一、前言

最近做项目的时候，使用Util进行开发，使用

Razor

写前端页面。初次使用感觉还是不大习惯，之前都是前后端分离的方式开发的，但是使用Util封装后的

Angular

后，感觉开发效率还是杠杠滴。

二、问题

在发布代码的时候，

Webpack

打包异常，提示是缺少了某些

Html

文件，我看了下相应的目录，发现目录缺少了部分Html文件，然后就问了何镇汐大大，给出的解决方案是，每个页面都需要访问一下才能生成相应的Html静态文件。这时候就产生了疑虑，是否有一种方式能获取所有路由，然后只需访问一次即可生成所有的Html页面。

三、解决方案

3.1 每次访问生成Html

解决方案思路：

• 继承

  ActionFilterAttribute

  特性，重写执行方法
• 访问的时候判断访问的

  Result

  是否

  ViewResult

  ，如果是方可生成Html
• 从

  RazorViewEngine

  中查找到

  View

  后进行渲染

/// <summary>
/// 生成Html静态文件
/// </summary>
public class HtmlAttribute : ActionFilterAttribute {
/// <summary>
/// 生成路径，相对根路径，范例：/Typings/app/app.component.html
/// </summary>
public string Path { get; set; }

/// <summary>
/// 路径模板，范例：Typings/app/{area}/{controller}/{controller}-{action}.component.html
/// </summary>
public string Template { get; set; }

/// <summary>
/// 执行生成
/// </summary>
public override async Task OnResultExecutionAsync( ResultExecutingContext context, ResultExecutionDelegate next ) {
await WriteViewToFileAsync( context );
await base.OnResultExecutionAsync( context, next );
}

/// <summary>
/// 将视图写入html文件
/// </summary>
private async Task WriteViewToFileAsync( ResultExecutingContext context ) {
try {
var html = await RenderToStringAsync( context );
if( string.IsNullOrWhiteSpace( html ) )
return;
var path = Util.Helpers.Common.GetPhysicalPath( string.IsNullOrWhiteSpace( Path ) ? GetPath( context ) : Path );
var directory = System.IO.Path.GetDirectoryName( path );
if( string.IsNullOrWhiteSpace( directory ) )
return;
if( Directory.Exists( directory ) == false )
Directory.CreateDirectory( directory );
File.WriteAllText( path, html );
}
catch( Exception ex ) {
ex.Log( Log.GetLog().Caption( "生成html静态文件失败" ) );
}
}

/// <summary>
/// 渲染视图
/// </summary>
protected async Task<string> RenderToStringAsync( ResultExecutingContext context ) {
string viewName = "";
object model = null;
if( context.Result is ViewResult result ) {
viewName = result.ViewName;
viewName = string.IsNullOrWhiteSpace( viewName ) ? context.RouteData.Values["action"].SafeString() : viewName;
model = result.Model;
}
var razorViewEngine = Ioc.Create<IRazorViewEngine>();
var tempDataProvider = Ioc.Create<ITempDataProvider>();
var serviceProvider = Ioc.Create<IServiceProvider>();
var httpContext = new DefaultHttpContext { RequestServices = serviceProvider };
var actionContext = new ActionContext( httpContext, context.RouteData, new ActionDescriptor() );
using( var stringWriter = new StringWriter() ) {
var viewResult = razorViewEngine.FindView( actionContext, viewName, true );
if( viewResult.View == null )
throw new ArgumentNullException( $"未找到视图： {viewName}" );
var viewDictionary = new ViewDataDictionary( new EmptyModelMetadataProvider(), new ModelStateDictionary() ) { Model = model };
var viewContext = new ViewContext( actionContext, viewResult.View, viewDictionary, new TempDataDictionary( actionContext.HttpContext, tempDataProvider ), stringWriter, new HtmlHelperOptions() );
await viewResult.View.RenderAsync( viewContext );
return stringWriter.ToString();
}
}

/// <summary>
/// 获取Html默认生成路径
/// </summary>
protected virtual string GetPath( ResultExecutingContext context ) {
var area = context.RouteData.Values["area"].SafeString();
var controller = context.RouteData.Values["controller"].SafeString();
var action = context.RouteData.Values["action"].SafeString();
var path = Template.Replace( "{area}", area ).Replace( "{controller}", controller ).Replace( "{action}", action );
return path.ToLower();
}
}

3.2 一次访问生成所有Html

解决方案思路：

• 获取所有已注册的路由
• 获取使用

  RazorHtml

  自定义特性的路由
• 忽略Api接口的路由
• 构建

  RouteData

  信息，用于在

  RazorViewEngine

  中查找到相应的视图
• 构建

  ViewContext

  用于渲染出Html字符串
• 将渲染得到的Html字符串写入文件

获取所有注册的路由，此处是比较重要的，其他地方也可以用到。

/// <summary>
/// 获取所有路由信息
/// </summary>
/// <returns></returns>
public IEnumerable<RouteInformation> GetAllRouteInformations()
{
List<RouteInformation> list = new List<RouteInformation>();

var actionDescriptors = this._actionDescriptorCollectionProvider.ActionDescriptors.Items;
foreach (var actionDescriptor in actionDescriptors)
{
RouteInformation info = new RouteInformation();

if (actionDescriptor.RouteValues.ContainsKey("area"))
{
info.AreaName = actionDescriptor.RouteValues["area"];
}

