Blazor Server，即運行在伺服器上的 Blazor 應用程式，它的優點是應用程式在首次運行時，客戶端不需要下載運行時。但它的代碼是在伺服器上執行的，然後通過 SignalR 通信來更新客戶端的 UI，所以它要求必須建立 Web Socket 連接。用於 Blazor 應用的 Signal ...

十二、實現登入

在學習ASP.NET Core Blazor編程系列二十二——登錄（1）至學習ASP.NET Core Blazor編程系列二十六——登錄（5）

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

在Visual Studio 2022的解決方案資源管理器中，滑鼠右鍵單擊“BlazorAppDemo”項目名稱，在彈出菜單中選擇 “添加—>新建文件夾”，並將新建文件夾改為“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”文件夾，右鍵單擊，在彈出菜單中選擇“添加—>新建項”，在彈出對話框中，選擇“API控制器-空”，並將控制器命名為“AuthController”。如下圖。並添加如下代碼：

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，更好的做法是查詢用戶表來實現
            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，回傳客戶端
            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”文件夾，右鍵單擊，在彈出菜單中選擇“添加—>類”，在彈出對話框中，將類命名為“UserToken”。並添加如下代碼：

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”文件夾，右鍵單擊，在彈出菜單中選擇“添加—>類”，在彈出對話框中，將類命名為“TokenManager”。並添加如下代碼：

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”文件夾，右鍵單擊，在彈出菜單中選擇“添加—>新建項”，在彈出對話框中，選擇“介面”，並將介面命名為“IAuthService”。如下圖。並添加如下代碼：

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”文件夾，右鍵單擊，在彈出菜單中選擇“添加—>類”，在彈出對話框中，將類命名為“AuthService”。並添加如下代碼：

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登錄方法的實現功能：

將賬號與密碼，發送到AuthController做驗證，驗證成功生成UserToken實例
將token寫到TokenManger實例中
通知前面頁面更新登錄狀態
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文件，對代碼進行修改。具體代碼如下：

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()
        {
            //確認是否已經登錄
            UserToken userToken;
                TokenManager.Instance.TryGetValue(TokenManager.Token,out userToken);
            string tokenInLocalStorage=string.Empty;
            if (userToken != null)
            {
                tokenInLocalStorage = userToken.Token;
            }
            if (string.IsNullOrEmpty(tokenInLocalStorage))
            {
                //沒有登錄，則返回匿名登錄者
                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.驗證用戶賬號密碼是否正確
            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文件，將之在文本編輯器中打開，將我們寫的AuthController和框架中的HttpClient，使用DI方式註入，添加Controller服務。具體代碼如下：

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()
    {
        //驗證發佈者
        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, "資料庫數據初始化錯誤.");
    }
}
 

app.UseHttpsRedirection();

app.UseStaticFiles();

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

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

 
app.Run();