Merge pull request 'Improve general readability' (#69) from Hecate/Hash2Pub:readability into mainline

brings several readability enhancements:

- Text is always unqualified
- The Servant API declaration is moved to its own file
- Redundant imports are removed

src/Hash2Pub/PostService.hs

@@ -12,16 +12,16 @@ import           Control.Concurrent
 import           Control.Concurrent.Async
 import           Control.Concurrent.STM
 import           Control.Exception         (Exception (..), try)
-import           Control.Monad             (foldM, forM, forM_, forever, void,
+import           Control.Monad             (foldM, forM_, forever, void, when)
-                                            when)
 import           Control.Monad.IO.Class    (liftIO)
 import           Data.Bifunctor
 import qualified Data.ByteString.Lazy.UTF8 as BSUL
 import qualified Data.ByteString.UTF8      as BSU
 import qualified Data.HashMap.Strict       as HMap
 import qualified Data.HashSet              as HSet
-import           Data.Maybe                (fromMaybe, isJust)
+import           Data.Maybe                (isJust)
 import           Data.String               (fromString)
+import           Data.Text.Lazy            (Text)
 import qualified Data.Text.Lazy            as Txt
 import           Data.Text.Normalize       (NormalizationMode (NFC), normalize)
 import           Data.Time.Clock.POSIX
@@ -36,6 +36,7 @@ import           Servant
 import           Servant.Client
 
 import           Hash2Pub.FediChordTypes
+import           Hash2Pub.PostService.API
 import           Hash2Pub.RingMap
 
 
@@ -48,7 +49,7 @@ data PostService d = PostService
     -- ^ 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)
+    , ownPosts             :: TVar (HSet.HashSet Text)
     -- ^ just store the existence of posts for saving memory,
     , relayInQueue         :: TQueue (Hashtag, PostID, PostContent)
     -- ^ Queue for processing incoming posts of own instance asynchronously
@@ -58,9 +59,9 @@ data PostService d = PostService
     }
     deriving (Typeable)
 
-type Hashtag = Txt.Text
+type Hashtag = Text
-type PostID = Txt.Text
+type PostID = Text
-type PostContent = Txt.Text
+type PostContent = Text
 -- | For each handled tag, store its subscribers and provide a
 -- broadcast 'TChan' for enqueuing posts
 type RelayTags = RingMap NodeID (TagSubscribersSTM, TChan PostID, Hashtag)
@@ -131,38 +132,13 @@ postServiceApplication :: DHT d => PostService d -> Application
 postServiceApplication serv = serve exposedPostServiceAPI $ postServer serv
 
 
--- | needed for guiding type inference
-exposedPostServiceAPI :: Proxy PostServiceAPI
-exposedPostServiceAPI = Proxy
-
 -- ========= constants ===========
 
-placeholderPost :: Txt.Text
+placeholderPost :: Text
 placeholderPost = Txt.take 5120 . Txt.repeat $ 'O' -- size 5KiB
 
 -- ========= HTTP API and handlers =============
 
-type PostServiceAPI = "relay" :> "inbox" :> Capture "hashtag" Txt.Text :> ReqBody '[PlainText] Txt.Text :> PutCreated '[PlainText] NoContent
-                 -- delivery endpoint at responsible relay for delivering posts of $tag for distribution
-                 :<|> "relay" :> "subscribers" :> Capture "senderID" Integer :> ReqBody '[PlainText] Txt.Text :> PostNoContent '[PlainText] Txt.Text
-                 -- endpoint for delivering the subscriptions and outstanding queue
-                 :<|> "post" :> Capture "postid" Txt.Text :> Get '[PlainText] Txt.Text
-                 -- fetch endpoint for posts, full post ID is http://$domain/post/$postid
-                 :<|> "posts" :> ReqBody '[PlainText] Txt.Text :> Post '[PlainText] Txt.Text
-                 -- endpoint for fetching multiple posts at once
-                 :<|> "posts" :> "inbox" :> ReqBody '[PlainText] Txt.Text :> PutCreated '[PlainText] NoContent
-                 -- delivery endpoint of newly published posts of the relay's instance
-                 :<|> "tags" :> Capture "hashtag" Txt.Text :> ReqBody '[PlainText] Txt.Text :> PostCreated '[PlainText] Txt.Text
-                 -- delivery endpoint for posts of $tag at subscribing instance
-                 :<|> "tags" :> Capture "hashtag" Txt.Text :> "subscribe" :> Header "Origin" Txt.Text :> Get '[PlainText] Integer
-                 -- endpoint for subscribing the instance specified in
-                 -- the Origin header to $hashtag.
-                 -- Returns subscription lease time in seconds.
-                 :<|> "tags" :> Capture "hashtag" Txt.Text :> "unsubscribe" :> Header "Origin" Txt.Text :> Get '[PlainText] Txt.Text
-                 -- endpoint for unsubscribing the instance specified in
-                 -- the Origin header to $hashtag
-
-
 postServer :: DHT d => PostService d -> Server PostServiceAPI
 postServer service = relayInbox service
         :<|> subscriptionDelivery service
@@ -174,7 +150,7 @@ postServer service = relayInbox service
         :<|> tagUnsubscribe service
 
