Move server api behind the server namespace

backend/src/Server/API/Channels.hs

@@ -0,0 +1,75 @@
+{-# Language DataKinds #-}
+{-# Language TypeFamilies #-}
+{-# Language TypeOperators #-}
+{-# Language NoImplicitPrelude #-}
+{-# Language MultiParamTypeClasses #-}
+{-# Language OverloadedStrings #-}
+{-# Language TemplateHaskell #-}
+{-# Language QuasiQuotes #-}
+{-# Language RecordWildCards #-}
+{-# Language DeriveGeneric #-}
+{-# Language FlexibleInstances #-}
+{-# Language TypeApplications #-}
+{-# Language DataKinds #-}
+{-# Language DuplicateRecordFields #-}
+{-# Language NamedFieldPuns #-}
+module Server.API.Channels (API, handler, JsonChannel(..)) where
+
+import Servant
+import Types
+import ClassyPrelude
+import Server.Auth
+import Servant.Auth as SA
+import Control.Monad.Logger
+import Database
+import Database.Channel
+import Data.Aeson
+import Control.Lens
+import Data.Generics.Product
+
+data JsonChannel = JsonChannel { channel :: Text
+                               , visibility :: Visibility }
+                 deriving (Show, Generic)
+data UpdateChannel = UpdateChannel { identifier :: ChannelID
+                                   , channel :: Text
+                                   , visibility :: Visibility }
+                 deriving (Show, Generic)
+
+instance ToJSON JsonChannel
+instance FromJSON JsonChannel
+instance ToJSON UpdateChannel
+instance FromJSON UpdateChannel
+
+type API = Auth '[SA.BasicAuth, SA.Cookie, SA.JWT] SafeUser :> BaseAPI
+
+type BaseAPI = "channels" :> ReqBody '[JSON] JsonChannel :> Post '[JSON] UpdateChannel
+          :<|> "channels" :> Capture "channel_id" ChannelID :> ReqBody '[JSON] UpdateChannel :> Put '[JSON] UpdateChannel
+          :<|> "channels" :> Get '[JSON] [JsonChannel]
+
+handler :: ServerT API AppM
+handler user = newChannelHandler user :<|> updateChannelHandler user :<|> listChannelsHandler user
+
+requireChannelOwner :: AuthResult SafeUser -> ChannelID -> (SafeUser -> AppM a) -> AppM a
+requireChannelOwner auth channelId f = flip requireLoggedIn auth $ \u@SafeUser{username} -> do
+  unlessM (runDB . channelExists $ channelId) $ throwM err404
+  runDB (isChannelOwner channelId username) >>= \o -> if o then f u else throwM err403
+
+updateChannelHandler :: AuthResult SafeUser -> ChannelID -> UpdateChannel -> AppM UpdateChannel
+updateChannelHandler auth channelId UpdateChannel{visibility} = requireChannelOwner auth channelId $ \_ -> do
+  mChannel <- fmap toChannel <$> runDB (updateChannelPrivacy channelId visibility)
+  maybe (throwM err403) return mChannel
+
+listChannelsHandler :: AuthResult SafeUser -> AppM [JsonChannel]
+listChannelsHandler = requireLoggedIn $ \user ->
+  -- I could use the super thing from generic-lens, but then I would need to
+  -- use the 'channel' accessor somehow or export it
+  fmap (\Channel{..} -> JsonChannel{..}) <$> runDB (userChannels (view (field @"username") user))
+
+newChannelHandler :: AuthResult SafeUser -> JsonChannel -> AppM UpdateChannel
+newChannelHandler auth JsonChannel{..} = flip requireLoggedIn auth $ \user -> do
+  $logInfo $ "Creating channel for user " <> pack (show user)
+  mChannel <- fmap toChannel <$> runDB (insertChannel (view (field @"username") user) channel visibility)
+  maybe (throwM err403{errBody="Could not create the channel"}) return mChannel
+
+toChannel :: Channel -> UpdateChannel
+toChannel Channel{..} = UpdateChannel{..}