十二、實現登入

在學習ASP.NET Core Blazor程式設計系列二十二——登入（1）至學習ASP.NET Core Blazor程式設計系列二十六——登入（5）

系列文章中學習了使用AuthenticationStateProvider實現模擬登入。今天的文章實現JWT登入，使用WebAPI介面來實現通過JWT令牌登入。

在Visual Studio 2022的解決方案資源管理器中，滑鼠右鍵單擊「BlazorAppDemo」專案名稱，在彈出選單中選擇「新增—>新建資料夾」，並將新建資料夾改為「Api」。如下圖。

2.在Visual Studio 2022的解決方案資源管理器中，滑鼠左鍵選中「Api」資料夾，右鍵單擊，在彈出選單中選擇「新增—>新建項」，在彈出對話方塊中，選擇「API控制器-空」，並將控制器命名為「AuthController」。如下圖。並新增如下程式碼：

using BlazorAppDemo.Models;
using BlazorAppDemo.Utils;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Identity;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Configuration;
using Microsoft.IdentityModel.Tokens;
using Newtonsoft.Json.Linq;
using System.IdentityModel.Tokens.Jwt;
using System.Security.Claims;
using System.Text;
 
namespace BlazorAppDemo.Api
{
    [Route("api/[controller]")]
    [ApiController]
    public class AuthController : ControllerBase
    {
        private readonly IJWTHelper jwtHelper;
       
 
        public AuthController(IJWTHelper _IJWTHelper)
        {
            this.jwtHelper = _IJWTHelper;
           
            }
 
        [HttpPost("Login")]
            public async Task<ActionResult<UserToken>> Login(UserInfo userInfo)
        {
            //Demo用，更好的做法是查詢使用者表來實現
            if (userInfo.UserName == "admin" && userInfo.Password == "111111")
            {
                return BuildToken(userInfo);
            }
            else
            {
                UserToken userToken = new UserToken()
                {
                    StatusCode = System.Net.HttpStatusCode.Unauthorized,
                    IsSuccess = false
                   
                };
                return userToken;
            }
        }
      
 
        /// <summary>
        /// 建立Token
        /// </summary>
        /// <param name="userInfo"></param>
        /// <returns></returns>
        private UserToken BuildToken(UserInfo userInfo)
        {
          
            string jwtToken = jwtHelper.CreateJwtToken<UserInfo>(userInfo);

            //建立UserToken，回傳使用者端
            UserToken userToken = new UserToken()
            {

                StatusCode = System.Net.HttpStatusCode.OK,
                Token = jwtToken,
                ExpireTime = DateTime.Now.AddMinutes(30),
                IsSuccess= true
               
            };

            return userToken;
        }
    }
}

3.在Visual Studio 2022的解決方案資源管理器中，滑鼠左鍵選中「Models」資料夾，右鍵單擊，在彈出選單中選擇「新增—>類」，在彈出對話方塊中，將類命名為「UserToken」。並新增如下程式碼：

using System.Net;
namespace BlazorAppDemo.Models
{
    public class UserToken
    {

        public bool IsSuccess { get ; set; } 
        public HttpStatusCode StatusCode { get; set; }
        public string Token { get; set; }
        public DateTime ExpireTime { get; set; }
     }
}

4.在Visual Studio 2022的解決方案資源管理器中，滑鼠左鍵選中「Utils」資料夾，右鍵單擊，在彈出選單中選擇「新增—>類」，在彈出對話方塊中，將類命名為「TokenManager」。並新增如下程式碼：

using BlazorAppDemo.Models;
using System.Collections.Concurrent;
 
namespace BlazorAppDemo.Utils
{
    public class TokenManager
    {
        private const string TOKEN = "authToken";
 
        private static readonly ConcurrentDictionary<string, UserToken> tokenManager;

         static TokenManager()
        {

            tokenManager=new ConcurrentDictionary<string, UserToken>();
        }

        public static ConcurrentDictionary<string, UserToken> Instance { get { return tokenManager; } }

        public static string Token { get { return TOKEN; } }
    }
}

5.在Visual Studio 2022的解決方案資源管理器中，滑鼠左鍵選中「Auth」資料夾，右鍵單擊，在彈出選單中選擇「新增—>新建項」，在彈出對話方塊中，選擇「介面」，並將介面命名為「IAuthService」。如下圖。並新增如下程式碼：

using BlazorAppDemo.Models;

namespace BlazorAppDemo.Auth
{

    public interface IAuthService
    {

        Task<UserToken> LoginAsync(UserInfo userInfo);

