{-# LANGUAGE OverloadedStrings #-}
module Network.HTTP.Date.Parser (parseHTTPDate) where
import Control.Applicative
import Control.Monad
import Data.Attoparsec.ByteString
import Data.Attoparsec.ByteString.Char8
import Data.ByteString
import Data.Char
import Network.HTTP.Date.Types
parseHTTPDate :: ByteString -> Maybe HTTPDate
parseHTTPDate :: ByteString -> Maybe HTTPDate
parseHTTPDate ByteString
bs = case Parser HTTPDate -> ByteString -> Either String HTTPDate
forall a. Parser a -> ByteString -> Either String a
parseOnly Parser HTTPDate
rfc1123Date ByteString
bs of
Right HTTPDate
ut -> HTTPDate -> Maybe HTTPDate
forall a. a -> Maybe a
Just HTTPDate
ut
Either String HTTPDate
_ -> Maybe HTTPDate
forall a. Maybe a
Nothing
rfc1123Date :: Parser HTTPDate
rfc1123Date :: Parser HTTPDate
rfc1123Date = do
w <- Parser Int
wkday
void $ string ", "
(y,m,d) <- date1
sp
(h,n,s) <- time
sp
void $ string "GMT" <|> string "+0000" <|> string "UTC"
return $ defaultHTTPDate {
hdYear = y
, hdMonth = m
, hdDay = d
, hdHour = h
, hdMinute = n
, hdSecond = s
, hdWkday = w
}
wkday :: Parser Int
wkday :: Parser Int
wkday = Int
1 Int -> Parser ByteString ByteString -> Parser Int
forall a b. a -> Parser ByteString b -> Parser ByteString a
forall (f :: * -> *) a b. Functor f => a -> f b -> f a
<$ ByteString -> Parser ByteString ByteString
string ByteString
"Mon"
Parser Int -> Parser Int -> Parser Int
forall a.
Parser ByteString a -> Parser ByteString a -> Parser ByteString a
forall (f :: * -> *) a. Alternative f => f a -> f a -> f a
<|> Int
2 Int -> Parser ByteString ByteString -> Parser Int
forall a b. a -> Parser ByteString b -> Parser ByteString a
forall (f :: * -> *) a b. Functor f => a -> f b -> f a
<$ ByteString -> Parser ByteString ByteString
string ByteString
"Tue"
Parser Int -> Parser Int -> Parser Int
forall a.
Parser ByteString a -> Parser ByteString a -> Parser ByteString a
forall (f :: * -> *) a. Alternative f => f a -> f a -> f a
<|> Int
3 Int -> Parser ByteString ByteString -> Parser Int
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<$ ByteString -> Parser ByteString ByteString
string ByteString
"Wed"
Parser Int -> Parser Int -> Parser Int
forall a.
Parser ByteString a -> Parser ByteString a -> Parser ByteString a
forall (f :: * -> *) a. Alternative f => f a -> f a -> f a
<|> Int
4 Int -> Parser ByteString ByteString -> Parser Int
forall a b. a -> Parser ByteString b -> Parser ByteString a
forall (f :: * -> *) a b. Functor f => a -> f b -> f a
<$ ByteString -> Parser ByteString ByteString
string ByteString
"Thu"
Parser Int -> Parser Int -> Parser Int
forall a.
Parser ByteString a -> Parser ByteString a -> Parser ByteString a
forall (f :: * -> *) a. Alternative f => f a -> f a -> f a
<|> Int
5 Int -> Parser ByteString ByteString -> Parser Int
forall a b. a -> Parser ByteString b -> Parser ByteString a
forall (f :: * -> *) a b. Functor f => a -> f b -> f a
<$ ByteString -> Parser ByteString ByteString
string ByteString
"Fri"
Parser Int -> Parser Int -> Parser Int
forall a.
Parser ByteString a -> Parser ByteString a -> Parser ByteString a
forall (f :: * -> *) a. Alternative f => f a -> f a -> f a
<|> Int
6 Int -> Parser ByteString ByteString -> Parser Int
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<$ ByteString -> Parser ByteString ByteString
string ByteString
"Sat"
Parser Int -> Parser Int -> Parser Int
forall a.
