Added ErrorReceived to embedded auth server

Also style the default HTML site based on error/success values. Fixes #566

SpotifyAPI.Docs/docs/authorization_code.md

@@ -81,6 +81,7 @@ public static async Task Main()
   await _server.Start();
 
   _server.AuthorizationCodeReceived += OnAuthorizationCodeReceived;
+  _server.ErrorReceived += OnErrorReceived;
 
   var request = new LoginRequest(_server.BaseUri, "ClientId", LoginRequest.ResponseType.Code)
   {
@@ -103,6 +104,12 @@ private static async Task OnAuthorizationCodeReceived(object sender, Authorizati
   var spotify = new SpotifyClient(tokenResponse.AccessToken);
   // do calls with Spotify and save token?
 }
+
+private static async Task OnErrorReceived(object sender, string error, string state)
+{
+  Console.WriteLine($"Aborting authorization, error received: {error}");
+  await _server.Stop();
+}
 ```
 
 For real examples, have a look at [Example.CLI.PersistentConfig](https://github.com/JohnnyCrazy/SpotifyAPI-NET/tree/master/SpotifyAPI.Web.Examples/Example.CLI.PersistentConfig) and [Example.CLI.CustomHTML](https://github.com/JohnnyCrazy/SpotifyAPI-NET/tree/master/SpotifyAPI.Web.Examples/Example.CLI.CustomHTML)

SpotifyAPI.Docs/docs/implicit_grant.md

@@ -89,6 +89,7 @@ public static async Task Main()
   await _server.Start();
 
   _server.ImplictGrantReceived += OnImplicitGrantReceived;
+  _server.ErrorReceived += OnErrorReceived;
 
   var request = new LoginRequest(_server.BaseUri, "ClientId", LoginRequest.ResponseType.Token)
   {
@@ -103,6 +104,12 @@ private static async Task OnImplicitGrantReceived(object sender, ImplictGrantRes
   var spotify = new SpotifyClient(response.AccessToken);
   // do calls with Spotify
 }
+
+private static async Task OnErrorReceived(object sender, string error, string state)
+{
+  Console.WriteLine($"Aborting authorization, error received: {error}");
+  await _server.Stop();
+}
 ```
 
 For real examples, have a look at [Example.CLI.PersistentConfig](https://github.com/JohnnyCrazy/SpotifyAPI-NET/tree/master/SpotifyAPI.Web.Examples/Example.CLI.PersistentConfig) and [Example.CLI.CustomHTML](https://github.com/JohnnyCrazy/SpotifyAPI-NET/tree/master/SpotifyAPI.Web.Examples/Example.CLI.CustomHTML)

SpotifyAPI.Web.Auth/EmbedIOAuthServer.cs

@@ -14,6 +14,7 @@ namespace SpotifyAPI.Web.Auth
   {
     public event Func<object, AuthorizationCodeResponse, Task>? AuthorizationCodeReceived;
     public event Func<object, ImplictGrantResponse, Task>? ImplictGrantReceived;
+    public event Func<object, string, string?, Task>? ErrorReceived;
 
     private const string AssetsResourcePath = "SpotifyAPI.Web.Auth.Resources.auth_assets";
     private const string DefaultResourcePath = "SpotifyAPI.Web.Auth.Resources.default_site";
@@ -38,6 +39,7 @@ namespace SpotifyAPI.Web.Auth
           var error = query["error"];
           if (error != null)
           {
+            ErrorReceived?.Invoke(this, error, query["state"]);
             throw new AuthException(error, query["state"]);
           }
 

SpotifyAPI.Web.Auth/Resources/auth_assets/main.css

@@ -20,3 +20,7 @@ main {
 .logo {
   margin-bottom: 50px;
 }
+
+.hidden {
+  visibility: hidden;
+}

SpotifyAPI.Web.Auth/Resources/auth_assets/main.js

@@ -1,43 +1,54 @@
 function getUrlParams(hash, start) {
-  const hashes = hash.slice(hash.indexOf(start) + 1).split('&')
+  const hashes = hash.slice(hash.indexOf(start) + 1).split("&");
 
   if (!hashes || hashes.length === 0 || hashes[0] === "") {
     return undefined;
   }
 
