Implemented LiteCharms Security TokenService

LiteCharms.Features/Api/Configuration/LiteCharmsClientSettings.cs

@@ -0,0 +1,14 @@
+namespace LiteCharms.Features.Api.Configuration;
+
+public sealed class LiteCharmsClientSettings
+{
+    public string? Authority { get; set; }
+
+    public string? GrantType { get; set; }
+
+    public string? ClientId { get; set; }
+
+    public string? ClientSecret { get; set; }
+
+    public string? Scope { get; set; }
+}

LiteCharms.Features/Api/Models/TokenErrorResponse.cs

@@ -0,0 +1,13 @@
+namespace LiteCharms.Features.Api.Models;
+
+public sealed class TokenErrorResponse
+{
+    [JsonPropertyName("error")]
+    public string? Error { get; set; }
+
+    [JsonPropertyName("error_description")]
+    public string? ErrorDescription { get; set; }
+
+    [JsonPropertyName("error_uri")]
+    public string? ErrorUri { get; set; }
+}

LiteCharms.Features/Api/Models/TokenRequest.cs

@@ -0,0 +1,20 @@
+namespace LiteCharms.Features.Api.Models;
+
+public sealed class TokenRequest
+{
+    [JsonPropertyName("grant_type")]
+    [AliasAs("grant_type")]
+    public string? GrantType { get; set; }
+
+    [JsonPropertyName("client_id")]
+    [AliasAs("client_id")]
+    public string? ClientId { get; set; }
+
+    [JsonPropertyName("client_secret")]
+    [AliasAs("client_secret")]
+    public string? ClientSecret { get; set; }
+
+    [JsonPropertyName("scope")]
+    [AliasAs("scope")]
+    public string? Scope { get; set; }
+}

LiteCharms.Features/Api/Models/TokenResponse.cs

@@ -0,0 +1,17 @@
+namespace LiteCharms.Features.Api.Models;
+
+public sealed class TokenResponse
+{
+    [JsonPropertyName("access_token")]
+    public string? AccessToken { get; set; }
+
+    [JsonPropertyName("expires_in")]
+    public int ExpiresIn { get; set; }
+
+    [JsonPropertyName("token_type")]
+    public string? TokenType { get; set; }
+
+    [JsonPropertyName("scope")]
+    public string? Scope { get; set; }
+}
+

LiteCharms.Features/Api/Sdk/IConnectApi.cs

@@ -0,0 +1,10 @@
+using LiteCharms.Features.Api.Models;
+
+namespace LiteCharms.Features.Api.Sdk;
+
+public interface IConnectApi
+{
+    [Post("/connect/token")]
+    ValueTask<HttpResponseMessage> GetToken([Body(BodySerializationMethod.UrlEncoded)] TokenRequest request, 
+        CancellationToken cancellationToken = default);
+}

LiteCharms.Features/Api/TokenService.cs

@@ -0,0 +1,67 @@
+using LiteCharms.Features.Abstractions;
+using LiteCharms.Features.Api.Configuration;
+using LiteCharms.Features.Api.Models;
+using LiteCharms.Features.Api.Sdk;
+
+namespace LiteCharms.Features.Api;
+
+public sealed class TokenService(IConnectApi connectApi, IOptions<LiteCharmsClientSettings> clientOptions) : IService
+{
+    private readonly LiteCharmsClientSettings clientSettings = clientOptions.Value;
+
+    public async Task<Result<TokenResponse>> GenerateAsync(CancellationToken cancellationToken = default)
+    {
+        try
+        {
+            var request = new TokenRequest
+            {
+                ClientId = clientSettings.ClientId,
+                ClientSecret = clientSettings.ClientSecret,
+                GrantType = clientSettings.GrantType,
+                Scope = clientSettings.Scope,
+            };
+
+            using var response = await connectApi.GetToken(request, cancellationToken);
+
+            var contentRaw = await response.Content.ReadAsStringAsync(cancellationToken);
+
+            if (string.IsNullOrWhiteSpace(contentRaw))
+                return Result.Fail(new Error($"The authentication endpoint returned an empty payload. Status code: {response.StatusCode}"));
+
+            if (response.IsSuccessStatusCode)
+            {
+                var tokenResponse = JsonSerializer.Deserialize<TokenResponse>(contentRaw);
+
+                return !string.IsNullOrWhiteSpace(tokenResponse?.AccessToken)
+                    ? Result.Ok(tokenResponse)
+                    : Result.Fail<TokenResponse>(new Error("Authentication succeeded, but no access token was found in the response payload."));
+            }
+
+            try
+            {
+                var errorResult = JsonSerializer.Deserialize<TokenErrorResponse>(contentRaw);
+
+                if (errorResult != null)
+                {
+                    string summary = $"{errorResult.Error}: {errorResult.ErrorDescription}";
+
+                    return Result.Fail(new Error(summary));
+                }
+            }
+            catch
+            {
+                return Result.Fail(new Error($"Authentication failed: {contentRaw}"));
+            }
+
+            return Result.Fail(new Error($"Authentication failed with status code: {response.StatusCode}"));
+        }
+        catch (OperationCanceledException ex)
+        {
+            return Result.Fail(new Error("The token generation request was canceled.").CausedBy(ex));
+        }
+        catch (Exception ex)
+        {
+            return Result.Fail(new Error(ex.Message).CausedBy(ex));
+        }
+    }
+}

