MonoRail/Castle.MonoRail.Framework/Filters/LocalizationFilter.cs

   1 // Copyright 2004-2008 Castle Project - http://www.castleproject.org/
   2 //
   3 // Licensed under the Apache License, Version 2.0 (the "License");
   4 // you may not use this file except in compliance with the License.
   5 // You may obtain a copy of the License at
   6 //
   7 //     http://www.apache.org/licenses/LICENSE-2.0
   8 //
   9 // Unless required by applicable law or agreed to in writing, software
  10 // distributed under the License is distributed on an "AS IS" BASIS,
  11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12 // See the License for the specific language governing permissions and
  13 // limitations under the License.
  14
  15 namespace Castle.MonoRail.Framework.Filters
  16 {
  17         using System;
  18         using System.Configuration;
  19         using System.Globalization;
  20         using System.Threading;
  21
  22         /// <summary>
  23         /// Enum to identify where a value is stored.
  24         /// </summary>
  25         public enum RequestStore
  26         {
  27                 /// <summary>
  28                 /// Value is stored in the Session object.
  29                 /// </summary>
  30                 Session = 1,
  31                 /// <summary>
  32                 /// Value is stored in a cookie object.
  33                 /// </summary>
  34                 Cookie = 2,
  35                 /// <summary>
  36                 /// Value is stored in the querystring.
  37                 /// </summary>
  38                 QueryString = 3,
  39                 /// <summary>
  40                 /// Value is stored in the form collection.
  41                 /// </summary>
  42                 Form = 4,
  43                 /// <summary>
  44                 /// Value is stored in either query string or form collection.
  45                 /// </summary>
  46                 Params = 5
  47         }
  48
  49         /// <summary>
  50         /// The LocalizationFilter can be used to determine the culture to use
  51         /// for resources and UI.
  52         /// </summary>
  53         public class LocalizationFilter : IFilter, IFilterAttributeAware
  54         {
  55                 private LocalizationFilterAttribute setup;
  56
  57                 #region IFilterAttributeAware Members
  58
  59                 /// <summary>
  60                 /// Sets the filter.
  61                 /// </summary>
  62                 /// <value>The filter.</value>
  63                 public FilterAttribute Filter
  64                 {
  65                         set
  66                         {
  67                                 if (!(value is LocalizationFilterAttribute))
  68                                 {
  69                                         String message = "LocalizationFilter can only be defined by a LocalizationFilterAttribute.";
  70                                         throw new ConfigurationErrorsException(message);
  71                                 }
  72
  73                                 setup = value as LocalizationFilterAttribute;
  74                         }
  75                 }
  76
  77                 #endregion
  78
  79                 #region IFilter Members
  80
  81                 /// <summary>
  82                 /// Executes a sequence of steps to determine the browser location/culture.
  83                 /// </summary>
  84                 /// <param name="exec">When this filter is being invoked</param>
  85                 /// <param name="context">Current context</param>
  86                 /// <param name="controller">The controller instance</param>
  87                 /// <param name="controllerContext">The controller context.</param>
  88                 /// <returns>
  89                 ///     <c>true</c> if the action should be invoked, otherwise <c>false</c>
  90                 /// </returns>
  91                 public bool Perform(ExecuteWhen exec, IEngineContext context, IController controller, IControllerContext controllerContext)
  92                 {
  93                         try
  94                         {
  95                                 String localeId = GetLocaleId(context);
  96
  97                                 if (localeId == null && setup.UseBrowser)
  98                                         localeId = GetUserLanguage(context.Request);
  99
 100                                 if (localeId != null)
 101                                 {
 102                                         CultureInfo culture = CultureInfo.CreateSpecificCulture(localeId);
 103
 104                                         Thread.CurrentThread.CurrentCulture = culture;
 105                                         Thread.CurrentThread.CurrentUICulture = culture;
 106                                 }
 107                         }
 108                         catch
 109                         {
 110                                 if (setup.FailOnError) throw;
 111                         }
 112
 113                         return true;
 114                 }
 115
 116                 #endregion
 117
 118                 #region Get locale id from the store
 119
 120                 /// <summary>
 121                 /// Gets the user language.
 122                 /// </summary>
 123                 /// <param name="request">The request.</param>
 124                 /// <returns></returns>
 125                 private String GetUserLanguage(IRequest request)
 126                 {
 127                         if (request.UserLanguages != null && request.UserLanguages.Length > 0)
 128                                 return request.UserLanguages[0];
 129
 130                         return null;
 131                 }
 132
 133                 /// <summary>
 134                 /// Gets the locale id.
 135                 /// </summary>
 136                 /// <param name="context">The context.</param>
 137                 /// <returns></returns>
 138                 private String GetLocaleId(IEngineContext context)
 139                 {
 140                         switch(setup.Store)
 141                         {
 142                                 case RequestStore.Session:
 143                                         return context.Session[setup.Key] as String;
 144                                 case RequestStore.Cookie:
 145                                         return context.Request.ReadCookie(setup.Key);
 146                                 case RequestStore.QueryString:
 147                                         return context.Request.QueryString[setup.Key];
 148                                 case RequestStore.Form:
 149                                         return context.Request.Form[setup.Key];
 150                                 case RequestStore.Params:
 151                                         return context.Request.Params[setup.Key];
 152                         }
 153
 154                         return null;
 155                 }
 156
 157                 #endregion
 158         }
 159 }