求ASP.NET Core 2.2网站访客统计计数器实现方案

下面是适配ASP.NET Core 2.2的访客统计实现，包含在线人数、今日访问量、当月访问量、总访问量四个功能，替代你提供的ASP.NET MVC Global.asax逻辑：

1. 核心中间件实现 #

中间件负责处理每个请求的统计逻辑，替代原Global.asax的请求拦截：

using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Caching.Memory;
using System;
using System.Collections.Generic;
using System.Threading.Tasks;

public class VisitorCounterMiddleware
{
    private readonly RequestDelegate _next;
    private readonly IMemoryCache _cache;

    public VisitorCounterMiddleware(RequestDelegate next, IMemoryCache cache)
    {
        _next = next;
        _cache = cache;
    }

    public async Task InvokeAsync(HttpContext context)
    {
        var today = DateTime.Today;
        var currentMonth = new DateTime(today.Year, today.Month, 1);
        const string visitorIdCookie = "VisitorId";
        const string lastVisitCookie = "LastVisitDate";

        // 生成或获取访客唯一标识
        if (!context.Request.Cookies.TryGetValue(visitorIdCookie, out var visitorId))
        {
            visitorId = Guid.NewGuid().ToString();
            context.Response.Cookies.Append(visitorIdCookie, visitorId, new CookieOptions
            {
                Expires = DateTime.Now.AddYears(1),
                HttpOnly = true,
                IsEssential = true
            });
        }

        // 更新在线人数（30分钟无活动视为离线）
        var onlineUsersKey = "OnlineUsers";
        var onlineUsers = _cache.GetOrCreate(onlineUsersKey, entry => new HashSet<string>());
        
        // 清理超时用户
        onlineUsers.RemoveWhere(id => 
            _cache.TryGetValue($"LastActive_{id}", out DateTime lastActive) && 
            DateTime.Now - lastActive > TimeSpan.FromMinutes(30));
        
        onlineUsers.Add(visitorId);
        _cache.Set(onlineUsersKey, onlineUsers, TimeSpan.FromHours(1));
        _cache.Set($"LastActive_{visitorId}", DateTime.Now, TimeSpan.FromMinutes(35));

        // 判断是否为今日/当月新访问
        bool isNewToday = false;
        bool isNewMonth = false;

        if (context.Request.Cookies.TryGetValue(lastVisitCookie, out var lastVisitStr) && 
            DateTime.TryParse(lastVisitStr, out var lastVisit))
        {
            isNewToday = lastVisit.Date != today;
            isNewMonth = lastVisit.Year != today.Year || lastVisit.Month != today.Month;
        }
        else
        {
            isNewToday = true;
            isNewMonth = true;
        }

        // 更新访问量统计
        if (isNewToday)
        {
            var todayKey = $"TodayVisits_{today:yyyyMMdd}";
            _cache.Set(todayKey, (_cache.Get<int?>(todayKey) ?? 0) + 1, TimeSpan.FromDays(1));
            
            var totalKey = "TotalVisits";
            _cache.Set(totalKey, (_cache.Get<int?>(totalKey) ?? 0) + 1, TimeSpan.FromDays(365));
        }

        if (isNewMonth)
        {
            var monthKey = $"MonthVisits_{currentMonth:yyyyMM}";
            _cache.Set(monthKey, (_cache.Get<int?>(monthKey) ?? 0) + 1, TimeSpan.FromDays(31));
        }

        // 更新最后访问日期Cookie
        context.Response.Cookies.Append(lastVisitCookie, today.ToString("yyyy-MM-dd"), new CookieOptions
        {
            Expires = DateTime.Now.AddDays(1),
            HttpOnly = true,
            IsEssential = true
        });

        // 继续处理后续请求
        await _next(context);
    }
}

2. 配置Startup.cs #

在Startup.cs中注册缓存服务和中间件：

ConfigureServices方法 #

添加内存缓存支持：

public void ConfigureServices(IServiceCollection services)
{
    services.AddMemoryCache();
    // 其他服务注册（如AddMvc等）
    services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);
}

Configure方法 #

添加中间件（确保放在UseStaticFiles之后，UseRouting/UseMvc之前）：

public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
    // 其他中间件（如UseStaticFiles、UseDeveloperExceptionPage等）
    app.UseStaticFiles();

    // 添加访客统计中间件
    app.UseMiddleware<VisitorCounterMiddleware>();

    app.UseMvc(routes =>
    {
        routes.MapRoute(
            name: "default",
            template: "{controller=Home}/{action=Index}/{id?}");
    });
}

3. 获取统计数据的API控制器 #

创建API控制器用于前端或后端获取统计数据：

using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Caching.Memory;
using System;

[Route("api/visitor-stats")]
[ApiController]
public class VisitorStatsController : ControllerBase
{
    private readonly IMemoryCache _cache;

    public VisitorStatsController(IMemoryCache cache)
    {
        _cache = cache;
    }

    [HttpGet]
    public IActionResult GetStats()
    {
        var today = DateTime.Today;
        var currentMonth = new DateTime(today.Year, today.Month, 1);

        var stats = new
        {
            OnlineUsers = _cache.Get<HashSet<string>>("OnlineUsers")?.Count ?? 0,
            TodayVisits = _cache.Get<int?>($"TodayVisits_{today:yyyyMMdd}") ?? 0,
            MonthVisits = _cache.Get<int?>($"MonthVisits_{currentMonth:yyyyMM}") ?? 0,
            TotalVisits = _cache.Get<int?>("TotalVisits") ?? 0
        };

        return Ok(stats);
    }
}

关键说明 #

• 缓存机制：使用IMemoryCache存储统计数据，单服务器场景下足够；如果是多服务器集群，需替换为IDistributedCache（如Redis）实现跨节点数据共享
• 数据持久化：内存缓存数据会在应用重启后丢失，若需持久化，可添加定时任务将每日/每月统计数据写入数据库，重启时从数据库加载历史数据
• 在线人数逻辑：通过访客ID的最后活动时间判断，30分钟无活动自动移除，避免统计无效在线用户
• Cookie处理：遵循ASP.NET Core的Cookie操作规范，设置IsEssential确保合规性

内容的提问来源于stack exchange，提问作者Sina