netcore 使用redis session 分布式共享

首先准备redis服务器（docker 和redis3.0内置的哨兵进行高可用设置）
网站配置Redis作为存储session的介质（配置文件这些略）。然后可以了解一下MachineKey这个东西.（MachineKey是用来生成session和解密session的一个xml格式对象）

生成MachineKey

再startup  config里面配置如下代码
     //抽取key-xxxxx.xml 
     services.AddDataProtection().PersistKeysToFileSystem(new DirectoryInfo(@"D:\"));
然后再对应的磁盘路径上面找到格式后缀为xml的文件

将文件用记事本打开，然后新增一个类来替换网站默认使用的MachineKey。

using Microsoft.AspNetCore.DataProtection.Repositories;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Xml.Linq;

namespace Session02
{
    public class CustomXmlRepository : IXmlRepository
    {
        /// <summary>
        /// 设置MachineKey这里的内容就是复制出xml文件的内容
        /// </summary>
        private readonly string keyContent =
        @"<?xml version='1.0' encoding='utf-8'?>
        <key id='6e0d77ae-807d-4dd5-9b33-1f364f6c1f3e' version='1'>
          <creationDate>2018-07-25T07:01:39.5356164Z</creationDate>
          <activationDate>2018-07-25T07:01:39.4800644Z</activationDate>
          <expirationDate>2018-10-23T07:01:39.4800644Z</expirationDate>
          <descriptor deserializerType='Microsoft.AspNetCore.DataProtection.AuthenticatedEncryption.ConfigurationModel.AuthenticatedEncryptorDescriptorDeserializer, Microsoft.AspNetCore.DataProtection, Version=2.1.1.0, Culture=neutral, PublicKeyToken=adb9793829ddae60'>
            <descriptor>
              <encryption algorithm='AES_256_CBC' />
              <validation algorithm='HMACSHA256' />
              <masterKey p4:requiresEncryption='true' xmlns:p4='http://schemas.asp.net/2015/03/dataProtection'>
                <!-- Warning: the key below is in an unencrypted form. -->
                <value>lPUxFutB30oi1KU990Y5nKxeCBnHg7h1JX26nvDlpxdbYciXQr2gdUpLxrL52O/vg8Htrr9F3Xf2fqnVhhAjhw==</value>
              </masterKey>
            </descriptor>
          </descriptor>
        </key>";

        public virtual IReadOnlyCollection<XElement> GetAllElements()
        {
            return GetAllElementsCore().ToList().AsReadOnly();
        }

        private IEnumerable<XElement> GetAllElementsCore()
        {
            yield return XElement.Parse(keyContent);
        }
        public virtual void StoreElement(XElement element, string friendlyName)
        {
            if (element == null)
            {
                throw new ArgumentNullException(nameof(element));
            }
            StoreElementCore(element, friendlyName);
        }

        private void StoreElementCore(XElement element, string filename)
        {
        }
    }
}

在startup里面注入CustomXmlRepository使用默认的key来生成session

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.DataProtection.Repositories;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;

namespace Session02
{
    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)
        {
            //抽取key-xxxxx.xml 
            //services.AddDataProtection().PersistKeysToFileSystem(new DirectoryInfo(@"D:\"));
            services.AddSingleton<IXmlRepository, CustomXmlRepository>();
            services.AddDataProtection(configure =>
            {
                configure.ApplicationDiscriminator = "Seesion.testweb";
            });
            services.AddDistributedRedisCache(option =>
            {
                //redis 数据库连接字符串
                option.Configuration = Configuration.GetConnectionString("RedisConnection");
                //redis 实例名
                option.InstanceName = "test";
            });
            services.AddSession();
            services.AddMvc();
        }

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