5.在Visual Studio 2022的解决方案资源管理器中，鼠标左键选中“Utils”文件夹，右键单击，在弹出菜单中选择“添加—>新建项”，在弹出对话框中，选择“接口”，并将接口命名为“IJWTHelper”。如下图。并添加如下代码：

using Microsoft.IdentityModel.Tokens;
using System.Security.Claims;
 

namespace BlazorAppDemo.Utils
{

    public interface IJWTHelper

    {

        string CreateJwtToken<T>(T user);

        T GetToken<T>(string Token);

        IEnumerable<Claim> ParseToken(string token);

        string? ValidateJwtToken(IEnumerable<Claim> jwtToken);

        TokenValidationParameters ValidParameters();

    }
}

 

6.在Visual Studio 2022的解决方案资源管理器中，鼠标左键选中“Utils”文件夹，右键单击，在弹出菜单中选择“添加—>类”，在弹出对话框中，并将类命名为“JWTHelper”。并继承IJWTHelper接口，添加如下代码：

 

using BlazorAppDemo.Models;
using Microsoft.IdentityModel.Tokens;
using System.IdentityModel.Tokens.Jwt;
using System.Reflection;
using System.Security.Claims;
using System.Text;
 
namespace BlazorAppDemo.Utils
{

    public class JWTHelper : IJWTHelper
    {
        private readonly IConfiguration _configuration;
        private readonly JwtSecurityTokenHandler _jwtSecurityTokenHandler;

        public JWTHelper(IConfiguration configuration, 
JwtSecurityTokenHandler jwtSecurityTokenHandler)
        {
            _configuration = configuration;
            _jwtSecurityTokenHandler = jwtSecurityTokenHandler;

        }
        /// <summary>
        /// 创建加密JwtToken
        /// </summary>
        /// <param name="user"></param>
        /// <returns></returns>

        public string CreateJwtToken<T>(T user)
        {
            var signingAlogorithm = SecurityAlgorithms.HmacSha256;

            var claimList = this.CreateClaimList(user);
            //Signature

            //取出私钥并以utf8编码字节输出
            var secretByte = Encoding.UTF8.GetBytes(_configuration["Authentication:SecretKey"]);
            //使用非对称算法对私钥进行加密
            var signingKey = new SymmetricSecurityKey(secretByte);
            //使用HmacSha256来验证加密后的私钥生成数字签名

            var signingCredentials = new SigningCredentials(signingKey, signingAlogorithm);
            //在 RFC 7519 规范中(Section#4)，一共定义了 7 个预设的 Claims。
            //生成Token
            var Token = new JwtSecurityToken(
          issuer: _configuration["Authentication:Issuer"], //发布者
            audience: _configuration["Authentication:Audience"], //接收者
            claims: claimList, //存放的用户信息
            notBefore: DateTime.UtcNow, //发布时间
            expires: DateTime.UtcNow.AddDays(1), //有效期设置为1天
            signingCredentials //数字签名

            );

            //生成字符串token
            var TokenStr = new JwtSecurityTokenHandler().WriteToken(Token);
            return TokenStr;
        }
 
        public T GetToken<T>(string Token)
        {
            Type t = typeof(T);
 
            object objA = Activator.CreateInstance(t);
            var b = _jwtSecurityTokenHandler.ReadJwtToken(Token);
            foreach (var item in b.Claims)
            {
                PropertyInfo _Property = t.GetProperty(item.Type);
                if (_Property != null && _Property.CanRead)
                {
                    _Property.SetValue(objA, item.Value, null);
                }
 
            }
            return (T)objA;
        }

        /// <summary>
        /// 创建包含用户信息的CalimList
        /// </summary>
        /// <param name="authUser"></param>
        /// <returns></returns>

        private List<Claim> CreateClaimList<T>(T authUser)
        {

            var Class = typeof(UserInfo);
            List<Claim> claimList = new List<Claim>();

            foreach (var item in Class.GetProperties())
            {

                if (item.Name == "Password")
                {

                    continue;
                }

                claimList.Add(new Claim(ClaimTypes.Name, 
Convert.ToString(item.GetValue(authUser))));
            }

            return claimList;
        }
    

        /// /// <summary>
        /// 从令牌中获取数据声明
        /// </summary>
        /// <param name="token">令牌</param>
        /// <returns></returns>
        public IEnumerable<Claim> ParseToken(string token)
        {
            var tokenHandler = new JwtSecurityTokenHandler();
            var validateParameter = ValidParameters();
            token = token.Replace("Bearer ", "");
            try
            {
                tokenHandler.ValidateToken(token, validateParameter,
 out SecurityToken validatedToken);
                var jwtToken = tokenHandler.ReadJwtToken(token);
                return jwtToken.Claims;
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
                return null;
            }
        }
}
}

