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