logo + oidc client PostIt

src/PostIt/PostIt/Assets/yavsc-logo.svg

@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 240 240" role="img" aria-label="Yavsc — Yet Another Very Small Company">
+  <title>Yavsc</title>
+  <desc>Yet Another Very Small Company</desc>
+  <defs>
+    <linearGradient id="g" x1="0" y1="0" x2="1" y2="1">
+      <stop offset="0%" stop-color="#0EA5E9"/>
+      <stop offset="100%" stop-color="#1E40AF"/>
+    </linearGradient>
+  </defs>
+  <!-- Rounded square badge -->
+  <rect x="8" y="8" width="224" height="224" rx="44" ry="44" fill="url(#g)"/>
+  <!-- Stylized Y formed by three strokes converging -->
+  <g fill="none" stroke="#ffffff" stroke-width="22" stroke-linecap="round" stroke-linejoin="round">
+    <path d="M70 60 L120 130"/>
+    <path d="M170 60 L120 130"/>
+    <path d="M120 130 L120 188"/>
+  </g>
+  <!-- Small dot: the "very small" wink -->
+  <circle cx="120" cy="46" r="8" fill="#FACC15"/>
+</svg>

src/PostIt/PostIt/ViewModels/MainViewModel.cs

@@ -2,6 +2,12 @@
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Linq;
+using System.Net.Http;
+using System.Net.Http.Headers;
+using System.Net.Http.Json;
+using System.Text;
+using System.Text.Json;
+using System.Text.Json.Serialization;
 using System.Threading.Tasks;
 using CommunityToolkit.Mvvm.ComponentModel;
 using CommunityToolkit.Mvvm.Input;
@@ -12,6 +18,18 @@ namespace PostIt.ViewModels;
 
 public partial class MainViewModel : ViewModelBase
 {
+    [ObservableProperty]
+    private string _authority = "https://localhost:5001";
+
+    [ObservableProperty]
+    private string _clientId = "postit";
+
+    [ObservableProperty]
+    private string _clientSecret = "postit-secret";
+
+    [ObservableProperty]
+    private string _scope = "blog";
+
     [ObservableProperty]
     private string _apiUrl = "http://localhost:5000";
 
@@ -79,6 +97,19 @@ public partial class MainViewModel : ViewModelBase
         ApplyFilter();
     }
 
+    [RelayCommand]
+    public async Task LoginAsync()
+    {
+        await ExecuteAsync(async () =>
+        {
+            var tokenResponse = await RequestClientCredentialsTokenAsync();
+            BearerToken = tokenResponse.AccessToken;
+            StatusMessage = string.IsNullOrWhiteSpace(tokenResponse.Error)
+                ? "Bearer token acquired."
+                : $"Token acquired with warning: {tokenResponse.ErrorDescription}";
+        });
+    }
+
     [RelayCommand]
     public async Task SaveAsync()
     {
@@ -200,6 +231,52 @@ public partial class MainViewModel : ViewModelBase
         }
     }
 
+    private async Task<TokenResponse> RequestClientCredentialsTokenAsync()
+    {
+        using var client = new HttpClient();
+        var discoveryUrl = Authority.TrimEnd('/') + "/.well-known/openid-configuration";
+        var discoveryDocument = await client.GetFromJsonAsync<DiscoveryDocument>(discoveryUrl, JsonOptions);
+
+        if (discoveryDocument is null || string.IsNullOrWhiteSpace(discoveryDocument.TokenEndpoint))
+        {
+            throw new InvalidOperationException("Unable to discover the token endpoint from the authority.");
+        }
+
+        var request = new HttpRequestMessage(HttpMethod.Post, discoveryDocument.TokenEndpoint)
+        {
+            Content = new FormUrlEncodedContent(new Dictionary<string, string>
+            {
+                ["grant_type"] = "client_credentials",
+                ["client_id"] = ClientId,
+                ["client_secret"] = ClientSecret,
+                ["scope"] = Scope,
+            })
+        };
+
+        var response = await client.SendAsync(request).ConfigureAwait(false);
+
+        var payload = await response.Content.ReadFromJsonAsync<TokenResponse>(JsonOptions);
+        if (payload is null)
+        {
+            throw new InvalidOperationException("Invalid token response from the identity provider.");
+        }
+
+        if (!response.IsSuccessStatusCode)
+        {
+            var message = string.IsNullOrWhiteSpace(payload.ErrorDescription)
+                ? payload.Error ?? "Unknown token error"
+                : payload.ErrorDescription;
+            throw new InvalidOperationException(message);
+        }
+
+        return payload;
+    }
+
+    private static readonly JsonSerializerOptions JsonOptions = new()
+    {
+        PropertyNameCaseInsensitive = true
+    };
+
     private BlogApiClient CreateClient()
         => new BlogApiClient(ApiUrl, BearerToken);
 
