C#客户端Redis服务器的分布式缓存
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C#客户端Redis服务器的分布式缓存
鱼煎 发表于2年前
C#客户端Redis服务器的分布式缓存
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介绍

在这篇文章中,我想介绍我知道的一种最紧凑的安装和配置Redis服务器的方式。另外,我想简短地概述一下在.NET / C#客户端下Redis hash(哈希类型)和list(链表)的使用。

在这篇文章主要讲到:

  • 安装Redis服务器(附完整的应用程序文件设置
  • Redis服务器保护(配置身份验证)
  • 配置服务器复制
  • 从C#应用程序访问缓存
  • 使用Redis ASP.NET会话状态
  • Redis 集合(Set)、列表(List)和事务处理用法示例
  • 说明附加的源(Redis Funq LoC MVC项目:举例)
  • 缓存的优化思路

背景

Redis是最快也是功能最丰富的内存Key-Value数据存储系统之一。

缺点

  • 没有本地数据缓存(如在Azure缓存同步本地数据缓存)
  • 没有完全集群化的支持(不过,可能今年年底会实现)

优点

  • 易于配置
  • 使用简单
  • 高性能
  • 支持不同的数据类型(如hash(哈希类型)、list(链表)、set(集合)、sorted set(有序集))
  • ASP.NET会话集成
  • Web UI用于浏览缓存内容

下面我将简单说明如何在服务器上安装和配置Redis,并用C#使用它。

Redis的安装

https://github.com/dmajkic/redis/downloads(win32 win64直接链接)下载二进制文件,解包档案到应用程序目录(如C:\Program Files\Redis)

下载从https://github.com/kcherenkov/redis-windows-service/downloads编译的Redis服务,然后复制到程序文件夹(如C:\Program Files\Redis)。如果配置文件丢失,也可以下载复制到应用程序目录。有效的Redis配置文件的范例在https://raw.github.com/antirez/redis/2.6/redis.conf

Redis应用程序的完整文件也可以从压缩文件(x64)得到。

当你拥有了全套的应用程序文件(如下图所示),

redis application folder conten

导航到应用程序目录,然后运行以下命令:

sc create %name% binpath= "\"%binpath%\" %configpath%" start= "auto" DisplayName= "Redis"

其中:

  • %name%——服务实例的名称,例如:redis-instance;
  • %binpath%——到项目exe文件的路径,例如:C:\Program Files\Redis\RedisService_1.1.exe;
  • %configpath%——到Redis配置文件的路径,例如:C:\Program Files\Redis\redis.conf;

举例:

sc create Redis start= auto DisplayName= Redis binpath= "\"C:\Program Files\Redis\RedisService_1.1.exe\
" \"C:\Program Files\Redis\redis.conf\""

即应该是这样的:

请确保有足够的权限启动该服务。安装完毕后,请检查该服务是否创建成功,当前是否正在运行:

或者,你可以使用安装程序(我没试过):https://github.com/rgl/redis/downloads

Redis服务器保护:密码,IP过滤

保护Redis服务器的主要方式是使用Windows防火墙或活跃的网络连接属性设置IP过滤。此外,还可以使用Redis密码设置额外保护。这需要用下面的方式更新Redis配置文件(redis.conf):

首先,找到这行:

# requirepass foobared

删除开头的#符号,用新密码替换foobared:

requirepass foobared

然后,重新启动Redis Windows服务!

当具体使用客户端的时候,使用带密码的构造函数:

RedisClient client = new RedisClient(serverHost, port, redisPassword);

Redis服务器复制(主—从配置)

Redis支持主从同步,即,每次主服务器修改,从服务器得到通知,并自动同步。大多复制用于读取(但不能写)扩展和数据冗余和服务器故障转移。设置两个Redis实例(在相同或不同服务器上的两个服务),然后配置其中之一作为从站。为了让Redis服务器实例是另一台服务器的从属,可以这样更改配置文件:

找到以下代码:

# slaveof <masterip> <masterport>

替换为:

slaveof 192.168.1.1 6379

(可以自定义指定主服务器的真实IP和端口)。如果主服务器配置为需要密码(验证),可以如下所示改变redis.conf,找到这一行代码:

