " ++
+        fmtDec 4 (fromInteger year)
+        ++ " " ++
+        fmtDec 2 (todHour timeOfDay)
+        ++ ":" ++
+        fmtDec 2 (todMin timeOfDay)
+        ++ ":" ++
+        fmtDec 2 (floor (todSec timeOfDay))
+        ++ " " ++
+        id       (timeZoneName timeZone)
+      
 
+-- |Format a 'System.Time.ClockTime' to HTTP Date and Time. Time zone
+-- will be always UTC but prints as GMT.
+formatHTTPDateTime :: UTCTime -> String
+formatHTTPDateTime utcTime
+    = let timeZone  = TimeZone 0 False "GMT"
+          zonedTime = utcToZonedTime timeZone utcTime
+      in
+        formatRFC1123DateTime zonedTime
 
-parseHTTPDateTime :: String -> Maybe ClockTime
+
+-- |Parse an HTTP Date and Time.
+--
+-- Limitation: RFC 2616 (HTTP\/1.1) says we must accept these three
+-- formats:
+--
+-- * @Sun, 06 Nov 1994 08:49:37 GMT  ; RFC 822, updated by RFC 1123@
+--
+-- * @Sunday, 06-Nov-94 08:49:37 GMT ; RFC 850, obsoleted by RFC 1036@
+--
+-- * @Sun Nov  6 08:49:37 1994       ; ANSI C's asctime() format@
+--
+-- ...but currently this function only supports the RFC 1123
+-- format. This is a violation of RFC 2616 so this should be fixed
+-- later. What a bother!
+parseHTTPDateTime :: Lazy.ByteString -> Maybe UTCTime
 parseHTTPDateTime src
-    = case parseStr httpDateTime src of
-        (Success ct, _) -> Just ct
-        _               -> Nothing
+    = case parse httpDateTime src of
+        (# Success ct, _ #) -> Just ct
+        (# _         , _ #) -> Nothing
 
 
-httpDateTime :: Parser ClockTime
-httpDateTime = do foldl (<|>) (fail "") (map string week)
+httpDateTime :: Parser UTCTime
+httpDateTime = do foldl (<|>) failP (map string weekStr)
                   char ','
                   char ' '
                   day  <- liftM read (count 2 digit)
                   char ' '
-                  mon  <- foldl (<|>) (fail "") (map tryEqToFst (zip month [1..]))
+                  mon  <- foldl (<|>) failP (map tryEqToFst (zip monthStr [1..]))
                   char ' '
                   year <- liftM read (count 4 digit)
                   char ' '
@@ -54,24 +95,14 @@ httpDateTime = do foldl (<|>) (fail "") (map string week)
                   char ':'
                   min  <- liftM read (count 2 digit)
                   char ':'
-                  sec  <- liftM read (count 2 digit)
+                  sec  <- liftM read (count 2 digit) :: Parser Int
                   char ' '
                   string "GMT"
                   eof
-                  return $ toClockTime $ CalendarTime {
-                               ctYear    = year
-                             , ctMonth   = toEnum (mon - 1)
-                             , ctDay     = day
-                             , ctHour    = hour
-                             , ctMin     = min
-                             , ctSec     = sec
-                             , ctPicosec = 0
-                             , ctTZ      = 0
-                             , ctWDay    = undefined
-                             , ctYDay    = undefined
-                             , ctTZName  = undefined
-                             , ctIsDST   = undefined
-                             }
+                  let julianDay = fromGregorian year mon day
+                      timeOfDay = TimeOfDay hour min (fromIntegral sec)
+                      utcTime   = UTCTime julianDay (timeOfDayToTime timeOfDay)
+                  return utcTime
     where
       tryEqToFst :: (String, a) -> Parser a
       tryEqToFst (str, a) = string str >> return a