C#开源磁盘/内存缓存引擎

C#开源磁盘/内存缓存引擎

前言

昨天写了个 《基于STSdb和fastJson的磁盘/内存缓存》，大家可以先看看。下午用到业务系统时候，觉得可以改进一下，昨晚想了一个晚上，刚才重新实现一下。

更新

1. 增加了对批量处理的支持，写操作速度提升5倍，读操作提升100倍

2. 增加了一个存储provider，可以选择不用STSdb做存储，而用物理文件/Dictionary。

3. 增加了对并发的支持

需求

业务系统用的是数据库，数据量大，部分只读或相对稳定业务查询复杂，每次页面加载都要花耗不少时间(不讨论异步)，觉得可以做一下高速缓存，譬如用nosql那种key/value快速存取结果

目的

提供一个简单易用的解决缓存方案，可以根据数据的大小缓存到内存或者磁盘。

实现

存取

方法1. 基于STSdb，提供高效的Key/Value存取，支持磁盘/内存，对Key无限制

方法2. 基于直接物理文件/Dictionary。Key必须是基本类型，譬如int/long/uint/ulong/DateTime/string等。

代码

代码比较简单，花了2个小时写的，很多情况没考虑，譬如磁盘空间/内存不足，自动回收过期缓存等，这些留给大家做家庭作业吧。另外，为了发布方便，STSdb和fastJson的代码都合并到一个项目里。

BaseCahce.cs

这是一个抽象基类，提供存取接口。

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using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
 
namespace Com.SuperCache.Engine
{
    public abstract class BaseCache
    {
        protected internal const string KeyExpiration = "Expiration";
 
        public abstract void Add<K>(string Category, K Key, object Data);
        public abstract void Add<K, V>(string Category, IEnumerable<KeyValuePair<K, V>> Items, DateTime? ExpirationDate);
        public abstract void Add<K>(string Category, K Key, object Data, DateTime? ExpirationDate);
        public abstract List<KeyValuePair<K, V>> Get<K, V>(string Category, IEnumerable<K> Keys);
        public abstract V Get<K, V>(string Category, K Key);
    }
}

　　

CahceEngine.cs

主要调用缓存引擎

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using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using STSdb4.Database;
using fastJSON;
using System.IO;
 
namespace Com.SuperCache.Engine
{
    public enum CacheProviders
    {
        Default = 1,
        Raw = 2
    }
 
    public class CacheEngine
    {
        private BaseCache cacheProvider = null;
 
        public CacheEngine(string DataPath): this(CacheProviders.Default, DataPath)
        {
        }
 
        public CacheEngine(CacheProviders Provider, string DataPath)
        {
            switch (Provider)
            {
                case CacheProviders.Default:
                    cacheProvider = new STSdbCache(DataPath);
                    break;
                case CacheProviders.Raw:
                    cacheProvider = new RawCache(DataPath);
                    break;
                default:
                    break;
            }
        }
 
        public void Add<K>(string Category, K Key, object Data)
        {
            cacheProvider.Add<K>(Category, Key, Data);
        }
 
        public void Add<K, V>(string Category, IEnumerable<KeyValuePair<K, V>> Items, DateTime? ExpirationDate)
        {
            cacheProvider.Add<K, V>(Category, Items, ExpirationDate);
        }
 
        public void Add<K>(string Category, K Key, object Data, DateTime? ExpirationDate)
        {
            cacheProvider.Add<K>(Category, Key, Data, ExpirationDate);
        }
 
        public List<KeyValuePair<K, V>> Get<K, V>(string Category, IEnumerable<K> Keys)
        {
            return cacheProvider.Get<K, V>(Category, Keys);
        }
 
        public V Get<K, V>(string Category, K Key)
        {
            return cacheProvider.Get<K, V>(Category, Key);
        }
    }
}

　　

　　

STSdbCache.cs

STSdb存储引擎　　

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using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using STSdb4.Database;
using fastJSON;
using System.IO;
 
namespace Com.SuperCache.Engine
{
    public class STSdbCache : BaseCache
    {
        private string dataPath;
        private static IStorageEngine memoryInstance = null;
        private static object syncRoot = new object();
        private bool isMemory = false;
 
        public STSdbCache(string DataPath)
        {
            dataPath = DataPath;
            if (!dataPath.EndsWith(Path.DirectorySeparatorChar.ToString()))
                dataPath += Path.DirectorySeparatorChar;
 
            isMemory = string.IsNullOrEmpty(DataPath);
        }
 
        public override void Add<K>(string Category, K Key, object Data)
        {
            Add(Category, Key, Data, null);
        }
 
        private IStorageEngine Engine
        {
            get
            {
                if (isMemory)
                {
                    lock (syncRoot)
                    {
                        if (memoryInstance == null)
                            memoryInstance = STSdb.FromMemory();
                    }
                    return memoryInstance;
                }
                else
                    return STSdb.FromFile(GetFile(false), GetFile(true));
            }
        }
 
