module Data.Time.RFC2822 (
RFC2822(showRFC2822, readRFC2822)
) where
import Data.Time.Format
import Data.Time.LocalTime
import Data.Time.Calendar
import Data.Maybe
import System.Locale
test1 = "Fri, 21 Nov 1997 09:55:06 -0600"
test2 = "Tue, 15 Nov 1994 12:45:26 GMT"
test3 = "Tue, 1 Jul 2003 10:52:37 +0200"
test4 = "Thu, 13 Feb 1969 23:32:54 -0330"
test5 = "Mon, 24 Nov 1997 14:22:01 -0800"
test6 = "Thu, 13\n Feb\n 1969\n 23:32\n -0330"
test7 = "Thu, 13\n Feb\n 1969\n 23:32\n -0330 (Newfoundland Time)"
test8 = "24 Nov 1997 14:22:01 -0800"
test9 = "15 Nov 1994 12:45:26 GMT"
test10 = "Mon,24 Nov 1997 14:22:01 -0800"
test11 = "Thu,\t13\n Feb\n 1969\n 23:32\n -0330 (Newfoundland Time)"
test12 = "Thu, 13 Feb 1969 23:32 -0330 (Newfoundland Time)"
tests :: [String]
tests = [test1, test2, test3, test4, test5, test6, test7, test8, test9, test10
, test11, test12]
testParse = length (catMaybes (map readRFC2822 tests)) == length tests
class RFC2822 a where
showRFC2822 :: ZonedTime -> a
readRFC2822 :: a -> Maybe ZonedTime
formatRFC2822 :: [a]
instance RFC2822 String where
showRFC2822 zt@(ZonedTime lt z) =
formatTime defaultTimeLocale "%a, %e %b %Y %T" zt ++ printZone
where
timeZoneStr = timeZoneOffsetString z
printZone = if timeZoneStr == timeZoneOffsetString utc
then " GMT"
else " " ++ timeZoneStr
formatRFC2822 = [ "%a, %e %b %Y %T GMT"
, "%a, %e %b %Y %T %z"
, "%e %b %Y %T GMT"
, "%e %b %Y %T %z"
, "%a, %e %b %Y %R GMT"
, "%a, %e %b %Y %R %z"
, "%e %b %Y %R GMT"
, "%e %b %Y %R %z"
]
readRFC2822 t = foldr (tryP t') Nothing $ map p formatRFC2822
where
p :: String -> String -> Maybe ZonedTime
p f s = parseTime defaultTimeLocale f s
tryP :: String -> (String -> Maybe a) -> Maybe a -> Maybe a
tryP s f acc | isJust acc = acc
| otherwise = f s
t' :: String
t' = lines t >>= ("" ++)
showTime :: IO String
showTime = getZonedTime >>= return . showRFC2822