HttpMethodConstraint.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / xsp / System / Web / Routing / HttpMethodConstraint.cs / 1305376 / HttpMethodConstraint.cs
                        

                        
                            namespace System.Web.Routing { 
    using System;
    using System.Collections.Generic;
    using System.Globalization;
    using System.Linq; 
    using System.Runtime.CompilerServices;
 
    [TypeForwardedFrom("System.Web.Routing, Version=3.5.0.0, Culture=Neutral, PublicKeyToken=31bf3856ad364e35")] 
    public class HttpMethodConstraint : IRouteConstraint {
 
        public HttpMethodConstraint(params string[] allowedMethods) {
            if (allowedMethods == null) {
                throw new ArgumentNullException("allowedMethods");
            } 

            AllowedMethods = allowedMethods.ToList().AsReadOnly(); 
        } 

        public ICollection AllowedMethods { 
            get;
            private set;
        }
 
        protected virtual bool Match(HttpContextBase httpContext, Route route, string parameterName, RouteValueDictionary values, RouteDirection routeDirection) {
            if (httpContext == null) { 
                throw new ArgumentNullException("httpContext"); 
            }
            if (route == null) { 
                throw new ArgumentNullException("route");
            }
            if (parameterName == null) {
                throw new ArgumentNullException("parameterName"); 
            }
            if (values == null) { 
                throw new ArgumentNullException("values"); 
            }
 
            switch (routeDirection) {
                case RouteDirection.IncomingRequest:
                    return AllowedMethods.Any(method => String.Equals(method, httpContext.Request.HttpMethod,
                        StringComparison.OrdinalIgnoreCase)); 

                case RouteDirection.UrlGeneration: 
                    // We need to see if the user specified the HTTP method explicitly.  Consider these two routes: 
                    //
                    // a) Route: Url = "/{foo}", Constraints = { httpMethod = new HttpMethodConstraint("GET") } 
                    // b) Route: Url = "/{foo}", Constraints = { httpMethod = new HttpMethodConstraint("POST") }
                    //
                    // A user might know ahead of time that a URL he is generating might be used with a particular HTTP
                    // method.  If a URL will be used for an HTTP POST but we match on (a) while generating the URL, then 
                    // the HTTP GET-specific route will be used for URL generation, which might have undesired behavior.
                    // To prevent this, a user might call RouteCollection.GetVirtualPath(..., { httpMethod = "POST" }) to 
                    // signal that he is generating a URL that will be used for an HTTP POST, so he wants the URL 
                    // generation to be performed by the (b) route instead of the (a) route, consistent with what would
                    // happen on incoming requests. 

                    object parameterValue;
                    if (!values.TryGetValue(parameterName, out parameterValue)) {
                        return true; 
                    }
 
                    string parameterValueString = parameterValue as string; 
                    if (parameterValueString == null) {
                        throw new InvalidOperationException(String.Format(CultureInfo.CurrentUICulture, 
                            SR.GetString(SR.HttpMethodConstraint_ParameterValueMustBeString), parameterName, route.Url));
                    }

                    return AllowedMethods.Any(method => String.Equals(method, parameterValueString, 
                        StringComparison.OrdinalIgnoreCase));
 
                default: 
                    return true;
            } 
        }

        #region IRouteConstraint Members
        bool IRouteConstraint.Match(HttpContextBase httpContext, Route route, string parameterName, RouteValueDictionary values, RouteDirection routeDirection) { 
            return Match(httpContext, route, parameterName, values, routeDirection);
        } 
        #endregion 

    } 
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.

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