Code clean-up using convertible-text.

[Lucu.git] / Network / HTTP / Lucu / Utils.hs

diff --git a/Network/HTTP/Lucu/Utils.hs b/Network/HTTP/Lucu/Utils.hs
index 387cca24a58f16bf3b08f4a63a99e2a3f41aeedc..297ea3a762ef64992466469a3845053ffb86d7af 100644 (file)
--- a/Network/HTTP/Lucu/Utils.hs
+++ b/Network/HTTP/Lucu/Utils.hs
@@ -1,79 +1,168 @@
 {-# LANGUAGE
-    BangPatterns
+    FlexibleContexts
   , OverloadedStrings
   , UnicodeSyntax
   #-}
--- |Utility functions used internally in the Lucu httpd. These
--- functions may be useful too for something else.
+-- |Utility functions used internally in this package.
 module Network.HTTP.Lucu.Utils
-    ( splitBy
-    , joinWith
+    ( Host
+    , PathSegment
+    , Path
+
+    , splitBy
     , quoteStr
     , parseWWWFormURLEncoded
+    , uriHost
+    , uriPathSegments
+    , trim
+
+    , (⊲)
+    , (⊳)
+    , (⋈)
+    , mapM
+
+    , getLastModified
     )
     where
-import Control.Monad
+import Control.Applicative hiding (empty)
+import Control.Monad hiding (mapM)
 import Data.Ascii (Ascii, AsciiBuilder)
 import qualified Data.Ascii as A
+import Data.ByteString (ByteString)
 import qualified Data.ByteString.Char8 as BS
-import Data.List hiding (last)
+import Data.CaseInsensitive (CI)
+import qualified Data.CaseInsensitive as CI
+import Data.Char
+import Data.Collections
+import Data.Collections.BaseInstances ()
+import Data.Convertible.Base
+import Data.Convertible.Instances.Time ()
+import Data.Maybe
 import Data.Monoid.Unicode
+import Data.Text (Text)
+import qualified Data.Text as T
+import Data.Time
 import Network.URI
-import Prelude hiding (last)
+import Prelude hiding (last, mapM, null, reverse)
 import Prelude.Unicode
+import System.Directory
+
+-- |'Host' represents an IP address or a host name in an URI
+-- authority.
+type Host = CI Text
+
+-- |'PathSegment' represents an URI path segment, split by slashes and
+-- percent-decoded.
+type PathSegment = ByteString
+
+-- |'Path' is a list of URI path segments.
+type Path = [PathSegment]
 
--- |> splitBy (== ':') "ab:c:def"
---  > ==> ["ab", "c", "def"]
+-- |>>> splitBy (== ':') "ab:c:def"
+-- ["ab", "c", "def"]
 splitBy ∷ (a → Bool) → [a] → [[a]]
+{-# INLINEABLE splitBy #-}
 splitBy isSep src
-    = case break isSep src
-      of (last , []       ) → [last]
-         (first, _sep:rest) → first : splitBy isSep rest
-
--- |> joinWith ":" ["ab", "c", "def"]
---  > ==> "ab:c:def"
-joinWith ∷ Ascii → [Ascii] → AsciiBuilder
-{-# INLINEABLE joinWith #-}
-joinWith sep = flip go (∅)
-    where
-      go ∷ [Ascii] → A.AsciiBuilder → A.AsciiBuilder
-      {-# INLINE go #-}
-      go []     ab = ab
-      go (x:[]) ab = ab ⊕ A.toAsciiBuilder x
-      go (x:xs) ab = go xs ( ab ⊕
-                             A.toAsciiBuilder sep ⊕
-                             A.toAsciiBuilder x )
-
--- |> quoteStr "abc"
---  > ==> "\"abc\""
+    = case break isSep src of
+        (last , []       ) → [last]
+        (first, _sep:rest) → first : splitBy isSep rest
+
+-- |>>> quoteStr "abc"
+-- "\"abc\""
 --
---  > quoteStr "ab\"c"
---  > ==> "\"ab\\\"c\""
+-- >>> quoteStr "ab\"c"
+-- "\"ab\\\"c\""
 quoteStr ∷ Ascii → AsciiBuilder
 quoteStr str = A.toAsciiBuilder "\"" ⊕
                go (A.toByteString str) (∅) ⊕
                A.toAsciiBuilder "\""
     where
-      go ∷ BS.ByteString → AsciiBuilder → AsciiBuilder
+      go ∷ ByteString → AsciiBuilder → AsciiBuilder
       go bs ab
           = case BS.break (≡ '"') bs of
               (x, y)
-                  | BS.null y → ab ⊕ b2ab x
-                  | otherwise → go (BS.tail y) (ab ⊕ b2ab x
-                                                   ⊕ A.toAsciiBuilder "\\\"")
+                  | BS.null y
+                      → ab ⊕ b2ab x
+                  | otherwise
+                      → go (BS.tail y)
+                           (ab ⊕ b2ab x ⊕ A.toAsciiBuilder "\\\"")
 
