src/FuncTorrent/Metainfo.hs

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