normalise hastag unicode representation of incoming posts

key now needs to be explicitly given at insert, instead of
deriving it from the value. This makes it possible to store values where
a key cannot be extracted from (HasKeyID)

contributes to #62, #32, #41

Hash2Pub.cabal

@@ -46,7 +46,7 @@ category:            Network
 extra-source-files:  CHANGELOG.md
 
 common deps
-  build-depends:       base ^>=4.12.0.0, containers ^>=0.6.0.1, bytestring, utf8-string ^>=1.0.1.1, network ^>=2.8.0.1, time ^>=1.8.0.2, cmdargs ^>= 0.10, cryptonite ^>= 0.25, memory, async, stm, asn1-encoding, asn1-types, asn1-parse, publicsuffix, network-byte-order, safe, iproute, mtl, random, servant, servant-server, servant-client, warp, text, unordered-containers
+  build-depends:       base ^>=4.12.0.0, containers ^>=0.6.0.1, bytestring, utf8-string ^>=1.0.1.1, network ^>=2.8.0.1, time ^>=1.8.0.2, cmdargs ^>= 0.10, cryptonite ^>= 0.25, memory, async, stm, asn1-encoding, asn1-types, asn1-parse, publicsuffix, network-byte-order, safe, iproute, mtl, random, servant, servant-server, servant-client, warp, text, unordered-containers, hashable, unicode-transforms
   ghc-options:         -Wall
 
 

src/Hash2Pub/DHTProtocol.hs

@@ -130,23 +130,25 @@ closestCachePredecessors remainingLookups lastID nCache
 -- Looks up the successor of the lookup key on a 'RingMap' representation of the
 -- predecessor list with the node itself added. If the result is the same as the node
 -- itself then it falls into the responsibility interval.
-isInOwnResponsibilitySlice :: HasKeyID a NodeID => a -> LocalNodeState -> Bool
-isInOwnResponsibilitySlice lookupTarget ownNs = (getKeyID <$> rMapLookupSucc (getKeyID lookupTarget :: NodeID) predecessorRMap) == pure (getNid ownNs)
+isInOwnResponsibilitySlice :: HasKeyID NodeID a => a -> LocalNodeState -> Bool
+isInOwnResponsibilitySlice lookupTarget ownNs = (fst <$> rMapLookupSucc (getKeyID lookupTarget :: NodeID) predecessorRMap) == pure (getNid ownNs)
   where
     predecessorList = predecessors ownNs
     -- add node itself to RingMap representation, to distinguish between
     -- responsibility of own node and predecessor
-    predecessorRMap = addRMapEntry (toRemoteNodeState ownNs) $ rMapFromList predecessorList
+    predecessorRMap = addRMapEntry (getKeyID ownRemote) ownRemote $ rMapFromList (keyValuePair <$> predecessorList) :: RingMap NodeID RemoteNodeState
+    ownRemote = toRemoteNodeState ownNs
     closestPredecessor = headMay predecessorList
 
-isPossiblePredecessor :: HasKeyID a NodeID => a -> LocalNodeState -> Bool
+isPossiblePredecessor :: HasKeyID NodeID a => a -> LocalNodeState -> Bool
 isPossiblePredecessor = isInOwnResponsibilitySlice
 
-isPossibleSuccessor :: HasKeyID a NodeID => a -> LocalNodeState -> Bool
-isPossibleSuccessor lookupTarget ownNs = (getKeyID <$> rMapLookupPred (getKeyID lookupTarget :: NodeID) successorRMap) == pure (getNid ownNs)
+isPossibleSuccessor :: HasKeyID NodeID a => a -> LocalNodeState -> Bool
+isPossibleSuccessor lookupTarget ownNs = (fst <$> rMapLookupPred (getKeyID lookupTarget :: NodeID) successorRMap) == pure (getNid ownNs)
   where
     successorList = successors ownNs
-    successorRMap = addRMapEntry (toRemoteNodeState ownNs) $ rMapFromList successorList
+    successorRMap = addRMapEntry (getKeyID ownRemote) ownRemote $ rMapFromList (keyValuePair <$> successorList)
+    ownRemote = toRemoteNodeState ownNs
     closestSuccessor = headMay successorList
 
 -- cache operations
@@ -169,7 +171,8 @@ addCacheEntryPure now (RemoteCacheEntry ns ts) cache =
     let
         -- TODO: limit diffSeconds to some maximum value to prevent malicious nodes from inserting entries valid nearly until eternity
         timestamp' = if ts <= now then ts else now
-        newCache = addRMapEntryWith insertCombineFunction (CacheEntry False ns timestamp') cache
+        newEntry = CacheEntry False ns timestamp'
+        newCache = addRMapEntryWith insertCombineFunction (getKeyID newEntry) newEntry cache
         insertCombineFunction newVal@(KeyEntry (CacheEntry newValidationState newNode newTimestamp)) oldVal =
             case oldVal of
               ProxyEntry n _ -> ProxyEntry n (Just newVal)
@@ -202,7 +205,7 @@ addNodeAsVerifiedPure :: POSIXTime
                       -> RemoteNodeState
                       -> NodeCache
                       -> NodeCache
-addNodeAsVerifiedPure now node = addRMapEntry (CacheEntry True node now)
+addNodeAsVerifiedPure now node = addRMapEntry (getKeyID node) (CacheEntry True node now)
 