@@ -213,4 +290,12 @@ public partial class MainViewModel : ViewModelBase
 
     private bool CanSave() => SelectedPost is not null && !IsBusy;
     private bool CanDelete() => SelectedPost is not null && SelectedPost.Id != 0 && !IsBusy;
+
+    private sealed record DiscoveryDocument([property: JsonPropertyName("token_endpoint")] string? TokenEndpoint);
+    private sealed record TokenResponse(
+        [property: JsonPropertyName("access_token")] string? AccessToken,
+        [property: JsonPropertyName("token_type")] string? TokenType,
+        [property: JsonPropertyName("expires_in")] int ExpiresIn,
+        [property: JsonPropertyName("error")] string? Error,
+        [property: JsonPropertyName("error_description")] string? ErrorDescription);
 }

src/PostIt/PostIt/Views/MainView.axaml

@@ -16,17 +16,27 @@
     <StackPanel Margin="12" Spacing="12">
         <TextBlock Text="PostIt Blog API Interface" FontSize="20" FontWeight="Bold" />
 
-        <Grid ColumnDefinitions="Auto,1*" RowDefinitions="Auto,Auto,Auto,Auto" ColumnSpacing="8" RowSpacing="8">
-            <TextBlock Text="API URL" VerticalAlignment="Center" />
-            <TextBox Grid.Column="1" Text="{Binding ApiUrl, Mode=TwoWay}" />
+        <Grid ColumnDefinitions="Auto,1*" RowDefinitions="Auto,Auto,Auto,Auto,Auto,Auto,Auto" ColumnSpacing="8" RowSpacing="8">
+            <TextBlock Text="Authority" VerticalAlignment="Center" />
+            <TextBox Grid.Column="1" Text="{Binding Authority, Mode=TwoWay}" PlaceholderText="https://localhost:5001" />
 
-            <TextBlock Grid.Row="1" Text="Bearer token" VerticalAlignment="Center" />
-            <TextBox Grid.Row="1" Grid.Column="1" Text="{Binding BearerToken, Mode=TwoWay}" PlaceholderText="Optional token for blog scope" />
+            <TextBlock Grid.Row="1" Text="Client ID" VerticalAlignment="Center" />
+            <TextBox Grid.Row="1" Grid.Column="1" Text="{Binding ClientId, Mode=TwoWay}" />
 
-            <TextBlock Grid.Row="2" Text="Search" VerticalAlignment="Center" />
-            <TextBox Grid.Row="2" Grid.Column="1" Text="{Binding SearchText, Mode=TwoWay}" PlaceholderText="Search title, article, author" />
+            <TextBlock Grid.Row="2" Text="Client secret" VerticalAlignment="Center" />
+            <TextBox Grid.Row="2" Grid.Column="1" Text="{Binding ClientSecret, Mode=TwoWay}" />
 
-            <StackPanel Grid.Row="3" Grid.ColumnSpan="2" Orientation="Horizontal" Spacing="8">
+            <TextBlock Grid.Row="3" Text="Scope" VerticalAlignment="Center" />
+            <TextBox Grid.Row="3" Grid.Column="1" Text="{Binding Scope, Mode=TwoWay}" />
+
+            <TextBlock Grid.Row="4" Text="API URL" VerticalAlignment="Center" />
+            <TextBox Grid.Row="4" Grid.Column="1" Text="{Binding ApiUrl, Mode=TwoWay}" />
+
+            <TextBlock Grid.Row="5" Text="Bearer token" VerticalAlignment="Center" />
+            <TextBox Grid.Row="5" Grid.Column="1" Text="{Binding BearerToken, Mode=TwoWay}" PlaceholderText="Token for blog scope" />
+
+            <StackPanel Grid.Row="6" Grid.ColumnSpan="2" Orientation="Horizontal" Spacing="8">
+                <Button Command="{Binding LoginCommand}" Content="Acquire token" />
                 <Button Command="{Binding LoadPostsCommand}" Content="Load posts" />
                 <Button Command="{Binding SearchCommand}" Content="Filter" />
                 <Button Command="{Binding NewCommand}" Content="New post" />

src/PostIt/PostIt/Views/MainWindow.axaml

@@ -6,7 +6,7 @@
         xmlns:views="using:PostIt.Views"
         mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
         x:Class="PostIt.Views.MainWindow"
-        Icon="/Assets/avalonia-logo.ico"
+        Icon="/Assets/yavsc-logo.ico"
         Title="PostIt">
         <views:MainView />
 </Window>