 

 

 

 

7. 在Visual Studio 2022的解决方案资源管理器中，使用鼠标左键双击“Auth”文件夹中的“ImitateAuthStateProvider.cs”文件，在文本编辑器中打开，对代码进行修改。具体代码如下：

using BlazorAppDemo.Models;
using BlazorAppDemo.Utils;
using Microsoft.AspNetCore.Components.Authorization;
using System.Security.Claims;


namespace BlazorAppDemo.Auth
{
    public class ImitateAuthStateProvider : AuthenticationStateProvider
    {

        private readonly IJWTHelper jwt;
        public ImitateAuthStateProvider(IJWTHelper _jwt) => jwt = _jwt; //DI

        bool isLogin = false;
        string token = string.Empty;
        public override Task<AuthenticationState> GetAuthenticationStateAsync()
        {

            if (isLogin)
            {
 
                var claims = new List<Claim>()
            {

                new Claim(ClaimTypes.Name,"user"),
                new Claim(ClaimTypes.Role, "admin")
            };

                var anonymous = new ClaimsIdentity(claims, "testAuthType");
                return Task.FromResult(new AuthenticationState(new ClaimsPrincipal(anonymous)));

            }
            else

            {

            var anonymous = new ClaimsIdentity();
 
            return Task.FromResult(new AuthenticationState(new ClaimsPrincipal(anonymous)));
        }

        }
        public void Login(UserInfo request)
        {
 
            //1.验证用户账号密码是否正确
            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());
        }
    }
}

 

8.在Visual Studio 2022的解决方案管理器中，使用鼠标左键，双击Program.cs文件，将之在文本编辑器中打开，将我们写的JWTHelper与JwtSecurityTokenHandler、使用DI方式注入，添加JWT认证服务。具体代码如下：

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;

 

var builder = WebApplication.CreateBuilder(args);
 

// Add services to the container.

builder.Services.AddRazorPages();

builder.Services.AddServerSideBlazor();

builder.Services.AddSingleton<WeatherForecastService>();

System.Console.WriteLine(ConfigHelper.Configuration["ConnectionStrings:BookContext"]);
builder.Services.AddDbContextFactory<BookContext>(opt =>
 opt.UseSqlServer(ConfigHelper.Configuration["ConnectionStrings:BookContext"]));

//builder.Services.AddScoped<AuthenticationStateProvider, ImitateAuthStateProvider>();

builder.Services.AddScoped<ImitateAuthStateProvider>();
builder.Services.AddScoped<AuthenticationStateProvider>(implementationFactory =>

implementationFactory.GetRequiredService<ImitateAuthStateProvider>());
builder.Services.AddScoped<JwtSecurityTokenHandler>();
 
//JWT
//JWT认证

builder.Services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme).AddJwtBearer(options =>
{

    //取出私钥
    var secretByte = Encoding.UTF8.GetBytes(builder.Configuration["Authentication:SecretKey"]);
    options.TokenValidationParameters = new TokenValidationParameters()

    {
        //验证发布者
        ValidateIssuer = true,
        ValidIssuer = builder.Configuration["Authentication:Issuer"],
        //验证接收者
        ValidateAudience = true,

        ValidAudience = builder.Configuration["Authentication:Audience"],
        //验证是否过期
        ValidateLifetime = true,
        //验证私钥
        IssuerSigningKey = new SymmetricSecurityKey(secretByte)
    };

});
//自己写的Jwt 扩展
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("数据库开始初始化。");
        var context = services.GetRequiredService<BookContext>();
        // requires using Microsoft.EntityFrameworkCore;

        context.Database.Migrate();

        // Requires using RazorPagesMovie.Models;
        SeedData.Initialize(services);
        Console.WriteLine("数据库初始化结束。");
    } 

    catch (Exception ex)

    {
        var logger = services.GetRequiredService<ILogger<Program>>();
        logger.LogError(ex, "数据库数据初始化错误.");

    }
}


app.UseHttpsRedirection();
 
app.UseStaticFiles();

 
app.UseRouting();


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

 

app.Run();

 

9.在Visual Studio 2022的菜单栏上，找到“调试-->开始调试”或是按F5键，Visual Studio 2022会生成BlazorAppDemo应用程序，浏览器中会Login登录页面。

10.我们在用户名输入框中输入用户名，在密码输入框中输入密码，点击“登录”按钮，进行模拟登录。我们进入了系统。并且生成了JWT Token。如下图。