 
-relayInbox :: DHT d => PostService d -> Hashtag -> Txt.Text -> Handler NoContent
+relayInbox :: DHT d => PostService d -> Hashtag -> Text -> Handler NoContent
 relayInbox serv tag posts = do
     let
     -- skip checking whether the post actually contains the tag, just drop full post
@@ -202,7 +178,7 @@ newtype UnhandledTagException = UnhandledTagException String
 
 instance Exception UnhandledTagException
 
-subscriptionDelivery :: DHT d => PostService d -> Integer -> Txt.Text -> Handler Txt.Text
+subscriptionDelivery :: DHT d => PostService d -> Integer -> Text -> Handler Text
 subscriptionDelivery serv senderID subList = do
     let
         tagSubs = Txt.lines subList
@@ -236,7 +212,7 @@ subscriptionDelivery serv senderID subList = do
       Right _  -> pure ""
     -- TODO: check and only accept tags in own (future?) responsibility
   where
-      processTag :: TVar RelayTags -> Txt.Text -> STM ()
+      processTag :: TVar RelayTags -> Text -> STM ()
       processTag subscriberSTM tagData = do
           let
             tag:subText:lease:posts:_ = Txt.splitOn "," tagData
@@ -247,7 +223,7 @@ subscriptionDelivery serv senderID subList = do
           enqueueSubscription subscriberSTM (normaliseTag tag) sub postList leaseTime
 
 
-postFetch :: PostService d -> Txt.Text -> Handler Txt.Text
+postFetch :: PostService d -> Text -> Handler Text
 postFetch serv postID = do
     postSet <- liftIO . readTVarIO . ownPosts $ serv
     if HSet.member postID postSet
@@ -256,7 +232,7 @@ postFetch serv postID = do
        else throwError $ err404 { errBody = "No post found with this ID" }
 
 
-postMultiFetch :: PostService d -> Txt.Text -> Handler Txt.Text
+postMultiFetch :: PostService d -> Text -> Handler Text
 postMultiFetch serv postIDs = do
     let idList = Txt.lines postIDs
     postSet <- liftIO . readTVarIO . ownPosts $ serv
@@ -268,7 +244,7 @@ postMultiFetch serv postIDs = do
           ) "" idList
 
 
-postInbox :: PostService d -> Txt.Text -> Handler NoContent
+postInbox :: PostService d -> Text -> Handler NoContent
 postInbox serv post = do
     -- extract contained hashtags
     let
@@ -278,13 +254,13 @@ postInbox serv post = do
     -- 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 ->
+    liftIO $ forM_ (containedTags :: [Text]) (\tag ->
         atomically $ writeTQueue (relayInQueue serv) (tag, postId,  post)
                                  )
     pure NoContent
 
 
-tagDelivery :: PostService d -> Txt.Text -> Txt.Text -> Handler Txt.Text
+tagDelivery :: PostService d -> Text -> Text -> Handler Text
 tagDelivery serv hashtag posts = do
     let postIDs = Txt.lines posts
     subscriptions <- liftIO . readTVarIO . ownSubscriptions $ serv
@@ -295,7 +271,7 @@ tagDelivery serv hashtag posts = do
             pure ()
     pure $ "Received a postID for tag " <> hashtag
 
-tagSubscribe :: DHT d => PostService d -> Txt.Text -> Maybe Txt.Text -> Handler Integer
+tagSubscribe :: DHT d => PostService d -> Text -> Maybe Text -> Handler Integer
 tagSubscribe serv hashtag origin = do
     responsible <- liftIO $ isResponsibleFor (baseDHT serv) (hashtagToId hashtag)
     if not responsible
@@ -314,7 +290,7 @@ tagSubscribe serv hashtag origin = do
     pure $ round leaseTime
 
 
-tagUnsubscribe :: DHT d => PostService d -> Txt.Text -> Maybe Txt.Text -> Handler Txt.Text
+tagUnsubscribe :: DHT d => PostService d -> Text -> Maybe Text -> Handler Text
 tagUnsubscribe serv hashtag origin = do
     responsible <- liftIO $ isResponsibleFor (baseDHT serv) (hashtagToId hashtag)
     if not responsible
@@ -334,8 +310,15 @@ tagUnsubscribe serv hashtag origin = do
 clientAPI :: Proxy PostServiceAPI
 clientAPI = Proxy
 
-
+relayInboxClient :: Text -> Text -> ClientM NoContent
-relayInboxClient :<|> subscriptionDeliveryClient :<|> postFetchClient :<|> postMultiFetchClient :<|> postInboxClient :<|> tagDeliveryClient :<|> tagSubscribeClient :<|> tagUnsubscribeClient = client clientAPI
+relayInboxClient :<|> subscriptionDeliveryClient
+                 :<|> postFetchClient
+                 :<|> postMultiFetchClient
+                 :<|> postInboxClient
+                 :<|> tagDeliveryClient
+                 :<|> tagSubscribeClient
+                 :<|> tagUnsubscribeClient
+                 = client clientAPI
 