 
 

src/Hash2Pub/FediChordTypes.hs

@@ -1,5 +1,6 @@
 {-# LANGUAGE DataKinds                  #-}
 {-# LANGUAGE DerivingStrategies         #-}
+{-# LANGUAGE FlexibleContexts           #-}
 {-# LANGUAGE FlexibleInstances          #-}
 {-# LANGUAGE GeneralizedNewtypeDeriving #-}
 {-# LANGUAGE MultiParamTypeClasses      #-}
@@ -26,8 +27,7 @@ module Hash2Pub.FediChordTypes (
   , CacheEntry(..)
   , RingEntry(..)
   , RingMap(..)
-  , HasKeyID
-  , getKeyID
+  , HasKeyID(..)
   , rMapSize
   , rMapLookup
   , rMapLookupPred
@@ -271,31 +271,31 @@ instance Typeable a => Show (TQueue a) where
 
 -- | convenience function that replaces the predecessors of a 'LocalNodeState' with the k closest nodes from the provided list
 setPredecessors :: [RemoteNodeState] -> LocalNodeState -> LocalNodeState
-setPredecessors preds ns = ns {predecessors = takeRMapPredecessors (getNid ns) (kNeighbours ns) . rMapFromList . filter ((/=) (getNid ns) . getNid) $ preds}
+setPredecessors preds ns = ns {predecessors = takeRMapPredecessors (getNid ns) (kNeighbours ns) . rMapFromList . fmap keyValuePair . filter ((/=) (getNid ns) . getNid) $ preds}
 
 -- | convenience function that replaces the successors of a 'LocalNodeState' with the k closest nodes from the provided list
 setSuccessors :: [RemoteNodeState] -> LocalNodeState -> LocalNodeState
-setSuccessors succs ns = ns {successors = takeRMapSuccessors (getNid ns) (kNeighbours ns) . rMapFromList . filter ((/=) (getNid ns) . getNid) $ succs}
+setSuccessors succs ns = ns {successors = takeRMapSuccessors (getNid ns) (kNeighbours ns) . rMapFromList . fmap keyValuePair . filter ((/=) (getNid ns) . getNid) $ succs}
 
 -- | sets the predecessors of a 'LocalNodeState' to the closest k nodes of the current predecessors and the provided list, combined
 addPredecessors :: [RemoteNodeState] -> LocalNodeState -> LocalNodeState
-addPredecessors preds ns = ns {predecessors = takeRMapPredecessors (getNid ns) (kNeighbours ns) . addRMapEntries (filter ((/=) (getNid ns) . getNid) preds) . rMapFromList  $ predecessors ns}
+addPredecessors preds ns = ns {predecessors = takeRMapPredecessors (getNid ns) (kNeighbours ns) . addRMapEntries (keyValuePair <$> filter ((/=) (getNid ns) . getNid) preds) . rMapFromList . fmap keyValuePair  $ predecessors ns}
 
 -- | sets the successors of a 'LocalNodeState' to the closest k nodes of the current successors and the provided list, combined
 addSuccessors :: [RemoteNodeState] -> LocalNodeState -> LocalNodeState
-addSuccessors succs ns = ns {successors = takeRMapSuccessors (getNid ns) (kNeighbours ns) . addRMapEntries (filter ((/=) (getNid ns) . getNid) succs) . rMapFromList  $ successors ns}
+addSuccessors succs ns = ns {successors = takeRMapSuccessors (getNid ns) (kNeighbours ns) . addRMapEntries (keyValuePair <$> filter ((/=) (getNid ns) . getNid) succs) . rMapFromList . fmap keyValuePair $ successors ns}
 
-instance HasKeyID RemoteNodeState NodeID where
+instance HasKeyID NodeID RemoteNodeState where
     getKeyID = getNid
 
