System.Web.Routing命名空间代码解析（二） Routing类（上）

 

Route类提供了五个属性，并且包装了一个ParsedRoute对象（即已解析过的Route规则），通过察看Route类的构造函数和Url属性的Set方法，我们可以知道的是：Route规则是在添加的时候就解析的，即，在Route类事例化的时候设置Url属性的时候就生成了ParsedRoute对象。

 其他的四个属性分别是 ：默认值，约束规则，自带数据，处理Handler.

可以把Router类对比和RouterData类作对比。。。。

Route类的四个方法我将会在 Routing类（下）中介绍。

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Security.Permissions;
using System.Text.RegularExpressions;
using System.Web;

namespace System.Web.Routing
{
    public enum RouteDirection
    {
        IncomingRequest,
        UrlGeneration
    }

    [AspNetHostingPermission(SecurityAction.InheritanceDemand, Level = AspNetHostingPermissionLevel.Minimal),
     AspNetHostingPermission(SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal)]
    public class Route : RouteBase
    {
        // Fields
        private ParsedRoute _parsedRoute;
        private string _url;
        private const string HttpMethodParameterName = "httpMethod";

        Constructions#region Constructions

        public Route(string url, IRouteHandler routeHandler)
        {
            this.Url = url;
            this.RouteHandler = routeHandler;
        }

        public Route(string url, RouteValueDictionary defaults, IRouteHandler routeHandler)
        {
            this.Url = url;
            this.Defaults = defaults;
            this.RouteHandler = routeHandler;
        }

        public Route(string url, RouteValueDictionary defaults, RouteValueDictionary constraints,
                     IRouteHandler routeHandler)
        {
            this.Url = url;
            this.Defaults = defaults;
            this.Constraints = constraints;
            this.RouteHandler = routeHandler;
        }

        public Route(string url, RouteValueDictionary defaults, RouteValueDictionary constraints,
                     RouteValueDictionary dataTokens, IRouteHandler routeHandler)
        {
            this.Url = url;
            this.Defaults = defaults;
            this.Constraints = constraints;
            this.DataTokens = dataTokens;
            this.RouteHandler = routeHandler;
        }

        #endregion

        public override RouteData GetRouteData(HttpContextBase httpContext)
        {
            string virtualPath = httpContext.Request.AppRelativeCurrentExecutionFilePath.Substring(2) +
                                 httpContext.Request.PathInfo;
            RouteValueDictionary values = this._parsedRoute.Match(virtualPath, this.Defaults);
            if (values == null)
                return null;
            RouteData data = new RouteData(this, this.RouteHandler);
            if (!this.ProcessConstraints(httpContext, values, RouteDirection.IncomingRequest))
                return null;
            foreach (KeyValuePair<string, object> pair in values)
                data.Values.Add(pair.Key, pair.Value);
            if (this.DataTokens != null)
                foreach (KeyValuePair<string, object> pair2 in this.DataTokens)
                    data.DataTokens[pair2.Key] = pair2.Value;
            return data;
        }

        public override VirtualPathData GetVirtualPath(RequestContext requestContext, RouteValueDictionary values)
        {
            BoundUrl url = this._parsedRoute.Bind(requestContext.RouteData.Values, values, this.Defaults,
                                                  this.Constraints);
            if (url == null)
                return null;
            if (!this.ProcessConstraints(requestContext.HttpContext, url.Values, RouteDirection.UrlGeneration))
                return null;
            VirtualPathData data = new VirtualPathData(this, url.Url);
            if (this.DataTokens != null)
                foreach (KeyValuePair<string, object> pair in this.DataTokens)
                    data.DataTokens[pair.Key] = pair.Value;
            return data;
        }

        protected virtual bool ProcessConstraint(HttpContextBase httpContext, object constraint, string parameterName,
                                                 RouteValueDictionary values, RouteDirection routeDirection)
        {
            object obj2;
            IRouteConstraint constraint2 = constraint as IRouteConstraint;
            if (constraint2 != null)
                return constraint2.Match(httpContext, this, parameterName, values, routeDirection);
            string str = constraint as string;
            if (str == null)
                throw new InvalidOperationException(string.Format(CultureInfo.CurrentUICulture,
                                                                  RoutingResources.
                                                                      Route_ValidationMustBeStringOrCustomConstraint,
                                                                  new object[] {parameterName, this.Url}));
            values.TryGetValue(parameterName, out obj2);
            string input = Convert.ToString(obj2, CultureInfo.InvariantCulture);
            string pattern = "^(" + str + ")$";
            return Regex.IsMatch(input, pattern, RegexOptions.CultureInvariant | RegexOptions.IgnoreCase);
        }

        private bool ProcessConstraints(HttpContextBase httpContext, RouteValueDictionary values,
                                        RouteDirection routeDirection)
        {
            if (this.Constraints != null)
                foreach (KeyValuePair<string, object> pair in this.Constraints)
                    if (!this.ProcessConstraint(httpContext, pair.Value, pair.Key, values, routeDirection))
                        return false;
            return true;
        }

        // Properties
        public RouteValueDictionary Constraints { get; set; }

        public RouteValueDictionary DataTokens { get; set; }

        public RouteValueDictionary Defaults { get; set; }

        public IRouteHandler RouteHandler { get; set; }

        public string Url
        {
            get { return (this._url ?? string.Empty); }
            set
            {
                this._parsedRoute = RouteParser.Parse(value);
                this._url = value;
            }
        }
    }
}