wip - enable logout (#202)

## Purpose
<!-- Describe the intention of the changes being proposed. What problem
does it solve or functionality does it add? -->
* ...

## Does this introduce a breaking change?
<!-- Mark one with an "x". -->
```
[ ] Yes
[ ] No
```

## Pull Request Type
What kind of change does this Pull Request introduce?

<!-- Please check the one that applies to this PR using "x". -->
```
[ ] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Documentation content changes
[ ] Other... Please describe:
```

## How to Test
*  Get the code

```
git clone [repo-address]
cd [repo-name]
git checkout [branch-name]
npm install
```

* Test the code
<!-- Add steps to run the tests suite and/or manually test -->
```
```

## What to Check
Verify that the following are valid
* ...

## Other Information
<!-- Add any other helpful information that may be needed here. -->

app/backend/Extensions/WebApplicationExtensions.cs

@@ -23,9 +23,19 @@ internal static WebApplication MapApi(this WebApplication app)
         // Get DALL-E image result from prompt
         api.MapPost("images", OnPostImagePromptAsync);
 
+        api.MapGet("enableLogout", OnGetEnableLogout);
+
         return app;
     }
 
+    private static IResult OnGetEnableLogout(HttpContext context)
+    {
+        var header = context.Request.Headers["X-MS-CLIENT-PRINCIPAL-ID"];
+        var enableLogout = !string.IsNullOrEmpty(header);
+
+        return TypedResults.Ok(enableLogout);
+    }
+
     private static async IAsyncEnumerable<ChatChunkResponse> OnPostChatPromptAsync(
         PromptRequest prompt,
         OpenAIClient client,

app/backend/Program.cs

@@ -76,10 +76,10 @@
 
 app.UseHttpsRedirection();
 app.UseOutputCache();
+app.UseRouting();
+app.UseStaticFiles();
 app.UseCors();
 app.UseBlazorFrameworkFiles();
-app.UseStaticFiles();
-app.UseRouting();
 app.MapRazorPages();
 app.MapControllers();
 app.MapFallbackToFile("index.html");

app/frontend/Services/ApiClient.cs

@@ -20,6 +20,14 @@ public sealed class ApiClient
         return await response.Content.ReadFromJsonAsync<ImageResponse>();
     }
 
+    public async Task<bool> ShowLogoutButtonAsync()
+    {
+        var response = await _httpClient.GetAsync("api/enableLogout");
+        response.EnsureSuccessStatusCode();
+
+        return await response.Content.ReadFromJsonAsync<bool>();
+    }
+
     public async Task<UploadDocumentsResponse> UploadDocumentsAsync(
         IReadOnlyList<IBrowserFile> files,
         long maxAllowedSize)

app/frontend/Shared/LogoutDisplay.razor

@@ -0,0 +1,33 @@
+@inject NavigationManager Nav
+@inject ILogger<LogoutDisplay> Logger
+@inject ApiClient ApiClient
+
+@if (ShowLogoutButton)
+{
+    <MudIconButton Icon="@Icons.Material.Filled.Logout" Color="Color.Inherit" Size="Size.Large"
+                   Title="Logout of the app." OnClick="SignOut" />
+}
+
+@code {
+    [Parameter] public bool ShowLogoutButton { get; set; } = true;
+
+    protected override async Task OnInitializedAsync()
+    {
+        await base.OnInitializedAsync();
+        try
+        {
+            Logger.LogInformation("start retrieve logout button visibility.");
+            ShowLogoutButton = await ApiClient.ShowLogoutButtonAsync();
+        }
+        catch(Exception e)
+        {
+            Logger.LogError(e.Message);
+        }
+    }
+
+    private void SignOut()
+    {
+        Logger.LogInformation("User start logged out.");
+        Nav.NavigateTo(".auth/logout", true);
+    }
+}

app/frontend/Shared/MainLayout.razor

@@ -41,6 +41,7 @@
             <MudIconButton Icon="@Icons.Custom.Brands.GitHub" Color="Color.Inherit" Size="Size.Large"
                         Title="Visit the Azure Samples: GitHub repository for this app."
                         Href="https://github.com/Azure-Samples/azure-search-openai-demo-csharp" Target="_blank" />
+            <LogoutDisplay />
         </MudAppBar>
         <MudDrawer @bind-Open="_drawerOpen" Elevation="5" id="drawer">
             <MudDrawerHeader>
@@ -64,4 +65,4 @@
             <SettingsPanel @ref="_settingsPanel" @bind-Open="@_settingsOpen" />
         </MudMainContent>
     </MudLayout>
-</MudRTLProvider>
+</MudRTLProvider>

app/frontend/wwwroot/service-worker.published.js

@@ -4,7 +4,7 @@
 self.importScripts('./service-worker-assets.js');
 self.addEventListener('install', event => event.waitUntil(onInstall(event)));
 self.addEventListener('activate', event => event.waitUntil(onActivate(event)));
-self.addEventListener('fetch', event => event.respondWith(onFetch(event)));
+self.addEventListener('fetch', () => { });
 
 const cacheNamePrefix = 'offline-cache-';
 const cacheName = `${cacheNamePrefix}${self.assetsManifest.version}`;
@@ -30,19 +30,4 @@ async function onActivate(event) {
     await Promise.all(cacheKeys
         .filter(key => key.startsWith(cacheNamePrefix) && key !== cacheName)
         .map(key => caches.delete(key)));
-}
-
-async function onFetch(event) {
-    let cachedResponse = null;
-    if (event.request.method === 'GET') {
-        // For all navigation requests, try to serve index.html from cache
-        // If you need some URLs to be server-rendered, edit the following check to exclude those URLs
-        const shouldServeIndexHtml = event.request.mode === 'navigate';
-
-        const request = shouldServeIndexHtml ? 'index.html' : event.request;
-        const cache = await caches.open(cacheName);
-        cachedResponse = await cache.match(request);
-    }
-
-    return cachedResponse || fetch(event.request);
-}
+}