NopCommerce源码架构详解-Cache缓存相关源码分析

为了提高一个系统或网站的性能和IO吞吐量,我们一般都会采用缓存技术。当然NopCommerce也不例外,本文我们就来给大家分析一下nop中Cache缓存相关类设计、核心源码及实现原理。

NopCommerce源码架构详解概述

文章目录

概述

NopCommerce源码架构详解-Cache缓存相关源码分析。

内容

为了提高一个系统或网站的性能和IO吞吐量,我们一般都会采用缓存技术。当然NopCommerce也不例外,本文我们就来给大家分析一下nop中Cache缓存相关类设计、核心源码及实现原理。

1、Nop.Core.Caching.ICacheManager

Nop首先抽象出了一个缓存存储和读取相关管理接口Nop.Core.Caching.ICacheManager。

namespace Nop.Core.Caching
{
    /// <summary>
    /// Cache manager interface
    /// </summary>
    public interface ICacheManager
    {
        /// <summary>
        /// Gets or sets the value associated with the specified key.
        /// </summary>
        /// <typeparam name="T">Type</typeparam>
        /// <param name="key">The key of the value to get.</param>
        /// <returns>The value associated with the specified key.</returns>
        T Get<T>(string key);

        /// <summary>
        /// Adds the specified key and object to the cache.
        /// </summary>
        /// <param name="key">key</param>
        /// <param name="data">Data</param>
        /// <param name="cacheTime">Cache time</param>
        void Set(string key, object data, int cacheTime);

        /// <summary>
        /// Gets a value indicating whether the value associated with the specified key is cached
        /// </summary>
        /// <param name="key">key</param>
        /// <returns>Result</returns>
        bool IsSet(string key);

        /// <summary>
        /// Removes the value with the specified key from the cache
        /// </summary>
        /// <param name="key">/key</param>
        void Remove(string key);

        /// <summary>
        /// Removes items by pattern
        /// </summary>
        /// <param name="pattern">pattern</param>
        void RemoveByPattern(string pattern);

        /// <summary>
        /// Clear all cache data
        /// </summary>
        void Clear();
    }
}

2、Nop.Core.Caching.MemoryCacheManager

接口ICacheManager具体实现是在类Nop.Core.Caching.MemoryCacheManager:

using System;
using System.Collections.Generic;
using System.Runtime.Caching;
using System.Text.RegularExpressions;

namespace Nop.Core.Caching
{
    /// <summary>
    /// Represents a manager for caching between HTTP requests (long term caching)
    /// </summary>
    public partial class MemoryCacheManager : ICacheManager
    {
        protected ObjectCache Cache
        {
            get
            {
                return MemoryCache.Default;
            }
        }

        /// <summary>
        /// Gets or sets the value associated with the specified key.
        /// </summary>
        /// <typeparam name="T">Type</typeparam>
        /// <param name="key">The key of the value to get.</param>
        /// <returns>The value associated with the specified key.</returns>
        public virtual T Get<T>(string key)
        {
            return (T)Cache[key];
        }

        /// <summary>
        /// Adds the specified key and object to the cache.
        /// </summary>
        /// <param name="key">key</param>
        /// <param name="data">Data</param>
        /// <param name="cacheTime">Cache time</param>
        public virtual void Set(string key, object data, int cacheTime)
        {
            if (data == null)
                return;

            var policy = new CacheItemPolicy();
            policy.AbsoluteExpiration = DateTime.Now + TimeSpan.FromMinutes(cacheTime);
            Cache.Add(new CacheItem(key, data), policy);
        }

        /// <summary>
        /// Gets a value indicating whether the value associated with the specified key is cached
        /// </summary>
        /// <param name="key">key</param>
        /// <returns>Result</returns>
        public virtual bool IsSet(string key)
        {
            return (Cache.Contains(key));
        }

        /// <summary>
        /// Removes the value with the specified key from the cache
        /// </summary>
        /// <param name="key">/key</param>
        public virtual void Remove(string key)
        {
            Cache.Remove(key);
        }

