NetCore插件化开发

使用NetCore3.1完成框架基本开发后实际应用于项目，需要保证框架的独立性与项目的个性化， 就需要类似于下图的插件化形式将项目放入框架这个容器中启动，下面开始详细介绍实现步骤

​

项目dll扫描

在框架根目录创建Plugin文件夹，项目在生成后事件使用copy命令拷贝至Plugin文件夹，框架启动时会扫描该文件夹并进行ShadowCopy到PluginTemplate文件夹中

   private static void ScanPlugin()
        {
            if (!PluginFolder.Exists)
            {
                PluginFolder.Create();
            }
            if (!TempPluginFolder.Exists)
            {
                TempPluginFolder.Create();
            }

            TempPluginFolder.Attributes = FileAttributes.Normal & FileAttributes.Directory;
            PluginFolder.Attributes = FileAttributes.Normal & FileAttributes.Directory;
            //清理临时文件。
            foreach (var file in TempPluginFolder.GetFiles("*.dll", SearchOption.AllDirectories))
            {
                try
                {
                    File.SetAttributes(file.FullName, FileAttributes.Normal);
                    file.Delete();
                }
                catch (Exception e)
                {
                    throw new Exception("请检查IIS权限");
                }

            }
            //复制插件进临时文件夹。
            foreach (var plugin in PluginFolder.GetFiles("*.dll", SearchOption.AllDirectories))
            {
                try
                {
                    string CopyFilePath = Path.Combine(TempPluginFolder.FullName, plugin.Name);
                    File.Copy(plugin.FullName, CopyFilePath, true);
                    File.SetAttributes(CopyFilePath, FileAttributes.Normal);
                }
                catch (Exception e)
                {
                    throw new Exception("请检查IIS权限");
                }
            }
        }

项目dll加载

直接使用ApplicationParts加载AssemblyPart即可

     public static void LoadPlugin()
        {
            ScanPlugin();
            IEnumerable<Assembly> AssemblyList = GetPluginAssemblies();
            foreach (Assembly assembly in AssemblyList)
            {
                foreach (var type in assembly.GetTypes())
                {
                    if (type.IsAssignableFrom(typeof(Controller)) && type.Name.Contains("Controller") && type.IsClass && !type.IsAbstract)
                    {
                        string Name = type.Name;
                        //如果有自定义的路由注解
                        if (type.IsDefined(typeof(Route), false))
                        {
                            var areaattribute = type.GetCustomAttributes(typeof(Route), false).FirstOrDefault();
                            Name = ((Route)areaattribute).Name;
                            Name += "Controller";

                        }
                        if (!ControllerTypeDic.ContainsKey(Name))
                        {
                            ControllerTypeDic.Add(Name, type);
                        }
                    }
                }
                var controllerAssemblyPart = new AssemblyPart(assembly);
                CloudUtil.GetBuilder().ConfigureApplicationPartManager(apm =>
                {
                    apm.ApplicationParts.Add(controllerAssemblyPart);
                });
            }
            CloudUtil.GetBuilder().SetCompatibilityVersion(CompatibilityVersion.Version_3_0);
            StartPluginRefreshWatch();
        }

项目视图

项目的cshtml视图文件可以手动拷贝到部署的框架Views文件夹中（正式环境），也可以通过监控当前项目的Views文件夹，如果变动进行自动拷贝（开发环境）

  private static void StartPluginRefreshWatch()
        {
            _FileSystemWatcher.Path = CloudUtil.GetContentPath() + "/Plugin";
            _FileSystemWatcher.Filter = "*.dll";
            _FileSystemWatcher.Changed += _FileSystemWatcher_Changed;

            _FileSystemWatcher.IncludeSubdirectories = true;
            _FileSystemWatcher.NotifyFilter =
                NotifyFilters.Attributes | NotifyFilters.CreationTime | NotifyFilters.DirectoryName | NotifyFilters.FileName | NotifyFilters.LastAccess | NotifyFilters.LastWrite | NotifyFilters.Security | NotifyFilters.Size;
            _FileSystemWatcher.EnableRaisingEvents = true;

            if (AppConfigUtil.Configuration["Frame:ViewsPublishType"]=="AutoCopy"
                && !string.IsNullOrEmpty(AppConfigUtil.Configuration["Frame:ViewsVirtualPath"]) 
                && Directory.Exists(AppConfigUtil.Configuration["Frame:ViewsVirtualPath"]))
            {
                FileSystemWatcher ViewsWatcher = new FileSystemWatcher();
                ViewsWatcher.Path = AppConfigUtil.Configuration["Frame:ViewsVirtualPath"];
                ViewsWatcher.Changed += ViewsWatcher_Changed;

                ViewsWatcher.IncludeSubdirectories = true;
                ViewsWatcher.NotifyFilter =
                    NotifyFilters.Attributes | NotifyFilters.CreationTime | NotifyFilters.DirectoryName | NotifyFilters.FileName | NotifyFilters.LastAccess | NotifyFilters.LastWrite | NotifyFilters.Security | NotifyFilters.Size;
                ViewsWatcher.EnableRaisingEvents = true;

                //系统启动时整个文件夹拷贝
                DirectoryInfo FrameWorkViews = new DirectoryInfo(CloudUtil.GetContentPath() + "/Views");
                DirectoryInfo ProjectViews = new DirectoryInfo(AppConfigUtil.Configuration["Frame:ViewsVirtualPath"]);
                foreach (DirectoryInfo FDir in FrameWorkViews.GetDirectories())
                {
                    foreach (DirectoryInfo PDir in ProjectViews.GetDirectories())
                    {
                        if (PDir.Name== FDir.Name)
                        {
                            FileUtil.DeleteDirectoryContent(FDir.FullName);
                        }
                    }
                }
                FileUtil.CopyDirectory(AppConfigUtil.Configuration["Frame:ViewsVirtualPath"],CloudUtil.GetContentPath() + "/Views", true);
            }
        }

项目dll热更新

监控Plugin文件夹，若有变调用IApplicationLifetime的StopApplication重启系统

 public void Configure(IApplicationBuilder app, IWebHostEnvironment env, IConfiguration configuration, Microsoft.AspNetCore.Hosting.IApplicationLifetime applicationLifetime)
 {
      CloudUtil.SetAPP(applicationLifetime);
 }


 private static void _FileSystemWatcher_Changed(object sender, FileSystemEventArgs e)
 {
      CloudUtil.Restrat();
 }

 public static void Restrat()
 {
      APP.StopApplication();
 }