ASP.NET Core 实现基本认证的示例代码

HTTP基本认证

在HTTP中,HTTP基本认证(Basic Authentication)是一种允许网页浏览器或其他客户端程序以(用户名:口令) 请求资源的身份验证方式,不要求cookie,session identifier、login page等标记或载体。

- 所有浏览器据支持HTTP基本认证方式

- 基本身证原理不保证传输凭证的安全性,仅被based64编码,并没有encrypted或者hashed,一般部署在客户端和服务端互信的网络,在公网中应用BA认证通常与https结合

https://en.wikipedia.org/wiki/Basic_access_authentication

BA标准协议

BA认证协议的实施主要依靠约定的请求头/响应头,典型的浏览器和服务器的BA认证流程:

① 浏览器请求应用了BA协议的网站,服务端响应一个401认证失败响应码,并写入WWW-Authenticate响应头,指示服务端支持BA协议

HTTP/1.1 401 Unauthorized
WWW-Authenticate: Basic realm="our site" # WWW-Authenticate响应头包含一个realm域属性,指明HTTP基本认证的是这个资源集

或客户端在第一次请求时发送正确Authorization标头,从而避免被质询

② 客户端based64(用户名:口令),作为Authorization标头值 重新发送请求。

Authorization: Basic userid:password

ASP.NET Core 实现基本认证的示例代码

所以在HTTP基本认证中认证范围与 realm有关(具体由服务端定义)

> 一般浏览器客户端对于www-Authenticate质询结果,会弹出口令输入窗.

BA编程实践

aspnetcore网站利用FileServerMiddleware 将路径映射到某文件资源, 现对该 文件资源访问路径应用 Http BA协议。

ASP.NET Core服务端实现BA认证:

① 实现服务端基本认证的认证过程、质询逻辑

②实现基本身份认证交互中间件BasicAuthenticationMiddleware ,要求对HttpContext使用 BA.Scheme

③ASP.NET Core 添加认证计划 , 为文件资源访问路径启用 BA中间件,注意使用UseWhen插入中间件

using System;
using System.Net.Http.Headers;
using System.Security.Claims;
using System.Text;
using System.Text.Encodings.Web;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Authentication;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;

namespace EqidManager.Services
{
  public static class BasicAuthenticationScheme
  {
    public const string DefaultScheme = "Basic";
  }

  public class BasicAuthenticationOption:AuthenticationSchemeOptions
  {
    public string Realm { get; set; }
    public string UserName { get; set; }
    public string UserPwd { get; set; }
  }

  public class BasicAuthenticationHandler : AuthenticationHandler<BasicAuthenticationOption>
  {
    private readonly BasicAuthenticationOption authOptions;
    public BasicAuthenticationHandler(
      IOptionsMonitor<BasicAuthenticationOption> options,
      ILoggerFactory logger,
      UrlEncoder encoder,
      ISystemClock clock)
      : base(options, logger, encoder, clock)
    {
      authOptions = options.CurrentValue;
    }

    /// <summary>
    /// 认证
    /// </summary>
    /// <returns></returns>
    protected override async Task<AuthenticateResult> HandleAuthenticateAsync()
    {
      if (!Request.Headers.ContainsKey("Authorization"))
        return AuthenticateResult.Fail("Missing Authorization Header");
      string username, password;
      try
      {
        var authHeader = AuthenticationHeaderValue.Parse(Request.Headers["Authorization"]);
        var credentialBytes = Convert.FromBase64String(authHeader.Parameter);
        var credentials = Encoding.UTF8.GetString(credentialBytes).Split(':');
         username = credentials[0];
         password = credentials[1];
         var isValidUser= IsAuthorized(username,password);
        if(isValidUser== false)
        {
          return AuthenticateResult.Fail("Invalid username or password");
        }
      }
      catch
      {
        return AuthenticateResult.Fail("Invalid Authorization Header");
      }

      var claims = new[] {
        new Claim(ClaimTypes.NameIdentifier,username),
        new Claim(ClaimTypes.Name,username),
      };
      var identity = new ClaimsIdentity(claims, Scheme.Name);
      var principal = new ClaimsPrincipal(identity);
      var ticket = new AuthenticationTicket(principal, Scheme.Name);
      return await Task.FromResult(AuthenticateResult.Success(ticket));
    }

    /// <summary>
    /// 质询
    /// </summary>
    /// <param name="properties"></param>
    /// <returns></returns>
    protected override async Task HandleChallengeAsync(AuthenticationProperties properties)
    {
      Response.Headers["WWW-Authenticate"] = $"Basic realm=\"{Options.Realm}\"";
      await base.HandleChallengeAsync(properties);
    }

    /// <summary>
    /// 认证失败
    /// </summary>
    /// <param name="properties"></param>
    /// <returns></returns>
    protected override async Task HandleForbiddenAsync(AuthenticationProperties properties)
    {
      await base.HandleForbiddenAsync(properties); 
    }

    private bool IsAuthorized(string username, string password)
    {
      return username.Equals(authOptions.UserName, StringComparison.InvariantCultureIgnoreCase)
          && password.Equals(authOptions.UserPwd);
    }
  }
}

ASP.NET Core 实现基本认证的示例代码

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