        /// <summary>
        /// Removes items by pattern
        /// </summary>
        /// <param name="pattern">pattern</param>
        public virtual void RemoveByPattern(string pattern)
        {
            var regex = new Regex(pattern, RegexOptions.Singleline | RegexOptions.Compiled | RegexOptions.IgnoreCase);
            var keysToRemove = new List<String>();

            foreach (var item in Cache)
                if (regex.IsMatch(item.Key))
                    keysToRemove.Add(item.Key);

            foreach (string key in keysToRemove)
            {
                Remove(key);
            }
        }

        /// <summary>
        /// Clear all cache data
        /// </summary>
        public virtual void Clear()
        {
            foreach (var item in Cache)
                Remove(item.Key);
        }
    }
}

可以看到上面Nop的缓存数据是使用的的MemoryCache.Default来存储的,MemoryCache.Default是获取对默认 System.Runtime.Caching.MemoryCache 实例的引用,缓存的默认实例,也就是程序运行的内存中。

Nop除了提供了一个MemoryCacheManager,还有一个Nop.Core.Caching.PerRequestCacheManager类,它提供的是MemoryCacheManager相同的功能,不过它是把数据存在HttpContextBase.Items中,如下:

using System;
using System.Collections;
using System.Collections.Generic;
using System.Text.RegularExpressions;
using System.Web;

namespace Nop.Core.Caching
{
    /// <summary>
    /// Represents a manager for caching during an HTTP request (short term caching)
    /// </summary>
    public partial class PerRequestCacheManager : ICacheManager
    {
        private readonly HttpContextBase _context;

        /// <summary>
        /// Ctor
        /// </summary>
        /// <param name="context">Context</param>
        public PerRequestCacheManager(HttpContextBase context)
        {
            this._context = context;
        }

        /// <summary>
        /// Creates a new instance of the NopRequestCache class
        /// </summary>
        protected virtual IDictionary GetItems()
        {
            if (_context != null)
                return _context.Items;

            return null;
        }

        //省略其它代码....
    }
}

3、缓存接口ICacheManager依赖注入

缓存接口ICacheManager使用了依赖注入,我们在Nop.Web.Framework.DependencyRegistrar类中就能找到对ICacheManager的注册代码:

//cache manager
builder.RegisterType<MemoryCacheManager>().As<ICacheManager>().Named<ICacheManager>("nop_cache_static").SingleInstance();
builder.RegisterType<PerRequestCacheManager>().As<ICacheManager>().Named<ICacheManager>("nop_cache_per_request").InstancePerLifetimeScope();

//pass MemoryCacheManager as cacheManager (cache settings between requests)
builder.RegisterType<ProductTagService>().As<IProductTagService>()
.WithParameter(ResolvedParameter.ForNamed<ICacheManager>("nop_cache_static"))
.InstancePerLifetimeScope();

//pass MemoryCacheManager as cacheManager (cache settings between requests)
builder.RegisterType<PermissionService>().As<IPermissionService>()
.WithParameter(ResolvedParameter.ForNamed<ICacheManager>("nop_cache_static"))
.InstancePerLifetimeScope();

//pass MemoryCacheManager as cacheManager (cache settings between requests)
builder.RegisterType<AclService>().As<IAclService>()
.WithParameter(ResolvedParameter.ForNamed<ICacheManager>("nop_cache_static"))
.InstancePerLifetimeScope();

//pass MemoryCacheManager as cacheManager (cache settings between requests)
builder.RegisterType<PriceCalculationService>().As<IPriceCalculationService>()
.WithParameter(ResolvedParameter.ForNamed<ICacheManager>("nop_cache_static"))
.InstancePerLifetimeScope();

//pass MemoryCacheManager as cacheManager (cache settings between requests)
builder.RegisterType<CustomerActivityService>().As<ICustomerActivityService>()
.WithParameter(ResolvedParameter.ForNamed<ICacheManager>("nop_cache_static"))
.InstancePerLifetimeScope();

