การ Get Client IP Address บน ASP.NET Core 3

สร้างโปรเจ็กส์ทดสอบแบบ WebApplication แล้วเลือก API ตั้งชื่อ WebApi

ทำการ inject HttpContextAccessor ในไฟล์ Startup.cs

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;

namespace WebApi
{
    public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddControllers();
            services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }

            app.UseRouting();

            app.UseAuthorization();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllers();
            });
        }
    }
}

เพิ่ม API Controller ชื่อ ValuesController.cs

ประกาศตัวแปร httpContextAccessor และกำหนดค่าให้ตัวแปรใน Constructor

using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using System.Collections.Generic;

namespace WebApi.Controllers
{
    [Route("api/[controller]")]
    [ApiController]
    public class ValuesController : ControllerBase
    {
        private readonly IHttpContextAccessor httpContextAccessor;

        public ValuesController(IHttpContextAccessor httpContextAccessor)
        {
            this.httpContextAccessor = httpContextAccessor;
        }

        // GET: api/<ValuesController>
        [HttpGet]
        public IEnumerable<string> Get()
        {
            string clientIpAddress = this.httpContextAccessor.HttpContext.Connection.RemoteIpAddress.ToString();
            return new string[] { "clientIpAddress ", clientIpAddress };
        }
    }
}

รันโปรแกรมแล้วลองเรียกไปที่ http://localhost:58691/api/values

จะได้

["clientIpAddress ","::1"]

ถ้าจะจัดเก็บค่า IP Address ลง database ก็กำหนด ขนาด field ไว้ที่ 45 characters

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