第四篇 基于.net搭建热插拔式web框架（RazorEngine实现）
在开头也是先给大家道个歉，由于最近准备婚事导致这篇文章耽误了许久，同时也谢谢老婆大人对我的支持。
回顾上篇文章，我们重造了一个controller，这个controller中用到了视图引擎，我们的视图引擎虽然也叫Razor，但此Razor非mvc中的Razor，MVC中的Razor同样依赖于HttpContext,我们实现的Razor借用 RazorEngine。关于RazorEngine的更多介绍请参阅http://antaris.github.io/RazorEngine/。
在上篇文章中无论是View方法还是PartialView方法，都用到了CompileView对象，我们先来看一下CompileView类的实现。
/// <summary>
/// 视图编译类
/// </summary>
public class CompileView
{
private static Regex layoutEx = new Regex("Layout\\s*=\\s*@?\"(\\S*)\";");//匹配视图中的layout
static InvalidatingCachingProvider cache = new InvalidatingCachingProvider();
static FileSystemWatcher m_Watcher = new FileSystemWatcher();
static CompileView()
{
var config = new TemplateServiceConfiguration();
config.BaseTemplateType = typeof(HuberImplementingTemplateBase<>);
config.ReferenceResolver = new HuberReferenceResolver();
config.CachingProvider = cache;
cache.InvalidateAll();
Engine.Razor = RazorEngineService.Create(config);
//添加文件修改监控，以便在cshtml文件修改时重新编译该文件
m_Watcher.Path = HuberVariable.CurWebDir;
m_Watcher.IncludeSubdirectories = true;
m_Watcher.Filter = "*.*";
m_Watcher.NotifyFilter = NotifyFilters.LastWrite | NotifyFilters.FileName;
m_Watcher.Created += new FileSystemEventHandler(OnChanged);
m_Watcher.Changed += new FileSystemEventHandler(OnChanged);
m_Watcher.Deleted += new FileSystemEventHandler(OnChanged);
m_Watcher.EnableRaisingEvents = true;
}
//当视图被修改后清除缓存
private static void OnChanged(object sender, FileSystemEventArgs e)
{
if (e.FullPath.EndsWith(".cshtml"))
{
string s = e.FullPath.Replace(HuberVariable.CurWebDir, "/");
var key = Engine.Razor.GetKey(s);
cache.InvalidateCache(key);
}
}
public CompileView()
{
}
public string RunCompile(ITemplateKey key, Type modelType, object model, DynamicViewBag viewBag)
{
//判断唯一视图的缓存
string path = (HuberVariable.CurWebDir + key.Name).Replace(@"\\", @"\");
ICompiledTemplate cacheTemplate;
cache.TryRetrieveTemplate(key, null, out cacheTemplate);
if (cacheTemplate == null || !cacheTemplate.Key.Name.Trim().Equals(key.Name.Trim()))
{
CompileViewAndLayout(key, null, model, viewBag);
}
//当缓存存在返回结果
return Engine.Razor.RunCompile(key, null, model, viewBag);
}
/// <summary>
/// 编译视图和层layout
/// </summary>
/// <param name="key">视图的唯一路径</param>
/// <param name="modelType">视图类型 :视图/layout</param>
/// <param name="model">页面 MODEL</param>
/// <param name="viewBag">viewBag</param>
public void CompileViewAndLayout(ITemplateKey key, Type modelType, object model, DynamicViewBag viewBag)
{
//获取视图
string FullPath = (HuberVariable.CurWebDir + key.Name.Replace("/", @"\")).Replace(@"\\", @"\");
string content = System.IO.File.ReadAllText(FullPath);
//匹配layout
var matchs = layoutEx.Matches(content);
string layoutPath = string.Empty;
if (matchs != null)
{
foreach (Match m in matchs)
{
layoutPath = m.Groups[1].Value;
}
}
if (layoutPath != string.Empty)
{
//添加layout到模板
string FullLayoutPath = (HuberVariable.CurWebDir + layoutPath.Replace("/", @"\")).Replace(@"\\", @"\");
if (File.Exists(FullLayoutPath))
{
ITemplateKey layoutKey = Engine.Razor.GetKey(layoutPath, ResolveType.Layout);
CompileViewAndLayout(layoutKey, null, model, viewBag);
}
}
if (key.TemplateType == ResolveType.Layout)
{
Engine.Razor.AddTemplate(key, content);
}
else
{
//编译视图
Engine.Razor.RunCompile(content, key, null, model);
}
}
}
InvalidatingCachingProvider是RazorEngine对视图文件编译结果的一种缓存策略，RazorEngine提供的缓存策略还有DefaultCachingProvider，也可以自己实现一种缓存策略只要继承ICachingProvider。
HuberImplementingTemplateBase：我们自定义的一种Razor模板标签，如“@Html.Raw”，这个例子也可以在RazorEngine官方文档中找到。我们还可以按照规则定义更多用法，下边是我的一些实现：
/// <summary>页面帮助类
/// A simple helper demonstrating the @Html.Raw
/// </summary>
/// <typeparam name="T"></typeparam>
public class HuberImplementingTemplateBase<T> : TemplateBase<T>
{
/// <summary>
/// A simple helper demonstrating the @Html.Raw
/// </summary>
public HuberImplementingTemplateBase()
{
Html = new RazorHtmlHelper();
}
/// <summary>
/// A simple helper demonstrating the @Html.Raw
///
/// </summary>
public RazorHtmlHelper Html { get; set; }
}
public class RazorHtmlHelper
{
/// <summary>
/// 调用Action视图
/// </summary>
/// <param name="actionName">action方法名称</param>
/// <param name="controllerName">控制器名称</param>
/// <returns></returns>
public IEncodedString Action(string actionName, string controllerName)
{
