Add a message for login failed and a couple comments

Author: CorruptComputer

BlazorWasmOsmOauth/Layout/MainLayout.razor.cs

@@ -18,6 +18,9 @@ public partial class MainLayout(AppConfig config, NavigationManager navManager,
 
     private async Task GoToLogin()
     {
+        // Note: This is a simple example, in a real application you'd probably want 
+        //       to use a more secure method of generating these values.
+
         Guid state = Guid.NewGuid();
         await localStorageService.SetItemAsync(LocalStorageService.OsmStateKey, state, CancellationToken.None);
 

BlazorWasmOsmOauth/Pages/AuthCompletePage.razor

@@ -1,3 +1,5 @@
 @page "/oauth2-redirect"
 
 <PageTitle>Auth Complete</PageTitle>
+
+<!-- Nothing to really display here, the code-behind for this page will handle everything, then redirect to home -->

BlazorWasmOsmOauth/Pages/AuthCompletePage.razor.cs

@@ -52,13 +52,8 @@ private async Task GetToken()
             return;
         }
 
-        if (State == null
-            || State != await localStorageService.GetItemAsync<Guid>(LocalStorageService.OsmStateKey, CancellationToken.None))
+        if (!await ValidateState())
         {
-            // Wait for the dialog to close, then redirect to the home page
-            IDialogReference dialogReference = await dialogService.ShowErrorAsync("The state value supplied by OSM is invalid.", title: "Invalid State");
-            await dialogReference.Result;
-
             navManager.NavigateTo("/");
             return;
         }
@@ -77,11 +72,36 @@ private async Task GetToken()
 
         TokenResponse? tokenResp = await osmClient.GetTokenAsync(Code, config.RedirectUri, config.ClientId, pkce);
 
-        if (tokenResp != null)
+        if (tokenResp == null)
         {
-            await authenticationStateProvider.SetCurrentUserAsync(tokenResp, CancellationToken.None);
+            // Wait for the dialog to close, then redirect to the home page
+            IDialogReference dialogReference = await dialogService.ShowErrorAsync("The OSM login failed.", title: "Login failed");
+            await dialogReference.Result;
+
+            navManager.NavigateTo("/");
+            return;
         }
 
+        await authenticationStateProvider.SetCurrentUserAsync(tokenResp, CancellationToken.None);
+
         navManager.NavigateTo("/");
     }
+
+    private async Task<bool> ValidateState() 
+    {
+        Guid? stateFromStorage = await localStorageService.GetItemAsync<Guid>(LocalStorageService.OsmStateKey, CancellationToken.None);
+        if (State == null
+            || stateFromStorage == null
+            || State != stateFromStorage)
+        {
+            // Wait for the dialog to close, then return
+            IDialogReference dialogReference = await dialogService.ShowErrorAsync("The state value supplied by OSM is invalid.", title: "Invalid State");
+            await dialogReference.Result;
+
+            
+            return false;
+        }
+
+        return true;
+    }
 }

BlazorWasmOsmOauth/Pages/HomePage.razor

@@ -2,7 +2,6 @@
 
 <PageTitle>Blazor WASM OSM Oauth2 Example</PageTitle>
 
-
 <AuthorizeView>
     <Authorized>
         <div>

BlazorWasmOsmOauth/Program.cs

@@ -58,8 +58,8 @@ public static async Task Main(string[] args)
         config.RedirectUri = $"http{(thisHost == "127.0.0.1:8123" ? string.Empty : "s")}://{thisHost}/oauth2-redirect";
 
         config.SourceRevisionId = Assembly.GetEntryAssembly()?
-                                          .GetCustomAttribute<AssemblyInformationalVersionAttribute>()
-                                            // For example: 0.0.1+b9d1873a
+                                          .GetCustomAttribute<AssemblyInformationalVersionAttribute>()
+                                          // For example: 0.0.1+b9d1873a
                                           ?.InformationalVersion.Split('+')[1] ?? "ERROR";
 
         builder.Services.AddSingleton(config);