LiteCharms.Features/Extensions/Api.cs

@@ -1,7 +1,7 @@
 using LiteCharms.Features.Abstractions;
 using LiteCharms.Features.Api;
 using LiteCharms.Features.Api.Configuration;
-using Microsoft.AspNetCore.Authentication.JwtBearer;
+using LiteCharms.Features.Api.Sdk;
 
 namespace LiteCharms.Features.Extensions;
 
@@ -9,6 +9,36 @@ public static class Api
 {
     public const string Books = nameof(Books);
     public const string Payments = nameof(Payments);
+    
+    public static IServiceCollection AddSecurityApiSdk(this IServiceCollection services, IConfiguration configuration)
+    {
+        var configSection = configuration.GetSection(nameof(LiteCharmsClientSettings));
+
+        var authOptions = new LiteCharmsClientSettings();
+        configSection.Bind(authOptions);
+
+        services.Configure<LiteCharmsClientSettings>(configSection);
+
+        if (string.IsNullOrWhiteSpace(authOptions.Authority))
+            return services;
+
+        if (!authOptions.Authority.EndsWith("/", StringComparison.Ordinal)) authOptions.Authority += "/";
+
+        services.AddRefitClient<IConnectApi>()
+            .ConfigureHttpClient(config =>
+            {
+                config.BaseAddress = new Uri(authOptions.Authority);
+                config.Timeout = TimeSpan.FromSeconds(15);
+            })
+            .AddStandardResilienceHandler(options =>
+            {
+                options.Retry.MaxRetryAttempts = 3;
+                options.Retry.Delay = TimeSpan.FromSeconds(1);
+                options.Retry.BackoffType = Polly.DelayBackoffType.Exponential;
+            });
+
+        return services;
+    }
 
     public static IServiceCollection AddLiteCharmsWebSecurity(this IServiceCollection services, IConfiguration configuration)
     {

LiteCharms.Features/LiteCharms.Features.csproj

@@ -37,11 +37,23 @@
     <PackageReference Include="IdentityModel" Version="6.2.0" />
     <PackageReference Include="Microsoft.AspNetCore.Authentication.Certificate" Version="10.0.9" />
     <PackageReference Include="Microsoft.AspNetCore.Authentication.JwtBearer" Version="10.0.9" />
+    <PackageReference Include="Microsoft.Extensions.Http.Polly" Version="10.0.9" />
+    <PackageReference Include="Microsoft.Extensions.Http.Resilience" Version="10.7.0" />
+    <PackageReference Include="Polly" Version="8.7.0" />
+    <PackageReference Include="Polly.Extensions" Version="8.7.0" />
 
     <Using Include="Microsoft.AspNetCore.Authentication" />
     <Using Include="Microsoft.AspNetCore.Authentication.OpenIdConnect" />
     <Using Include="Microsoft.AspNetCore.Authentication.Cookies" />
     <Using Include="IdentityModel.AspNetCore.OAuth2Introspection" />
+    <Using Include="Microsoft.AspNetCore.Authentication.JwtBearer" />
+  </ItemGroup>
+
+  <!-- API SDK Composer-->
+  <ItemGroup>
+    <PackageReference Include="Refit.HttpClientFactory" Version="11.0.1" />
+
+    <Using Include="Refit" />
   </ItemGroup>
 
   <!-- API Versioning -->
@@ -183,6 +195,7 @@
   <!-- Shared Usings -->
   <ItemGroup>
     <Using Include="Microsoft.AspNetCore.Components.Server.ProtectedBrowserStorage" />
+    <Using Include="System.Text.Json.Serialization" />
     <Using Include="System.Reflection" />
     <Using Include="Microsoft.Extensions.DependencyInjection.Extensions" />
     <Using Include="Microsoft.AspNetCore.Routing" />