-instance HasKeyID a k => HasKeyID (CacheEntry a) k where
+instance HasKeyID k a => HasKeyID k (CacheEntry a) where
     getKeyID (CacheEntry _ obj _) = getKeyID obj
 
 instance HasKeyID NodeID NodeID where
     getKeyID = id
 
 type NodeCacheEntry = CacheEntry RemoteNodeState
-type NodeCache = RingMap NodeCacheEntry NodeID
+type NodeCache = RingMap NodeID NodeCacheEntry
 
 type LookupCacheEntry = CacheEntry (String, PortNumber)
 type LookupCache = Map.Map NodeID LookupCacheEntry
@@ -319,12 +319,15 @@ cacheLookup = rMapLookup
 cacheLookupSucc :: NodeID           -- ^lookup key
                 -> NodeCache        -- ^ring cache
                 -> Maybe NodeCacheEntry
-cacheLookupSucc = rMapLookupSucc
+cacheLookupSucc key cache = snd <$> rMapLookupSucc key cache
 
 cacheLookupPred :: NodeID           -- ^lookup key
                 -> NodeCache        -- ^ring cache
                 -> Maybe NodeCacheEntry
-cacheLookupPred = rMapLookupPred
+cacheLookupPred key cache = snd <$> rMapLookupPred key cache
+
+-- clean up cache entries: once now - entry > maxAge
+-- transfer difference now - entry to other node
 
 -- | return the @NodeState@ data from a cache entry without checking its validation status
 cacheGetNodeStateUnvalidated :: CacheEntry RemoteNodeState -> RemoteNodeState
@@ -410,7 +413,7 @@ data FediChordConf = FediChordConf
 
 class DHT d where
     -- | lookup the responsible host handling a given key string,
-    -- possibly from a lookup cache
+    -- possiblggy from a lookup cache
     lookupKey :: d -> String -> IO (Maybe (String, PortNumber))
     -- | lookup the responsible host handling a given key string,
     -- but force the DHT to do a fresh lookup instead of returning a cached result.

src/Hash2Pub/PostService.hs

@@ -1,54 +1,100 @@
 {-# LANGUAGE DataKinds             #-}
 {-# LANGUAGE FlexibleInstances     #-}
+{-# LANGUAGE InstanceSigs          #-}
 {-# LANGUAGE MultiParamTypeClasses #-}
 {-# LANGUAGE OverloadedStrings     #-}
 {-# LANGUAGE RankNTypes            #-}
 {-# LANGUAGE TypeOperators         #-}
-{-# LANGUAGE InstanceSigs          #-}
 
 module Hash2Pub.PostService where
 
 import           Control.Concurrent
-import qualified Data.ByteString.Lazy.UTF8 as BSU
-import           Data.Maybe                (fromMaybe)
-import           Data.String               (fromString)
-import qualified Data.Text                 as Txt
+import           Control.Concurrent.STM
+import           Control.Concurrent.STM.TChan
+import           Control.Concurrent.STM.TQueue
+import           Control.Concurrent.STM.TVar
+import           Control.Monad                 (forM_, forever)
+import           Control.Monad.IO.Class        (liftIO)
+import qualified Data.ByteString.Lazy.UTF8     as BSU
+import qualified Data.HashMap.Strict           as HMap
+import qualified Data.HashSet                  as HSet
+import           Data.Maybe                    (fromMaybe)
+import           Data.String                   (fromString)
+import qualified Data.Text.Lazy                as Txt
+import           Data.Text.Normalize           (NormalizationMode (NFC),
+                                                normalize)
+import           Data.Time.Clock.POSIX
+import           System.Random
 
-import qualified Network.Wai.Handler.Warp  as Warp
+import qualified Network.Wai.Handler.Warp      as Warp
 import           Servant
 
-import           Hash2Pub.FediChord
+import           Hash2Pub.FediChordTypes
+import           Hash2Pub.RingMap
 import           Hash2Pub.ServiceTypes
 
 
 data PostService d = PostService
-    { psPort        :: Warp.Port
-    , psHost        :: String
+    { psPort           :: Warp.Port
+    , psHost           :: String
     -- queues, other data structures
-    , baseDHT       ::   (DHT d) => d
-    , serviceThread :: ThreadId
+    , baseDHT          ::   (DHT d) => d
+    , serviceThread    :: TVar ThreadId
+    , subscribers      :: TVar (RingMap NodeID TagSubscribers)
+    -- ^ for each tag store the subscribers + their queue
+    , ownSubscriptions :: TVar (HMap.HashMap NodeID POSIXTime)
+    -- ^ tags subscribed by the own node have an assigned lease time
+    , ownPosts         :: TVar (HSet.HashSet Txt.Text)
+    -- ^ just store the existence of posts for saving memory,
+    , relayInQueue     :: TQueue (Hashtag, PostID, PostContent)
+    -- ^ Queue for processing incoming posts of own instance asynchronously
     }
 
