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|
-- |
-- Copyright : (c) Sam T. 2013
-- License : MIT
-- Maintainer : pxqr.sta@gmail.com
-- Stability : experimental
-- Portability : non-portable
--
-- This module provides high level API for peer->tracker
-- communication.
--
{-# LANGUAGE RecordWildCards #-}
module Network.BitTorrent.Tracker
( module Network.BitTorrent.Tracker.Scrape
, withTracker, completedReq
-- * Progress
, Progress(..), startProgress
-- * Connection
, TConnection(..), tconnection
-- * Session
, TSession
, getPeerAddr, getPeerList
, getProgress, waitInterval
-- * Re-export
, defaultPorts
) where
import Control.Applicative
import Control.Concurrent
import Control.Concurrent.STM
import Control.Exception
import Control.Monad
import Data.IORef
import Data.Torrent
import Network
import Network.URI
import Network.BitTorrent.Internal
import Network.BitTorrent.Peer
import Network.BitTorrent.Tracker.Protocol
import Network.BitTorrent.Tracker.Scrape
-- | 'TConnection' (shorthand for Tracker session) combines tracker request
-- fields neccessary for tracker, torrent and client identification.
--
-- This data is considered as static within one session.
--
data TConnection = TConnection {
tconnAnnounce :: URI -- ^ Announce URL.
, tconnInfoHash :: InfoHash -- ^ Hash of info part of current .torrent file.
, tconnPeerID :: PeerID -- ^ Client peer ID.
, tconnPort :: PortNumber -- ^ The port number the client is listenning on.
} deriving Show
tconnection :: Torrent -> PeerID -> PortNumber -> TConnection
tconnection t = TConnection (tAnnounce t) (tInfoHash t)
-- | used to avoid boilerplate; do NOT export me
genericReq :: TConnection -> Progress -> TRequest
genericReq ses pr = TRequest {
reqAnnounce = tconnAnnounce ses
, reqInfoHash = tconnInfoHash ses
, reqPeerID = tconnPeerID ses
, reqPort = tconnPort ses
, reqUploaded = prUploaded pr
, reqDownloaded = prDownloaded pr
, reqLeft = prLeft pr
, reqIP = Nothing
, reqNumWant = Nothing
, reqEvent = Nothing
}
-- | The first request to the tracker that should be created is 'startedReq'.
-- It includes necessary 'Started' event field.
--
startedReq :: TConnection -> Progress -> TRequest
startedReq ses pr = (genericReq ses pr) {
reqIP = Nothing
, reqNumWant = Just defaultNumWant
, reqEvent = Just Started
}
-- | Regular request must be sent to keep track new peers and
-- notify tracker about current state of the client
-- so new peers could connect to the client.
--
regularReq :: Int -> TConnection -> Progress -> TRequest
regularReq numWant ses pr = (genericReq ses pr) {
reqIP = Nothing
, reqNumWant = Just numWant
, reqEvent = Nothing
}
-- | Must be sent to the tracker if the client is shutting down
-- gracefully.
--
stoppedReq :: TConnection -> Progress -> TRequest
stoppedReq ses pr = (genericReq ses pr) {
reqIP = Nothing
, reqNumWant = Nothing
, reqEvent = Just Stopped
}
-- | Must be sent to the tracker when the download completes.
-- However, must not be sent if the download was already 100%
-- complete.
--
completedReq :: TConnection -> Progress -> TRequest
completedReq ses pr = (genericReq ses pr) {
reqIP = Nothing
, reqNumWant = Nothing
, reqEvent = Just Completed
}
data TSession = TSession {
seProgress :: TVar Progress
, seInterval :: IORef Int
, sePeers :: Chan PeerAddr
-- TODO use something like 'TVar (Set PeerAddr)'
-- otherwise we might get space leak
}
newSession :: Progress -> Int -> [PeerAddr] -> IO TSession
newSession pr i ps = do
chan <- newChan
writeList2Chan chan ps
TSession <$> newTVarIO pr
<*> newIORef i
<*> pure chan
getPeerAddr :: TSession -> IO PeerAddr
getPeerAddr = readChan . sePeers
getPeerList :: TSession -> IO [PeerAddr]
getPeerList = getChanContents . sePeers
getProgress :: TSession -> IO Progress
getProgress = readTVarIO . seProgress
waitInterval :: TSession -> IO ()
waitInterval = readIORef . seInterval >=> threadDelay
withTracker :: Progress -> TConnection -> (TSession -> IO a) -> IO a
withTracker initProgress conn action = bracket start end (action . fst)
where
start = do
resp <- askTracker (startedReq conn initProgress)
se <- newSession initProgress (respInterval resp) (respPeers resp)
tid <- forkIO (syncSession se)
return (se, tid)
syncSession se @ TSession {..} = forever $ do
waitInterval se
pr <- getProgress se
resp <- tryJust isIOException $ do
askTracker (regularReq defaultNumWant conn pr)
case resp of
Right (OK {..}) -> do
writeIORef seInterval respInterval
writeList2Chan sePeers respPeers
_ -> return ()
where
isIOException :: IOException -> Maybe IOException
isIOException = return
end (se, tid) = do
killThread tid
pr <- getProgress se
askTracker $ stoppedReq conn pr
|
