HttpClientStudy/HttpClientStudy.UnitTest/DelegatingHandlerTest.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;

using Microsoft.Extensions.Logging;

namespace HttpClientStudy.UnitTest
{
    public class DelegatingHandlerTest
    {
        private readonly ITestOutputHelper _logger;
        public DelegatingHandlerTest(ITestOutputHelper outputHelper) 
        {
            _logger = outputHelper;
        }

        [Fact]
        public async Task Test()
        { 
            //构建管道
            var handler = new HandlerA() 
            { 
                //相当于下一个中间件(管道)
                InnerHandler = new HandlerB() 
            };

            HttpClient httpClient = new HttpClient(handler);

            var sd = await httpClient.GetAsync("http://127.0.0.1");
            var contentText = await sd.Content.ReadAsStringAsync();

            _logger.WriteLine(contentText);
        }
    }

    public class HandlerB : DelegatingHandler
    {
        protected override async Task<HttpResponseMessage> SendAsync( HttpRequestMessage request, CancellationToken cancellationToken)
        {
            InnerHandler = new SocketsHttpHandler() { };

            //请求前业务

            var response = await base.SendAsync(request, cancellationToken);

            //响应后业务

            return response;
        }
    }

    public class HandlerA : DelegatingHandler
    {
        protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
        {
            //请求前业务

            var response = await base.SendAsync(request, cancellationToken);

            //响应后业务

            return response;
        }
    }
}