module Data.Time.RFC822.Parsec
( rfc822DateAndTime
, rfc822time
)
where
import Control.Monad
import Data.Fixed
import Data.Time
import Data.Time.Calendar.WeekDate
import Data.Time.HTTP.Common
import Text.Parsec
rfc822DateAndTime :: Stream s m Char => ParsecT s u m ZonedTime
rfc822DateAndTime = dateTime
dateTime :: Stream s m Char => ParsecT s u m ZonedTime
dateTime = do weekDay <- optionMaybe $
do w <- shortWeekDayNameP
_ <- string ", "
return w
gregDay <- date
case weekDay of
Nothing
-> return ()
Just givenWD
-> assertWeekDayIsGood givenWD gregDay
(tod, timeZone) <- rfc822time
let lt = LocalTime gregDay tod
zt = ZonedTime lt timeZone
return zt
date :: Stream s m Char => ParsecT s u m Day
date = do day <- read2
_ <- char ' '
month <- shortMonthNameP
_ <- char ' '
year <- liftM (+ 1900) read2
_ <- char ' '
assertGregorianDateIsGood year month day
rfc822time :: Stream s m Char => ParsecT s u m (TimeOfDay, TimeZone)
rfc822time = do tod <- hour
_ <- char ' '
tz <- zone
return (tod, tz)
hour :: Stream s m Char => ParsecT s u m TimeOfDay
hour = do hour <- read2
minute <- char ':' >> read2
second <- option 0 (char ':' >> read2)
assertTimeOfDayIsGood hour minute second
zone :: Stream s m Char => ParsecT s u m TimeZone
zone = choice [ string "UT" >> return (TimeZone 0 False "UT" )
, string "GMT" >> return (TimeZone 0 False "GMT")
, char 'E'
>> choice [ string "ST" >> return (TimeZone ((5) * 60) False "EST")
, string "DT" >> return (TimeZone ((4) * 60) True "EDT")
]
, char 'C'
>> choice [ string "ST" >> return (TimeZone ((6) * 60) False "CST")
, string "DT" >> return (TimeZone ((5) * 60) True "CDT")
]
, char 'M'
>> choice [ string "ST" >> return (TimeZone ((7) * 60) False "MST")
, string "DT" >> return (TimeZone ((6) * 60) True "MDT")
, return (TimeZone ((12) * 60) False "M")
]
, char 'P'
>> choice [ string "ST" >> return (TimeZone ((8) * 60) False "PST")
, string "DT" >> return (TimeZone ((7) * 60) True "PDT")
]
, char 'Z' >> return (TimeZone 0 False "Z")
, char 'A' >> return (TimeZone ((1) * 60) False "A")
, char 'N' >> return (TimeZone ( 1 * 60) False "N")
, char 'Y' >> return (TimeZone ( 12 * 60) False "Y")
, read4digitsTZ
]