# masterauth <master-password>

删除开头的#符号,用主服务器的密码替换<master-password>,即:

masterauth mastpassword

现在这个Redis实例可以被用来作为主服务器的只读同步副本。

用C#代码使用Redis缓存

用C#代码使用Redis运行Manage NuGet包插件,找到ServiceStack.Redis包,并进行安装。

直接从实例化客户端使用Set/Get方法示例:

string host = "localhost";
string elementKey = "testKeyRedis";

using (RedisClient redisClient = new RedisClient(host))
{
      if (redisClient.Get<string>(elementKey) == null)
      {
           // adding delay to see the difference
           Thread.Sleep(5000); 
           // save value in cache
           redisClient.Set(elementKey, "some cached value");
      }
      // get value from the cache by key
      message = "Item value is: " + redisClient.Get<string>("some cached value");
 }

类型化实体集更有意思和更实用,这是因为它们操作的是确切类型的对象。在下面的代码示例中,有两个类分别定义为Phone和Person——phone的主人。每个phone实例引用它的主人。下面的代码演示我们如何通过标准添加、删除和发现缓存项:

public class Phone
{
   public int Id { get; set; }
   public string Model { get; set; }
   public string Manufacturer { get; set; }
   public Person Owner { get; set; }
}

public class Person
{
    public int Id { get; set; }
    public string Name { get; set; }
    public string Surname { get; set; }
    public int Age { get; set; }
    public string Profession { get; set; }
}

using (RedisClient redisClient = new RedisClient(host))
{
     IRedisTypedClient<phone> phones = redisClient.As<phone>();
     Phone phoneFive = phones.GetValue("5");
     if (phoneFive == null)
     {
          // make a small delay
          Thread.Sleep(5000);
          // creating a new Phone entry
          phoneFive = new Phone
          {
               Id = 5,
               Manufacturer = "Motorolla",
               Model = "xxxxx",
               Owner = new Person
               {
                    Id = 1,
                    Age = 90,
                    Name = "OldOne",
                    Profession = "sportsmen",
                    Surname = "OldManSurname"
               }
          };
          // adding Entry to the typed entity set
          phones.SetEntry(phoneFive.Id.ToString(), phoneFive);
     }
     message = "Phone model is " + phoneFive.Manufacturer;
     message += "Phone Owner Name is: " + phoneFive.Owner.Name;
}

在上面的例子中,我们实例化了输入端IRedisTypedClient,它与缓存对象的特定类型——Phone类型一起工作。

Redis ASP.NET会话状态

要用Redis提供商配置ASP.NET会话状态,添加新文件到你的Web项目,命名为RedisSessionStateProvider.cs,可以从https://github.com/chadman/redis-service-provider/raw/master/RedisProvider/SessionProvider/RedisSessionProvider.cs复制代码,然后添加或更改配置文件中的以下部分(sessionState标签已经内置于system.web标签),或者你也可以下载附加来源和复制代码。

<sessionstate timeout="1" mode="Custom" 
customprovider="RedisSessionStateProvider" cookieless="false">
      <providers>
        <add name="RedisSessionStateProvider" writeexceptionstoeventlog="false" 
        type="RedisProvider.SessionProvider.CustomServiceProvider" 
        server="localhost" port="6379" password="pasword">
      </add> </providers>
</sessionstate>

注意,此密码是可以选择的,看服务器是否需要认证。它必须被真实的值替换或删除,如果Redis服务器不需要身份验证,那么服务器属性和端口得由具体的数值代替(默认端口为6379)。然后在项目中,你才可以使用会话状态:

// in the Global.asax
public class MvcApplication1 : System.Web.HttpApplication
{
    protected void Application_Start()
    {
        //....
    }

    protected void Session_Start()
    {
        Session["testRedisSession"] = "Message from the redis ression";
    }
}

在Home controller(主控制器):

public class HomeController : Controller
{
    public ActionResult Index()
    {
       //...
       ViewBag.Message = Session["testRedisSession"];
       return View();
    }
//...
}

结果:

ASP.NET输出缓存提供者,并且Redis可以用类似的方式进行配置。

Redis Set(集合)和List(列表)

主要要注意的是,Redis列表实现IList<T>,而Redis集合实现ICollection<T>。下面来说说如何使用它们。

当需要区分相同类型的不同分类对象时,使用列表。例如,我们有“mostSelling(热销手机)”和“oldCollection(回收手机)”两个列表:

string host = "localhost";
using (var redisClient = new RedisClient(host))
{
    //Create a 'strongly-typed' API that makes all Redis Value operations to apply against Phones
    IRedisTypedClient<phone> redis = redisClient.As<phone>();