 
 -- | Deliver the subscriber list of all hashtags in the interval [fromTag, toTag]
@@ -543,7 +526,7 @@ lookupTagSubscriptions tag = rMapLookup (hashtagToId tag)
 
 
 -- normalise the unicode representation of a string to NFC
-normaliseTag :: Txt.Text -> Txt.Text
+normaliseTag :: Text -> Text
 normaliseTag = Txt.fromStrict . normalize NFC . Txt.toStrict
 
 
@@ -601,7 +584,7 @@ fetchTagPosts serv = forever $ do
     -- TODO: batching, retry
     -- TODO: process multiple in parallel
     pIdUri <- atomically . readTQueue $ postFetchQueue serv
-    fetchReq <- HTTP.parseRequest . Txt.unpack $pIdUri
+    fetchReq <- HTTP.parseRequest . Txt.unpack $ pIdUri
     resp <- try $ HTTP.httpLbs fetchReq (httpMan serv) :: IO (Either HTTP.HttpException (HTTP.Response BSUL.ByteString))
     case resp of
       Right response ->

src/Hash2Pub/PostService/API.hs

@@ -0,0 +1,37 @@
+{-# LANGUAGE DataKinds             #-}
+{-# LANGUAGE FlexibleInstances     #-}
+{-# LANGUAGE InstanceSigs          #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
+{-# LANGUAGE OverloadedStrings     #-}
+{-# LANGUAGE RankNTypes            #-}
+{-# LANGUAGE TypeOperators         #-}
+module Hash2Pub.PostService.API where
+
+import           Data.Text.Lazy (Text)
+
+import           Servant
+
+type PostServiceAPI = "relay" :> "inbox" :> Capture "hashtag" Text :> ReqBody '[PlainText] Text :> PutCreated '[PlainText] NoContent
+                 -- delivery endpoint at responsible relay for delivering posts of $tag for distribution
+                 :<|> "relay" :> "subscribers" :> Capture "senderID" Integer :> ReqBody '[PlainText] Text :> PostNoContent '[PlainText] Text
+                 -- endpoint for delivering the subscriptions and outstanding queue
+                 :<|> "post" :> Capture "postid" Text :> Get '[PlainText] Text
+                 -- fetch endpoint for posts, full post ID is http://$domain/post/$postid
+                 :<|> "posts" :> ReqBody '[PlainText] Text :> Post '[PlainText] Text
+                 -- endpoint for fetching multiple posts at once
+                 :<|> "posts" :> "inbox" :> ReqBody '[PlainText] Text :> PutCreated '[PlainText] NoContent
+                 -- delivery endpoint of newly published posts of the relay's instance
+                 :<|> "tags" :> Capture "hashtag" Text :> ReqBody '[PlainText] Text :> PostCreated '[PlainText] Text
+                 -- delivery endpoint for posts of $tag at subscribing instance
+                 :<|> "tags" :> Capture "hashtag" Text :> "subscribe" :> Header "Origin" Text :> Get '[PlainText] Integer
+                 -- endpoint for subscribing the instance specified in
+                 -- the Origin header to $hashtag.
+                 -- Returns subscription lease time in seconds.
+                 :<|> "tags" :> Capture "hashtag" Text :> "unsubscribe" :> Header "Origin" Text :> Get '[PlainText] Text
+                 -- endpoint for unsubscribing the instance specified in
+                 -- the Origin header to $hashtag
+
+-- | needed for guiding type inference
+exposedPostServiceAPI :: Proxy PostServiceAPI
+exposedPostServiceAPI = Proxy
+

src/Hash2Pub/ProtocolTypes.hs

@@ -1,7 +1,5 @@
 module Hash2Pub.ProtocolTypes where
 
-import qualified Data.Map                as Map
-import           Data.Maybe              (mapMaybe)
 import qualified Data.Set                as Set
 import           Data.Time.Clock.POSIX   (POSIXTime)
 

src/Hash2Pub/RingMap.hs

@@ -23,7 +23,7 @@ instance (Bounded k, Ord k, Eq a) => Eq (RingMap k a) where
     a == b = getRingMap a == getRingMap b
 
 instance (Bounded k, Ord k, Show k, Show a) => Show (RingMap k a) where
-    show rmap = shows "RingMap " (show $ getRingMap rmap)
+    show rmap = shows ("RingMap " :: String) (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.
@@ -207,7 +207,7 @@ takeEntriesUntil_ :: (Integral i, Bounded k, Ord k)
                  -> Maybe i     -- possible number limit
                  -> [a]
                  -> [a]
-takeEntriesUntil_ rmap' getterFunc' havingReached previousEntry (Just remaining) takeAcc
+takeEntriesUntil_ _rmap' _getterFunc' _havingReached _previousEntry (Just remaining) takeAcc
   -- length limit reached
   | remaining <= 0 = takeAcc
 takeEntriesUntil_ rmap' getterFunc' havingReached previousEntry numLimit takeAcc =