        Task<UserToken> LogoutAsync();
    }
}

6.在Visual Studio 2022的解決方案資源管理器中，滑鼠左鍵選中「Auth」資料夾，右鍵單擊，在彈出選單中選擇「新增—>類」，在彈出對話方塊中，將類命名為「AuthService」。並新增如下程式碼：

using BlazorAppDemo.Models;
using BlazorAppDemo.Utils;
using Microsoft.AspNetCore.Components.Authorization;
using Microsoft.AspNetCore.Identity;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System.Collections.Concurrent;
using System.Net.Http;
using System.Text;
 
namespace BlazorAppDemo.Auth
{
 
    public class AuthService : IAuthService
    {
        private readonly HttpClient httpClient;
        private readonly AuthenticationStateProvider authenticationStateProvider;
        private readonly IConfiguration configuration;
        private readonly Api.AuthController authController;
        private readonly string currentUserUrl, loginUrl, logoutUrl;
 
     
        public AuthService( HttpClient httpClient, AuthenticationStateProvider authenticationStateProvider, IConfiguration configuration,Api.AuthController authController)
        {
            this.authController = authController;
            this.httpClient = httpClient;
            this.authenticationStateProvider = authenticationStateProvider;
            this.configuration = configuration;
            currentUserUrl = configuration["AuthUrl:Current"] ?? "Auth/Current/";
            loginUrl = configuration["AuthUrl:Login"] ?? "api/Auth/Login";
            logoutUrl = configuration["AuthUrl:Logout"] ?? "/api/Auth/Logout/";
        }
        public async Task<UserToken> LoginAsync(UserInfo userInfo)
        {

            var result = authController.Login(userInfo);
            var loginResponse =  result.Result.Value;
            if (loginResponse != null && loginResponse.IsSuccess)
                {                  
                    TokenManager.Instance.TryAdd(TokenManager.Token, loginResponse);
                   ((ImitateAuthStateProvider)authenticationStateProvider).NotifyUserAuthentication(loginResponse.Token);

                    httpClient.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("bearer", loginResponse.Token);
                     return loginResponse;
                }

            return new UserToken() { IsSuccess = false };
        }

        public Task<UserToken> LogoutAsync()
        {
            throw new NotImplementedException();
        }
    }
}

LoginAsync登入方法的實現功能：

將賬號與密碼，傳送到AuthController做驗證，驗證成功生成UserToken範例
將token寫到TokenManger範例中
通知前面頁面更新登入狀態
每次request的header將bearer token都帶上。

7. 在Visual Studio 2022的解決方案管理器中，使用滑鼠左鍵，雙擊ImitateAuthStateProvider.cs檔案，對程式碼進行修改。具體程式碼如下：

using BlazorAppDemo.Models;
using BlazorAppDemo.Utils;
using Microsoft.AspNetCore.Components.Authorization;
using System.Net.Http;
using System.Security.Claims;
 
namespace BlazorAppDemo.Auth
{
    public class ImitateAuthStateProvider : AuthenticationStateProvider
    {
        private readonly IJWTHelper jwt;
        private AuthenticationState anonymous;
        private readonly HttpClient httpClient;
 
        public ImitateAuthStateProvider(IJWTHelper _jwt, HttpClient httpClient)
        {

            anonymous = new AuthenticationState(new ClaimsPrincipal(new ClaimsIdentity()));
            jwt = _jwt;
            this.httpClient = httpClient;
        }
 
        bool isLogin = false;
        string token = string.Empty;
        public override Task<AuthenticationState> GetAuthenticationStateAsync()
        {
            //確認是否已經登入
            UserToken userToken;
                TokenManager.Instance.TryGetValue(TokenManager.Token,out userToken);
            string tokenInLocalStorage=string.Empty;
            if (userToken != null)
            {
                tokenInLocalStorage = userToken.Token;
            }
            if (string.IsNullOrEmpty(tokenInLocalStorage))
            {
                //沒有登入，則返回匿名登入者
                return Task.FromResult(anonymous);
            }
 
            //將token取出轉換為claim
            var claims = jwt.ParseToken(tokenInLocalStorage);
 
            //在每次request的header中都將加入bearer token
            httpClient.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("bearer", 
tokenInLocalStorage);
 
            //回傳帶有user claim的AuthenticationState
            return Task.FromResult(new AuthenticationState(new ClaimsPrincipal(new ClaimsIdentity(claims, "jwt"))));
 
        }
        public void Login(UserInfo request)
        {
            //1.驗證使用者賬號密碼是否正確
            if (request == null)
            {
                isLogin=false;
            }
            if (request.UserName == "user" && request.Password == "111111")
            {
                isLogin = true;
               token= jwt.CreateJwtToken<UserInfo>(request);
                Console.WriteLine($"JWT Token={token}");
            }
            NotifyAuthenticationStateChanged(GetAuthenticationStateAsync());
        }

        public void NotifyUserAuthentication(string token)
        {
            var claims = jwt.ParseToken(token);
            var authenticatedUser = new ClaimsPrincipal(new ClaimsIdentity(claims, "jwt"));

            var authState = Task.FromResult(new AuthenticationState(authenticatedUser));
            NotifyAuthenticationStateChanged(authState);
       }

