webapi项目添加访问IP限制

第一步：在项目中添加一个cs文件，内容如下，代码中的RemoteEndpointMessageProperty需要引用System.ServiceModel.Channels，如果没有，去NuGet工具箱搜索安装System.ServiceModel.Primitives

using System;
using System.Collections.Generic;
using System.Configuration;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Threading;
using System.Threading.Tasks;
using System.Web;
using System.ServiceModel.Channels;

public class IPFilterHandler : DelegatingHandler
{
    private readonly HashSet<string> _allowedIPs;

    public IPFilterHandler()
    {
        var ips = ConfigurationManager.AppSettings["AllowedIPs"] ?? "";
        _allowedIPs = new HashSet<string>(ips.Split(','), StringComparer.OrdinalIgnoreCase);
    }

    protected override async Task<HttpResponseMessage> SendAsync(
        HttpRequestMessage request, CancellationToken cancellationToken)
    {
        var clientIP = GetClientIp(request);

        if (_allowedIPs.Contains(clientIP))
        {
            return await base.SendAsync(request, cancellationToken);
        }

        return request.CreateResponse(HttpStatusCode.Forbidden, new
        {
            Code = 403,
            Message = $"IP {clientIP} 无访问权限"
        });
    }

    private string GetClientIp(HttpRequestMessage request)
    {
        // 尝试从 X-Forwarded-For 获取（适用于反向代理场景）
        if (request.Headers.TryGetValues("X-Forwarded-For", out var forwardedFor))
        {
            return forwardedFor.First().Split(',').First().Trim();
        }

        // 标准方式获取 IP
        if (request.Properties.ContainsKey("MS_HttpContext"))
        {
            return ((HttpContextWrapper)request.Properties["MS_HttpContext"]).Request.UserHostAddress;
        }

        if (request.Properties.ContainsKey(RemoteEndpointMessageProperty.Name))
        {
            var prop = (RemoteEndpointMessageProperty)request.Properties[RemoteEndpointMessageProperty.Name];
            return prop.Address;
        }

        return "0.0.0.0";
    }
}

第二步：注册，在 WebApiConfig.cs 中，添加

config.MessageHandlers.Add(new IPFilterHandler());

第三步：在Web.config的<appSettings>中添加，value中添加限制的ip，多个用英文逗号隔开

<add key="AllowedIPs" value="10.10.10.1" />