+type Hashtag = Txt.Text
+type PostID = Txt.Text
+type PostContent = Txt.Text
+-- | For each handled tag, store its subscribers and provide a
+-- broadcast 'TChan' for enqueuing posts
+type RelayTags = RingMap NodeID (TagSubscribers, TChan PostContent)
+-- | each subscriber is identified by its contact data "hostname" "port"
+-- and holds a TChan duplicated from the broadcast TChan of the tag
+type TagSubscribers = HMap.HashMap (String, Int) (TChan PostContent)
+
+
 instance DHT d => Service PostService d where
+    -- | initialise 'PostService' data structures and run server
     runService dht host port = do
+        -- create necessary TVars
+        threadVar <- newTVarIO =<< myThreadId -- own thread ID as placeholder
+        subscriberVar <- newTVarIO emptyRMap
+        ownSubsVar <- newTVarIO HMap.empty
+        ownPostVar <- newTVarIO HSet.empty
+        relayInQueue' <- newTQueueIO
         let
+            thisService = PostService {
+                psPort = port'
+              , psHost = host
+              , baseDHT = dht
+              , serviceThread = threadVar
+              , subscribers = subscriberVar
+              , ownSubscriptions = ownSubsVar
+              , ownPosts = ownPostVar
+              , relayInQueue = relayInQueue'
+                                      }
             port' = fromIntegral port
             warpSettings = Warp.setPort port' . Warp.setHost (fromString host) $ Warp.defaultSettings
-        servThread <- forkIO $ Warp.runSettings warpSettings postServiceApplication
-        pure $ PostService {
-            psPort = port'
-          , psHost = host
-          , baseDHT = dht
-          , serviceThread = servThread
-                           }
+        servThreadID <- forkIO $ Warp.runSettings warpSettings $ postServiceApplication thisService
+        -- update thread ID after fork
+        atomically $ writeTVar threadVar servThreadID
+        pure thisService
+
     getServicePort s = fromIntegral $ psPort s
 
 
 -- | return a WAI application
-postServiceApplication :: Application
-postServiceApplication = serve exposedPostServiceAPI postServer
+postServiceApplication :: PostService d -> Application
+postServiceApplication serv = serve exposedPostServiceAPI $ postServer serv
 
-servicePort = 8081
 
 -- | needed for guiding type inference
 exposedPostServiceAPI :: Proxy PostServiceAPI
@@ -58,7 +104,7 @@ exposedPostServiceAPI = Proxy
 
 -- ========= HTTP API and handlers =============
 
-type PostServiceAPI = "relay" :> "inbox" :> ReqBody '[PlainText] Txt.Text :> PostCreated '[PlainText] Txt.Text
+type PostServiceAPI = "relay" :> "inbox" :> ReqBody '[PlainText] Txt.Text :> PutCreated '[PlainText] NoContent
                  -- ^ delivery endpoint of newly published posts of the relay's instance
                  :<|> "relay" :> "subscribers" :> ReqBody '[PlainText] Txt.Text :> Post '[PlainText] Txt.Text
                  -- ^ endpoint for delivering the subscriptions and outstanding queue
@@ -77,37 +123,51 @@ type PostServiceAPI = "relay" :> "inbox" :> ReqBody '[PlainText] Txt.Text :> Pos
                  -- the Origin header to $hashtag
 
 
-postServer :: Server PostServiceAPI
-postServer = relayInbox
-        :<|> subscriptionDelivery
-        :<|> postFetch
-        :<|> postMultiFetch
-        :<|> tagDelivery
-        :<|> tagSubscribe
-        :<|> tagUnsubscribe
+postServer :: PostService d -> Server PostServiceAPI
+postServer service = relayInbox service
+        :<|> subscriptionDelivery service
+        :<|> postFetch service
+        :<|> postMultiFetch service
+        :<|> tagDelivery service
+        :<|> tagSubscribe service
+        :<|> tagUnsubscribe service
 
 
-relayInbox :: Txt.Text -> Handler Txt.Text
-relayInbox post = pure $ "Here be InboxDragons with " <> post
+relayInbox :: PostService d -> Txt.Text -> Handler NoContent
+relayInbox serv post = do
+    -- extract contained hashtags
+    let
+        containedTags = fmap (Txt.fromStrict . normalize NFC . Txt.toStrict . Txt.tail) . filter ((==) '#' . Txt.head) . Txt.words $ post
+    -- generate post ID
+    postId <- liftIO $ Txt.pack . show <$> (randomRIO (0, 2^128-1) :: IO Integer)
+    -- add ID to own posts
+    liftIO . atomically $ modifyTVar' (ownPosts serv) (HSet.insert postId)
+    -- enqueue a relay job for each tag
+    liftIO $ forM_ (containedTags :: [Txt.Text]) (\tag ->
+        atomically $ writeTQueue (relayInQueue serv) (tag, postId,  post)
+                                 )
+    pure NoContent
 
-subscriptionDelivery :: Txt.Text -> Handler Txt.Text
-subscriptionDelivery subList = pure $ "Here be Subscription List dragons: " <> subList
 
