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|
-- |
-- Copyright : (c) Sam T. 2013
-- License : MIT
-- Maintainer : pxqr.sta@gmail.com
-- Stability : experimental
-- Portability : portable
--
-- By convention most trackers support another form of request,
-- which queries the state of a given torrent (or all torrents) that the
-- tracker is managing. This module provides a way to easily request
-- scrape info for a particular torrent list.
--
{-# LANGUAGE OverloadedStrings #-}
module Network.BitTorrent.Tracker.Scrape
( ScrapeInfo(..), Scrape
, scrapeURL
-- * Requests
, scrape
, scrapeOne
) where
import Control.Applicative
import Data.BEncode
import Data.ByteString (ByteString)
import qualified Data.ByteString as B
import qualified Data.ByteString.Char8 as BC
import Data.Map (Map)
import qualified Data.Map as M
import Data.Monoid
import Data.Torrent.InfoHash
import Network.URI
import Network.HTTP
-- | Information about particular torrent.
data ScrapeInfo = ScrapeInfo {
siComplete :: Int
-- ^ Number of seeders - peers with the entire file.
, siDownloaded :: Int
-- ^ Total number of times the tracker has registered a completion.
, siIncomplete :: Int
-- ^ Number of leechers.
, siName :: Maybe ByteString
-- ^ Name of the torrent file, as specified by the "name"
-- file in the info section of the .torrent file.
} deriving (Show, Eq)
-- | Scrape info about a set of torrents.
type Scrape = Map InfoHash ScrapeInfo
instance BEncodable ScrapeInfo where
toBEncode si = fromAssocs
[ "complete" --> siComplete si
, "downloaded" --> siDownloaded si
, "incomplete" --> siIncomplete si
, "name" -->? siName si
]
fromBEncode (BDict d) =
ScrapeInfo <$> d >-- "complete"
<*> d >-- "downloaded"
<*> d >-- "incomplete"
<*> d >--? "name"
fromBEncode _ = decodingError "ScrapeInfo"
-- | Trying to convert /announce/ URL to /scrape/ URL. If 'scrapeURL'
-- gives 'Nothing' then tracker do not support scraping. The info hash
-- list is used to restrict the tracker's report to that particular
-- torrents. Note that scrapping of multiple torrents may not be
-- supported. (Even if scrapping convention is supported)
--
scrapeURL :: URI -> [InfoHash] -> Maybe URI
scrapeURL uri ihs = do
newPath <- replace (BC.pack (uriPath uri))
let newURI = uri { uriPath = BC.unpack newPath }
return (foldl addHashToURI newURI ihs)
where
replace :: ByteString -> Maybe ByteString
replace p
| ps <- BC.splitWith (== '/') p
, "announce" `B.isPrefixOf` last ps
= let newSuff = "scrape" <> B.drop (B.length "announce") (last ps)
in Just (B.intercalate "/" (init ps ++ [newSuff]))
| otherwise = Nothing
-- | For each 'InfoHash' of torrents request scrape info from the tracker.
-- However if the info hash list is 'null', the tracker should list
-- all available torrents.
-- Note that the 'URI' should be /announce/ URI, not /scrape/ URI.
--
scrape :: URI -- ^ Announce 'URI'.
-> [InfoHash] -- ^ Torrents to be scrapped.
-> IO (Result Scrape) -- ^ 'ScrapeInfo' for each torrent.
scrape announce ihs
| Just uri<- scrapeURL announce ihs = do
rawResp <- simpleHTTP (Request uri GET [] "")
respBody <- getResponseBody rawResp
return (decoded (BC.pack respBody))
| otherwise = return (Left "Tracker do not support scraping")
-- | More particular version of 'scrape', just for one torrent.
--
scrapeOne :: URI -- ^ Announce 'URI'
-> InfoHash -- ^ Hash of the torrent info.
-> IO (Result ScrapeInfo) -- ^ 'ScrapeInfo' for the torrent.
scrapeOne uri ih = extract <$> scrape uri [ih]
where
extract (Right m)
| Just s <- M.lookup ih m = Right s
| otherwise = Left "unable to find info hash in response dict"
extract (Left e) = Left e
|
