Redis實戰 - 1.String和計數器

在.NET Core 項目中操練String

使用 StackExchange.Redis 訪問 Redis

static void Main(string[] args)
        {
            using (ConnectionMultiplexer redis = ConnectionMultiplexer.Connect("localhost:6379"))
            {

                IDatabase db = redis.GetDatabase();
                db.StringSet("name", "Michal Jackson");
                string name = db.StringGet("name");
                Console.WriteLine(name); //結果：Michal Jackson

                db.StringSet("age", "11");
                //incr 自增
                db.StringIncrement("age");
                RedisValue age = db.StringGet("age");
                Console.WriteLine(age);//結果：12
                //incrby 指定增量
                age = db.StringIncrement("age", 5);
                Console.WriteLine(age);//結果：17
                //decr 自減
                age = db.StringDecrement("age");
                Console.WriteLine(age);//結果：16
                //decrby 指定減量
                age = db.StringDecrement("age", 5);
                Console.WriteLine(age);//結果：11

                //mset 設置多個值
                db.StringSet(new KeyValuePair<RedisKey, RedisValue>[]
                {
                    new KeyValuePair<RedisKey, RedisValue>("aa", "aa"),
                    new KeyValuePair<RedisKey, RedisValue>("bb", "bb"),
                    new KeyValuePair<RedisKey, RedisValue>("cc", "5"),
                });

                //mget 取多個值
                var values = db.StringGet(new RedisKey[] { "aa", "bb", "cc" });
                foreach (RedisValue redisValue in values)
                {
                    Console.Write(redisValue + ",");
                }
                //結果：aa,bb,5

                //exists 是否存在
                db.StringSet("name1", "Dave1");
                bool existsResult = db.KeyExists("name1");
                Console.WriteLine(existsResult); //結果：true

                //del 刪除
                bool delResult = db.KeyDelete("name1");
                Console.WriteLine(delResult); //結果：true
                existsResult = db.KeyExists("name1");
                Console.WriteLine(existsResult); //結果：false

                //type 判斷類型
                db.StringSet("name2", "Dave2");
                var typeOfValue = db.KeyType("name2");
                Console.WriteLine(typeOfValue); //String 
                
                //expire 過時時間
                db.StringSet("name3", "Dave3");
                db.KeyExpire("name3", TimeSpan.FromSeconds(5));
                RedisValue value = db.StringGet("name3"); 
                Console.WriteLine(value);       //Dave3
                Console.WriteLine("此處等待6秒...");
                Thread.Sleep(6 * 1000);
                value = db.StringGet("name3"); //啥也沒有..
                Console.WriteLine(value);

                //ex 設置key直接設置有效期
                db.StringSet("name4","Dave4", TimeSpan.FromSeconds(5));
                RedisValue value4 = db.StringGet("name4"); 
                Console.WriteLine(value4);       //Dave4
                Console.WriteLine("此處等待6秒...");
                Thread.Sleep(6 * 1000);
                value4 = db.StringGet("name4"); //啥也沒有..
                Console.WriteLine(value4);

                //ttl 查看過時時間
                db.StringSet("name6","Dave6", TimeSpan.FromSeconds(5));
                for (int i = 1; i < 7; i++)
                {
                     Thread.Sleep( 1000);
                    RedisValue valueTTL = db.StringGet("name6");
                   var ttl =  db.KeyTimeToLive("name6");
                    if (ttl==null)
                    {
                        Console.WriteLine($"{i}秒事後：Dave6已過時");
                    }
                    else
                    {
                        Console.WriteLine($"{i}秒事後：{valueTTL}還能存活{ttl}秒");
                    }
                    
                 }
                // 1秒事後：Dave6還能存活00：00：03.9970000秒
                // 2秒事後：Dave6還能存活00：00：02.9040000秒
                // 3秒事後：Daue6還能存活00：00：01.9040000秒
                // 4秒事後：Dave6還能存活00：00：00.9030000秒
                // 5秒事後：Dave6已過時
                // 6秒事後：Daue6已過時
            }

            Console.ReadKey();
        }

1.string值寫到前臺，取RedisValue

先 Startup.cs 注入 IConnectionMultiplexer

services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);

            services.AddSingleton<IConnectionMultiplexer>(ConnectionMultiplexer.Connect("localhost:6379"));

在 HomeController.cs

public class HomeController : Controller
    {
        private readonly IConnectionMultiplexer _redis;
        private readonly IDatabase _db;

        public HomeController(IConnectionMultiplexer redis)
        {
            _redis = redis;
            _db = _redis.GetDatabase();
        }

        public IActionResult Index()
        {
            _db.StringSet("fullname", "Michael Jackson");
            var name = _db.StringGet("fullname");
            return View("Index", name);
        }
    }

視圖 Index

@model StackExchange.Redis.RedisValue

<div class="text-center">
    <h1 class="display-4"> Welcome:@Model </h1>
    <p>Learn about <a href="https://docs.microsoft.com/aspnet/core">building Web apps with ASP.NET Core</a>.</p>
</div>

2.計數器

2.1 視圖組件 ViewComponent

建立 CounterViewComponent 類

using System;
using System.Collections.Generic;
using System.Linq;
using Microsoft.AspNetCore.Mvc;
using System.Threading.Tasks;
using StackExchange.Redis;

namespace RedisToEsay.ViewComponents
{
    public class CounterViewComponent : ViewComponent
    {
        private readonly IDatabase _db;

        public CounterViewComponent(IConnectionMultiplexer redis)
        {
            _db = redis.GetDatabase();
        }

        public async Task<IViewComponentResult> InvokeAsync()
        {
            string controller = RouteData.Values["controller"].ToString();
            string action     = RouteData.Values["action"].ToString();
            if (!string.IsNullOrWhiteSpace(controller) && !string.IsNullOrWhiteSpace(action))
            {
                var pageId = $"{controller}-{action}";
                await _db.StringIncrementAsync(pageId);
                var count = _db.StringGet(pageId);
                return View("Default", pageId + ":" + count);
            }

            throw new Exception("can't get pageId");
        }
    }
}

建立 Default 視圖

@model string

<h4>@Model</h4>

而後在Shared_Layout.cshtml 調用

<div>
        @await Component.InvokeAsync("Counter")
    </div>

報錯：Defualt 建立的位置不對

An unhandled exception occurred while processing the request.
InvalidOperationException: The view 'Components/Counter/Default' was not found. The following locations were searched:
/Views/Home/Components/Counter/Default.cshtml
/Views/Shared/Components/Counter/Default.cshtml
/Pages/Shared/Components/Counter/Default.cshtml

因此建立的位置在 /Views/Shared/Components/Counter/Default.cshtml

參考：

草根專欄，Redis in .NET Core 入門：(2) String
楊旭(Video)，Redis in ASP.NET Core 1. 計數器