    IRedisList<phone> mostSelling = redis.Lists["urn:phones:mostselling"];
    IRedisList<phone> oldCollection = redis.Lists["urn:phones:oldcollection"];

    Person phonesOwner = new Person
        {
            Id = 7,
            Age = 90,
            Name = "OldOne",
            Profession = "sportsmen",
            Surname = "OldManSurname"
        };

    // adding new items to the list
    mostSelling.Add(new Phone
            {
                Id = 5,
                Manufacturer = "Sony",
                Model = "768564564566",
                Owner = phonesOwner
            });

    oldCollection.Add(new Phone
            {
                Id = 8,
                Manufacturer = "Motorolla",
                Model = "324557546754",
                Owner = phonesOwner
            });

    var upgradedPhone  = new Phone
    {
        Id = 3,
        Manufacturer = "LG",
        Model = "634563456",
        Owner = phonesOwner
    };

    mostSelling.Add(upgradedPhone);

    // remove item from the list
    oldCollection.Remove(upgradedPhone);

    // find objects in the cache
    IEnumerable<phone> LGPhones = mostSelling.Where(ph => ph.Manufacturer == "LG");

    // find specific
    Phone singleElement = mostSelling.FirstOrDefault(ph => ph.Id == 8);

    //reset sequence and delete all lists
    redis.SetSequence(0);
    redisClient.Remove("urn:phones:mostselling");
    redisClient.Remove("urn:phones:oldcollection");
}

当需要存储相关的数据集和收集统计信息,例如answer -> queustion给答案或问题投票时,Redis集合就非常好使。假设我们有很多的问题(queustion)和答案(answer ),需要将它们存储在缓存中。使用Redis,我们可以这么做:

/// <summary>
/// Gets or sets the Redis Manager. The built-in IoC used with ServiceStack autowires this property.
/// </summary>
IRedisClientsManager RedisManager { get; set; }
/// <summary>
/// Delete question by performing compensating actions to 
/// StoreQuestion() to keep the datastore in a consistent state
/// </summary>
/// <param name="questionId">
public void DeleteQuestion(long questionId)
{
    using (var redis = RedisManager.GetClient())
    {
        var redisQuestions = redis.As<question>();

        var question = redisQuestions.GetById(questionId);
        if (question == null) return;

        //decrement score in tags list
        question.Tags.ForEach(tag => redis.IncrementItemInSortedSet("urn:tags", tag, -1));

        //remove all related answers
        redisQuestions.DeleteRelatedEntities<answer>(questionId);

        //remove this question from user index
        redis.RemoveItemFromSet("urn:user>q:" + question.UserId, questionId.ToString());

        //remove tag => questions index for each tag
        question.Tags.ForEach("urn:tags>q:" + tag.ToLower(), questionId.ToString()));

        redisQuestions.DeleteById(questionId);
    }
}

public void StoreQuestion(Question question)
{
    using (var redis = RedisManager.GetClient())
    {
        var redisQuestions = redis.As<question>();

        if (question.Tags == null) question.Tags = new List<string>();
        if (question.Id == default(long))
        {
            question.Id = redisQuestions.GetNextSequence();
            question.CreatedDate = DateTime.UtcNow;

            //Increment the popularity for each new question tag
            question.Tags.ForEach(tag => redis.IncrementItemInSortedSet("urn:tags", tag, 1));
        }

        redisQuestions.Store(question);
        redisQuestions.AddToRecentsList(question);
        redis.AddItemToSet("urn:user>q:" + question.UserId, question.Id.ToString());

        //Usage of tags - Populate tag => questions index for each tag
        question.Tags.ForEach(tag => redis.AddItemToSet
        ("urn:tags>q:" + tag.ToLower(), question.Id.ToString()));
    }
}

/// <summary>
/// Delete Answer by performing compensating actions to 
/// StoreAnswer() to keep the datastore in a consistent state
/// </summary>
/// <param name="questionId">
/// <param name="answerId">
public void DeleteAnswer(long questionId, long answerId)
{
    using (var redis = RedisManager.GetClient())
    {
        var answer = redis.As<question>().GetRelatedEntities<answer>
        (questionId).FirstOrDefault(x => x.Id == answerId);
        if (answer == null) return;

        redis.As<question>().DeleteRelatedEntity<answer>(questionId, answerId);

