RouteDebugger分析

RouteDebugger的介绍  http://www.cnblogs.com/suizhikuo/archive/2012/07/25/2608889.html

2.RouteDebugger结构，一共有5个文件，将逐一解释每个文件的作用

RouteDebug.cs

using System.Web.Routing;namespace RouteDebug{    public class DebugRoute : Route    {        static readonly DebugRoute singleton = new DebugRoute();        public static DebugRoute Singleton        {            get { return singleton; }        }        private DebugRoute()            : base("{*catchall}", new DebugRouteHandler()) { }    }}

全局单例的DebugRoute,构造函数传入了DebugRouteHandler。

 

DebugRouteHandler.cs

using System.Web;using System.Web.Routing;namespace RouteDebug{    public class DebugRouteHandler : IRouteHandler    {        public IHttpHandler GetHttpHandler(RequestContext requestContext)        {            return new DebugHttpHandler();        }    }}

核心都在DebugHttpHandler最后再解释。

 

PreApplicationStart.cs

using System;using System.Configuration;using System.Web;using RouteDebug;[assembly: PreApplicationStartMethod(typeof(PreApplicationStart), "Start")]namespace RouteDebug{    public class PreApplicationStart    {        public static void Start()        {            bool enabled = Convert.ToBoolean(ConfigurationManager.AppSettings["RouteDebugger:Enabled"]);            if (enabled)            {                Microsoft.Web.Infrastructure.DynamicModuleHelper.DynamicModuleUtility.RegisterModule(typeof(RouteDebuggerHttpModule));            }        }    }}

项目启动时利用DynamicModuleUtility根据Webconfig配置动态的注册RouteDebuggerHttpModule.

 

RouteDebuggerHttpModule.cs

namespace RouteDebug{    public class RouteDebuggerHttpModule : IHttpModule    {        public void Init(HttpApplication context)        {            context.EndRequest += OnEndRequest;            context.BeginRequest += OnBeginRequest;        }        static void OnBeginRequest(object sender, System.EventArgs e)        {            if (RouteTable.Routes.Last() != DebugRoute.Singleton)            {                RouteTable.Routes.Add(DebugRoute.Singleton);            }        }        static void OnEndRequest(object sender, System.EventArgs e)        {            var handler = new DebugHttpHandler();            handler.ProcessRequest(HttpContext.Current);        }        public void Dispose()        {        }    }}

OnBeginRequest向路由表添加DebugRoute.

OnEndRequest输出RouteDebugger信息.

 