return Action(actionName, controllerName, new { });
}
/// <summary>
/// 调用Action视图
/// </summary>
/// <param name="actionName"></param>
/// <param name="controllerName"></param>
/// <param name="routeValues">传入参数</param>
/// <returns></returns>
public IEncodedString Action(string actionName, string controllerName, object routeValues)
{
RefRequestEntity paras = SetParamValue(routeValues);
var t = HuberHttpModule.CurDomainAssembly.GetType(HuberHttpModule.CurDomainAssemblyName + ".Controllers." + controllerName + "Controller");
var m = t.GetMethod(actionName);
object dObj = Activator.CreateInstance(t);
object result = m.Invoke(dObj, new object[] { paras });
return new RawString((result as RefRespondEntity).ResultContext.ToString());
}
/// <summary>
/// 根据model设置传入参数
/// </summary>
/// <param name="routeValues"></param>
/// <returns></returns>
private static RefRequestEntity SetParamValue(object routeValues)
{
RefRequestEntity paras = new RefRequestEntity();
Type t1 = routeValues.GetType();
PropertyInfo[] pis = t1.GetProperties();
foreach (PropertyInfo pi in pis)
{
paras.Request.Add(pi.Name, pi.GetValue(routeValues));
}
return paras;
}
public IEncodedString RenderAction(string actionName, string controllerName)
{
return Action(actionName, controllerName, new { });
}
public IEncodedString RenderAction(string actionName, string controllerName, object routeValues)
{
return Action(actionName, controllerName, routeValues);
}
public IEncodedString RenderPartial(string partialViewName, string controllerName)
{
return RenderPartial(partialViewName, controllerName, new { }, new DynamicViewBag());
}
// Renders the partial view with the given view data and, implicitly, the given view data's model
public IEncodedString RenderPartial(string partialViewName, string controllerName, DynamicViewBag ViewBag)
{
return RenderPartial(partialViewName, controllerName, new { }, ViewBag);
}
// Renders the partial view with an empty view data and the given model
public IEncodedString RenderPartial(string partialViewName, string controllerName, object model)
{
return RenderPartial(partialViewName, controllerName, model, new DynamicViewBag());
}
// Renders the partial view with a copy of the given view data plus the given model
/// <summary>
/// 部分视图
/// </summary>
/// <param name="partialViewName">部分视图名称</param>
/// <param name="controllerName">控制器名称</param>
/// <param name="model"> model</param>
/// <param name="ViewBag">ViewBag</param>
/// <returns></returns>
public IEncodedString RenderPartial(string partialViewName, string controllerName, object model, DynamicViewBag ViewBag)
{
RefRequestEntity paras = SetParamValue(model);
var t = HuberHttpModule.CurDomainAssembly.GetType(HuberHttpModule.CurDomainAssemblyName + ".Controllers." + controllerName + "Controller");
var ActionFunc = t.GetMethod(partialViewName);
object dObj = Activator.CreateInstance(t);
var AddViewBageFunc = t.GetMethod("AddViewBageValues");
foreach (string key in ViewBag.GetDynamicMemberNames())
{
AddViewBageFunc.Invoke(dObj, new object[] { key, Impromptu.InvokeGet(ViewBag, key) });
}
object result = ActionFunc.Invoke(dObj, new object[] { paras });
return new RawString((result as RefRespondEntity).ResultContext.ToString());
}
}
HuberReferenceResolver：我们定义的Razor中用的类库依赖。
public class HuberReferenceResolver : IReferenceResolver
{
static List<CompilerReference> compilerReference;
static HuberReferenceResolver()
{
//加载本地所有类库,@using 使用
compilerReference = new List<CompilerReference>();
IEnumerable<string> loadedAssemblies = (new UseCurrentAssembliesReferenceResolver())
.GetReferences(null, null)
.Select(r => r.GetFile())
.ToArray();
foreach (var l in loadedAssemblies)
{
compilerReference.Add(CompilerReference.From(l));
}
}
public string FindLoaded(IEnumerable<string> refs, string find)
{
return refs.First(r => r.EndsWith(System.IO.Path.DirectorySeparatorChar + find));
}
public IEnumerable<CompilerReference> GetReferences(TypeContext context, IEnumerable<CompilerReference> includeAssemblies)
{
#region 加载依赖程序集 此处是加载所有程序集，效率需要改进
return compilerReference;
#endregion
}
}
CompileViewAndLayout()是编译视图文件的主要部分，其中有路径的转换、key的定义规则等。
获取视图文件对应编译后的缓存key：Engine.Razor.GetKey()；
编译模板文件（即layout部分）：Engine.Razor.AddTemplate();
编译视图文件：Engine.Razor.RunCompile()。
转载请注明出处：http://www.cnblogs.com/eric-z/p/5102718.html