.NET7之MiniAPI(特别篇) ：Preview5优化了JWT验证（下）

　　Preview5对策略验证的方式没有改变，只不过内置了Token的生成，和《.NET6之MiniAPI(十)：基于策略的身份验证和授权》的验证方式基本相同，都是生成和验证使用的验证参数要一致，用继承AuthorizationHandler的子类来作每次请求的验证。

　　在具体的路由上，用RequireAuthorization("Permission")来配置策略名称，以达到请求转向验证。

　　不多说了，看代码实现，可以《.NET6之MiniAPI(十)：基于策略的身份验证和授权》作个比较。

using Microsoft.AspNetCore.Authorization;
using Microsoft.IdentityModel.Tokens;
using System.IdentityModel.Tokens.Jwt;
using System.Security.Claims;
using System.Text;

var builder = WebApplication.CreateBuilder(args);

#region 添加策略验证参数
builder.Authentication.AddJwtBearer(opt =>
{    
    opt.TokenValidationParameters = new TokenValidationParameters
    {
        ValidateIssuerSigningKey = true,
        IssuerSigningKey = new SymmetricSecurityKey(Encoding.ASCII.GetBytes("1234567890abcdefg")),
        ValidateIssuer = true,
        ValidIssuer = "http://localhost:5274",
        ValidateAudience = true,
        ValidAudience = "http://localhost:5274",
        ClockSkew = TimeSpan.Zero,
        RequireExpirationTime = true,
    }; ;
});

//添加策略名和注与策略验证服务
builder.Services
    .AddAuthorization(options =>
    {
        //添加策略名称
        options.AddPolicy("Permission", policyBuilder => policyBuilder.AddRequirements(new PermissionRequirement()));
    })
    .AddSingleton(new List<Permission> { new Permission { RoleName = "admin", Url = "/Policy", Method = "get" } })
    .AddSingleton<IAuthorizationHandler, PermissionHandler>();

var app = builder.Build();
//登录，生成token
app.MapGet("/login", () =>
{
    //用JWTSecurityTokenHandler生成token
    return new JwtSecurityTokenHandler().WriteToken(
        new JwtSecurityToken(
            issuer: "http://localhost:5274",
            audience: "http://localhost:5274",
            claims: new Claim[] {
                new Claim(ClaimTypes.Role, "admin"),
                new Claim(ClaimTypes.Name, "桂素伟")
            },
            notBefore: DateTime.UtcNow,
            expires: DateTime.UtcNow.AddSeconds(500000),
            signingCredentials: new SigningCredentials(
                new SymmetricSecurityKey(Encoding.ASCII.GetBytes("1234567890abcdefg")),
                SecurityAlgorithms.HmacSha256)
            )
        );
});
app.MapGet("/policy", (ClaimsPrincipal user) => $"Hello 用户：{user.Identity?.Name}, 角色：{user.Claims?.Where(s => s.Type == ClaimTypes.Role).First().Value}. This is a policy!").RequireAuthorization("Permission");
app.Run();


#region 策略验证功能
public class PermissionRequirement : IAuthorizationRequirement
{
}
//权限的实体集合
public class Permission
{
    public string? RoleName { get; set; }
    public string? Url { get; set; }
    public string? Method { get; set; }
}
//权限验证类
public class PermissionHandler : AuthorizationHandler<PermissionRequirement>
{
    private readonly List<Permission> _userPermissions;
    public PermissionHandler(List<Permission> permissions)
    {
        _userPermissions = permissions;
    }
    protected override Task HandleRequirementAsync(AuthorizationHandlerContext context, PermissionRequirement requirement)
    {
        if (context.Resource is DefaultHttpContext)
        {
            var httpContext = context.Resource as DefaultHttpContext;
            var questPath = httpContext?.Request?.Path;
            var method = httpContext?.Request?.Method;
            var isAuthenticated = context?.User?.Identity?.IsAuthenticated;
            if (isAuthenticated.HasValue && isAuthenticated.Value)
            {
                var role = context?.User?.Claims?.SingleOrDefault(s => s.Type == ClaimTypes.Role)?.Value;
                if (_userPermissions.Where(w => w.RoleName == role && w.Method?.ToUpper() == method?.ToUpper() && w.Url?.ToLower() == questPath).Count() > 0)
                {
                    context?.Succeed(requirement);
                }
                else
                {
                    context?.Fail();
                }
            }
        }
        return Task.CompletedTask;
    }
}
#endregion