// Razor页面路径以及调用
if (actionDescriptor is PageActionDescriptor pageActionDescriptor)
{
info.Path = pageActionDescriptor.ViewEnginePath;
info.Invocation = pageActionDescriptor.RelativePath;
}

// 路由属性路径
if (actionDescriptor.AttributeRouteInfo != null)
{
info.Path = $"/{actionDescriptor.AttributeRouteInfo.Template}";
}

// Controller/Action 的路径以及调用
if (actionDescriptor is ControllerActionDescriptor controllerActionDescriptor)
{
if (info.Path.IsEmpty())
{
info.Path =
$"/{controllerActionDescriptor.ControllerName}/{controllerActionDescriptor.ActionName}";
}

var controllerHtmlAttribute = controllerActionDescriptor.ControllerTypeInfo.GetCustomAttribute<RazorHtmlAttribute>();

if (controllerHtmlAttribute != null)
{
info.FilePath = controllerHtmlAttribute.Path;
info.TemplatePath = controllerHtmlAttribute.Template;
}

var htmlAttribute = controllerActionDescriptor.MethodInfo.GetCustomAttribute<RazorHtmlAttribute>();

if (htmlAttribute != null)
{
info.FilePath = htmlAttribute.Path;
info.TemplatePath = htmlAttribute.Template;
}

info.ControllerName = controllerActionDescriptor.ControllerName;
info.ActionName = controllerActionDescriptor.ActionName;
info.Invocation = $"{controllerActionDescriptor.ControllerName}Controller.{controllerActionDescriptor.ActionName}";
}

info.Invocation += $"({actionDescriptor.DisplayName})";

list.Add(info);
}

return list;
}

生成Html静态文件

/// <summary>
/// 生成Html文件
/// </summary>
/// <returns></returns>
public async Task Generate()
{
foreach (var routeInformation in _routeAnalyzer.GetAllRouteInformations())
{
// 跳过API的处理
if (routeInformation.Path.StartsWith("/api"))
{
continue;
}
await WriteViewToFileAsync(routeInformation);
}
}

/// <summary>
/// 渲染视图为字符串
/// </summary>
/// <param name="info">路由信息</param>
/// <returns></returns>
public async Task<string> RenderToStringAsync(RouteInformation info)
{
var razorViewEngine = Ioc.Create<IRazorViewEngine>();
var tempDataProvider = Ioc.Create<ITempDataProvider>();
var serviceProvider = Ioc.Create<IServiceProvider>();

var routeData = new RouteData();
if (!info.AreaName.IsEmpty())
{
routeData.Values.Add("area", info.AreaName);
}

if (!info.ControllerName.IsEmpty())
{
routeData.Values.Add("controller", info.ControllerName);
}

if (!info.ActionName.IsEmpty())
{
routeData.Values.Add("action", info.ActionName);
}

var httpContext = new DefaultHttpContext { RequestServices = serviceProvider };
var actionContext = new ActionContext(httpContext, routeData, new ActionDescriptor());

var viewResult = razorViewEngine.FindView(actionContext, info.ActionName, true);
if (!viewResult.Success)
{
throw new InvalidOperationException($"找不到视图模板 {info.ActionName}");
}

using (var stringWriter = new StringWriter())
{
var viewDictionary = new ViewDataDictionary(new EmptyModelMetadataProvider(), new ModelStateDictionary());
var viewContext = new ViewContext(actionContext, viewResult.View, viewDictionary, new TempDataDictionary(actionContext.HttpContext, tempDataProvider), stringWriter, new HtmlHelperOptions());
await viewResult.View.RenderAsync(viewContext);
return stringWriter.ToString();
}
}

/// <summary>
/// 将视图写入文件
/// </summary>
/// <param name="info">路由信息</param>
/// <returns></returns>
public async Task WriteViewToFileAsync(RouteInformation info)
{
try
{
var html = await RenderToStringAsync(info);
if (string.IsNullOrWhiteSpace(html))
return;

var path = Utils.Helpers.Common.GetPhysicalPath(string.IsNullOrWhiteSpace(info.FilePath) ? GetPath(info) : info.FilePath);
var directory = System.IO.Path.GetDirectoryName(path);
if (string.IsNullOrWhiteSpace(directory))
return;
if (Directory.Exists(directory) == false)
Directory.CreateDirectory(directory);
File.WriteAllText(path, html);
}
catch (Exception ex)
{
ex.Log(Log.GetLog().Caption("生成html静态文件失败"));
}
}

protected virtual string GetPath(RouteInformation info)
{
var area = info.AreaName.SafeString();
var controller = info.ControllerName.SafeString();
var action = info.ActionName.SafeString();
var path = info.TemplatePath.Replace("{area}", area).Replace("{controller}", controller).Replace("{action}", action);
return path.ToLower();
}

四、使用方式

• MVC控制器配置
  

• Startup配置
  

• 一次性生成方式，调用一次接口即可
  

五、源码地址

Util
Bing.NetCore
Razor生成静态Html文件：https://github.com/dotnetcore/Util/tree/master/src/Util.Webs/Razors 或者 https://github.com/bing-framework/Bing.NetCore/tree/master/src/Bing.Webs/Razors

六、参考

获取所有已注册的路由：https://github.com/kobake/AspNetCore.RouteAnalyzer