        private string GetExpirationTable(string Category)
        {
            return KeyExpiration + "_" + Category;
        }
 
        public override void Add<K, V>(string Category, IEnumerable<KeyValuePair<K, V>> Items, DateTime? ExpirationDate)
        {
            lock (syncRoot)
            {
                var engine = Engine;
                var table = engine.OpenXIndex<K, string>(Category);
                Items.ForEach(i =>
                    {
                        var key = i.Key;
                        var data = i.Value;
                        //will only serialize object other than string
                        var result = typeof(V) == typeof(string) ? data as string: JSON.Instance.ToJSON(data);
                        table[key] = result;
                        table.Flush();
 
                        //specify expiration
                        var expiration = engine.OpenXIndex<K, DateTime>(GetExpirationTable(Category));
                        //default 30 mins to expire from now
                        var expirationDate = ExpirationDate == null || ExpirationDate <= DateTime.Now ? DateTime.Now.AddMinutes(30) : (DateTime)ExpirationDate;
                        expiration[key] = expirationDate;
                        expiration.Flush();
                    });
                engine.Commit();
 
                //only dispose disk-based engine
                if (!isMemory)
                    engine.Dispose();
            }
        }
 
        public override void Add<K>(string Category, K Key, object Data, DateTime? ExpirationDate)
        {
            Add<K, object>(Category, new List<KeyValuePair<K, object>> { new KeyValuePair<K, object>(Key, Data) }, ExpirationDate);
        }
 
        private string GetFile(bool IsData)
        {
            if (!Directory.Exists(dataPath))
                Directory.CreateDirectory(dataPath);
            return dataPath + "SuperCache." + (IsData ? "dat" : "sys");
        }
 
        public override List<KeyValuePair<K, V>> Get<K, V>(string Category, IEnumerable<K> Keys)
        {
            var result = new List<KeyValuePair<K, V>>();
            lock (syncRoot)
            {
                var engine = Engine;
                var table = engine.OpenXIndex<K, string>(Category);
                var expiration = engine.OpenXIndex<K, DateTime>(GetExpirationTable(Category));
                var isCommitRequired = false;
 
                Keys.ForEach(key =>
                    {
                        string buffer;
                        V value;
                        if (table.TryGet(key, out buffer))
                        {
                            //will only deserialize object other than string
                            value = typeof(V) == typeof(string) ? (V)(object)buffer : JSON.Instance.ToObject<V>(buffer);
                            DateTime expirationDate;
                            //get expiration date
                            if (expiration.TryGet(key, out expirationDate))
                            {
                                //expired
                                if (expirationDate < DateTime.Now)
                                {
                                    value = default(V);
                                    table.Delete(key);
                                    table.Flush();
                                    expiration.Delete(key);
                                    expiration.Flush();
                                    isCommitRequired = true;
                                }
                            }
                        }
                        else
                            value = default(V);
 
                        result.Add(new KeyValuePair<K, V>(key, value));
                    });
 
                //only need to commit write actions
                if (isCommitRequired)
                    engine.Commit();
 
                //only dispose disk-based engine
                if (!isMemory)
                    engine.Dispose();
            }
            return result;
        }
 
        public override V Get<K, V>(string Category, K Key)
        {
            var buffer = Get<K, V>(Category, new K[] { Key });
            var result = buffer.FirstOrDefault();
            return result.Value;
        }
    }
}

　　

RawCache.cs

物理文件/Dictionary引擎

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using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using STSdb4.Database;
using fastJSON;
using System.IO;
 
namespace Com.SuperCache.Engine
{
    public class RawCache : BaseCache
    {
        private string dataPath;
        private static Dictionary<string, object> memoryData = new Dictionary<string, object>();
        private static Dictionary<string, DateTime?> memoryExpiration = new Dictionary<string, DateTime?>();
        private static object syncRoot = new object();
        private bool isMemory = false;
 
        public RawCache(string DataPath)
        {
            dataPath = DataPath;
            if (!dataPath.EndsWith(Path.DirectorySeparatorChar.ToString()))
                dataPath += Path.DirectorySeparatorChar;
 
            isMemory = string.IsNullOrEmpty(DataPath);
        }
 
        public override void Add<K>(string Category, K Key, object Data)
        {
            Add(Category, Key, Data, null);
        }
 
        private string GetExpirationTable(string Category)
        {
            return KeyExpiration + "_" + Category;
        }
 
        public override void Add<K, V>(string Category, IEnumerable<KeyValuePair<K, V>> Items, DateTime? ExpirationDate)
        {
            lock (syncRoot)
            {
                Items.ForEach(i =>
                    {
                        var key = i.Key;
                        var data = i.Value;
 
