.Net Core中自定义认证实现

一、起因

　最近项目中需要对项目同时支持JWT认证，以及自定义的认证校验方式认证。通过对官方文档了解，得到认证实现主要通过继承IAuthenticationHandler 或 AuthenticationHandler<TOptions>来实现自定义认证的处理。　

　那么接下来实现一个自定义的认证访问。

二、自定义认证实现

　1、根据前面内容得知，处理认证通过IAuthenticationHandler 实例处理；那么首先添加一个自定义IAuthenticationHandler 类型：

/// <summary>
/// 方式一：自定义认证处理器
/// </summary>
public class CustomerAuthenticationHandler : IAuthenticationHandler
{
    private IUserService _userService;
    public CustomerAuthenticationHandler(IUserService userService)
    {
        _userService = userService;
    }

    /// <summary>
    /// 自定义认证Scheme名称
    /// </summary>
    public const string CustomerSchemeName = "cusAuth";

    private AuthenticationScheme _scheme;
    private HttpContext _context;

    /// <summary>
    /// 认证逻辑：认证校验主要逻辑
    /// </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))
        {
            //认证模拟basic认证：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("未登陆");
            else
            {
                var ticket = GetAuthTicket(loginInfo.Username, "admin");
                result = AuthenticateResult.Success(ticket);
            }
        }
        else
        {
            result = AuthenticateResult.Fail("未登陆");
        }
        return Task.FromResult(result);
    }

    /// <summary>
    /// 未登录时的处理
    /// </summary>
    /// <param name="properties"></param>
    /// <returns></returns>
    public Task ChallengeAsync(AuthenticationProperties properties)
    {
        _context.Response.StatusCode = (int)HttpStatusCode.Unauthorized;
        return Task.CompletedTask;
    }

    /// <summary>
    /// 权限不足时处理
    /// </summary>
    /// <param name="properties"></param>
    /// <returns></returns>
    public Task ForbidAsync(AuthenticationProperties properties)
    {
        _context.Response.StatusCode = (int)HttpStatusCode.Forbidden;
        return Task.CompletedTask;
    }

    /// <summary>
    /// 初始化认证
    /// </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 认证校验逻辑

    /// <summary>
    /// 生成认证票据
    /// </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：继承已实现的基类
/// </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中启用自定义认证：

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后；UseEndpoints前添加以下代码
    app.UseAuthentication();
    app.UseAuthorization();

    //other code
    app.UseEndpoints()
}

　3、在控制器上添加认证标记，测试验证

//指定认证时，采用CustomerAuthenticationHandler.CustomerSchemeName
[Authorize(AuthenticationSchemes = CustomerAuthenticationHandler.CustomerSchemeName)]
[Route("api/[controller]")]
[ApiController]
public class AuditLogController : ControllerBase
{
 //code
}

　　调用

　　

三、多认证支持

　在实际项目中可能存在，对一个控制器支持多种认证方式如：常用的Jwt认证、自定义认证等，那么如何实现呢？

　1、在Startup的ConfigureServices 方法中添加以下逻辑：

public void ConfigureServices(IServiceCollection services)
{
    //other code
    services.Configure<JwtSetting>(Configuration.GetSection("JWTSetting"));
    var token = Configuration.GetSection("JWTSetting").Get<JwtSetting>();
    //JWT认证
    services.AddAuthentication(x =>
    {
        x.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;
        x.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;
　　　　　//添加自定义认证处理器
        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、在需要支持多种认证方式的控制器上添加标记：

//指定认证时，采用CustomerAuthenticationHandler.CustomerSchemeName
[Authorize(AuthenticationSchemes = CustomerAuthenticationHandler.CustomerSchemeName)]
[Route("api/[controller]")]
[ApiController]
public class AuditLogController : ControllerBase
{
 //code
}

//指定认证采用JWT
[Authorize(AuthenticationSchemes = JwtBearerDefaults.AuthenticationScheme)]
public class WeatherForecastController : ControllerBase
{
  //code
}

　　这样就支持了两种认证方式

　3、一个控制器支持多种认证类型：继承Jwt认证处理，并根据Scheme那么调用自定义的认证处理器：

/// <summary>
/// 方式二：同时支持多种认证方式
/// </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("未认证"));
        }
        else
            return base.AuthenticateAsync();
    }

    private AuthenticationTicket Valid()
    {
        Context.Request.Headers.TryGetValue("Authorization", out StringValues values);
        string valStr = values.ToString();
        if (!string.IsNullOrWhiteSpace(valStr))
        {
            //认证模拟basic认证：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>
    /// 生成认证票据
    /// </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、总结

　.Net Core中的自定义认证主要通过实现IAuthenticationHandler 接口实现，如果要实现多认证方式通过AddScheme 应用自定义实现的认证处理器。

　源码：github

　参考：认证