-postFetch :: Txt.Text -> Handler Txt.Text
-postFetch postID = pure $ "Here be a post with dragon ID " <> postID
 
-postMultiFetch :: Txt.Text -> Handler Txt.Text
-postMultiFetch postIDs = pure $ "Here be multiple post dragons: "
+subscriptionDelivery :: PostService d -> Txt.Text -> Handler Txt.Text
+subscriptionDelivery serv subList = pure $ "Here be Subscription List dragons: " <> subList
+
+postFetch :: PostService d -> Txt.Text -> Handler Txt.Text
+postFetch serv postID = pure $ "Here be a post with dragon ID " <> postID
+
+postMultiFetch :: PostService d -> Txt.Text -> Handler Txt.Text
+postMultiFetch serv postIDs = pure $ "Here be multiple post dragons: "
                       <> (Txt.unwords . Txt.lines $ postIDs)
 
-tagDelivery :: Txt.Text -> Txt.Text -> Handler Txt.Text
-tagDelivery hashtag posts = pure $ "Here be #" <> hashtag <> " dragons with " <> posts
+tagDelivery :: PostService d -> Txt.Text -> Txt.Text -> Handler Txt.Text
+tagDelivery serv hashtag posts = pure $ "Here be #" <> hashtag <> " dragons with " <> posts
 
-tagSubscribe :: Txt.Text -> Maybe Txt.Text -> Handler Integer
-tagSubscribe hashtag origin = pure 42
+tagSubscribe :: PostService d -> Txt.Text -> Maybe Txt.Text -> Handler Integer
+tagSubscribe serv hashtag origin = pure 42
 
-tagUnsubscribe :: Txt.Text -> Maybe Txt.Text -> Handler Txt.Text
-tagUnsubscribe hashtag origin = pure $ "Here be a dragon unsubscription from " <> fromMaybe "Nothing" origin <> " to " <> hashtag
+tagUnsubscribe :: PostService d -> Txt.Text -> Maybe Txt.Text -> Handler Txt.Text
+tagUnsubscribe serv hashtag origin = pure $ "Here be a dragon unsubscription from " <> fromMaybe "Nothing" origin <> " to " <> hashtag
 
 
 -- | define how to convert all showable types to PlainText

src/Hash2Pub/RingMap.hs

@@ -5,36 +5,38 @@ module Hash2Pub.RingMap where
 
 import           Data.Foldable   (foldr')
 import qualified Data.Map.Strict as Map
-import           Data.Maybe      (fromJust, isJust, isNothing, mapMaybe)
+import           Data.Maybe      (isJust, isNothing, mapMaybe)
 
 
 -- | Class for all types that can be identified via a EpiChord key.
 -- Used for restricting the types a 'RingMap' can store
-class (Eq a, Show a, Bounded k, Ord k) => HasKeyID a k where
+class (Eq a, Show a, Bounded k, Ord k) => HasKeyID k a where
     getKeyID :: a -> k
+    keyValuePair :: a -> (k, a)
+    keyValuePair val = (getKeyID val, val)
 
 
 -- | generic data structure for holding elements with a key and modular lookup
-newtype RingMap a k = RingMap { getRingMap :: (HasKeyID a k, Bounded k, Ord k) => Map.Map k (RingEntry a k) }
+newtype RingMap k a = RingMap { getRingMap :: (Bounded k, Ord k) => Map.Map k (RingEntry k a) }
 
-instance (HasKeyID a k, Bounded k, Ord k) => Eq (RingMap a k) where
+instance (Bounded k, Ord k, Eq a) => Eq (RingMap k a) where
     a == b = getRingMap a == getRingMap b
 
-instance (HasKeyID a k, Bounded k, Ord k, Show k) => Show (RingMap a k) where
+instance (Bounded k, Ord k, Show k, Show a) => Show (RingMap k a) where
     show rmap = shows "RingMap " (show $ getRingMap rmap)
 
 -- | entry of a 'RingMap' that holds a value and can also
 -- wrap around the lookup direction at the edges of the name space.
-data RingEntry a k = KeyEntry a
-    | ProxyEntry (k, ProxyDirection) (Maybe (RingEntry a k))
+data RingEntry k a = KeyEntry a
+    | ProxyEntry (k, ProxyDirection) (Maybe (RingEntry k a))
     deriving (Show, Eq)
 
 -- | as a compromise, only KeyEntry components are ordered by their key
 -- while ProxyEntry components should never be tried to be ordered.
-instance (HasKeyID a k, Eq k, Ord a, Bounded k, Ord k) => Ord (RingEntry a k) where
+instance (HasKeyID k a, Eq k, Ord a, Bounded k, Ord k) => Ord (RingEntry k a) where
     a `compare` b = compare (extractID a) (extractID b)
         where
-            extractID :: (HasKeyID a k, Ord a, Bounded k, Ord k) => RingEntry a k -> k
+            extractID :: (HasKeyID k a, Ord a, Bounded k, Ord k) => RingEntry k a -> k
             extractID (KeyEntry e) = getKeyID e
             extractID ProxyEntry{} = error "proxy entries should never appear outside of the RingMap"
 
