add pagination to rest api

1 files changed, 32 insertions, 0 deletions

diff --git a/backend/lib/ACMS/API/REST/Collection/Paginated.hs b/backend/lib/ACMS/API/REST/Collection/Paginated.hs
new file mode 100644
index 0000000..ad98888
--- /dev/null
+++ b/backend/lib/ACMS/API/REST/Collection/Paginated.hs
@@ -0,0 +1,32 @@
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE RecordWildCards #-}
+
+module ACMS.API.REST.Collection.Paginated where
+
+import ACMS.API.REST (APIMonad, fetch, restRequest)
+import Collection
+import Data.Aeson qualified as A
+import Data.Function ((&))
+import GHC.Generics (Generic)
+import Text.Printf (printf)
+
+data Pagination = Pagination
+  { limit :: Int,
+    offset :: Int
+  }
+
+data Paginated a = Paginated
+  { count :: Int,
+    data_ :: [a]
+  }
+  deriving (Eq, Show, Generic)
+
+instance (A.FromJSON a) => A.FromJSON (Paginated a)
+
+instance (A.ToJSON a) => A.ToJSON (Paginated a)
+
+list :: (APIMonad m) => Pagination -> Collection -> m (Paginated A.Object)
+list p c =
+  restRequest (printf "/collection/%s/paginated/%d/%d" c.name p.limit p.offset)
+    & fetch
+    >>= A.throwDecode