From e50e234747498b231ba4642d97d0bba01d93d819 Mon Sep 17 00:00:00 2001
From: Mats Rauhala <mats.rauhala@iki.fi>
Date: Tue, 14 Aug 2018 22:11:52 +0300
Subject: [PATCH] Start working opds (#2)

- Relates to #2
---
 ebook-manager.cabal  |  3 ---
 src/API/Catalogue.hs | 45 +++++++++++++++++++++++++-------------------
 src/Servant/XML.hs   | 10 ++++++++++
 3 files changed, 36 insertions(+), 22 deletions(-)

diff --git a/ebook-manager.cabal b/ebook-manager.cabal
index 2d699d6..4d262ee 100644
--- a/ebook-manager.cabal
+++ b/ebook-manager.cabal
@@ -1,6 +1,3 @@
--- Initial ebook-manager.cabal generated by cabal init.  For further
--- documentation, see http://haskell.org/cabal/users-guide/
-
 name:                ebook-manager
 version:             0.1.0.0
 -- synopsis:
diff --git a/src/API/Catalogue.hs b/src/API/Catalogue.hs
index de125dc..37a813c 100644
--- a/src/API/Catalogue.hs
+++ b/src/API/Catalogue.hs
@@ -98,28 +98,33 @@ 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)
+  getChannels = getChannelsV1
+
+getChannelsV1 :: SafeUser -> AppM (Catalog 1)
+getChannelsV1 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 CatalogContent = '[XML, OPDS]
+
+type RootCatalog (v :: Nat) = "catalog" :> Get CatalogContent (Catalog v)
+type ChannelCatalog (v :: Nat) = "catalog" :> "channel" :> Capture "channel_id" Channel.ChannelID :> Get CatalogContent (Catalog v)
 type BaseAPI (v :: Nat) = RootCatalog v
                     :<|> ChannelCatalog v
 
@@ -127,6 +132,8 @@ handler :: forall v. VersionedCatalog AppM v => ServerT (VersionedAPI v) AppM
 handler auth = catalogRoot :<|> catalogChannels
   where
     catalogChannels :: Channel.ChannelID -> AppM (Catalog v)
+    -- Channel specific catalog returns tags inside the catalog
     catalogChannels _ = throwM err403{errBody="Not implemented"}
     catalogRoot :: AppM (Catalog v)
+    -- catalog root returns channels
     catalogRoot = flip requireLoggedIn auth getChannels
diff --git a/src/Servant/XML.hs b/src/Servant/XML.hs
index 42a2fca..cbc2c7b 100644
--- a/src/Servant/XML.hs
+++ b/src/Servant/XML.hs
@@ -1,9 +1,11 @@
 {-# Language OverloadedStrings #-}
 {-# Language FlexibleInstances #-}
 {-# Language MultiParamTypeClasses #-}
+{-# Language TypeApplications #-}
 module Servant.XML
   ( ToNode(..)
   , XML
+  , OPDS
   , Text.Hamlet.XML.xml
   , iso8601 )
   where
@@ -16,14 +18,22 @@ import Network.HTTP.Media.MediaType
 
 data XML
 
+data OPDS
+
 instance (ToNode a) => MimeRender XML a where
   mimeRender _ a =
     let [NodeElement root] = toNode a
     in renderLBS def (Document (Prologue [] Nothing []) root [])
 
+instance (ToNode a) => MimeRender OPDS a where
+  mimeRender _ a = mimeRender (Proxy @XML) a
+
 instance Accept XML where
   contentType _ = "application" // "xml" /: ("charset", "utf-8")
 
+instance Accept OPDS where
+  contentType _ = "application" // "atom+xml" /: ("charset", "utf-8") /: ("profile", "opds-catalog")
+
 iso8601 :: UTCTime -> Text
 iso8601 = pack . formatTime defaultTimeLocale "%Y-%m-%dT%H:%M:%SZ"