70 lines
2.3 KiB
Haskell
70 lines
2.3 KiB
Haskell
{-# LANGUAGE DeriveDataTypeable #-}
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{-# LANGUAGE DeriveGeneric #-}
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{-# LANGUAGE ViewPatterns #-}
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module Servant.Common.BaseUrl (
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-- * types
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BaseUrl (..)
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, InvalidBaseUrlException
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, Scheme (..)
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-- * functions
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, parseBaseUrl
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, showBaseUrl
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) where
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import Control.Monad.Catch (Exception, MonadThrow, throwM)
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import Data.List
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import Data.Typeable
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import GHC.Generics
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import Network.URI
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import Safe
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import Text.Read
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-- | URI scheme to use
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data Scheme =
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Http -- ^ http://
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| Https -- ^ https://
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deriving (Show, Eq, Ord, Generic)
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-- | Simple data type to represent the target of HTTP requests
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-- for servant's automatically-generated clients.
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data BaseUrl = BaseUrl
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{ baseUrlScheme :: Scheme -- ^ URI scheme to use
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, baseUrlHost :: String -- ^ host (eg "haskell.org")
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, baseUrlPort :: Int -- ^ port (eg 80)
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} deriving (Show, Eq, Ord, Generic)
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showBaseUrl :: BaseUrl -> String
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showBaseUrl (BaseUrl urlscheme host port) =
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schemeString ++ "//" ++ host ++ portString
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where
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schemeString = case urlscheme of
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Http -> "http:"
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Https -> "https:"
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portString = case (urlscheme, port) of
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(Http, 80) -> ""
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(Https, 443) -> ""
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_ -> ":" ++ show port
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data InvalidBaseUrlException = InvalidBaseUrlException String deriving (Show, Typeable)
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instance Exception InvalidBaseUrlException
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parseBaseUrl :: MonadThrow m => String -> m BaseUrl
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parseBaseUrl s = case parseURI (removeTrailingSlash s) of
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-- This is a rather hacky implementation and should be replaced with something
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-- implemented in attoparsec (which is already a dependency anyhow (via aeson)).
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Just (URI "http:" (Just (URIAuth "" host (':' : (readMaybe -> Just port)))) "" "" "") ->
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return (BaseUrl Http host port)
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Just (URI "http:" (Just (URIAuth "" host "")) "" "" "") ->
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return (BaseUrl Http host 80)
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Just (URI "https:" (Just (URIAuth "" host (':' : (readMaybe -> Just port)))) "" "" "") ->
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return (BaseUrl Https host port)
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Just (URI "https:" (Just (URIAuth "" host "")) "" "" "") ->
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return (BaseUrl Https host 443)
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_ -> if "://" `isInfixOf` s
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then throwM (InvalidBaseUrlException $ "Invalid base URL: " ++ s)
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else parseBaseUrl ("http://" ++ s)
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where
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removeTrailingSlash str = case lastMay str of
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Just '/' -> init str
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_ -> str
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