        //remove user => answer index
        redis.RemoveItemFromSet("urn:user>a:" + answer.UserId, answerId.ToString());
    }
}

public void StoreAnswer(Answer answer)
{
    using (var redis = RedisManager.GetClient())
    {
        if (answer.Id == default(long))
        {
            answer.Id = redis.As<answer>().GetNextSequence();
            answer.CreatedDate = DateTime.UtcNow;
        }

        //Store as a 'Related Answer' to the parent Question
        redis.As<question>().StoreRelatedEntities(answer.QuestionId, answer);
        //Populate user => answer index
        redis.AddItemToSet("urn:user>a:" + answer.UserId, answer.Id.ToString());
    }
}

public List<answer> GetAnswersForQuestion(long questionId)
{
    using (var redis = RedisManager.GetClient())
    {
        return redis.As<question>().GetRelatedEntities<answer>(questionId);
    }
}

public void VoteQuestionUp(long userId, long questionId)
{
    //Populate Question => User and User => Question set indexes in a single transaction
    RedisManager.ExecTrans(trans =>
    {
        //Register upvote against question and remove any downvotes if any
        trans.QueueCommand(redis => 
        redis.AddItemToSet("urn:q>user+:" + questionId, userId.ToString()));
        trans.QueueCommand(redis => 
        redis.RemoveItemFromSet("urn:q>user-:" + questionId, userId.ToString()));

        //Register upvote against user and remove any downvotes if any
        trans.QueueCommand(redis => 
        redis.AddItemToSet("urn:user>q+:" + userId, questionId.ToString()));
        trans.QueueCommand(redis => 
        redis.RemoveItemFromSet("urn:user>q-:" + userId, questionId.ToString()));
    });
}

public void VoteQuestionDown(long userId, long questionId)
{
    //Populate Question => User and User => Question set indexes in a single transaction
    RedisManager.ExecTrans(trans =>
    {
        //Register downvote against question and remove any upvotes if any
        trans.QueueCommand(redis => 
        redis.AddItemToSet("urn:q>user-:" + questionId, userId.ToString()));
        trans.QueueCommand(redis => 
        redis.RemoveItemFromSet("urn:q>user+:" + questionId, userId.ToString()));

        //Register downvote against user and remove any upvotes if any
        trans.QueueCommand(redis => 
        redis.AddItemToSet"urn:user>q-:" + userId, questionId.ToString()));
        trans.QueueCommand(redis => 
        redis.RemoveItemFromSet("urn:user>q+:" + userId, questionId.ToString()));
    });
}

public void VoteAnswerUp(long userId, long answerId)
{
    //Populate Question => User and User => Question set indexes in a single transaction
    RedisManager.ExecTrans(trans =>
    {
        //Register upvote against answer and remove any downvotes if any
        trans.QueueCommand(redis => 
        redis.AddItemToSet("urn:a>user+:" + answerId, userId.ToString()));
        trans.QueueCommand(redis => 
        redis.RemoveItemFromSet("urn:a>user-:" + answerId, userId.ToString()));

        //Register upvote against user and remove any downvotes if any
        trans.QueueCommand(redis => 
        redis.AddItemToSet("urn:user>a+:" + userId, answerId.ToString()));
        trans.QueueCommand(redis => 
        redis.RemoveItemFromSet("urn:user>a-:" + userId, answerId.ToString()));
    });
}

public void VoteAnswerDown(long userId, long answerId)
{
    //Populate Question => User and User => Question set indexes in a single transaction
    RedisManager.ExecTrans(trans =>
    {
        //Register downvote against answer and remove any upvotes if any
        trans.QueueCommand(redis => 
        redis.AddItemToSet("urn:a>user-:" + answerId, userId.ToString()));
        trans.QueueCommand(redis => 
        redis.RemoveItemFromSet("urn:a>user+:" + answerId, userId.ToString()));

