RFC822

[time-http.git] / Data / Time / RFC822.hs

diff --git a/Data/Time/RFC822.hs b/Data/Time/RFC822.hs
index 152d99290f57e89915e72eaf80efd36e72c22e1e..a5c1a0bd97713e68f3420756b14dea3c2d18ba89 100644 (file)
--- a/Data/Time/RFC822.hs
+++ b/Data/Time/RFC822.hs
@@ -1,5 +1,9 @@
 {-# LANGUAGE
-    UnicodeSyntax
+    FlexibleInstances
+  , MultiParamTypeClasses
+  , OverloadedStrings
+  , TemplateHaskell
+  , UnicodeSyntax
   #-}
 -- |This module provides functions to parse and format RFC 822 date
 -- and time formats.
@@ -31,31 +35,143 @@
 -- >               | "Y"                ; +12
 -- >               | ("+" | "-") 4DIGIT ; Local diff: HHMM
 module Data.Time.RFC822
-    ( -- * Formatting
-      toAscii
-    , toAsciiBuilder
-
-      -- * Parsing
-    , fromAscii
+    ( RFC822
     , rfc822DateAndTime
+    , rfc822Time
     )
     where
-import Data.Ascii (Ascii)
+import Control.Applicative
+import Data.Ascii (Ascii, AsciiBuilder)
 import qualified Data.Ascii as A
-import qualified Data.Attoparsec.Char8 as P
+import Data.Attoparsec.Char8
+import Data.Convertible.Base
+import Data.Monoid.Unicode
+import Data.Tagged
 import Data.Time
-import Data.Time.RFC822.Internal
+import Data.Time.Calendar.WeekDate
+import Data.Time.HTTP.Common
 import Prelude.Unicode
 
--- |Convert a 'ZonedTime' to RFC 822 date and time string.
-toAscii ∷ ZonedTime → Ascii
-toAscii = A.fromAsciiBuilder ∘ toAsciiBuilder
+-- |FIXME: docs
+data RFC822
 
--- |Parse an RFC 822 date and time string. When the string can't be
--- parsed, it returns @'Left' err@.
-fromAscii ∷ Ascii → Either String ZonedTime
-fromAscii = P.parseOnly p ∘ A.toByteString
-    where
-      p = do zt ← rfc822DateAndTime
-             P.endOfInput
-             return zt
+instance ConvertSuccess ZonedTime (Tagged RFC822 Ascii) where
+    {-# INLINE convertSuccess #-}
+    convertSuccess = (A.fromAsciiBuilder <$>) ∘ cs
+
+instance ConvertSuccess ZonedTime (Tagged RFC822 AsciiBuilder) where
+    {-# INLINE convertSuccess #-}
+    convertSuccess = Tagged ∘ toAsciiBuilder
+
+instance ConvertSuccess TimeZone (Tagged RFC822 Ascii) where
+    {-# INLINE convertSuccess #-}
+    convertSuccess = (A.fromAsciiBuilder <$>) ∘ cs
+
+instance ConvertSuccess TimeZone (Tagged RFC822 AsciiBuilder) where
+    {-# INLINE convertSuccess #-}
+    convertSuccess tz
+        | timeZoneMinutes tz ≡ 0 = Tagged $ A.toAsciiBuilder "GMT"
+        | otherwise              = Tagged $ show4digitsTZ tz
+
+instance ConvertAttempt (Tagged RFC822 Ascii) ZonedTime where
+    {-# INLINE convertAttempt #-}
+    convertAttempt = parseAttempt' rfc822DateAndTime ∘ untag
+
+-- |Parse an RFC 822 date and time string.
+rfc822DateAndTime ∷ Parser ZonedTime
+rfc822DateAndTime = dateTime
+
+dateTime ∷ Parser 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 ∷ Parser Day
+date = do day   ← read2
+          _     ← char ' '
+          month ← shortMonthNameP
+          _     ← char ' '
+          year  ← (+ 1900) <$> read2
+          _     ← char ' '
+          assertGregorianDateIsGood year month day
+
+-- |Parse the time and time zone of an RFC 822 date and time string.
+rfc822Time ∷ Parser (TimeOfDay, TimeZone)
+rfc822Time = do tod ← hms
+                _   ← char ' '
+                tz  ← zone
+                return (tod, tz)
+
+hms ∷ Parser TimeOfDay
+hms = do hour   ← read2
+         minute ← char ':' *> read2
+         second ← option 0 (char ':' *> read2)
+         assertTimeOfDayIsGood hour minute second
+
+zone ∷ Parser 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
+              ]
+
+toAsciiBuilder ∷ ZonedTime → AsciiBuilder
+toAsciiBuilder zonedTime
+    = let localTime          = zonedTimeToLocalTime zonedTime
+          timeZone           = zonedTimeZone zonedTime
+          (year, month, day) = toGregorian (localDay localTime)
+          (_, _, week)       = toWeekDate  (localDay localTime)
+          timeOfDay          = localTimeOfDay localTime
+      in
+        shortWeekDayName week
+        ⊕ A.toAsciiBuilder ", "
+        ⊕ show2 day
+        ⊕ A.toAsciiBuilder " "
+        ⊕ shortMonthName month
+        ⊕ A.toAsciiBuilder " "
+        ⊕ show2 (year `mod` 100)
+        ⊕ A.toAsciiBuilder " "
+        ⊕ show2 (todHour timeOfDay)
+        ⊕ A.toAsciiBuilder ":"
+        ⊕ show2 (todMin timeOfDay)
+        ⊕ A.toAsciiBuilder ":"
+        ⊕ show2 (floor (todSec timeOfDay) ∷ Int)
+        ⊕ A.toAsciiBuilder " "
+        ⊕ untag (cs timeZone ∷ Tagged RFC822 AsciiBuilder)
+
+deriveAttempts [ ([t| ZonedTime |], [t| Tagged RFC822 Ascii        |])
+               , ([t| ZonedTime |], [t| Tagged RFC822 AsciiBuilder |])
+               , ([t| TimeZone  |], [t| Tagged RFC822 Ascii        |])
+               , ([t| TimeZone  |], [t| Tagged RFC822 AsciiBuilder |])
+               ]