Parser ByteString a -> Parser ByteString a -> Parser ByteString a
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<|> Int
7 Int -> Parser ByteString ByteString -> Parser Int
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forall (f :: * -> *) a b. Functor f => a -> f b -> f a
<$ ByteString -> Parser ByteString ByteString
string ByteString
"Sun"
date1 :: Parser (Int,Int,Int)
date1 :: Parser (Int, Int, Int)
date1 = do
d <- Parser Int
day
sp
m <- month
sp
y <- year
return (y,m,d)
where
day :: Parser Int
day = Parser Int
digit2
year :: Parser Int
year = Parser Int
digit4
sp :: Parser ()
sp :: Parser ByteString ()
sp = () () -> Parser ByteString Char -> Parser ByteString ()
forall a b. a -> Parser ByteString b -> Parser ByteString a
forall (f :: * -> *) a b. Functor f => a -> f b -> f a
<$ Char -> Parser ByteString Char
char Char
' '
time :: Parser (Int,Int,Int)
time :: Parser (Int, Int, Int)
time = do
h <- Parser Int
digit2
void $ char ':'
m <- digit2
void $ char ':'
s <- digit2
return (h,m,s)
month :: Parser Int
month :: Parser Int
month = Int
1 Int -> Parser ByteString ByteString -> Parser Int
forall a b. a -> Parser ByteString b -> Parser ByteString a
forall (f :: * -> *) a b. Functor f => a -> f b -> f a
<$ ByteString -> Parser ByteString ByteString
string ByteString
"Jan"
Parser Int -> Parser Int -> Parser Int
forall a.
Parser ByteString a -> Parser ByteString a -> Parser ByteString a
forall (f :: * -> *) a. Alternative f => f a -> f a -> f a
<|> Int
2 Int -> Parser ByteString ByteString -> Parser Int
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<$ ByteString -> Parser ByteString ByteString
string ByteString
"Feb"
Parser Int -> Parser Int -> Parser Int
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Parser ByteString a -> Parser ByteString a -> Parser ByteString a
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<|> Int
3 Int -> Parser ByteString ByteString -> Parser Int
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<$ ByteString -> Parser ByteString ByteString
string ByteString
"Mar"
Parser Int -> Parser Int -> Parser Int
forall a.
Parser ByteString a -> Parser ByteString a -> Parser ByteString a
forall (f :: * -> *) a. Alternative f => f a -> f a -> f a
<|> Int
4 Int -> Parser ByteString ByteString -> Parser Int
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<$ ByteString -> Parser ByteString ByteString
string ByteString
"Apr"
Parser Int -> Parser Int -> Parser Int
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<|> Int
5 Int -> Parser ByteString ByteString -> Parser Int
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<$ ByteString -> Parser ByteString ByteString
string ByteString
"May"
Parser Int -> Parser Int -> Parser Int
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<|> Int
6 Int -> Parser ByteString ByteString -> Parser Int
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string ByteString
"Jun"
Parser Int -> Parser Int -> Parser Int
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string ByteString
"Jul"
Parser Int -> Parser Int -> Parser Int
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string ByteString
"Aug"
Parser Int -> Parser Int -> Parser Int
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<|> Int
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<$ ByteString -> Parser ByteString ByteString
string ByteString
"Sep"
Parser Int -> Parser Int -> Parser Int
forall a.
Parser ByteString a -> Parser ByteString a -> Parser ByteString a
forall (f :: * -> *) a. Alternative f => f a -> f a -> f a
<|> Int
10 Int -> Parser ByteString ByteString -> Parser Int
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forall (f :: * -> *) a b. Functor f => a -> f b -> f a
<$ ByteString -> Parser ByteString ByteString
string ByteString
"Oct"
Parser Int -> Parser Int -> Parser Int
forall a.
Parser ByteString a -> Parser ByteString a -> Parser ByteString a
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<|> Int
11 Int -> Parser ByteString ByteString -> Parser Int
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<$ ByteString -> Parser ByteString ByteString
string ByteString
"Nov"
Parser Int -> Parser Int -> Parser Int
forall a.
Parser ByteString a -> Parser ByteString a -> Parser ByteString a
forall (f :: * -> *) a. Alternative f => f a -> f a -> f a
<|> Int
12 Int -> Parser ByteString ByteString -> Parser Int
forall a b. a -> Parser ByteString b -> Parser ByteString a
forall (f :: * -> *) a b. Functor f => a -> f b -> f a
<$ ByteString -> Parser ByteString ByteString
string ByteString
"Dec"
digit2 :: Parser Int
digit2 :: Parser Int
digit2 = do
x1 <- Char -> Int
toInt (Char -> Int) -> Parser ByteString Char -> Parser Int
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> Parser ByteString Char
digit
x2 <- toInt <$> digit
return $ x1 * 10 + x2
digit4 :: Parser Int
digit4 :: Parser Int
digit4 = do
x1 <- Char -> Int
toInt (Char -> Int) -> Parser ByteString Char -> Parser Int
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> Parser ByteString Char
digit
x2 <- toInt <$> digit
x3 <- toInt <$> digit
x4 <- toInt <$> digit
return $ x1 * 1000 + x2 * 100 + x3 * 10 + x4
toInt :: Char -> Int
toInt :: Char -> Int
toInt Char
c = Char -> Int
ord Char
c Int -> Int -> Int
forall a. Num a => a -> a -> a
- Char -> Int
ord Char
'0'