-  const params = {}
-  hashes.map(hash => {
-    const [key, val] = hash.split('=')
-    params[key] = decodeURIComponent(val)
-  })
-  return params
+  const params = {};
+  hashes.map((hash) => {
+    const [key, val] = hash.split("=");
+    params[key] = decodeURIComponent(val);
+  });
+  return params;
 }
 
 function handleImplicitGrant() {
-  const params = getUrlParams(window.location.hash, '#');
+  const params = getUrlParams(window.location.hash, "#");
   if (!params) {
     return;
   }
   params.request_type = "token";
 
   console.log("Sent request_type token to server", params);
-  fetch('?' + new URLSearchParams(params).toString(), {
-    method: 'POST',
+  fetch("?" + new URLSearchParams(params).toString(), {
+    method: "POST",
   });
 }
 handleImplicitGrant();
 
 function handleAuthenticationCode() {
-  const params = getUrlParams(window.location.search, '?');
+  const params = getUrlParams(window.location.search, "?");
   if (!params) {
     return;
   }
   params.request_type = "code";
 
   console.log("Sent request_type code to server", params);
-  fetch('?' + new URLSearchParams(params).toString(), {
-    method: 'POST',
+  fetch("?" + new URLSearchParams(params).toString(), {
+    method: "POST",
   });
 }
 handleAuthenticationCode();
 
+document.addEventListener("DOMContentLoaded", () => {
+  const errorContainer = document.querySelector("#error");
+  const successContainer = document.querySelector("#success");
+  const params = new URLSearchParams(window.location.search);
+
+  if (params.has("error")) {
+    errorContainer.classList.remove("hidden");
+  } else {
+    successContainer.classList.remove("hidden");
+  }
+});

SpotifyAPI.Web.Auth/Resources/default_site/index.html

@@ -1,13 +1,15 @@
 <!DOCTYPE html>
 <html>
-
   <head>
-  <meta charset='utf-8'>
-  <meta http-equiv='X-UA-Compatible' content='IE=edge'>
+    <meta charset="utf-8" />
+    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
     <title>Spotify Authorization</title>
-  <meta name='viewport' content='width=device-width, initial-scale=1'>
-  <link href="https://unpkg.com/tailwindcss@^1.0/dist/tailwind.min.css" rel="stylesheet">
-  <link href="/auth_assets/main.css" rel="stylesheet">
+    <meta name="viewport" content="width=device-width, initial-scale=1" />
+    <link
+      href="https://unpkg.com/tailwindcss@^1.0/dist/tailwind.min.css"
+      rel="stylesheet"
+    />
+    <link href="/auth_assets/main.css" rel="stylesheet" />
     <script src="/auth_assets/main.js"></script>
   </head>
 
@@ -18,21 +20,35 @@
           <img src="/auth_assets/logo.svg" width="120" height="120" />
         </div>
       </div>
+      <div id="error" class="hidden">
+        <h1 class="text-4xl">Error!</h1>
+        <p class="text-xl mx-2">
+          Spotify Authorization was not successful. You may want to retry.
+        </p>
+      </div>
+      <div id="success" class="hidden">
         <h1 class="text-4xl">Success!</h1>
         <p class="text-xl mx-2">
-      Spotify Authorization was successful. You can close this tab and go back to your app.
+          Spotify Authorization was successful. You can close this tab and go
+          back to your app.
         </p>
+      </div>
       <div class="text-center py-4 lg:px-4 my-6">
-      <div class="p-2 bg-teal-800 items-center text-teal-100 leading-none lg:rounded-full flex lg:inline-flex"
-        role="alert">
-        <span class="flex rounded-full bg-teal-500 uppercase px-2 py-1 text-xs font-bold mr-3">Tip</span>
+        <div
+          class="p-2 bg-teal-800 items-center text-teal-100 leading-none lg:rounded-full flex lg:inline-flex"
+          role="alert"
+        >
+          <span
+            class="flex rounded-full bg-teal-500 uppercase px-2 py-1 text-xs font-bold mr-3"
+            >Tip</span
+          >
           <span class="font-semibold mr-2 text-left flex-auto">
-          If the app does not detect the authorization, make sure you use one of the following supported Browsers:
+            If the app does not detect the authorization, make sure you use one
+            of the following supported Browsers:
             <b>Chrome</b>, <b>Edge</b> or <b>Firefox</b>
           </span>
         </div>
       </div>
     </main>
   </body>
-
 </html>