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|
-- |
-- Copyright : (c) Sam T. 2013
-- License : MIT
-- Maintainer : pxqr.sta@gmail.com
-- Stability : experimental
-- Portability : non-portable
--
--
-- This module provides straigthforward Tracker protocol
-- implementation. The tracker is an HTTP/HTTPS service:
--
-- * A tracker request is HTTP GET request; used to include
-- metrics from clients that help the tracker keep overall
-- statistics about the torrent.
--
-- * The tracker response includes a peer list that helps the
-- client participate in the torrent.
--
-- For more convenient high level API see Network.BitTorrent.Tracker
-- module.
--
{-# OPTIONS -fno-warn-orphans #-}
{-# LANGUAGE OverloadedStrings #-}
-- TODO: add "compact" field to TRequest
module Network.BitTorrent.Tracker.Protocol
( module Network.BitTorrent.Tracker.Scrape
, Event(..), TRequest(..), TResponse(..)
, sendRequest
-- * Defaults
, defaultPorts, defaultNumWant
)
where
import Control.Applicative
import Control.Monad
import Data.Char as Char
import Data.Word (Word32)
import Data.Map as M
import Data.Monoid
import Data.BEncode
import Data.ByteString as B
import Data.ByteString.Char8 as BC
import Data.Text as T
import Data.Serialize.Get hiding (Result)
import Data.URLEncoded as URL
import Data.Torrent
import Network
import Network.Socket
import Network.HTTP
import Network.URI
import Network.BitTorrent.Peer
import Network.BitTorrent.Tracker.Scrape
data Event = Started -- ^ For first request.
| Stopped -- ^ Sent when the peer is shutting down.
| Completed -- ^ To be sent when the peer completes a download.
deriving (Show, Read, Eq, Ord, Enum, Bounded)
data TRequest = TRequest { -- TODO peer here -- TODO detach announce
reqAnnounce :: URI -- ^ Announce url of the torrent.
, reqInfoHash :: InfoHash -- ^ Hash of info part of the torrent.
, reqPeerID :: PeerID -- ^ Id of the peer doing request. ()
, reqPort :: PortNumber -- ^ Port to listen to for connection from other peers.
, reqUploaded :: Integer -- ^ # of bytes that the peer has uploaded in the swarm.
, reqDownloaded :: Integer -- ^ # of bytes downloaded in the swarm by the peer.
, reqLeft :: Integer -- ^ # of bytes needed in order to complete download.
, reqIP :: Maybe HostAddress -- ^ The peer IP.
, reqNumWant :: Maybe Int -- ^ Number of peers that the peers wants to receive from.
, reqEvent :: Maybe Event -- ^ If not specified,
-- the request is regular periodic request.
} deriving Show
data TResponse =
Failure Text -- ^ Failure reason in human readable form.
| OK {
respWarning :: Maybe Text
, respInterval :: Int -- ^ Recommended interval to wait between requests.
, respMinInterval :: Maybe Int -- ^ Minimal amount of time between requests.
, respComplete :: Maybe Int -- ^ Number of peers completed the torrent. (seeders)
, respIncomplete :: Maybe Int -- ^ Number of peers downloading the torrent.
, respPeers :: [PeerAddr] -- ^ Peers that must be contacted.
} deriving Show
instance BEncodable TResponse where
toBEncode (Failure t) = fromAssocs ["failure reason" --> t]
toBEncode resp@(OK {}) = fromAssocs
[ "interval" --> respInterval resp
, "min interval" -->? respMinInterval resp
, "complete" -->? respComplete resp
, "incomplete" -->? respIncomplete resp
, "peers" --> respPeers resp
]
fromBEncode (BDict d)
| Just t <- M.lookup "failure reason" d = Failure <$> fromBEncode t
| otherwise = OK <$> d >--? "warning message"
<*> d >-- "interval"
<*> d >--? "min interval"
<*> d >--? "complete"
<*> d >--? "incomplete"
<*> getPeers (M.lookup "peers" d)
where
getPeers :: Maybe BEncode -> Result [PeerAddr]
getPeers (Just (BList l)) = fromBEncode (BList l)
getPeers (Just (BString s))
| B.length s `mod` 6 == 0 =
let cnt = B.length s `div` 6 in
runGet (replicateM cnt peerG) s
| otherwise = decodingError "peers length not a multiple of 6"
where
peerG = do
pip <- getWord32be
pport <- getWord16be
return (PeerAddr Nothing (fromIntegral pip) (fromIntegral pport))
getPeers _ = decodingError "Peers"
fromBEncode _ = decodingError "TResponse"
instance URLShow PortNumber where
urlShow = urlShow . fromEnum
instance URLShow Word32 where
urlShow = show
instance URLShow Event where
urlShow e = urlShow (Char.toLower x : xs)
where
-- this is always nonempty list
(x : xs) = show e
instance URLEncode TRequest where
urlEncode req = mconcat
[ s "peer_id" %= reqPeerID req
, s "port" %= reqPort req
, s "uploaded" %= reqUploaded req
, s "downloaded" %= reqDownloaded req
, s "left" %= reqLeft req
, s "ip" %=? reqIP req
, s "numwant" %=? reqNumWant req
, s "event" %=? reqEvent req
]
where s :: String -> String; s = id; {-# INLINE s #-}
encodeRequest :: TRequest -> URI
encodeRequest req = URL.urlEncode req
`addToURI` reqAnnounce req
`addHashToURI` reqInfoHash req
-- | Ports typically reserved for bittorrent.
defaultPorts :: [PortNumber]
defaultPorts = [6881..6889]
-- | Above 25, new peers are highly unlikely to increase download speed.
-- Even 30 peers is _plenty_, the official client version 3 in fact only
-- actively forms new connections if it has less than 30 peers and will
-- refuse connections if it has 55. So default value is set to 25.
--
defaultNumWant :: Int
defaultNumWant = 25
-- | TODO rename to ask for peers
--
sendRequest :: TRequest -> IO (Result TResponse)
sendRequest req = do
let r = mkHTTPRequest (encodeRequest req)
rawResp <- simpleHTTP r
respBody <- getResponseBody rawResp
return (decoded respBody)
where
mkHTTPRequest :: URI -> Request ByteString
mkHTTPRequest uri = Request uri GET [] ""
|
