.Net Core中自定義認證實現

chaney1992發表於2022-01-23

一、起因

　最近專案中需要對專案同時支援JWT認證，以及自定義的認證校驗方式認證。通過對官方文件瞭解，得到認證實現主要通過繼承 IAuthenticationHandler 或 AuthenticationHandler<TOptions>來實現自定義認證的處理。　

　那麼接下來實現一個自定義的認證訪問。

二、自定義認證實現 

　1、根據前面內容得知，處理認證通過IAuthenticationHandler 例項處理；那麼首先新增一個自定義IAuthenticationHandler 型別：

/// <summary>
/// 方式一：自定義認證處理器
/// </summary>
public class CustomerAuthenticationHandler : IAuthenticationHandler
{
    private IUserService _userService;
    public CustomerAuthenticationHandler(IUserService userService)
    {
        _userService = userService;
    }

    /// <summary>
    /// 自定義認證Scheme名稱
    /// </summary>
    public const string CustomerSchemeName = "cusAuth";

    private AuthenticationScheme _scheme;
    private HttpContext _context;

    /// <summary>
    /// 認證邏輯：認證校驗主要邏輯
    /// </summary>
    /// <returns></returns>
    public Task<AuthenticateResult> AuthenticateAsync()
    {
        AuthenticateResult result;
        _context.Request.Headers.TryGetValue("Authorization", out StringValues values);
        string valStr = values.ToString();
        if (!string.IsNullOrWhiteSpace(valStr))
        {
            //認證模擬basic認證：cusAuth YWRtaW46YWRtaW4=
            string[] authVal = System.Text.Encoding.UTF8.GetString(Convert.FromBase64String(valStr.Substring(CustomerSchemeName.Length + 1))).Split(':');
            var loginInfo = new Dto.LoginDto() { Username = authVal[0], Password = authVal[1] };
            var validVale = _userService.IsValid(loginInfo);
            if (!validVale)
                result = AuthenticateResult.Fail("未登陸");
            else
            {
                var ticket = GetAuthTicket(loginInfo.Username, "admin");
                result = AuthenticateResult.Success(ticket);
            }
        }
        else
        {
            result = AuthenticateResult.Fail("未登陸");
        }
        return Task.FromResult(result);
    }

    /// <summary>
    /// 未登入時的處理
    /// </summary>
    /// <param name="properties"></param>
    /// <returns></returns>
    public Task ChallengeAsync(AuthenticationProperties properties)
    {
        _context.Response.StatusCode = (int)HttpStatusCode.Unauthorized;
        return Task.CompletedTask;
    }

    /// <summary>
    /// 許可權不足時處理
    /// </summary>
    /// <param name="properties"></param>
    /// <returns></returns>
    public Task ForbidAsync(AuthenticationProperties properties)
    {
        _context.Response.StatusCode = (int)HttpStatusCode.Forbidden;
        return Task.CompletedTask;
    }

    /// <summary>
    /// 初始化認證
    /// </summary>
    /// <param name="scheme"></param>
    /// <param name="context"></param>
    /// <returns></returns>
    public Task InitializeAsync(AuthenticationScheme scheme, HttpContext context)
    {
        _scheme = scheme;
        _context = context;
        return Task.CompletedTask;
    }

    #region 認證校驗邏輯

    /// <summary>
    /// 生成認證票據
    /// </summary>
    /// <param name="name"></param>
    /// <param name="role"></param>
    /// <returns></returns>
    private AuthenticationTicket GetAuthTicket(string name, string role)
    {
        var claimsIdentity = new ClaimsIdentity(new Claim[]
        {
    new Claim(ClaimTypes.Name, name),
    new Claim(ClaimTypes.Role, role),
        }, CustomerSchemeName);
        var principal = new ClaimsPrincipal(claimsIdentity);
        return new AuthenticationTicket(principal, _scheme.Name);
    }

    #endregion
}

/// <summary>
/// 方式二：繼承已實現的基類
/// </summary>
public class SubAuthenticationHandler : AuthenticationHandler<AuthenticationSchemeOptions>
{
    public SubAuthenticationHandler(IOptionsMonitor<AuthenticationSchemeOptions> options, ILoggerFactory logger, UrlEncoder encoder, ISystemClock clock)
        : base(options, logger, encoder, clock)
    {
    }

    protected override Task<AuthenticateResult> HandleAuthenticateAsync()
    {
        throw new NotImplementedException();
    }
}

　2、在Startup.cs中啟用自定義認證：

public void ConfigureServices(IServiceCollection services)
{
    //other code
    services.AddAuthentication(o =>
    {
        x.DefaultAuthenticateScheme = CustomerAuthenticationHandler.CustomerSchemeName;
        x.DefaultChallengeScheme = CustomerAuthenticationHandler.CustomerSchemeName;
        o.AddScheme<CustomerAuthenticationHandler>(CustomerAuthenticationHandler.CustomerSchemeName, CustomerAuthenticationHandler.CustomerSchemeName);
    });
    //other code
}

public void Configure(IApplicationBuilder app)
{
    //other code
    app.UseRouting();

    //在UseRouting後；UseEndpoints前新增以下程式碼
    app.UseAuthentication();
    app.UseAuthorization();