@@ -49,51 +51,51 @@ instance Enum ProxyDirection where
     fromEnum Backwards = - 1
     fromEnum Forwards  = 1
 
--- | helper function for getting the a from a RingEntry a k
-extractRingEntry :: (HasKeyID a k, Bounded k, Ord k) => RingEntry a k -> Maybe a
+-- | helper function for getting the a from a RingEntry k a
+extractRingEntry :: (Bounded k, Ord k) => RingEntry k a -> Maybe a
 extractRingEntry (KeyEntry entry)                       = Just entry
 extractRingEntry (ProxyEntry _ (Just (KeyEntry entry))) = Just entry
 extractRingEntry _                                      = Nothing
 
 -- | An empty 'RingMap' needs to be initialised with 2 proxy entries,
 -- linking the modular name space together by connecting @minBound@ and @maxBound@
-emptyRMap :: (HasKeyID a k, Bounded k, Ord k) => RingMap a k
+emptyRMap :: (Bounded k, Ord k) => RingMap k a
 emptyRMap = RingMap . Map.fromList $ proxyEntry <$> [(maxBound, (minBound, Forwards)), (minBound, (maxBound, Backwards))]
   where
     proxyEntry (from,to) = (from, ProxyEntry to Nothing)
 
 -- | Maybe returns the entry stored at given key
-rMapLookup :: (HasKeyID a k, Bounded k, Ord k)
+rMapLookup :: (Bounded k, Ord k)
            => k       -- ^lookup key
-           -> RingMap a k    -- ^lookup cache
+           -> RingMap k a    -- ^lookup cache
            -> Maybe a
 rMapLookup key rmap =  extractRingEntry =<< Map.lookup key (getRingMap rmap)
 
 -- | returns number of present 'KeyEntry' in a properly initialised 'RingMap'
-rMapSize :: (HasKeyID a k, Integral i, Bounded k, Ord k)
-         => RingMap a k
+rMapSize :: (Integral i, Bounded k, Ord k)
+         => RingMap k a
          -> i
 rMapSize rmap = fromIntegral $ Map.size innerMap - oneIfEntry rmap minBound - oneIfEntry rmap maxBound
   where
     innerMap = getRingMap rmap
-    oneIfEntry :: (HasKeyID a k, Integral i, Bounded k, Ord k) => RingMap a k -> k -> i
+    oneIfEntry :: (Integral i, Bounded k, Ord k) => RingMap k a -> k -> i
     oneIfEntry rmap' nid
       | isNothing (rMapLookup nid rmap') = 1
       | otherwise = 0
 
 -- | a wrapper around lookup functions, making the lookup redirectable by a @ProxyEntry@
 -- to simulate a modular ring
-lookupWrapper :: (HasKeyID a k, Bounded k, Ord k, Num k)
-              => (k -> Map.Map k (RingEntry a k) -> Maybe (k, RingEntry a k))
-              -> (k -> Map.Map k (RingEntry a k) -> Maybe (k, RingEntry a k))
+lookupWrapper :: (Bounded k, Ord k, Num k)
+              => (k -> Map.Map k (RingEntry k a) -> Maybe (k, RingEntry k a))
+              -> (k -> Map.Map k (RingEntry k a) -> Maybe (k, RingEntry k a))
               -> ProxyDirection
               -> k
-              -> RingMap a k
-              -> Maybe a
+              -> RingMap k a
+              -> Maybe (k, a)
 lookupWrapper f fRepeat direction key rmap =
     case f key $ getRingMap rmap of
         -- the proxy entry found holds a
-        Just (_, ProxyEntry _ (Just (KeyEntry entry))) -> Just entry
+        Just (foundKey, ProxyEntry _ (Just (KeyEntry entry))) -> Just (foundKey, entry)
         -- proxy entry holds another proxy entry, this should not happen
         Just (_, ProxyEntry _ (Just (ProxyEntry _ _))) -> Nothing
         -- proxy entry without own entry is a pointer on where to continue
@@ -106,10 +108,10 @@ lookupWrapper f fRepeat direction key rmap =
                then lookupWrapper fRepeat fRepeat direction newKey rmap
                else Nothing
         -- normal entries are returned
-        Just (_, KeyEntry entry) -> Just entry
+        Just (foundKey, KeyEntry entry) -> Just (foundKey, entry)
         Nothing -> Nothing
   where
-    rMapNotEmpty :: (HasKeyID a k, Bounded k, Ord k) => RingMap a k -> Bool
+    rMapNotEmpty :: (Bounded k, Ord k) => RingMap k a -> Bool
     rMapNotEmpty rmap' = (Map.size (getRingMap rmap') > 2)     -- there are more than the 2 ProxyEntries
                    || isJust (rMapLookup minBound rmap') -- or one of the ProxyEntries holds a node
                    || isJust (rMapLookup maxBound rmap')
@@ -117,32 +119,34 @@ lookupWrapper f fRepeat direction key rmap =
 -- | find the successor node to a given key on a modular EpiChord ring.
 -- Note: The EpiChord definition of "successor" includes the node at the key itself,
 -- if existing.
-rMapLookupSucc :: (HasKeyID a k, Bounded k, Ord k, Num k)
+rMapLookupSucc :: (Bounded k, Ord k, Num k)
                => k           -- ^lookup key
-               -> RingMap a k       -- ^ring cache
-               -> Maybe a
+               -> RingMap k a       -- ^ring cache
+               -> Maybe (k, a)
 rMapLookupSucc = lookupWrapper Map.lookupGE Map.lookupGE Forwards
 
