插件化编程实现的一份糖炒栗子

易墨2016年7月2日大约 5 分钟

迷茫的原因是因为想得太多，做得太少。因为只是想真的很容易，转瞬之间就会产生无数个念头，或许是该做点什么了吧。

但是整个人都是懒的，是废的，是大脑控制不住自己的行为的。解决方案唯有一步一步的去把行为变成习惯。

坚持一件事挺不容易的，不论结果的好坏，过程中总有收获的，坚持，不会是一件坏事。

胡言乱语结束~~~

下面是记录分享的一点东西~~请笑纳

0.结构一览

1.定义插件接口

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace YimoCore
{
    public interface IPlugin
    {
        /// <summary>
        /// Gets or sets the plugin descriptor
        /// </summary>
        PluginDescriptor PluginDescriptor { get; set; }

        /// <summary>
        /// Install plugin
        /// </summary>
        void Install();

        /// <summary>
        /// Uninstall plugin
        /// </summary>
        void Uninstall();
    }
}

定义插件

2.添加插件信息类

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;

namespace YimoCore
{
    /// <summary>
    /// 插件信息
    /// </summary>
    public sealed class PluginDescriptor
    {
        /// <summary>
        /// 插件主目录
        /// </summary>
        public string PluginFileName { get; set; }
        /// <summary>
        /// 插件类型
        /// </summary>
        public Type PluginType { get; set; }

        /// <summary>
        /// 插件主程序集
        /// </summary>
        public Assembly ReferencedAssembly { get; internal set; }

        /// <summary>
        /// 原始程序集文件
        /// </summary>
        public FileInfo OriginalAssemblyFile { get; internal set; }
        /// <summary>
        /// 插件包目录
        /// </summary>
        public FileInfo PluginConfigFile { get; internal set; }
        /// <summary>
        /// 类别
        /// </summary>
        public string Group { get; set; }
        /// <summary>
        /// 插件名称
        /// </summary>
        public string FriendlyName { get; set; }
        /// <summary>
        /// 程序集名称
        /// </summary>
        public string SystemName { get; set; }
        /// <summary>
        /// 描述
        /// </summary>
        public string Description { get; set; }
        /// <summary>
        /// 版本号
        /// </summary>
        public string Version { get; set; }
        /// <summary>
        /// 支持版本
        /// </summary>
        public IList<string> SupportedVersions { get; set; }
        /// <summary>
        /// 作者
        /// </summary>
        public string Author { get; set; }
        /// <summary>
        /// 排序
        /// </summary>
        public int DisplayOrder { get; set; }
        /// <summary>
        /// 获取插件实例
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <returns></returns>
        public T Instance<T>() where T : class, IPlugin
        {
            var instance = Activator.CreateInstance(PluginType) as T;
            if (instance != null)
                instance.PluginDescriptor = this;

            return instance;
        }

        public IPlugin Instance()
        {
            return Instance<IPlugin>();
        }

        public int CompareTo(PluginDescriptor other)
        {
            if (DisplayOrder != other.DisplayOrder)
                return DisplayOrder.CompareTo(other.DisplayOrder);
            else
                return System.String.Compare(FriendlyName, other.FriendlyName, System.StringComparison.Ordinal);
        }

        public override string ToString()
        {
            return FriendlyName;
        }

        public override bool Equals(object obj)
        {
            var other = obj as PluginDescriptor;
            return other != null &&
                SystemName != null &&
                SystemName.Equals(other.SystemName);
        }

        public override int GetHashCode()
        {
            return SystemName.GetHashCode();
        }
    }
}