                        if (isMemory)
                        {
                            var memKey = GetKey(Category, key.ToString());
                            memoryData[memKey] = data;
                            memoryExpiration[memKey] = ExpirationDate;
                        }
                        else
                        {
                            //will only serialize object other than string
                            var result = typeof(V) == typeof(string) ? data as string : JSON.Instance.ToJSON(data);
                            File.WriteAllText(GetFile(Category, key.ToString(), true), result);
 
                            //specify expiration
                            //default 30 mins to expire from now
                            var expirationDate = ExpirationDate == null || ExpirationDate <= DateTime.Now ? DateTime.Now.AddMinutes(30) : (DateTime)ExpirationDate;
                            File.WriteAllText(GetFile(Category, key.ToString(), false), expirationDate.ToString());
                        }
                    });
            }
        }
 
        public override void Add<K>(string Category, K Key, object Data, DateTime? ExpirationDate)
        {
            Add<K, object>(Category, new List<KeyValuePair<K, object>> { new KeyValuePair<K, object>(Key, Data) }, ExpirationDate);
        }
 
        private string GetFile(string Category, string FileName, bool IsData)
        {
            var path = dataPath + Category.NormalizeFileName() + @"";
            if (!Directory.Exists(path))
                Directory.CreateDirectory(path);
            return path + FileName.NormalizeFileName() + "." + (IsData ? "dat" : "exp");
        }
 
        private string GetKey(string Category, string Key)
        {
            return Category + "_" + Key;
        }
 
        public override List<KeyValuePair<K, V>> Get<K, V>(string Category, IEnumerable<K> Keys)
        {
            var result = new List<KeyValuePair<K, V>>();
            lock (syncRoot)
            {
                Keys.ForEach(key =>
                    {
                        string buffer;
                        V value;
                        if (isMemory)
                        {
                            var memKey = GetKey(Category, key.ToString());
                            object memBuffer;
                            if (memoryData.TryGetValue(memKey, out memBuffer))
                            {
                                value = (V)memBuffer;
                                DateTime? expirationDate;
                                if (memoryExpiration.TryGetValue(memKey, out expirationDate))
                                {
                                    //expired
                                    if (expirationDate != null && (DateTime)expirationDate < DateTime.Now)
                                    {
                                        value = default(V);
                                        memoryData.Remove(memKey);
                                        memoryExpiration.Remove(memKey);
                                    }
                                }
                            }
                            else
                                value = default(V);
                        }
                        else
                        {
                            var dataFilePath = GetFile(Category, key.ToString(), true);
                            if (File.Exists(dataFilePath))
                            {
                                buffer = File.ReadAllText(dataFilePath);
 
                                //will only deserialize object other than string
                                value = typeof(V) == typeof(string) ? (V)(object)buffer : JSON.Instance.ToObject<V>(buffer);
                                DateTime expirationDate;
                                var expirationFilePath = GetFile(Category, key.ToString(), false);
                                if (File.Exists(expirationFilePath))
                                {
                                    buffer = File.ReadAllText(expirationFilePath);
                                    expirationDate = Convert.ToDateTime(buffer);
                                    //expired
                                    if (expirationDate < DateTime.Now)
                                    {
                                        value = default(V);
                                        File.Delete(dataFilePath);
                                        File.Delete(expirationFilePath);
                                    }
                                }
                            }
                            else
                                value = default(V);
                        }
 
                        result.Add(new KeyValuePair<K, V>(key, value));
                    });
            }
            return result;
        }
 
        public override V Get<K, V>(string Category, K Key)
        {
            var buffer = Get<K, V>(Category, new K[] { Key });
            var result = buffer.FirstOrDefault();
            return result.Value;
        }
    }
}

　　

　　

Extensions.cs

扩展函数

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using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
 
namespace Com.SuperCache.Engine
{
    public static class Extensions
    {
        public static void ForEach<T>(this IEnumerable<T> source, Action<T> action)
        {
            if (source != null)
            {
                foreach (var item in source)
                {
                    action(item);
                }
            }
        }
 
        public static string NormalizeFileName(this string FileName)
        {
            var result = FileName;
            Path.GetInvalidFileNameChars().ForEach(c =>
                {
                    result = result.Replace(c.ToString(), string.Empty);
                });
            return result;
        }
    }
}

　　

新建

构造CacheEngine需要传递缓存保存到哪个文件夹。

基于内存

如果你不喜欢基于磁盘的缓存，可以使用基于内存，构造函数传递空字符串便可。

增加/更新

同一个方法：Add。用户可以指定类型（Category），譬如User，Employee等。键（Key）支持泛型，值（Data）是object。有一个overload是过期日期（ExpirationDate），默认当前时间30分钟后

获取

Get方法需要指定类型（Category）和键（Key）。

 