 -- | find the predecessor node to a given key on a modular EpiChord ring.
-rMapLookupPred :: (HasKeyID a k, Bounded k, Ord k, Num k)
+rMapLookupPred :: (Bounded k, Ord k, Num k)
                => k           -- ^lookup key
-               -> RingMap a k        -- ^ring cache
-               -> Maybe a
+               -> RingMap k a        -- ^ring cache
+               -> Maybe (k, a)
 rMapLookupPred = lookupWrapper Map.lookupLT Map.lookupLE Backwards
 
-addRMapEntryWith :: (HasKeyID a k, Bounded k, Ord k)
-                 => (RingEntry a k -> RingEntry a k -> RingEntry a k)
-                 -> a
-                 -> RingMap a k
-                 -> RingMap a k
-addRMapEntryWith combineFunc entry = RingMap
-    . Map.insertWith combineFunc (getKeyID entry) (KeyEntry entry)
+addRMapEntryWith :: (Bounded k, Ord k)
+                 => (RingEntry k a -> RingEntry k a -> RingEntry k a)
+                 -> k   -- ^ key
+                 -> a   -- ^ value
+                 -> RingMap k a
+                 -> RingMap k a
+addRMapEntryWith combineFunc key entry = RingMap
+    . Map.insertWith combineFunc key (KeyEntry entry)
     . getRingMap
 
-addRMapEntry :: (HasKeyID a k, Bounded k, Ord k)
-             => a
-             -> RingMap a k
-             -> RingMap a k
+addRMapEntry :: (Bounded k, Ord k)
+             => k   -- ^ key
+             -> a   -- ^ value
+             -> RingMap k a
+             -> RingMap k a
 addRMapEntry = addRMapEntryWith insertCombineFunction
   where
     insertCombineFunction newVal oldVal =
@@ -151,30 +155,30 @@ addRMapEntry = addRMapEntryWith insertCombineFunction
           KeyEntry _     -> newVal
 
 
-addRMapEntries :: (Foldable t, HasKeyID a k, Bounded k, Ord k)
-               => t a
-               -> RingMap a k
-               -> RingMap a k
-addRMapEntries entries rmap = foldr' addRMapEntry rmap entries
+addRMapEntries :: (Foldable t, Bounded k, Ord k)
+               => t (k, a)
+               -> RingMap k a
+               -> RingMap k a
+addRMapEntries entries rmap = foldr' (\(k, v) rmap' -> addRMapEntry k v rmap') rmap entries
 
-setRMapEntries :: (Foldable t, HasKeyID a k, Bounded k, Ord k)
-               => t a
-               -> RingMap a k
+setRMapEntries :: (Foldable t, Bounded k, Ord k)
+               => t (k, a)
+               -> RingMap k a
 setRMapEntries entries = addRMapEntries entries emptyRMap
 
-deleteRMapEntry :: (HasKeyID a k, Bounded k, Ord k)
+deleteRMapEntry :: (Bounded k, Ord k)
                 => k
-                -> RingMap a k
-                -> RingMap a k
+                -> RingMap k a
+                -> RingMap k a
 deleteRMapEntry nid = RingMap . Map.update modifier nid . getRingMap
   where
     modifier (ProxyEntry idPointer _) = Just (ProxyEntry idPointer Nothing)
     modifier KeyEntry {}              = Nothing
 
-rMapToList :: (HasKeyID a k, Bounded k, Ord k) => RingMap a k -> [a]
+rMapToList :: (Bounded k, Ord k) => RingMap k a -> [a]
 rMapToList = mapMaybe extractRingEntry . Map.elems . getRingMap
 