插件信息类

3.插件读取

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;
using System.Web;

namespace YimoCore
{
    public class PluginManager
    {
        private const string PluginsPath = "/modules"; //插件目录
        private const string ShadowCopyPath = "/modules/bin"; //插件影子目录

        public static IEnumerable<PluginDescriptor> ReferencedPlugins { get; set; }

        public static void Init()
        {
            var appdir = AppDomain.CurrentDomain.BaseDirectory.Substring(0, AppDomain.CurrentDomain.BaseDirectory.LastIndexOf("\\"));
            appdir = appdir.Substring(0, appdir.LastIndexOf("\\"));
            appdir = appdir.Substring(0, appdir.LastIndexOf("\\"));
            //插件目录
            var pluginFolder = new DirectoryInfo(appdir + PluginsPath);
            //插件bin目录
            var shadowFolder = new DirectoryInfo(appdir + ShadowCopyPath);
            var referencedPlugins = new List<PluginDescriptor>();
            try
            {
                pluginFolder.Create();
                shadowFolder.Create();
                //清空bin目录
                foreach (var fileInfo in shadowFolder.GetFiles())
                {
                    fileInfo.Delete();
                }
                var pluginConfigFiles = pluginFolder.GetFiles("about.xml", SearchOption.AllDirectories);
                foreach (var pluginConfigFile in pluginConfigFiles)
                {
                    //获取插件信息
                    var pluginDescriptor = PluginFileParser.ParsePluginDescriptionFile(pluginConfigFile.FullName);
                    try
                    {
                        if (pluginConfigFile.Directory == null)
                            continue;
                        //获取插件所有的dll
                        var pluginFiles = pluginConfigFile.Directory.GetFiles("*.dll", SearchOption.AllDirectories);
                        var mainPluginFile = pluginFiles.FirstOrDefault(
                            item =>
                            item.Name.Equals(pluginDescriptor.PluginFileName,
                            StringComparison.InvariantCultureIgnoreCase));
                        pluginDescriptor.PluginConfigFile = pluginConfigFile;
                        pluginDescriptor.OriginalAssemblyFile = mainPluginFile;
                        pluginDescriptor.ReferencedAssembly = DeployDllFile(mainPluginFile, shadowFolder);
                        foreach (var t in pluginDescriptor.ReferencedAssembly.GetTypes())
                        {
                            if (typeof(IPlugin).IsAssignableFrom(t))
                            {
                                if (t.IsInterface == false && t.IsClass && !t.IsAbstract)
                                {
                                    pluginDescriptor.PluginType = t;
                                    break;
                                }
                            }
                        }

                        referencedPlugins.Add(pluginDescriptor);


                    }
                    catch (ReflectionTypeLoadException ex)
                    {

                        throw;
                    }


                }


            }
            catch (ReflectionTypeLoadException ex)
            {
            }

            ReferencedPlugins = referencedPlugins;

        }

        /// <summary>
        /// 部署程序集
        /// </summary>
        /// <param name="dllFile">插件程序集文件</param>
        /// <param name="shadowFolder">/Plugins/bin目录</param>
        private static Assembly DeployDllFile(FileInfo dllFile, DirectoryInfo shadowFolder)
        {
            DirectoryInfo copyFolder;
            //根据当前的信任级别设置复制目录

            copyFolder = shadowFolder;

            var newDllFile = new FileInfo(copyFolder.FullName + "\\" + dllFile.Name);
            try
            {
                File.Copy(dllFile.FullName, newDllFile.FullName, true);
            }
            catch (Exception ex1)//在某些情况下会出现"正由另一进程使用，因此该进程无法访问该文件"错误，所以先重命名再复制
            {
                try
                {
                    File.Move(newDllFile.FullName, newDllFile.FullName + Guid.NewGuid().ToString("N") + ".locked");
                }
                catch (Exception ex2)
                {
                    throw ex2;
                }

                File.Copy(dllFile.FullName, newDllFile.FullName, true);
            }

            var assembly = Assembly.LoadFrom(newDllFile.FullName);
            //将程序集添加到当前应用程序域
            //BuildManager.AddReferencedAssembly(assembly);
            return assembly;
        }
    }
}

