use backend REST library for frontend

1 files changed, 75 insertions, 0 deletions

diff --git a/backend/lib/ACMS/API/REST.hs b/backend/lib/ACMS/API/REST.hs
new file mode 100644
index 0000000..6aca780
--- /dev/null
+++ b/backend/lib/ACMS/API/REST.hs
@@ -0,0 +1,75 @@
+{-# LANGUAGE OverloadedStrings #-}
+
+module ACMS.API.REST where
+
+#ifndef ghcjs_HOST_OS
+import Network.HTTP.Simple
+#else
+import Data.ByteString.Char8 qualified as B
+import Data.Maybe
+import Data.String
+import JavaScript.Web.XMLHttpRequest
+import Miso.String qualified as J
+#endif
+import Control.Monad.Catch (MonadThrow)
+import Data.Aeson qualified as A
+import Data.ByteString.Lazy.Char8 qualified as LB
+import Data.ByteString.Lazy.UTF8 qualified as LB
+import Data.Function ((&))
+import Miso (JSM)
+import Miso.String (MisoString)
+
+schemaVersion :: (APIMonad m, A.FromJSON a) => m a
+schemaVersion =
+  "http://localhost:8081/api/rest/schemaVersion"
+    & fetch
+    >>= A.throwDecode
+
+listCollections :: (APIMonad m) => m [MisoString]
+listCollections =
+  "http://localhost:8081/api/rest/collection"
+    & fetch
+    >>= A.throwDecode
+
+createCollection :: (APIMonad m) => MisoString -> m ()
+createCollection collection =
+  "http://localhost:8081/api/rest/collections"
+    & setRequestMethod "POST"
+    & setRequestBodyLBS (A.encode (A.toJSON collection))
+    & fetch
+    >>= A.throwDecode
+
+class (MonadThrow m) => APIMonad m where
+  fetch :: Request -> m LB.ByteString
+
+instance APIMonad JSM where
+  fetch req = LB.fromStrict . getResponseBody <$> httpBS req
+
+#ifdef ghcjs_HOST_OS
+
+httpBS :: Request -> JSM (Response B.ByteString)
+httpBS req = xhrByteString req
+
+instance IsString Request where
+  fromString uri =
+    Request
+      { reqMethod = GET,
+        reqURI = J.pack uri,
+        reqLogin = Nothing,
+        reqHeaders = [],
+        reqWithCredentials = False,
+        reqData = NoData
+      }
+
+setRequestMethod :: B.ByteString -> Request -> Request
+setRequestMethod "POST" req = req {reqMethod = POST}
+
+setRequestBodyLBS :: LB.ByteString -> Request -> Request
+setRequestBodyLBS body req = req {reqData = StringData (J.pack (LB.toString body))}
+
+getResponseBody :: Response B.ByteString -> B.ByteString
+getResponseBody = fromMaybe "" . contents
+#else
+instance APIMonad IO where
+  fetch req = LB.fromStrict . getResponseBody <$> httpBS req
+#endif