4 files changed, 56 insertions, 0 deletions

diff --git a/bittorrent.cabal b/bittorrent.cabal
index c197cb91..347cc38d 100644
--- a/bittorrent.cabal
+++ b/bittorrent.cabal
@@ -237,6 +237,15 @@ test-suite spec
 --                     , bittorrent
 --  ghc-options:         -O2 -Wall -fno-warn-orphans
 
+executable gettorrent
+  default-language:    Haskell2010
+  hs-source-dirs:      examples
+  main-is:             GetTorrent.hs
+  build-depends:       base        == 4.*
+                     , optparse-applicative
+                     , data-default
+                     , bittorrent
+
 executable client-example
   default-language:    Haskell2010
   hs-source-dirs:      examples
diff --git a/examples/GetTorrent.hs b/examples/GetTorrent.hs
new file mode 100644
index 00000000..a9d2a44f
--- /dev/null
+++ b/examples/GetTorrent.hs
@@ -0,0 +1,37 @@
+module Main (main) where
+import Data.Default
+
+import Options.Applicative
+import Data.Torrent.InfoHash
+import Network.BitTorrent.Core
+
+
+data Params = Params
+  { infohash :: InfoHash
+  , thisNode :: NodeAddr IPv4
+  , bootNode :: NodeAddr IPv4
+  } deriving Show
+
+paramsParser :: Parser Params
+paramsParser = Params
+  <$> option (long    "infohash" <> short 'i'
+           <> metavar "SHA1"     <> help "infohash of torrent file")
+  <*> option (long    "node"     <> short 'n' <> value def
+           <> metavar "NODE"     <> help "this node address"
+             )
+  <*> option (long    "boot"     <> short 'b'
+           <> metavar "NODE"     <> help "bootstrap node address"
+             )
+
+programInfo :: ParserInfo Params
+programInfo = info (helper <*> paramsParser)
+   ( fullDesc
+  <> progDesc ""
+  <> header   "gettorrent - get torrent file by infohash"
+   )
+
+getTorrent :: Params -> IO ()
+getTorrent = print
+
+main :: IO ()
+main = execParser programInfo >>= getTorrent
diff --git a/src/Network/BitTorrent/Core/Node.hs b/src/Network/BitTorrent/Core/Node.hs
index da96ca43..116333c5 100644
--- a/src/Network/BitTorrent/Core/Node.hs
+++ b/src/Network/BitTorrent/Core/Node.hs
@@ -122,6 +122,9 @@ data NodeAddr a = NodeAddr
 
 $(deriveJSON omitRecordPrefix ''NodeAddr)
 
+instance Read (NodeAddr IPv4) where
+  readsPrec i x = [ (fromPeerAddr a, s) | (a, s) <- readsPrec i x ]
+
 -- | @127.0.0.1:6882@
 instance Default (NodeAddr IPv4) where
   def = "127.0.0.1:6882"
diff --git a/src/Network/BitTorrent/Core/PeerAddr.hs b/src/Network/BitTorrent/Core/PeerAddr.hs
index d634716c..e3e09fd6 100644
--- a/src/Network/BitTorrent/Core/PeerAddr.hs
+++ b/src/Network/BitTorrent/Core/PeerAddr.hs
@@ -251,6 +251,13 @@ instance IsString (PeerAddr IPv4) where
                 = PeerAddr Nothing hostAddr portNum
     | otherwise = error $ "fromString: unable to parse (PeerAddr IPv4): " ++ str
 
+instance Read (PeerAddr IPv4) where
+  readsPrec i = RP.readP_to_S $ do
+    ipv4 <- RP.readS_to_P (readsPrec i)
+    _    <- RP.char ':'
+    port <- toEnum <$> RP.readS_to_P (readsPrec i)
+    return $ PeerAddr Nothing ipv4 port
+
 readsIPv6_port :: String -> [((IPv6, PortNumber), String)]
 readsIPv6_port = RP.readP_to_S $ do
   ip <- RP.char '[' *> (RP.readS_to_P reads) <* RP.char ']'