mcs/class/System.Web/System.Web.Util/RequestValidator.cs

   1 //
   2 // Authors:
   3 //   Marek Habersack <mhabersack@novell.com>
   4 //
   5 // Copyright (C) 2010 Novell, Inc (http://novell.com/)
   6 //
   7
   8 //
   9 // Permission is hereby granted, free of charge, to any person obtaining
  10 // a copy of this software and associated documentation files (the
  11 // "Software"), to deal in the Software without restriction, including
  12 // without limitation the rights to use, copy, modify, merge, publish,
  13 // distribute, sublicense, and/or sell copies of the Software, and to
  14 // permit persons to whom the Software is furnished to do so, subject to
  15 // the following conditions:
  16 //
  17 // The above copyright notice and this permission notice shall be
  18 // included in all copies or substantial portions of the Software.
  19 //
  20 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  21 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  22 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  23 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  24 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  25 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  26 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  27 //
  28 using System;
  29 using System.Configuration;
  30 using System.Web;
  31 using System.Web.Configuration;
  32
  33 namespace System.Web.Util
  34 {
  35         public class RequestValidator
  36         {
  37                 static readonly object currentCreationLock = new object();
  38
  39                 static RequestValidator current;
  40                 static Lazy <RequestValidator> lazyLoader;
  41
  42                 // The stack trace from .NET shows it uses Lazy <T>:
  43                 //
  44                 //  Server stack trace:
  45                 //    at System.Web.Configuration.ConfigUtil.GetType(String typeName, String propertyName, ConfigurationElement configElement, XmlNode node, Boolean checkAptcaBit, Boolean ignoreCase)
  46                 //    at System.Web.Util.RequestValidator.GetCustomValidatorFromConfig()
  47                 //    at System.Lazy`1.CreateValue()
  48                 //
  49                 public static RequestValidator Current {
  50                         get {
  51                                 if (current == null)
  52                                         current = lazyLoader.Value;
  53
  54                                 return current;
  55                         }
  56
  57                         set {
  58                                 if (value == null)
  59                                         throw new ArgumentNullException ("value");
  60
  61                                 current = value;
  62                         }
  63                 }
  64
  65                 static RequestValidator ()
  66                 {
  67                         lazyLoader = new Lazy <RequestValidator> (new Func <RequestValidator> (LoadConfiguredValidator));
  68                 }
  69
  70                 public RequestValidator ()
  71                 {
  72                 }
  73
  74                 protected internal virtual bool IsValidRequestString (HttpContext context, string value, RequestValidationSource requestValidationSource,
  75                                                                       string collectionKey, out int validationFailureIndex)
  76                 {
  77                         validationFailureIndex = 0;
  78
  79                         return !HttpRequest.IsInvalidString (value, out validationFailureIndex);
  80                 }
  81
  82                 static void ParseTypeName (string spec, out string typeName, out string assemblyName)
  83                 {
  84                         try {
  85                                 if (String.IsNullOrEmpty (spec)) {
  86                                         typeName = null;
  87                                         assemblyName = null;
  88                                         return;
  89                                 }
  90
  91                                 int comma = spec.IndexOf (',');
  92                                 if (comma == -1) {
  93                                         typeName = spec;
  94                                         assemblyName = null;
  95                                         return;
  96                                 }
  97
  98                                 typeName = spec.Substring (0, comma).Trim ();
  99                                 assemblyName = spec.Substring (comma + 1).Trim ();
 100                         } catch {
 101                                 typeName = spec;
 102                                 assemblyName = null;
 103                         }
 104                 }
 105
 106                 static RequestValidator LoadConfiguredValidator ()
 107                 {
 108                         HttpRuntimeSection runtimeConfig = WebConfigurationManager.GetWebApplicationSection ("system.web/httpRuntime") as HttpRuntimeSection;
 109                         Type validatorType = null;
 110                         string typeSpec = runtimeConfig.RequestValidationType;
 111
 112                         try {
 113                                 validatorType = HttpApplication.LoadType <RequestValidator> (typeSpec, true);
 114                         } catch (TypeLoadException ex) {
 115                                 string typeName, assemblyName;
 116
 117                                 ParseTypeName (typeSpec, out typeName, out assemblyName);
 118                                 throw new ConfigurationErrorsException (
 119                                         String.Format ("Could not load type '{0}' from assembly '{1}'.", typeName, assemblyName),
 120                                         ex);
 121                         }
 122
 123                         return (RequestValidator) Activator.CreateInstance (validatorType);
 124                 }
 125         }
 126 }