例子

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using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Diagnostics;
using Com.SuperCache.Engine;
 
namespace Com.SuperCache.Test
{
    public class Foo
    {
        public string Name { get; set; }
        public int Age { get; set; }
        public double? Some { get; set; }
        public DateTime? Birthday { get; set; }
    }
 
    class Program
    {
        static void Main(string[] args)
        {
            //TestAddGet();
 
            //Thread.Sleep(4000);
            //TestExpiration();
 
            TestDefaultDiskPerformance();
            TestRawMemoryPerformance();
            TestRawDiskPerformance();
            TestRawMemoryPerformance();
 
            //TestConcurrent();
 
            Console.Read();
        }
 
        private static void TestConcurrent()
        {
            var w = new Stopwatch();
            w.Start();
            Parallel.For(1, 3, (a) =>
                {
                    var employees = Enumerable.Range((a - 1) * 1000, a * 1000).Select(i => new KeyValuePair<int, string>(i, "Wilson " + i + " Chen"));
                    var engine = new CacheEngine(@"....data");
                    engine.Add<int, string>("Employee", employees, DateTime.Now.AddMinutes(1));
                });
            w.Stop();
            Console.WriteLine("add:" + w.Elapsed);
 
            var engine2 = new CacheEngine(@"....data");
            var o = engine2.Get<int, string>("Employee", 1005);
            Console.WriteLine(o);
        }
 
        private static void TestDefaultDiskPerformance()
        {
            TestPerformance(CacheProviders.Default, @"....data");
        }
 
        private static void TestDefaultMemoryPerformance()
        {
            TestPerformance(CacheProviders.Default, string.Empty);
        }
 
        private static void TestRawDiskPerformance()
        {
            TestPerformance(CacheProviders.Raw, @"....data");
        }
 
        private static void TestRawMemoryPerformance()
        {
            TestPerformance(CacheProviders.Raw, string.Empty);
        }
 
        private static void TestPerformance(CacheProviders Provider, string DataPath)
        {
            Console.WriteLine("Performance Test: " + Provider.ToString() + ", " + (string.IsNullOrEmpty(DataPath) ? "Memory" : DataPath));
            var engine = new CacheEngine(Provider, DataPath);
            var w = new Stopwatch();
 
            w.Start();
            var employees = Enumerable.Range(0, 1000).Select(i => new KeyValuePair<int, string>(i, "Wilson " + i + " Chen"));
            engine.Add<int, string>("Employee", employees, DateTime.Now.AddMinutes(1));
            w.Stop();
            Console.WriteLine("add:" + w.Elapsed);
 
            /*w.Restart();
            employees.ForEach(key =>
                {
                    var o1 = engine.Get<int, string>("Employee", key.Key);
                });
            w.Stop();
            Console.WriteLine("individual get:" + w.Elapsed);*/
 
            w.Restart();
            var keys = employees.Select(i => i.Key);
            var o = engine.Get<int, string>("Employee", keys);
            w.Stop();
            Debug.Assert(o.Count == keys.Count());
            Console.WriteLine("get:" + w.Elapsed);
            Console.WriteLine();
        }
 
        private static void TestExpiration()
        {
            var engine = new CacheEngine(@"....data");
            var o = engine.Get<string, Foo>("User", "wchen");
            Console.WriteLine(o != null ? o.Name : "wchen does not exist or expired");
        }
 
        private static void TestAddGet()
        {
            var engine = new CacheEngine(@"....data");
            var f = new Foo { Name = "Wilson Chen", Age = 30, Birthday = DateTime.Now, Some = 123.456 };
            engine.Add("User", "wchen", f, DateTime.Now.AddSeconds(5));
 
            var o = engine.Get<string, Foo>("User", "wchen");
            Console.WriteLine(o.Name);
 
            var o4 = engine.Get<string, Foo>("User", "foo");
            Console.WriteLine(o4 != null ? o4.Name : "foo does not exist");
 
            var o3 = engine.Get<string, string>("PlainText", "A");
            Console.WriteLine(o3 ?? "A does not exist");
        }
    }
}

　　

性能

通过上述性能测试例子，你会发现STSdb的磁盘存取速度要比一个记录对应一个物理文件快。想了解更多，请访问官方网站。

测试条件：1000条记录，7200RPM磁盘，i7。

引擎 介质 写入 读取
STSdb 磁盘 1.3s 0.06s
  内存 0.01s 0.008s
Raw 磁盘 1.0s 0.16s
  内存　 0.0004s 0.0008s

 　　

说明

项目中引用了System.Management是因为STSdb支持内存数据库，需要判断最大物理内存。如果不喜欢，大家可以移除引用，并且去掉STSdb4.Database.STSdb.FromMemory方法便可。

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原文地址：https://www.cnblogs.com/Leo_wl/p/3172765.html