    }
}

8. 在Visual Studio 2022的解決方案管理器中，使用滑鼠左鍵，雙擊Program.cs檔案，將之在文字編輯器中開啟，將我們寫的AuthController和框架中的HttpClient，使用DI方式注入，新增Controller服務。具體程式碼如下：

using BlazorAppDemo.Data;
using BlazorAppDemo.Models;
using Microsoft.AspNetCore.Components;
using Microsoft.AspNetCore.Components.Web;
using Microsoft.Extensions.Configuration;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Hosting;
using Microsoft.AspNetCore.Components.Authorization;
using BlazorAppDemo.Auth;
using Microsoft.AspNetCore.Authentication.JwtBearer;
using Microsoft.IdentityModel.Tokens;
using System.Text;
using System.IdentityModel.Tokens.Jwt;
using BlazorAppDemo.Utils;
using BlazorAppDemo.Api;
 
var builder = WebApplication.CreateBuilder(args);
 
 

// Add services to the container.
builder.Services.AddRazorPages();
builder.Services.AddServerSideBlazor();
builder.Services.AddSingleton<WeatherForecastService>();
IConfiguration config = ConfigHelper.Configuration;
System.Console.WriteLine(config["ConnectionStrings:BookContext"]);
builder.Services.AddDbContextFactory<BookContext>(opt =>
   opt.UseSqlServer(ConfigHelper.Configuration["ConnectionStrings:BookContext"]));
builder.Services.AddScoped<ImitateAuthStateProvider>();
builder.Services.AddScoped<AuthenticationStateProvider>(implementationFactory =>
implementationFactory.GetRequiredService<ImitateAuthStateProvider>());
builder.Services.AddScoped<JwtSecurityTokenHandler>();
//此處的url地址改成自己實際的地址

builder.Services.AddScoped(sp => new HttpClient { BaseAddress = new Uri("http://localhost:7110") });
 
builder.Services.AddScoped<IAuthService, AuthService>();
builder.Services.AddScoped<AuthController>();
//JWT
//JWT認證

builder.Services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme).AddJwtBearer(options =>
{
    //取出私鑰
    var secretByte = Encoding.UTF8.GetBytes(builder.Configuration["Authentication:SecretKey"]);
    options.TokenValidationParameters = new TokenValidationParameters()
    {
        //驗證釋出者
        ValidateIssuer = true,
        ValidIssuer = builder.Configuration["Authentication:Issuer"],
        //驗證接收者
        ValidateAudience = true,
        ValidAudience = builder.Configuration["Authentication:Audience"],
        //驗證是否過期
        ValidateLifetime = true,
        //驗證私鑰
        IssuerSigningKey = new SymmetricSecurityKey(secretByte)
    };
});
;
builder.Services.AddScoped<IJWTHelper,JWTHelper>();
 
var app = builder.Build();
 
// Configure the HTTP request pipeline.
if (!app.Environment.IsDevelopment())
{
    app.UseExceptionHandler("/Error");
    // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
    app.UseHsts();
}
 
 
using (var scope = app.Services.CreateScope())
{
    var services = scope.ServiceProvider;
    try
    {
        Console.WriteLine("資料庫開始初始化。");
        var context = services.GetRequiredService<BookContext>();
        // requires using Microsoft.EntityFrameworkCore;
        context.Database.Migrate();
        // Requires using RazorPagesMovie.Models;
        SeedData.Initialize(services);
        Console.WriteLine("資料庫初始化結束。");
    }
 
    catch (Exception ex)
    {
        var logger = services.GetRequiredService<ILogger<Program>>();
        logger.LogError(ex, "資料庫資料初始化錯誤.");
    }
}
 

app.UseHttpsRedirection();

app.UseStaticFiles();

 
app.UseRouting();
app.MapControllers();

 
app.MapBlazorHub();
app.MapFallbackToPage("/_Host");
app.UseAuthentication();
app.UseAuthorization();

 
app.Run();

9. 在Visual Studio 2022的選單欄上，找到「偵錯-->開始偵錯」或是按F5鍵，Visual Studio 2022會生成BlazorAppDemo應用程式，並在瀏覽器使用Rest偵錯外掛，對api/auth/login介面進行偵錯，只要登入成功就可以取得token。如下圖。

10.我們在使用者名稱輸入框中輸入使用者名稱"admin"，在密碼輸入框中輸入密碼"111111"，點選「登入」按鈕，進行登入。我們進入了系統。如下圖。

學習ASP.NET Core Blazor程式設計系列二十八——JWT登入（3）

十二、實現登入