QYZH.InteractiveMagazine/QYZH.InteractiveMagazine.Infrastructure/Middleware/JwtAutoRefreshMiddleware.cs

using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Configuration;
using QYZH.InteractiveMagazine.Models.Settings;
using System.IdentityModel.Tokens.Jwt;

namespace QYZH.InteractiveMagazine.Infrastructure.Middleware;

/// <summary>
/// JWT 自动刷新中间件
/// 功能：
/// 每次请求都刷新 Redis 中 Token 的过期时间（保持会话活跃）
/// 前端永远使用同一个 Token，无需处理 Token 刷新
/// </summary>
public class JwtAutoRefreshMiddleware
{
    private readonly RequestDelegate _next;
    private readonly IConfiguration _configuration;
    private const string AdminTokenKeyPrefix = "InteractiveMagazine:AdminAuth:Token";
    private const string WeChatTokenKeyPrefix = "InteractiveMagazine:WeChatAuth:Token";

    public JwtAutoRefreshMiddleware(RequestDelegate next, IConfiguration configuration)
    {
        _next = next;
        _configuration = configuration;
    }

    public async Task InvokeAsync(HttpContext context)
    {
        var authHeader = context.Request.Headers.Authorization.FirstOrDefault();
        if (!string.IsNullOrEmpty(authHeader) && authHeader.StartsWith("Bearer "))
        {
            var token = authHeader.Substring("Bearer ".Length).Trim();
            await TryRefreshRedisTokenExpiryAsync(context, token);
        }

        await _next(context);
    }

    private async Task TryRefreshRedisTokenExpiryAsync(HttpContext context, string token)
    {
        try
        {
            var tokenHandler = new JwtSecurityTokenHandler();
            if (tokenHandler.ReadToken(token) is not JwtSecurityToken jwtToken)
            {
                return;
            }

            var expiryTime = jwtToken.ValidTo;
            var remainingTime = expiryTime - DateTime.Now;

            // JWT 已过期，不处理
            if (remainingTime <= TimeSpan.Zero)
            {
                return;
            }

            var userId = jwtToken.Claims.FirstOrDefault(c => c.Type == System.Security.Claims.ClaimTypes.NameIdentifier)?.Value;
            if (string.IsNullOrEmpty(userId))
            {
                return;
            }

            var jwtSettings = _configuration.GetSection("JwtSettings").Get<JwtSettings>();
            if (jwtSettings == null || jwtSettings.ExpiryMinutes <= 0)
            {
                return;
            }

            // 每次请求都刷新 Redis 中 Token 的过期时间
            await RefreshRedisTokenExpiryAsync(userId, token, jwtSettings.ExpiryMinutes);
        }
        catch
        {
            // 忽略自动刷新异常，由后续认证中间件处理
        }
    }

    /// <summary>
    /// 刷新 Redis 中已存在 Token 的过期时间（保持会话活跃）
    /// </summary>
    private async Task RefreshRedisTokenExpiryAsync(string userId, string currentToken, int expiryMinutes)
    {
        // 检查 Admin Token
        var adminTokenKey = $"{AdminTokenKeyPrefix}:{userId}";
        var adminToken = await RedisHelper.GetAsync(adminTokenKey);
        if (!string.IsNullOrEmpty(adminToken))
        {
            await RedisHelper.SetAsync(adminTokenKey, currentToken, TimeSpan.FromMinutes(expiryMinutes));
            return;
        }

        // 检查 WeChat Token
        var wechatTokenKey = $"{WeChatTokenKeyPrefix}:{userId}";
        var wechatToken = await RedisHelper.GetAsync(wechatTokenKey);
        if (!string.IsNullOrEmpty(wechatToken))
        {
            await RedisHelper.SetAsync(wechatTokenKey, currentToken, TimeSpan.FromMinutes(expiryMinutes));
        }
    }
}