Merge branch 'with-ghcjs' into 'master'

Use Haskell on the frontend

See merge request guyonvarch/shared-cost!2

1 files changed, 139 insertions, 0 deletions

diff --git a/client/src/Util/Ajax.hs b/client/src/Util/Ajax.hs
new file mode 100644
index 0000000..dcfd402
--- /dev/null
+++ b/client/src/Util/Ajax.hs
@@ -0,0 +1,139 @@
+module Util.Ajax
+  ( getNow
+  , get
+  , post
+  , postAndParseResult
+  , put
+  , putAndParseResult
+  , delete
+  ) where
+
+import           Control.Arrow        (left)
+import           Data.Aeson           (FromJSON, ToJSON)
+import qualified Data.Aeson           as Aeson
+import           Data.ByteString      (ByteString)
+import qualified Data.ByteString.Lazy as LBS
+import           Data.Default         (def)
+import qualified Data.Map.Lazy        as LM
+import           Data.Text            (Text)
+import qualified Data.Text            as T
+import qualified Data.Text.Encoding   as T
+import           Data.Time.Clock      (NominalDiffTime)
+import           Reflex.Dom           (Dynamic, Event, IsXhrPayload,
+                                       MonadWidget, XhrRequest,
+                                       XhrRequestConfig (..), XhrResponse,
+                                       XhrResponseHeaders (..))
+import qualified Reflex.Dom           as R
+
+import           Loadable             (Loadable)
+import qualified Loadable
+
+getNow :: forall t m a. (MonadWidget t m, FromJSON a) => Text -> m (Dynamic t (Loadable a))
+getNow url = do
+  postBuild <- R.getPostBuild
+  get (url <$ postBuild)
+    >>= R.debounce (0 :: NominalDiffTime) -- Fired 2 times otherwise
+    >>= Loadable.fromEvent
+
+get
+  :: forall t m a. (MonadWidget t m, FromJSON a)
+  => Event t Text
+  -> m (Event t (Either Text a))
+get url =
+  fmap getJsonResult <$>
+    R.performRequestAsync (R.ffor url $ \u -> jsonRequest "GET" u (Aeson.String ""))
+
+post
+  :: forall t m a. (MonadWidget t m, ToJSON a)
+  => Text
+  -> Event t a
+  -> m (Event t (Either Text ()))
+post url input =
+  fmap checkResult <$>
+    R.performRequestAsync (jsonRequest "POST" url <$> input)
+
+postAndParseResult
+  :: forall t m a b. (MonadWidget t m, ToJSON a, FromJSON b)
+  => Text
+  -> Event t a
+  -> m (Event t (Either Text b))
+postAndParseResult url input =
+  fmap getJsonResult <$>
+    R.performRequestAsync (jsonRequest "POST" url <$> input)
+
+put
+  :: forall t m a. (MonadWidget t m, ToJSON a)
+  => Text
+  -> Event t a
+  -> m (Event t (Either Text ()))
+put url input =
+  fmap checkResult <$>
+    R.performRequestAsync (jsonRequest "PUT" url <$> input)
+
+putAndParseResult
+  :: forall t m a b. (MonadWidget t m, ToJSON a, FromJSON b)
+  => Text
+  -> Event t a
+  -> m (Event t (Either Text b))
+putAndParseResult url input =
+  fmap getJsonResult <$>
+    R.performRequestAsync (jsonRequest "PUT" url <$> input)
+
+delete
+  :: forall t m a. (MonadWidget t m)
+  => Dynamic t Text
+  -> Event t ()
+  -> m (Event t (Either Text Text))
+delete url fire = do
+  fmap getResult <$>
+    (R.performRequestAsync $
+      R.attachWith (\u _ -> request "DELETE" u ()) (R.current url) fire)
+
+checkResult :: XhrResponse -> Either Text ()
+checkResult response =
+  () <$ getResult response
+
+getJsonResult :: forall a. (FromJSON a) => XhrResponse -> Either Text a
+getJsonResult response =
+  case getResult response of
+    Left l  -> Left l
+    Right r -> left T.pack . Aeson.eitherDecodeStrict $ (T.encodeUtf8 r)
+
+getResult :: XhrResponse -> Either Text Text
+getResult response =
+  case R._xhrResponse_responseText response of
+    Just responseText ->
+      if R._xhrResponse_status response == 200
+        then Right responseText
+        else Left responseText
+    _ -> Left "NoKey"
+
+request :: forall a. (IsXhrPayload a) => Text -> Text -> a -> XhrRequest a
+request method url payload =
+  let
+    config = XhrRequestConfig
+      { _xhrRequestConfig_headers = def
+      , _xhrRequestConfig_user = def
+      , _xhrRequestConfig_password = def
+      , _xhrRequestConfig_responseType = def
+      , _xhrRequestConfig_responseHeaders = def
+      , _xhrRequestConfig_withCredentials = False
+      , _xhrRequestConfig_sendData = payload
+      }
+  in
+    R.xhrRequest method url config
+
+jsonRequest :: forall a. (ToJSON a) => Text -> Text -> a -> XhrRequest ByteString
+jsonRequest method url payload =
+  let
+    config = XhrRequestConfig
+      { _xhrRequestConfig_headers = def
+      , _xhrRequestConfig_user = def
+      , _xhrRequestConfig_password = def
+      , _xhrRequestConfig_responseType = def
+      , _xhrRequestConfig_responseHeaders = def
+      , _xhrRequestConfig_withCredentials = False
+      , _xhrRequestConfig_sendData = LBS.toStrict $ Aeson.encode payload
+      }
+  in
+    R.xhrRequest method url config