Support echo server to test POST /verify

TL;DR:
- Add common dependencies like Servant, Aeson, Warp, Cors
- Define a POST /verify endpoint for our client to hit
- POST to /verify client-side onSignIn

website/sandbox/learnpianochords/shell.nix

@@ -5,8 +5,12 @@ in pkgs.mkShell {
     elmPackages.elm
     elmPackages.elm-format
     elmPackages.elm-live
-    (haskellPackages.ghcWithPackages (hpkgs: with hpkgs; [
+    (haskellPackages.ghcWithPackages (hpkgs: [
-      hspec
+      hpkgs.hspec
+      hpkgs.servant-server
+      hpkgs.aeson
+      hpkgs.wai-cors
+      hpkgs.warp
     ]))
   ];
 }

website/sandbox/learnpianochords/src/server/API.hs

@@ -0,0 +1,15 @@
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE TypeOperators #-}
+--------------------------------------------------------------------------------
+module API where
+--------------------------------------------------------------------------------
+import Data.Text
+import Servant.API
+import Web.Cookie
+
+import qualified Types as T
+--------------------------------------------------------------------------------
+
+type API = "verify"
+           :> ReqBody '[JSON] T.VerifyGoogleSignInRequest
+           :> Post '[JSON] NoContent

website/sandbox/learnpianochords/src/server/Main.hs

@@ -1,6 +1,35 @@
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE TypeApplications #-}
+{-# LANGUAGE RecordWildCards #-}
 --------------------------------------------------------------------------------
 module Main where
 --------------------------------------------------------------------------------
+import Servant
+import API
+import Control.Monad.IO.Class (liftIO)
+
+import qualified Network.Wai.Handler.Warp as Warp
+import qualified Network.Wai.Middleware.Cors as Cors
+import qualified Types as T
+--------------------------------------------------------------------------------
+
+server :: Server API
+server = verifyGoogleSignIn
+  where
+    verifyGoogleSignIn :: T.VerifyGoogleSignInRequest -> Handler NoContent
+    verifyGoogleSignIn T.VerifyGoogleSignInRequest{..} = do
+      liftIO $ putStrLn $ "Received: " ++ idToken
+      pure NoContent
 
 main :: IO ()
-main = putStrLn "Working!"
+main = do
+  Warp.run 3000 (enforceCors $ serve (Proxy @ API) $ server)
+  where
+    enforceCors = Cors.cors (const $ Just corsPolicy)
+    corsPolicy :: Cors.CorsResourcePolicy
+    corsPolicy =
+      Cors.simpleCorsResourcePolicy
+        { Cors.corsOrigins = Just (["http://localhost:8000"], True)
+        , Cors.corsMethods = Cors.simpleMethods ++ ["PUT", "PATCH", "DELETE", "OPTIONS"]
+        , Cors.corsRequestHeaders = Cors.simpleHeaders ++ ["Content-Type", "Authorization"]
+        }

website/sandbox/learnpianochords/src/server/Types.hs

@@ -0,0 +1,16 @@
+{-# LANGUAGE RecordWildCards #-}
+{-# LANGUAGE OverloadedStrings #-}
+--------------------------------------------------------------------------------
+module Types where
+--------------------------------------------------------------------------------
+import Data.Aeson
+--------------------------------------------------------------------------------
+
+data VerifyGoogleSignInRequest = VerifyGoogleSignInRequest
+  { idToken :: String
+  } deriving (Eq, Show)
+
+instance FromJSON VerifyGoogleSignInRequest where
+  parseJSON = withObject "" $ \x -> do
+    idToken <- x .: "idToken"
+    pure VerifyGoogleSignInRequest{..}

website/sandbox/learnpianochords/src/server/index.html

@@ -11,11 +11,18 @@
     <a href="#" onclick="signOut();">Sign out</a>
     <script>
      function onSignIn(googleUser) {
-       var profile = googleUser.getBasicProfile();
+       var idToken = googleUser.getAuthResponse().id_token;
-       console.log('ID: ' + profile.getId()); // Do not send to your backend! Use an ID token instead.
+       fetch('http://localhost:3000/verify', {
-       console.log('Name: ' + profile.getName());
+         method: 'POST',
-       console.log('Image URL: ' + profile.getImageUrl());
+         headers: {
-       console.log('Email: ' + profile.getEmail()); // This is null if the 'email' scope is not present.
+           'Content-Type': 'application/json',
+         },
+         body: JSON.stringify({
+           idToken: idToken,
+         })
+       })
+         .then(x => console.log(x))
+         .catch(err => console.error(err));
      }
      function signOut() {
        var auth2 = gapi.auth2.getAuthInstance();