src/FuncTorrent/Metainfo.hs

   1 {-
   2  - Copyright (C) 2015-2016 Ramakrishnan Muthukrishnan <ram@rkrishnan.org>
   3  -
   4  - This file is part of FuncTorrent.
   5  -
   6  - FuncTorrent is free software; you can redistribute it and/or modify
   7  - it under the terms of the GNU General Public License as published by
   8  - the Free Software Foundation; either version 3 of the License, or
   9  - (at your option) any later version.
  10  -
  11  - FuncTorrent is distributed in the hope that it will be useful,
  12  - but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  - GNU General Public License for more details.
  15  -
  16  - You should have received a copy of the GNU General Public License
  17  - along with FuncTorrent; if not,  see <http://www.gnu.org/licenses/>
  18  -}
  19
  20 {-# LANGUAGE DuplicateRecordFields #-}
  21
  22 module FuncTorrent.Metainfo
  23     (Info(..)
  24     , Metainfo(..)
  25     , DynamicInfo(..)
  26     , torrentToMetainfo
  27     ) where
  28
  29 import Prelude hiding (lookup)
  30 import Data.ByteString.Char8 (ByteString, unpack)
  31 import Data.Map as M ((!), lookup)
  32 import Crypto.Hash.SHA1 (hash)
  33 import Data.Maybe (maybeToList)
  34
  35 import FuncTorrent.Bencode (BVal(..), encode, decode, bstrToString, bValToInteger)
  36
  37 -- only single file mode supported for the time being.
  38 data Info = Info { pieceLength :: !Integer
  39                  , pieces :: !ByteString
  40                  , private :: !(Maybe Integer)
  41                  , dyninfo :: !DynamicInfo
  42                  } deriving (Eq, Show)
  43
  44 data DynamicInfo = SingleFileInfo { name :: String
  45                                   , lengthInBytes :: Integer
  46                                   , md5sum :: Maybe String
  47                                   }
  48                  | MultiFileInfo { dname :: String
  49                                  , files :: [FileInfo]
  50                                  }
  51                  deriving (Eq, Show)
  52
  53 data FileInfo = FileInfo { lengthInBytes :: Integer
  54                          , md5sum :: Maybe String
  55                          , path :: String
  56                          } deriving (Eq, Show)
  57
  58 data Metainfo = Metainfo { info :: !Info
  59                          , announceList :: ![String]
  60                          , creationDate :: !(Maybe Integer)
  61                          , comment :: !(Maybe String)
  62                          , createdBy :: !(Maybe String)
  63                          , encoding :: !(Maybe String)
  64                          , infoHash :: !ByteString
  65                          } deriving (Eq, Show)
  66
  67 mkInfo :: BVal -> Maybe Info
  68 mkInfo (Bdict m) = let (Bint pieceLength') = m ! "piece length"
  69                        (Bstr pieces') = m ! "pieces"
  70                        private' = Nothing
  71                        bdictfiles = lookup "files" m
  72                    in
  73                      case bdictfiles of
  74                        Just fs -> let (Blist files') = fs
  75                                       (Bstr name') = m ! "name"
  76                                   in
  77                                     Just Info { pieceLength = pieceLength'
  78                                               , pieces = pieces'
  79                                               , private = private'
  80                                               , dyninfo = MultiFileInfo {
  81                                                   dname = unpack name',
  82                                                   files =
  83                                                       map (\(Bdict f) ->
  84                                                             let (Just len') = bValToInteger (f ! "length")
  85                                                                 (Bstr s') = f ! "path"
  86                                                             in
  87                                                               FileInfo { lengthInBytes = len',
  88                                                                          md5sum = Nothing,
  89                                                                          path = unpack s'
  90                                                                      })
  91                                                       files' }
  92                                               }
  93                        Nothing -> let (Bstr name') = m ! "name"
  94                                       (Bint length') = m ! "length"
  95                                       md5sum' = Nothing
  96                                   in
  97                                     Just Info { pieceLength = pieceLength'
  98                                               , pieces = pieces'
  99                                               , private = private'
 100                                               , dyninfo = SingleFileInfo {
 101                                                   name = unpack name',
 102                                                   lengthInBytes = length',
 103                                                   md5sum = md5sum'}
 104                                               }
 105
 106 mkInfo _ = Nothing
 107
 108 mkMetaInfo :: BVal   -> Either String Metainfo
 109 mkMetaInfo (Bdict m)  =
 110     let (Just info')  = mkInfo $ m ! "info"
 111         announce'     = lookup "announce" m
 112         announceList' = lookup "announce-list" m
 113         creationDate' = lookup "creation date" m
 114         comment'      = lookup "comment" m
 115         createdBy'    = lookup "created by" m
 116         encoding'     = lookup "encoding" m
 117     in Right Metainfo {
 118                info         = info'
 119              , announceList = maybeToList (announce' >>= bstrToString)
 120                               ++ getAnnounceList announceList'
 121              , creationDate = bValToInteger =<< creationDate'
 122              , comment      = bstrToString  =<< comment'
 123              , createdBy    = bstrToString  =<< createdBy'
 124              , encoding     = bstrToString  =<< encoding'
 125              , infoHash     = hash . encode $ (m ! "info")
 126              }
 127 mkMetaInfo _ = Left "mkMetaInfo: expect an input dict"
 128
 129 getAnnounceList :: Maybe BVal -> [String]
 130 getAnnounceList Nothing          = []
 131 getAnnounceList (Just (Bint _))  = []
 132 getAnnounceList (Just (Bstr _))  = []
 133 getAnnounceList (Just (Blist l)) = map (\s -> case s of
 134                                                (Bstr s') ->  unpack s'
 135                                                (Blist s') -> case s' of
 136                                                               [Bstr s''] -> unpack s''
 137                                                               _ -> ""
 138                                                _ -> "") l
 139 getAnnounceList (Just (Bdict _)) = []
 140
 141 torrentToMetainfo :: ByteString -> Either String Metainfo
 142 torrentToMetainfo s =
 143   case decode s of
 144    Right d -> mkMetaInfo d
 145    Left e -> Left $ show e