    //other code
    app.UseEndpoints()
}

　3、在控制器上新增認證標記，測試驗證

//指定認證時，採用CustomerAuthenticationHandler.CustomerSchemeName
[Authorize(AuthenticationSchemes = CustomerAuthenticationHandler.CustomerSchemeName)]
[Route("api/[controller]")]
[ApiController]
public class AuditLogController : ControllerBase
{
 //code
}

　　呼叫

　　

三、多認證支援

　在實際專案中可能存在，對一個控制器支援多種認證方式如：常用的Jwt認證、自定義認證等，那麼如何實現呢？

　1、在Startup的ConfigureServices 方法中新增以下邏輯：

public void ConfigureServices(IServiceCollection services)
{
    //other code
    services.Configure<JwtSetting>(Configuration.GetSection("JWTSetting"));
    var token = Configuration.GetSection("JWTSetting").Get<JwtSetting>();
    //JWT認證
    services.AddAuthentication(x =>
    {
        x.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;
        x.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;
　　　　　//新增自定義認證處理器
        x.AddScheme<CustomerAuthenticationHandler>(CustomerAuthenticationHandler.CustomerSchemeName, CustomerAuthenticationHandler.CustomerSchemeName);
    }).AddJwtBearer(x =>
    {
        x.RequireHttpsMetadata = false;
        x.SaveToken = true;
        x.TokenValidationParameters = new TokenValidationParameters
        {
            ValidateIssuerSigningKey = true,
            IssuerSigningKey = new SymmetricSecurityKey(Encoding.ASCII.GetBytes(token.SecretKey)),
            ValidIssuer = token.Issuer,
            ValidAudience = token.Audience,
            ValidateIssuer = false,
            ValidateAudience = false
        };
    });
    //other code
}

　2、在需要支援多種認證方式的控制器上新增標記：

//指定認證時，採用CustomerAuthenticationHandler.CustomerSchemeName
[Authorize(AuthenticationSchemes = CustomerAuthenticationHandler.CustomerSchemeName)]
[Route("api/[controller]")]
[ApiController]
public class AuditLogController : ControllerBase
{
 //code
}



//指定認證採用JWT 
[Authorize(AuthenticationSchemes = JwtBearerDefaults.AuthenticationScheme)] 
public class WeatherForecastController : ControllerBase 
{
  //code 
}

 　　這樣就支援了兩種認證方式

　3、一個控制器支援多種認證型別：繼承Jwt認證處理，並根據Scheme那麼呼叫自定義的認證處理器：

/// <summary>
/// 方式二：同時支援多種認證方式
/// </summary>
public class MultAuthenticationHandler : JwtBearerHandler
{
    public const string MultAuthName = "MultAuth";
    IUserService _userService;
    public MultAuthenticationHandler(IOptionsMonitor<JwtBearerOptions> options, ILoggerFactory logger, UrlEncoder encoder, ISystemClock clock, IUserService userService)
        : base(options, logger, encoder, clock)
    {
        _userService = userService;
    }

    protected override Task<AuthenticateResult> HandleAuthenticateAsync()
    {
        Context.Request.Headers.TryGetValue("Authorization", out StringValues values);
        string valStr = values.ToString();
        if (valStr.StartsWith(CustomerAuthenticationHandler.CustomerSchemeName))
        {
            var result = Valid();
            if (result != null)
                return Task.FromResult(AuthenticateResult.Success(result));
            else
                return Task.FromResult(AuthenticateResult.Fail("未認證"));
        }
        else
            return base.AuthenticateAsync();
    }

    private AuthenticationTicket Valid()
    {
        Context.Request.Headers.TryGetValue("Authorization", out StringValues values);
        string valStr = values.ToString();
        if (!string.IsNullOrWhiteSpace(valStr))
        {
            //認證模擬basic認證：cusAuth YWRtaW46YWRtaW4=
            string[] authVal = System.Text.Encoding.UTF8.GetString(Convert.FromBase64String(valStr.Substring(CustomerAuthenticationHandler.CustomerSchemeName.Length + 1))).Split(':');
            var loginInfo = new Dto.LoginDto() { Username = authVal[0], Password = authVal[1] };
            if (_userService.IsValid(loginInfo))
                return GetAuthTicket(loginInfo.Username, "admin");
        }
        return null;
    }

    /// <summary>
    /// 生成認證票據
    /// </summary>
    /// <param name="name"></param>
    /// <param name="role"></param>
    /// <returns></returns>
    private AuthenticationTicket GetAuthTicket(string name, string role)
    {
        var claimsIdentity = new ClaimsIdentity(new Claim[]
        {
            new Claim(ClaimTypes.Name, name),
            new Claim(ClaimTypes.Role, role),
        }, CustomerAuthenticationHandler.CustomerSchemeName);
        var principal = new ClaimsPrincipal(claimsIdentity);
        return new AuthenticationTicket(principal, CustomerAuthenticationHandler.CustomerSchemeName);
    }
}

四、總結

 　.Net Core中的自定義認證主要通過實現IAuthenticationHandler 介面實現，如果要實現多認證方式通過AddScheme 應用自定義實現的認證處理器。

　原始碼：github

　參考：認證

　　

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