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|
module BlogDB where
import Control.Monad.Reader (ask)
import Control.Monad.State (get, put)
import Data.Acid
import Data.Acid.Advanced
import Data.Acid.Remote
import Data.ByteString (ByteString)
import Data.Data (Data, Typeable)
import Data.IxSet (Indexable (..), IxSet, Proxy (..), getOne, ixFun, ixSet, (@=))
import Data.SafeCopy (base, deriveSafeCopy)
import Data.Text (Text, pack)
import Data.Time
import Network (PortID (..))
import System.Environment (getEnv)
import qualified Crypto.Hash.SHA512 as SHA (hash)
import qualified Data.ByteString.Base64 as B64 (encode)
import qualified Data.ByteString.Char8 as B
import qualified Data.IxSet as IxSet
newtype EntryId = EntryId { unEntryId :: Integer }
deriving (Eq, Ord, Data, Enum, Typeable)
$(deriveSafeCopy 2 'base ''EntryId)
instance Show EntryId where
show = show . unEntryId
data BlogLang = EN | DE
deriving (Eq, Ord, Data, Typeable)
instance Show BlogLang where
show DE = "de"
show EN = "en"
$(deriveSafeCopy 0 'base ''BlogLang)
data Entry = Entry {
entryId :: EntryId,
lang :: BlogLang,
author :: Text,
title :: Text,
btext :: Text,
mtext :: Text,
edate :: UTCTime
} deriving (Eq, Ord, Show, Data, Typeable)
$(deriveSafeCopy 2 'base ''Entry)
-- ixSet requires different datatypes for field indexes, so let's define some
newtype Author = Author Text deriving (Eq, Ord, Data, Typeable)
newtype Title = Title Text deriving (Eq, Ord, Data, Typeable)
newtype BText = BText Text deriving (Eq, Ord, Data, Typeable) -- standard text
newtype MText = MText Text deriving (Eq, Ord, Data, Typeable) -- "read more" text
newtype Tag = Tag Text deriving (Eq, Ord, Data, Typeable)
newtype EDate = EDate UTCTime deriving (Eq, Ord, Data, Typeable)
newtype SDate = SDate UTCTime deriving (Eq, Ord, Data, Typeable)
newtype Username = Username Text deriving (Eq, Ord, Data, Typeable)
newtype SessionID = SessionID Text deriving (Eq, Ord, Data, Typeable)
$(deriveSafeCopy 2 'base ''Author)
$(deriveSafeCopy 2 'base ''Title)
$(deriveSafeCopy 2 'base ''BText)
$(deriveSafeCopy 2 'base ''MText)
$(deriveSafeCopy 2 'base ''Tag)
$(deriveSafeCopy 2 'base ''EDate)
$(deriveSafeCopy 2 'base ''SDate)
$(deriveSafeCopy 2 'base ''Username)
$(deriveSafeCopy 2 'base ''SessionID)
instance Indexable Entry where
empty = ixSet [ ixFun $ \e -> [ entryId e]
, ixFun $ (:[]) . lang
, ixFun $ \e -> [ Author $ author e ]
, ixFun $ \e -> [ Title $ title e]
, ixFun $ \e -> [ BText $ btext e]
, ixFun $ \e -> [ MText $ mtext e]
, ixFun $ \e -> [ EDate $ edate e]
]
data User = User {
username :: Text,
password :: ByteString
} deriving (Eq, Ord, Data, Typeable)
$(deriveSafeCopy 0 'base ''User)
data Session = Session {
sessionID :: Text,
user :: User,
sdate :: UTCTime
} deriving (Eq, Ord, Data, Typeable)
$(deriveSafeCopy 0 'base ''Session)
instance Indexable User where
empty = ixSet [ ixFun $ \u -> [Username $ username u]
, ixFun $ (:[]) . password
]
instance Indexable Session where
empty = ixSet [ ixFun $ \s -> [SessionID $ sessionID s]
, ixFun $ (:[]) . user
, ixFun $ \s -> [SDate $ sdate s]
]
data Blog = Blog {
blogSessions :: IxSet Session,
blogUsers :: IxSet User,
blogEntries :: IxSet Entry
} deriving (Data, Typeable)
$(deriveSafeCopy 0 'base ''Blog)
initialBlogState :: Blog
initialBlogState =
Blog { blogSessions = empty
, blogUsers = empty
, blogEntries = empty }
-- acid-state database functions (purity is necessary!)
insertEntry :: Entry -> Update Blog Entry
insertEntry e =
do b@Blog{..} <- get
put $ b { blogEntries = IxSet.insert e blogEntries }
return e
updateEntry :: Entry -> Update Blog Entry
updateEntry e =
do b@Blog{..} <- get
put $ b { blogEntries = IxSet.updateIx (entryId e) e blogEntries }
return e
deleteEntry :: EntryId -> Update Blog EntryId
deleteEntry entry =
do b@Blog{..} <- get
put $ b { blogEntries = IxSet.deleteIx entry blogEntries }
return entry
getEntry :: EntryId -> Query Blog (Maybe Entry)
getEntry eId =
do Blog{..} <- ask
return $ getOne $ blogEntries @= eId
latestEntries :: BlogLang -> Query Blog [Entry]
latestEntries lang =
do Blog{..} <- ask
return $ IxSet.toDescList (Proxy :: Proxy EDate) $ blogEntries @= lang
addSession :: Session -> Update Blog Session
addSession nSession =
do b@Blog{..} <- get
put $ b { blogSessions = IxSet.insert nSession blogSessions}
return nSession
getSession :: SessionID -> Query Blog (Maybe Session)
getSession sId =
do Blog{..} <- ask
return $ getOne $ blogSessions @= sId
clearSessions :: Update Blog [Session]
clearSessions =
do b@Blog{..} <- get
put $ b { blogSessions = empty }
return []
addUser :: Text -> String -> Update Blog User
addUser un pw =
do b@Blog{..} <- get
let u = User un $ hashString pw
put $ b { blogUsers = IxSet.insert u blogUsers}
return u
getUser :: Username -> Query Blog (Maybe User)
getUser uN =
do Blog{..} <- ask
return $ getOne $ blogUsers @= uN
checkUser :: Username -> String -> Query Blog Bool
checkUser uN pw =
do Blog{..} <- ask
let user = getOne $ blogUsers @= uN
case user of
Nothing -> return False
(Just u) -> return $ password u == hashString pw
-- various functions
hashString :: String -> ByteString
hashString = B64.encode . SHA.hash . B.pack
$(makeAcidic ''Blog
[ 'insertEntry
, 'updateEntry
, 'deleteEntry
, 'getEntry
, 'latestEntries
, 'addSession
, 'getSession
, 'addUser
, 'getUser
, 'checkUser
, 'clearSessions
])
interactiveUserAdd :: String -> IO ()
interactiveUserAdd dbHost = do
acid <- openRemoteState skipAuthenticationPerform dbHost (PortNumber 8070)
putStrLn "Username:"
un <- getLine
putStrLn "Password:"
pw <- getLine
update' acid (AddUser (pack un) pw)
closeAcidState acid
flushSessions :: IO ()
flushSessions = do
tbDir <- getEnv "TAZBLOG"
acid <- openLocalStateFrom (tbDir ++ "/BlogState") initialBlogState
update' acid ClearSessions
closeAcidState acid
archiveState :: IO ()
archiveState = do
tbDir <- getEnv "TAZBLOG"
acid <- openLocalStateFrom (tbDir ++ "/BlogState") initialBlogState
createArchive acid
closeAcidState acid
|