-rMapFromList :: (HasKeyID a k, Bounded k, Ord k) => [a] -> RingMap a k
+rMapFromList :: (Bounded k, Ord k) => [(k, a)] -> RingMap k a
 rMapFromList = setRMapEntries
 
 -- | takes up to i entries from a 'RingMap' by calling a getter function on a
@@ -182,49 +186,52 @@ rMapFromList = setRMapEntries
 -- Stops once i entries have been taken or an entry has been encountered twice
 -- (meaning the ring has been traversed completely).
 -- Forms the basis for 'takeRMapSuccessors' and 'takeRMapPredecessors'.
-takeRMapEntries_ :: (HasKeyID a k, Integral i, Bounded k, Ord k)
-                 => (k -> RingMap a k -> Maybe a)
-                 -> k
-                 -> i
-                 -> RingMap a k
-                 -> [a]
+takeRMapEntries_ :: (Integral i, Bounded k, Ord k)
+                 => (k -> RingMap k a -> Maybe (k, a))   -- ^ parameterisable getter function to determine lookup direction
+                 -> k   -- ^ starting key
+                 -> i   -- ^ number of maximum values to take
+                 -> RingMap k a
+                 -> [a] -- ^ values taken
 -- TODO: might be more efficient with dlists
 takeRMapEntries_ getterFunc startAt num rmap = reverse $
     case getterFunc startAt rmap of
       Nothing -> []
-      Just anEntry -> takeEntriesUntil rmap getterFunc (getKeyID anEntry) (getKeyID anEntry) (num-1) [anEntry]
+      Just (foundKey, anEntry) -> takeEntriesUntil rmap getterFunc foundKey foundKey (num-1) [anEntry]
   where
     -- for some reason, just reusing the already-bound @rmap@ and @getterFunc@
     -- variables leads to a type error, these need to be passed explicitly
-    takeEntriesUntil :: (HasKeyID a k, Integral i, Bounded k, Ord k)
-                     => RingMap a k
-                     -> (k -> RingMap a k -> Maybe a) -- getter function
+    takeEntriesUntil :: (Integral i, Bounded k, Ord k)
+                     => RingMap k a
+                     -> (k -> RingMap k a -> Maybe (k, a)) -- getter function
                      -> k
                      -> k
                      -> i
                      -> [a]
                      -> [a]
     takeEntriesUntil rmap' getterFunc' havingReached previousEntry remaining takeAcc
+      -- length limit reached
       | remaining <= 0 = takeAcc
-      | getKeyID (fromJust $ getterFunc' previousEntry rmap') == havingReached = takeAcc
-      | otherwise = let (Just gotEntry) = getterFunc' previousEntry rmap'
-                    in takeEntriesUntil rmap' getterFunc' havingReached (getKeyID gotEntry) (remaining-1) (gotEntry:takeAcc)
+      --
+      | otherwise = case nextEntry of
+                      Just (fKey, gotEntry)
+                        | fKey == havingReached -> takeAcc
+                        | otherwise -> takeEntriesUntil rmap' getterFunc' havingReached fKey (remaining - 1) (gotEntry:takeAcc)
+                      Nothing -> takeAcc
+        where
+            nextEntry = getterFunc' previousEntry rmap'
 
-takeRMapPredecessors :: (HasKeyID a k, Integral i, Bounded k, Ord k, Num k)
+
+takeRMapPredecessors :: (Integral i, Bounded k, Ord k, Num k)
                  => k
                  -> i
-                 -> RingMap a k
+                 -> RingMap k a
                  -> [a]
 takeRMapPredecessors = takeRMapEntries_ rMapLookupPred
 
-takeRMapSuccessors :: (HasKeyID a k, Integral i, Bounded k, Ord k, Num k)
+takeRMapSuccessors :: (Integral i, Bounded k, Ord k, Num k)
                  => k
                  -> i
-                 -> RingMap a k
+                 -> RingMap k a
                  -> [a]
 takeRMapSuccessors = takeRMapEntries_ rMapLookupSucc
 
--- clean up cache entries: once now - entry > maxAge
--- transfer difference now - entry to other node
-
-

src/Hash2Pub/ServiceTypes.hs

@@ -1,9 +1,15 @@
 {-# LANGUAGE MultiParamTypeClasses #-}
 module Hash2Pub.ServiceTypes where
 
-import           Hash2Pub.FediChord (DHT (..))
+import           Data.Hashable      (Hashable (..))
+
+import           Hash2Pub.FediChord (DHT (..), NodeID (..))
 
 class Service s d where
     -- | run the service
     runService :: (Integral i) => d -> String -> i -> IO (s d)
     getServicePort :: (Integral i) => s d -> i
+
+instance Hashable NodeID where
+    hashWithSalt salt = hashWithSalt salt . getNodeID
+    hash = hash . getNodeID