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();
          }
      }
  }

• 多个网站都用以上方法进行配置，然后测试一波