ebook-manager/src/API/Catalogue.hs

133 lines
5.1 KiB
Haskell

{-# Language DataKinds #-}
{-# Language NamedFieldPuns #-}
{-# Language TypeApplications #-}
{-# Language KindSignatures #-}
{-# Language TypeFamilies #-}
{-# Language GeneralizedNewtypeDeriving #-}
{-# Language DuplicateRecordFields #-}
{-# Language TypeOperators #-}
{-# Language StandaloneDeriving #-}
{-# Language DeriveGeneric #-}
{-# Language FlexibleInstances #-}
{-# Language FlexibleContexts #-}
{-# Language QuasiQuotes #-}
{-# Language TemplateHaskell #-}
{-# Language MultiParamTypeClasses #-}
{-# Language ScopedTypeVariables #-}
module API.Catalogue (VersionedAPI, handler) where
import Types
import Servant
import ClassyPrelude
import GHC.TypeLits
import Server.Auth
import Servant.Auth as SA
import Servant.XML
import qualified Database.Channel as Channel
import Database
-- This is my first try on going to versioned apis, things might change
-- I think my rule of thumb is that you can add new things as you want, but
-- deleting and modifying warrants a new version
data family Catalog :: Nat -> *
data family Entry :: Nat -> *
newtype Rel = Rel { unRel :: Text } deriving (IsString, Show)
data Pagination = Pagination { previous :: Maybe Rel
, next :: Maybe Rel }
deriving (Show)
newtype SubSection = SubSection Rel deriving (Show)
newtype Acquisition = Acquisition Rel deriving (Show)
data instance Entry 1 = EntryV1 { title :: Text
, identifier :: Text
, updated :: UTCTime
, content :: Text
, link :: Either SubSection Acquisition
}
data instance Catalog 1 = CatalogV1 { updated :: UTCTime
, self :: Rel
, start :: Rel
, pagination :: Pagination
, entries :: [Entry 1]
}
deriving instance Show (Catalog 1)
deriving instance Show (Entry 1)
deriving instance Generic (Catalog 1)
deriving instance Generic (Entry 1)
instance ToNode SubSection where
toNode (SubSection rel) = [xml|<link type="application/atom+xml;profile=opds-catalog;kind=acquisition" rel="subsection" href="#{unRel rel}">|]
instance ToNode Acquisition where
toNode (Acquisition rel) = [xml|<link type="application/epub+zip" rel="http://opds-spec.org/acquisition" href="#{unRel rel}">|]
instance ToNode (Entry 1) where
toNode EntryV1{..} = [xml|
<entry>
<title>#{title}
<id>#{identifier}
<updated>#{iso8601 updated}
<content>#{content}
^{either toNode toNode link}
|]
instance ToNode (Catalog 1) where
toNode CatalogV1{..} = [xml|
<feed xmlns="http://www.w3.org/2005/Atom" xmlns:opds="http://opds-spec.org/2010/catalog">
<id>#{unRel self}
<title>Give me a title
<updated>#{iso8601 updated}
<link type="application/atom+xml;profile=opds-catalog;kind=navigation" rel="self" href="#{unRel self}">
<link type="application/atom+xml;profile=opds-catalog;kind=navigation" rel="start" href="#{unRel start}">
$maybe n <- (next pagination)
<link type="application/atom+xml;profile=opds-catalog;kind=navigation" rel="next" href="#{unRel n}">
$maybe p <- (previous pagination)
<link type="application/atom+xml;profile=opds-catalog;kind=navigation" rel="previous" href="#{unRel p}">
^{toNode entries}
|]
class Monad m => VersionedCatalog m (v :: Nat) where
getChannels :: SafeUser -> m (Catalog v)
instance VersionedCatalog AppM 1 where
getChannels SafeUser{username} = do
updated <- liftIO getCurrentTime
let self = Rel ("/api/current/" <> selfUrl)
-- I'm not sure if this safe link approach is really useable with this
-- api hierarchy since I can't access the topmost api from here. Also
-- authentication would bring a little bit of extra effort as well
selfUrl = pack . uriPath . linkURI $ safeLink (Proxy @(BaseAPI 1)) (Proxy @(RootCatalog 1))
start = self
pagination = Pagination Nothing Nothing
entries <- map (fromChannel updated) <$> runDB (Channel.userChannels username)
pure CatalogV1{..}
where
fromChannel :: UTCTime -> Channel.Channel -> Entry 1
fromChannel updated Channel.Channel{..} =
let url = pack . uriPath . linkURI $ safeLink (Proxy @(BaseAPI 1)) (Proxy @(ChannelCatalog 1)) identifier
self = Rel ("/api/current/" <> url)
in EntryV1 channel channel updated channel (Left $ SubSection self)
type VersionedAPI (v :: Nat) = Auth '[SA.BasicAuth, SA.JWT] SafeUser :> BaseAPI v
type RootCatalog (v :: Nat) = "catalog" :> Get '[XML] (Catalog v)
type ChannelCatalog (v :: Nat) = "catalog" :> "channel" :> Capture "channel_id" Channel.ChannelID :> Get '[XML] (Catalog v)
type BaseAPI (v :: Nat) = RootCatalog v
:<|> ChannelCatalog v
handler :: forall v. VersionedCatalog AppM v => ServerT (VersionedAPI v) AppM
handler auth = catalogRoot :<|> catalogChannels
where
catalogChannels :: Channel.ChannelID -> AppM (Catalog v)
catalogChannels _ = throwM err403{errBody="Not implemented"}
catalogRoot :: AppM (Catalog v)
catalogRoot = flip requireLoggedIn auth getChannels