        //Register downvote against user and remove any upvotes if any
        trans.QueueCommand(redis => 
        redis.AddItemToSet("urn:user>a-:" + userId, answerId.ToString()));
        trans.QueueCommand(redis => 
        redis.RemoveItemFromSet("urn:user>a+:" + userId, answerId.ToString()));
    });
}

public QuestionResult GetQuestion(long questionId)
{
    var question = RedisManager.ExecAs<question>
    (redisQuestions => redisQuestions.GetById(questionId));
    if (question == null) return null;

    var result = ToQuestionResults(new[] { question })[0];
    var answers = GetAnswersForQuestion(questionId);
    var uniqueUserIds = answers.ConvertAll(x => x.UserId).ToHashSet();
    var usersMap = GetUsersByIds(uniqueUserIds).ToDictionary(x => x.Id);

    result.Answers = answers.ConvertAll(answer =>
        new AnswerResult { Answer = answer, User = usersMap[answer.UserId] });

    return result;
}

public List<user> GetUsersByIds(IEnumerable<long> userIds)
{
    return RedisManager.ExecAs<user>(redisUsers => redisUsers.GetByIds(userIds)).ToList();
}

public QuestionStat GetQuestionStats(long questionId)
{
    using (var redis = RedisManager.GetReadOnlyClient())
    {
        var result = new QuestionStat
        {
            VotesUpCount = redis.GetSetCount("urn:q>user+:" +questionId),
            VotesDownCount = redis.GetSetCount("urn:q>user-:" + questionId)
        };
        result.VotesTotal = result.VotesUpCount - result.VotesDownCount;
        return result;
    }
}

public List<tag> GetTagsByPopularity(int skip, int take)
{
    using (var redis = RedisManager.GetReadOnlyClient())
    {
        var tagEntries = redis.GetRangeWithScoresFromSortedSetDesc("urn:tags", skip, take);
        var tags = tagEntries.ConvertAll(kvp => new Tag { Name = kvp.Key, Score = (int)kvp.Value });
        return tags;
    }
}

public SiteStats GetSiteStats()
{
    using (var redis = RedisManager.GetClient())
    {
        return new SiteStats
        {
            QuestionsCount = redis.As<question>().TypeIdsSet.Count,
            AnswersCount = redis.As<answer>().TypeIdsSet.Count,
            TopTags = GetTagsByPopularity(0, 10)
        };
    }
}

附加资源说明

项目中引用的一些包在packages.config文件中配置。

Funq IoC的相关配置,以及注册类型和当前控制器目录,在Global.asax文件中配置。

基于IoC的缓存使用以及Global.asax可以打开以下URL:http://localhost:37447/Question/GetQuestions?tag=test 查看。

你可以将tag字段设置成test3,test1,test2等。

Redis缓存配置——在web config文件(<system.web><sessionState>节点)以及RedisSessionStateProvider.cs文件中。

在MVC项目中有很多待办事项,因此,如果你想改进/继续,请更新,并上传。

如果有人能提供使用Redis(以及Funq IOC)缓存的MVC应用程序示例,本人将不胜感激。Funq IOC已经配置,使用示例已经在Question controller中。

注:部分取样于“ServiceStack.Examples-master”解决方案。

结论。优化应用程序缓存以及快速本地缓存

由于Redis并不在本地存储(也不在本地复制)数据,那么通过在本地缓存区存储一些轻量级或用户依赖的对象(跳过序列化字符串和客户端—服务端数据转换)来优化性能是有意义的。例如,在Web应用中,对于轻量级的对象使用’System.Runtime.Caching.ObjectCache‘ 会更好——用户依赖,并且应用程序时常要用。否则,当经常性地需要使用该对象时,就必须在分布式Redis缓存中存储大量容积的内容。用户依赖的对象举例——个人资料信息,个性化信息 。常用对象——本地化数据,不同用户之间的共享信息,等等。

下载源代码(Redis Funq LoC MVC 4版本)

链接

如何运行Redis服务:

https://github.com/kcherenkov/redis-windows-service

文档:

http://redis.io/documentation

.NET / C#示例:

https://github.com/ServiceStack/ServiceStack.Examples

关于如何用C#在Windows上使用Redis的好建议:

http://maxivak.com/getting-started-with-redis-and-asp-net-mvc-under-windows/:

http://www.piotrwalat.net/using-redis-with-asp-net-web-api/

关于Redis:

https://github.com/ServiceStack/ServiceStack.Redis

Azure缓存

http://kotugoroshko.blogspot.ae/2013/07/windows-azure-caching-integration.html

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