插件读取

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Xml.Linq;

namespace YimoCore
{

    /// <summary>
    /// Plugin files parser
    /// </summary>
    public static class PluginFileParser
    {
        public static IList<string> ParseInstalledPluginsFile(string filePath)
        {
            if (!File.Exists(filePath))
                return new List<string>();

            var text = File.ReadAllText(filePath);
            if (String.IsNullOrEmpty(text))
                return new List<string>();

            var lines = new List<string>();
            using (var reader = new StringReader(text))
            {
                string str;
                while ((str = reader.ReadLine()) != null)
                {
                    if (String.IsNullOrWhiteSpace(str))
                        continue;
                    lines.Add(str.Trim());
                }
            }
            return lines;
        }

        public static void SaveInstalledPluginsFile(IList<String> pluginSystemNames, string filePath)
        {
            if (pluginSystemNames == null || pluginSystemNames.Count == 0)
                return;

            string result = "";
            foreach (var sn in pluginSystemNames)
                result += string.Format("{0}{1}", sn, Environment.NewLine);

            File.WriteAllText(filePath, result);
        }

        public static PluginDescriptor ParsePluginDescriptionFile(string filePath)
        {
            XDocument doc;

            try
            {
                doc = XDocument.Load(filePath);
            }
            catch (Exception)
            {
                return null;
            }

            var pluginEle = doc.Element("plugin");
            if (pluginEle == null)
                return null;

            var descriptor = new PluginDescriptor();

            var ele = pluginEle.Element("SystemName");
            if (ele != null)
                descriptor.SystemName = ele.Value;

            ele = pluginEle.Element("Group");
            if (ele != null)
                descriptor.Group = ele.Value;

            ele = pluginEle.Element("FriendlyName");
            if (ele != null)
                descriptor.FriendlyName = ele.Value;

            ele = pluginEle.Element("Description");
            if (ele != null)
                descriptor.Description = ele.Value;

            ele = pluginEle.Element("Version");
            if (ele != null)
                descriptor.Version = ele.Value;

            ele = pluginEle.Element("SupportedVersions");
            if (ele != null)
            {
                //parse supported versions
                descriptor.SupportedVersions = ele.Value.Split(new[] { ',' }, StringSplitOptions.RemoveEmptyEntries)
                    .Select(x => x.Trim())
                    .ToList();
            }

            ele = pluginEle.Element("Author");
            if (ele != null)
                descriptor.Author = ele.Value;

            ele = pluginEle.Element("DisplayOrder");
            if (ele != null)
            {
                int displayOrder;
                int.TryParse(ele.Value, out displayOrder);
                descriptor.DisplayOrder = displayOrder;
            }

            ele = pluginEle.Element("FileName");
            if (ele != null)
                descriptor.PluginFileName = ele.Value;

            if (descriptor.SupportedVersions.Count == 0)
                descriptor.SupportedVersions.Add("2.00");

            return descriptor;
        }

        public static void SavePluginDescriptionFile(PluginDescriptor plugin)
        {
            if (plugin == null)
                throw new ArgumentException("plugin");

            if (plugin.PluginConfigFile == null)
                throw new Exception(string.Format("没有加载插件 {0} 的配置文件", plugin.SystemName));

            var doc = new XDocument(
                 new XDeclaration("1.0", "utf-8", "yes"),
                 new XElement("Group", plugin.Group),
                 new XElement("FriendlyName", plugin.FriendlyName),
                 new XElement("SystemName", plugin.SystemName),
                 new XElement("Description", plugin.Description),
                 new XElement("Version", plugin.Version),
                 new XElement("SupportedVersions", string.Join(",", plugin.SupportedVersions)),
                 new XElement("Author", plugin.Author),
                 new XElement("DisplayOrder", plugin.DisplayOrder),
                 new XElement("FileName", plugin.PluginFileName)
             );

            doc.Save(plugin.PluginConfigFile.FullName);
        }
    }
}

加载插件-PluginFileParser

4.使用

4.0新建插件接口并继承IPlugin

4.1：为插件类库添加about.xml文件配置插件信息

<?xml version="1.0" encoding="utf-8" ?>
<plugin>
  <Group>Sign</Group>
  <FriendlyName>素材网</FriendlyName>
  <SystemName>素材网</SystemName>
  <Description>素材网签到</Description>
  <Version>1.0</Version>
  <SupportedVersions>1.0</SupportedVersions>
  <Author>YiMo</Author>
  <DisplayOrder>1</DisplayOrder>
  <FileName>素材网.dll</FileName>
</plugin>