src/FuncTorrent/Metainfo.hs

   1 module FuncTorrent.Metainfo
   2     (Info,
   3      Metainfo,
   4      announceList,
   5      mkMetaInfo,
   6      mkInfo,
   7      lengthInBytes,
   8      info,
   9      name,
  10     ) where
  11
  12 import Prelude hiding (lookup)
  13 import Data.ByteString.Char8 (ByteString, unpack)
  14 import Data.Map as M ((!), lookup)
  15
  16 import FuncTorrent.Bencode (BVal(..), bstrToString)
  17
  18 -- only single file mode supported for the time being.
  19 data Info = Info { pieceLength :: !Integer
  20                  , pieces :: !ByteString
  21                  , private :: !(Maybe Integer)
  22                  , name :: !String
  23                  , lengthInBytes :: !Integer
  24                  , md5sum :: !(Maybe String)
  25                  } deriving (Eq, Show)
  26
  27 data Metainfo = Metainfo { info :: !Info
  28                          , announceList :: ![String]
  29                          , creationDate :: !(Maybe String)
  30                          , comment :: !(Maybe String)
  31                          , createdBy :: !(Maybe String)
  32                          , encoding :: !(Maybe String)
  33                          } deriving (Eq, Show)
  34
  35 mkInfo :: BVal -> Maybe Info
  36 mkInfo (Bdict m) = let (Bint pieceLength') = m ! "piece length"
  37                        (Bstr pieces') = m ! "pieces"
  38                        private' = Nothing
  39                        (Bstr name') = m ! "name"
  40                        (Bint length') = m ! "length"
  41                        md5sum' = Nothing
  42                    in Just Info { pieceLength = pieceLength'
  43                                 , pieces = pieces'
  44                                 , private = private'
  45                                 , name = unpack name'
  46                                 , lengthInBytes = length'
  47                                 , md5sum = md5sum'}
  48 mkInfo _ = Nothing
  49
  50 maybeBstrToString :: Maybe BVal -> Maybe String
  51 maybeBstrToString Nothing = Nothing
  52 maybeBstrToString (Just s) = let (Bstr bs) = s
  53                              in Just (unpack bs)
  54
  55 mkMetaInfo :: BVal -> Maybe Metainfo
  56 mkMetaInfo (Bdict m) = let (Just info') = mkInfo $ m ! "info"
  57                            announce' = lookup "announce" m
  58                            announceList' = lookup "announce-list" m
  59                            -- creationDate = lookup (Bstr (pack "creation date")) m
  60                            creationDate' = Nothing
  61                            comment' = lookup "comment" m
  62                            createdBy' = lookup "created by" m
  63                            encoding' = lookup "encoding" m
  64                        in Just Metainfo { info = info'
  65                                         , announceList = maybeToList (announce' >>= bstrToString)
  66                                                          ++ getAnnounceList announceList'
  67                                         , creationDate = creationDate'
  68                                         , comment = maybeBstrToString comment'
  69                                         , createdBy = maybeBstrToString createdBy'
  70                                         , encoding = maybeBstrToString encoding'
  71                                         }
  72 mkMetaInfo _ = Nothing
  73
  74 maybeToList :: Maybe a -> [a]
  75 maybeToList  Nothing   = []
  76 maybeToList  (Just x)  = [x]
  77
  78 getAnnounceList :: Maybe BVal -> [String]
  79 getAnnounceList Nothing = []
  80 getAnnounceList (Just (Bint _)) = []
  81 getAnnounceList (Just (Bstr _)) = []
  82 getAnnounceList (Just (Blist l)) = map (\s -> case s of
  83                                                (Bstr s') ->  unpack s'
  84                                                (Blist s') -> case s' of
  85                                                               [Bstr s''] -> unpack s''
  86                                                               _ -> ""
  87                                                _ -> "") l
  88
  89 getAnnounceList (Just (Bdict _)) = []