implemented readMax

gemcap.cabal

@@ -40,6 +40,7 @@ library
     , tcp-streams >=1.0.1.1 && <1.1
     , text >=1.2.4.1 && <1.3
     , tls
+    , transformers
     , x509
   default-language: Haskell2010
   autogen-modules: Paths_gemcap
@@ -65,6 +66,7 @@ test-suite gemcap-test
     , tcp-streams >=1.0.1.1 && <1.1
     , text >=1.2.4.1 && <1.3
     , tls
+    , transformers
     , x509
   default-language: Haskell2010
   autogen-modules: Paths_gemcap

package.yaml

@@ -31,6 +31,7 @@ dependencies:
 - io-streams
 - network
 - tls
+- transformers
 - x509
 
 library:

src/Network/Gemini/Capsule/Internal.hs

@@ -40,10 +40,15 @@ module Network.Gemini.Capsule.Internal (
   stripCRLF
 ) where
 
+import Control.Monad.Trans.Class (lift)
+import Control.Monad.Trans.Maybe (MaybeT (..))
 import qualified Data.ByteString as BS
-import Data.Connection (Connection)
+import Data.ByteString.Builder (Builder, byteString, toLazyByteString)
+import qualified Data.ByteString.Lazy as BSL
+import Data.Connection (Connection, source)
 import qualified Data.Text as T
 import Data.Text.Encoding (decodeUtf8')
+import System.IO.Streams as S
 
 import Network.Gemini.Capsule.Encoding
 import Network.Gemini.Capsule.Types
@@ -99,11 +104,24 @@ readMax
   -> Connection a
   -- ^ the 'Connection' to read from
   -> IO (Maybe BS.ByteString)
-readMax = undefined
+readMax maxLen conn = do
+  let src = source conn
+  runMaybeT $
+    BS.pack . BSL.unpack . toLazyByteString
+    <$> readLoop maxLen src
 
 -- | Strips the CR/LF characters from the end of a string, retuning
 -- Nothing if they are not present
 stripCRLF :: String -> Maybe String
 stripCRLF = undefined
 
+readLoop :: Int -> S.InputStream BS.ByteString -> MaybeT IO Builder
+readLoop maxLen src =
+  lift (S.read src) >>= \case
+    Nothing -> return mempty
+    Just bs -> let len = BS.length bs in
+      if len > maxLen
+        then MaybeT $ return Nothing
+        else (byteString bs <>) <$> readLoop (maxLen - len) src
+
 --jl

test/Network/Gemini/Capsule/InternalSpec.hs

@@ -20,7 +20,7 @@ License along with this program.  If not, see
 
 -}
 
-{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE OverloadedStrings, RecordWildCards #-}
 
 module Network.Gemini.Capsule.InternalSpec (spec) where
 
@@ -28,7 +28,7 @@ import qualified Data.ByteString as BS
 import Data.Char (ord)
 import Data.Connection (Connection (..))
 import System.IO.Streams (nullInput, unRead)
-import Test.Hspec (Spec, context, describe, shouldReturn, xit)
+import Test.Hspec (Spec, context, describe, it, shouldReturn, xit)
 
 import Network.Gemini.Capsule.Types
 import Network.Gemini.Capsule.Internal
@@ -89,24 +89,42 @@ strFromConnSpec = describe "strFromConn" $ mapM_
   , ( "non-ASCII",    100,      mkInConn ["\xc3\xa9\r\n"], Just "\xe9" )
   ]
 
-mkInConn :: [BS.ByteString] -> IO (Connection a)
-mkInConn bss = do
-  s <- nullInput
-  mapM_ (`unRead` s) (reverse bss)
-  return sampleConnection { source = s }
-
-sampleConnection :: Connection a
-sampleConnection = Connection
-  { source        = undefined
-  , send          = const $ return ()
-  , close         = return ()
-  , connExtraInfo = undefined
-  }
-
 readMaxSpec :: Spec
-readMaxSpec = describe "readMax" $ return ()
+readMaxSpec = describe "readMax" $ mapM_
+  ( \(desc, maxLen, ioConn, expect) -> context desc $
+    it ("should return " ++ show expect) $ do
+      conn <- ioConn
+      readMax maxLen conn `shouldReturn` expect
+  )
+
+  --  description,    max length,   connection, expected
+  [ ( "single input", 1024,         singleConn,  Just singleBS )
+  , ( "multi input",  1024,         multiConn,   Just multiBS  )
+  , ( "long input",   longLen,      longConn,    Just longBS   )
+  , ( "too long",     pred longLen, longConn,    Nothing       )
+  , ( "empty input",  1024,         mkInConn [], Just ""       )
+  ]
+
+  where
+    singleConn = mkInConn ["foo"]
+    multiConn  = mkInConn ["foo", "bar", "baz"]
+    longConn   = mkInConn [longBS]
+    longLen    = BS.length longBS
+    singleBS   = "foo"
+    multiBS    = "foobarbaz"
+    longBS     = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 
 stripCRLFSpec :: Spec
 stripCRLFSpec = describe "stripCRLF" $ return ()
 
+mkInConn :: [BS.ByteString] -> IO (Connection ())
+mkInConn bss = do
+  source <- nullInput
+  mapM_ (`unRead` source) (reverse bss)
+  let
+    send          = const $ return ()
+    close         = return ()
+    connExtraInfo = ()
+  return Connection {..}
+
 --jl