-      b2ab ∷ BS.ByteString → AsciiBuilder
+      b2ab ∷ ByteString → AsciiBuilder
       b2ab = A.toAsciiBuilder ∘ A.unsafeFromByteString
 
--- |> parseWWWFormURLEncoded "aaa=bbb&ccc=ddd"
---  > ==> [("aaa", "bbb"), ("ccc", "ddd")]
-parseWWWFormURLEncoded ∷ String → [(String, String)]
+-- |>>> parseWWWFormURLEncoded "aaa=bbb&ccc=ddd"
+-- [("aaa", "bbb"), ("ccc", "ddd")]
+parseWWWFormURLEncoded ∷ Ascii → [(ByteString, ByteString)]
 parseWWWFormURLEncoded src
-    | src == "" = []
-    | otherwise = do pairStr <- splitBy (\ c → c == ';' || c == '&') src
-                     let (key, value) = break (== '=') pairStr
-                     return ( unEscapeString key
-                            , unEscapeString $ case value of
-                                                 ('=':val) → val
-                                                 val       → val
+    -- THINKME: We could gain some performance by using attoparsec
+    -- here.
+    | src ≡ ""  = []
+    | otherwise = do pairStr ← splitBy (\ c → c ≡ ';' ∨ c ≡ '&') (A.toString src)
+                     let (key, value) = break (≡ '=') pairStr
+                     return ( unescape key
+                            , unescape $ case value of
+                                           ('=':val) → val
+                                           val       → val
                             )
+    where
+      unescape ∷ String → ByteString
+      unescape = BS.pack ∘ unEscapeString ∘ (plusToSpace <$>)
+
+      plusToSpace ∷ Char → Char
+      plusToSpace '+' = ' '
+      plusToSpace c   = c
+
+-- |>>> uriHost "http://example.com/foo/bar"
+-- "example.com"
+uriHost ∷ URI → Host
+{-# INLINE uriHost #-}
+uriHost = CI.mk ∘ T.pack ∘ uriRegName ∘ fromJust ∘ uriAuthority
+
+-- |>>> uriPathSegments "http://example.com/foo/bar"
+-- ["foo", "bar"]
+uriPathSegments ∷ URI → Path
+uriPathSegments uri
+    = let reqPathStr = uriPath uri
+          reqPath    = [ unEscapeString x
+                         | x ← splitBy (≡ '/') reqPathStr, (¬) (null x) ]
+      in
+        BS.pack <$> reqPath
+
+-- |>>> trim "  ab c d "
+-- "ab c d"
+trim ∷ String → String
+trim = reverse ∘ f ∘ reverse ∘ f
+    where
+      f = dropWhile isSpace
+
+infixr 5 ⊲
+-- | (&#x22B2;) = ('<|')
+--
+-- U+22B2, NORMAL SUBGROUP OF
+(⊲) ∷ Sequence α a ⇒ a → α → α
+(⊲) = (<|)
+
+infixl 5 ⊳
+-- | (&#x22B3;) = ('|>')
+--
+-- U+22B3, CONTAINS AS NORMAL SUBGROUP
+(⊳) ∷ Sequence α a ⇒ α → a → α
+(⊳) = (|>)
+
+infixr 5 ⋈
+-- | (&#x22C8;) = ('><')
+--
+-- U+22C8, BOWTIE
+(⋈) ∷ Sequence α a ⇒ α → α → α
+(⋈) = (><)
+
+-- |Generalised @mapM@ from any 'Foldable' to 'Unfoldable'. Why isn't
+-- this in the @collections-api@?
+mapM ∷ (Foldable α a, Unfoldable β b, Functor m, Monad m)
+     ⇒ (a → m b) → α → m β
+{-# INLINE mapM #-}
+mapM = flip foldrM empty ∘ (flip ((<$>) ∘ flip insert) ∘)
+
+-- |Get the modification time of a given file.
+getLastModified ∷ FilePath → IO UTCTime
+getLastModified = (cs <$>) ∘ getModificationTime