DebugHttpHandler.cs

using System;using System.Collections.Generic;using System.Reflection;using System.Web;using System.Web.Hosting;using System.Web.Routing;namespace RouteDebug{    public class DebugHttpHandler : IHttpHandler    {        readonly VirtualPathProvider _virtualPathProvider;        public DebugHttpHandler() : this(null) { }        public DebugHttpHandler(VirtualPathProvider virtualPathProvider)        {            _virtualPathProvider = virtualPathProvider ?? HostingEnvironment.VirtualPathProvider;        }        public void ProcessRequest(HttpContext context)        {            var request = context.Request;            if (!IsRoutedRequest(request) || context.Response.ContentType == null || !context.Response.ContentType.Equals("text/html", StringComparison.OrdinalIgnoreCase))            {                return;            }            string generatedUrlInfo = string.Empty;            var requestContext = request.RequestContext;            if (request.QueryString.Count > 0)            {                var rvalues = new RouteValueDictionary();                foreach (string key in request.QueryString.Keys)                {                    if (key != null)                    {                        rvalues.Add(key, request.QueryString[key]);                    }                }                var vpd = RouteTable.Routes.GetVirtualPath(requestContext, rvalues);                if (vpd != null)                {                    generatedUrlInfo = "<p><label style=\"font-weight: bold; font-size: 1.1em;\">Generated URL</label>: ";                    generatedUrlInfo += "<strong style=\"color: #00a;\">" + vpd.VirtualPath + "</strong>";                    var vpdRoute = vpd.Route as Route;                    if (vpdRoute != null)                    {                        generatedUrlInfo += " using the route \"" + vpdRoute.Url + "\"</p>";                    }                }            }            const string htmlFormat = @"<html><div id=""haackroutedebugger"" style=""background-color: #fff; padding-bottom: 10px;"">    <style>        #haackroutedebugger, #haackroutedebugger td, #haackroutedebugger th {{background-color: #fff; font-family: verdana, helvetica, san-serif; font-size: small;}}        #haackroutedebugger tr.header td, #haackroutedebugger tr.header th {{background-color: #ffc;}}    </style>    <hr style=""width: 100%; border: solid 1px #000; margin:0; padding:0;"" />    <h1 style=""margin: 0; padding: 4px; border-bottom: solid 1px #bbb; padding-left: 10px; font-size: 1.2em; background-color: #ffc;"">Route Debugger</h1>    <div id=""main"" style=""margin-top:0; padding: 0 10px;"">        <p style=""font-size: .9em; padding-top:0"">            Type in a url in the address bar to see which defined routes match it.             A {{*catchall}} route is added to the list of routes automatically in             case none of your routes match.        </p>        <p style=""font-size: .9em;"">            To generate URLs using routing, supply route values via the query string. example: <code>http://localhost:14230/?id=123</code>        </p>        <p><label style=""font-weight: bold; font-size: 1.1em;"">Matched Route</label>: {1}</p>        {5}        <div style=""float: left;"">            <table border=""1"" cellpadding=""3"" cellspacing=""0"" width=""300"">                <caption style=""font-weight: bold;"">Route Data</caption>                <tr class=""header""><th>Key</th><th>Value</th></tr>                {0}            </table>        </div>        <div style=""float: left; margin-left: 10px;"">            <table border=""1"" cellpadding=""3"" cellspacing=""0"" width=""300"">                <caption style=""font-weight: bold;"">Data Tokens</caption>                <tr class=""header""><th>Key</th><th>Value</th></tr>                {4}            </table>        </div>        <hr style=""clear: both;"" />        <table border=""1"" cellpadding=""3"" cellspacing=""0"">            <caption style=""font-weight: bold;"">All Routes</caption>            <tr class=""header"">                <th>Matches Current Request</th>                <th>Url</th>                <th>Defaults</th>                <th>Constraints</th>                <th>DataTokens</th>            </tr>            {2}        </table>        <hr />        <h3>Current Request Info</h3>        <p>            AppRelativeCurrentExecutionFilePath is the portion of the request that Routing acts on.        </p>        <p><strong>AppRelativeCurrentExecutionFilePath</strong>: {3}</p>    </div></div>";            string routeDataRows = string.Empty;            var routeData = requestContext.RouteData;            var routeValues = routeData.Values;            var matchedRouteBase = routeData.Route;            string routes = string.Empty;            using (RouteTable.Routes.GetReadLock())            {                foreach (var routeBase in RouteTable.Routes)                {                    bool matchesCurrentRequest = (routeBase.GetRouteData(requestContext.HttpContext) != null);                    string matchText = string.Format(@"<span{0}>{1}</span>", BoolStyle(matchesCurrentRequest), matchesCurrentRequest);                    string url = "n/a";                    string defaults = "n/a";                    string constraints = "n/a";                    string dataTokens = "n/a";                    Route route = CastRoute(routeBase);                    if (route != null)                    {                        url = route.Url;                        defaults = FormatDictionary(route.Defaults);                        constraints = FormatDictionary(route.Constraints);                        dataTokens = FormatDictionary(route.DataTokens);                    }                    routes += string.Format(@"<tr><td>{0}</td><td>{1}</td><td>{2}</td><td>{3}</td><td>{4}</td></tr>"                            , matchText                            , url                            , defaults                            , constraints                            , dataTokens);                }            }            string matchedRouteUrl = "n/a";            string dataTokensRows = "";            if (!(matchedRouteBase is DebugRoute))            {                foreach (string key in routeValues.Keys)                {                    routeDataRows += string.Format("\t<tr><td>{0}</td><td>{1}&nbsp;</td></tr>", key, routeValues[key]);                }                foreach (string key in routeData.DataTokens.Keys)                {                    dataTokensRows += string.Format("\t<tr><td>{0}</td><td>{1}&nbsp;</td></tr>", key, routeData.DataTokens[key]);                }                var matchedRoute = matchedRouteBase as Route;                if (matchedRoute != null)                    matchedRouteUrl = matchedRoute.Url;            }            else            {                matchedRouteUrl = string.Format("<strong{0}>NO MATCH!</strong>", BoolStyle(false));            }            context.Response.Write(string.Format(htmlFormat                , routeDataRows                , matchedRouteUrl                , routes                , request.AppRelativeCurrentExecutionFilePath                , dataTokensRows                , generatedUrlInfo));        }        private Route CastRoute(RouteBase routeBase)        {            var route = routeBase as Route;            if (route == null)            {                // cheat!                // TODO: Create an interface for self reporting routes.                var type = routeBase.GetType();                var property = type.GetProperty("__DebugRoute", BindingFlags.NonPublic | BindingFlags.Instance);                if (property != null)                {                    route = property.GetValue(routeBase, null) as Route;                }            }            return route;        }        private static string FormatDictionary(IDictionary<string, object> values)        {            if (values == null)                return "(null)";            if (values.Count == 0)            {                return "(empty)";            }            string display = string.Empty;            foreach (string key in values.Keys)            {                display += string.Format("{0} = {1}, ", key, FormatObject(values[key]));            }            if (display.EndsWith(", "))                display = display.Substring(0, display.Length - 2);            return display;        }        private static string FormatObject(object value)        {            if (value == null)            {                return "(null)";            }            var values = value as object[];            if (values != null)            {                return string.Join(", ", values);            }            var dictionaryValues = value as IDictionary<string, object>;            if (dictionaryValues != null)            {                return FormatDictionary(dictionaryValues);            }            if (value.GetType().Name == "UrlParameter")            {                return "UrlParameter.Optional";            }            return value.ToString();        }        private static string BoolStyle(bool boolean)        {            if (boolean) return " style=\"color: #0c0\"";            return " style=\"color: #c00\"";        }        private bool IsRoutedRequest(HttpRequest request)        {            string path = request.AppRelativeCurrentExecutionFilePath;            if (path != "~/" && (_virtualPathProvider.FileExists(path) || _virtualPathProvider.DirectoryExists(path)))            {                return false;            }            return true;        }        public bool IsReusable        {            get { return true; }        }    }}

 

IHttpHandler接口肯定都不陌生，有两个地方会调用到ProcessRequest方法。一是RouteDebuggerHttpModule的EndRequest方法。二是匹配到DebugRoute，DebugRoute加在了路由表的最后，没有匹配到任何的Route的时候就会返回DebugRoute。 所以这个时候就会输出两次ProcessRequest. 这是RouteDebugger的核心，循环RouteTable.Routes判断是否匹并且输出。