上面最开始对接口ICacheManager两实现分别是MemoryCacheManager和PerRequestCacheManager并通过.Named来区分。Autofac高级特性–注册Named命名和Key Service服务

接下来可以配置不同的Service依赖不同的ICacheManager的实现:.WithParameter(ResolvedParameter.ForNamed(nop_cache_static))或者.WithParameter(ResolvedParameter.ForNamed(nop_cache_per_request))。

4、具体实例BlogController

下面我们来举例看一下怎么使用这个缓存的。我们就以Nop.Web.Controllers.BlogController的方法BlogTags为例:

[ChildActionOnly]
public ActionResult BlogTags()
{
    if (!_blogSettings.Enabled)
        return Content("");

    var cacheKey = string.Format(ModelCacheEventConsumer.BLOG_TAGS_MODEL_KEY, _workContext.WorkingLanguage.Id, _storeContext.CurrentStore.Id);
    var cachedModel = _cacheManager.Get(cacheKey, () =>
    {
        var model = new BlogPostTagListModel();

        //get tags
        var tags = _blogService.GetAllBlogPostTags(_storeContext.CurrentStore.Id, _workContext.WorkingLanguage.Id)
            .OrderByDescending(x => x.BlogPostCount)
            .Take(_blogSettings.NumberOfTags)
            .ToList();
        //sorting
        tags = tags.OrderBy(x => x.Name).ToList();

        foreach (var tag in tags)
            model.Tags.Add(new BlogPostTagModel()
            {
                Name = tag.Name,
                BlogPostCount = tag.BlogPostCount
            });
        return model;
    });

    return PartialView(cachedModel);
}

上面var cachedModel = _cacheManager.Get就是从缓存中读取数据,_cacheManager的Get方法第二个参数是一个lambda表达式,可以传一个方法,这时我们就可以把数据的从数据库中的逻辑放在里面,注意:当第二次请求数据时,如果缓存中有数据,这个Lambda方法是不会执行的。为什么呢?我们可以选中_cacheManager的Get方法按F12进去看这个方法的实现就知道了:

using System;

namespace Nop.Core.Caching
{
    /// <summary>
    /// Extensions
    /// </summary>
    public static class CacheExtensions
    {

        /// <summary>
        /// Get a cached item. If it's not in the cache yet, then load and cache it
        /// </summary>
        /// <typeparam name="T">Type</typeparam>
        /// <param name="cacheManager">Cache manager</param>
        /// <param name="key">Cache key</param>
        /// <param name="acquire">Function to load item if it's not in the cache yet</param>
        /// <returns>Cached item</returns>
        public static T Get<T>(this ICacheManager cacheManager, string key, Func<T> acquire)
        {
            return Get(cacheManager, key, 60, acquire);
        }

        /// <summary>
        /// Get a cached item. If it's not in the cache yet, then load and cache it
        /// </summary>
        /// <typeparam name="T">Type</typeparam>
        /// <param name="cacheManager">Cache manager</param>
        /// <param name="key">Cache key</param>
        /// <param name="cacheTime">Cache time in minutes (0 - do not cache)</param>
        /// <param name="acquire">Function to load item if it's not in the cache yet</param>
        /// <returns>Cached item</returns>
        public static T Get<T>(this ICacheManager cacheManager, string key, int cacheTime, Func<T> acquire) 
        {
            if (cacheManager.IsSet(key))
            {
                return cacheManager.Get<T>(key);
            }
            else
            {
                var result = acquire();
                if (cacheTime > 0)
                    cacheManager.Set(key, result, cacheTime);
                return result;
            }
        }

    }
}

可以看到其实上面_cacheManager.Get调用的是类型ICacheManager的一个扩展方法。第二个方法就可以知道,当缓存中有数据直接返回cacheManager.Get(key),如果没有才进入else分支,执行参数的Lambda表达方式acquire()。

原文出处:蓝狐软件工作室【蓝狐】

原文链接:http://m.lanhusoft.com/Article/349.html

本文观点不代表 .Net中文网 立场,转载请联系原作者。

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