接上一节
/// <summary>
/// Perform file deply
/// </summary>
/// <param name="plug">Plugin file info</param>
/// <returns>Assembly</returns>
private static Assembly PerformFileDeploy(FileInfo plug)
{
if (plug.Directory.Parent == null)
throw new InvalidOperationException("The plugin directory for the " + plug.Name +
" file exists in a folder outside of the allowed nopCommerce folder heirarchy");
FileInfo shadowCopiedPlug;
if (CommonHelper.GetTrustLevel() != AspNetHostingPermissionLevel.Unrestricted)
{
//all plugins will need to be copied to ~/Plugins/bin/
//this is aboslutely required because all of this relies on probingPaths being set statically in the web.config
//were running in med trust, so copy to custom bin folder
var shadowCopyPlugFolder = Directory.CreateDirectory(_shadowCopyFolder.FullName);
shadowCopiedPlug = InitializeMediumTrust(plug, shadowCopyPlugFolder);
}
else
{
var directory = AppDomain.CurrentDomain.DynamicDirectory;
Debug.WriteLine(plug.FullName + " to " + directory);
//were running in full trust so copy to standard dynamic folder
shadowCopiedPlug = InitializeFullTrust(plug, new DirectoryInfo(directory));
}
//we can now register the plugin definition
var shadowCopiedAssembly = Assembly.Load(AssemblyName.GetAssemblyName(shadowCopiedPlug.FullName));
//add the reference to the build manager
Debug.WriteLine("Adding to BuildManager: '{0}'", shadowCopiedAssembly.FullName);
BuildManager.AddReferencedAssembly(shadowCopiedAssembly);
return shadowCopiedAssembly;
}
查看CommonHelper.GetTrustLevel方法：
/// <summary>
/// Finds the trust level of the running application (http://blogs.msdn.com/dmitryr/archive/2007/01/23/finding-out-the-current-trust-level-in-asp-net.aspx)
/// </summary>
/// <returns>The current trust level.</returns>
public static AspNetHostingPermissionLevel GetTrustLevel()
{
if (!_trustLevel.HasValue)
{
//set minimum
_trustLevel = AspNetHostingPermissionLevel.None;
//determine maximum
foreach (AspNetHostingPermissionLevel trustLevel in new[] {
AspNetHostingPermissionLevel.Unrestricted,
AspNetHostingPermissionLevel.High,
AspNetHostingPermissionLevel.Medium,
AspNetHostingPermissionLevel.Low,
AspNetHostingPermissionLevel.Minimal
})
{
try
{
new AspNetHostingPermission(trustLevel).Demand();
_trustLevel = trustLevel;
break; //we've set the highest permission we can
}
catch (System.Security.SecurityException)
{
continue;
}
}
}
return _trustLevel.Value;
}
大体意思是：如果新人级别没有值，则先设置为不授予任何权限，然后遍历权限，从最大权限开始，如果授予权限成功 就返回，如果报错继续授予下一个权限，就是授予当前能授予的最大权限。
如果不是最大权限的话，创建BIN目录，并调用方法：
var shadowCopyPlugFolder = Directory.CreateDirectory(_shadowCopyFolder.FullName);
shadowCopiedPlug = InitializeMediumTrust(plug, shadowCopyPlugFolder);
InitializeMediumTrust方法如下：
// <summary>
/// Used to initialize plugins when running in Medium Trust
/// </summary>
/// <param name="plug"></param>
/// <param name="shadowCopyPlugFolder"></param>
/// <returns></returns>
private static FileInfo InitializeMediumTrust(FileInfo plug, DirectoryInfo shadowCopyPlugFolder)
{
var shouldCopy = true;
var shadowCopiedPlug = new FileInfo(Path.Combine(shadowCopyPlugFolder.FullName, plug.Name));
//check if a shadow copied file already exists and if it does, check if it's updated, if not don't copy
if (shadowCopiedPlug.Exists)
{
//it's better to use LastWriteTimeUTC, but not all file systems have this property
//maybe it is better to compare file hash?
var areFilesIdentical = shadowCopiedPlug.CreationTimeUtc.Ticks >= plug.CreationTimeUtc.Ticks;
if (areFilesIdentical)
{
Debug.WriteLine("Not copying; files appear identical: '{0}'", shadowCopiedPlug.Name);
shouldCopy = false;
}
else
{
//delete an existing file
//More info: http://www.nopcommerce.com/boards/t/11511/access-error-nopplugindiscountrulesbillingcountrydll.aspx?p=4#60838
Debug.WriteLine("New plugin found; Deleting the old file: '{0}'", shadowCopiedPlug.Name);
File.Delete(shadowCopiedPlug.FullName);
}
}
if (shouldCopy)
{
try
{
File.Copy(plug.FullName, shadowCopiedPlug.FullName, true);
}
catch (IOException)
{
Debug.WriteLine(shadowCopiedPlug.FullName + " is locked, attempting to rename");
//this occurs when the files are locked,
//for some reason devenv locks plugin files some times and for another crazy reason you are allowed to rename them
//which releases the lock, so that it what we are doing here, once it's renamed, we can re-shadow copy
try
{
var oldFile = shadowCopiedPlug.FullName + Guid.NewGuid().ToString("N") + ".old";
File.Move(shadowCopiedPlug.FullName, oldFile);
}
catch (IOException exc)
{
throw new IOException(shadowCopiedPlug.FullName + " rename failed, cannot initialize plugin", exc);
}
//ok, we've made it this far, now retry the shadow copy
File.Copy(plug.FullName, shadowCopiedPlug.FullName, true);
}
}
return shadowCopiedPlug;
}
根据传入值获得 bin目录的 new fileinfo,如果此文件已经存在，则比较创建的UTC时间。
如果是旧文件就删除，如果是新文件 就设置 需要拷贝为false.
如果需要拷贝为true,则进行拷贝到BIN。。。 最后返回BIN的全路径文件名。
最后根据这个文件名加载程序集，并返回这个程序集。
用foreach循环加载剩余的DLL。
最后设置PluginType类型的值 并添加到referencedPlugins。 最后赋值
ReferencedPlugins = referencedPlugins;
IncompatiblePlugins = incompatiblePlugins;
PluginManager类的init方法就是设置ReferencedPlugins 。
EnsurePluginsAreLoaded方法内将它（ReferencedPlugins .tolist）赋值给_plugins。
GetPluginDescriptors 方法：
/// <summary>
/// Get plugin descriptors
/// </summary>
/// <param name="loadMode">Load plugins mode</param>
/// <param name="storeId">Load records allowed only in a specified store; pass 0 to load all records</param>
/// <param name="group">Filter by plugin group; pass null to load all records</param>
/// <returns>Plugin descriptors</returns>
public virtual IEnumerable<PluginDescriptor> GetPluginDescriptors(LoadPluginsMode loadMode = LoadPluginsMode.InstalledOnly,
int storeId = 0, string group = null)
{
//ensure plugins are loaded
EnsurePluginsAreLoaded();
return _plugins.Where(p => CheckLoadMode(p, loadMode) && AuthenticateStore(p, storeId) && CheckGroup(p, group));
}
最后一句，帅选出 已安装的，并且在storeID内的。group为空也肯定为true 的plugins.