mcs/class/System.Web.Mvc2/System.Web.Mvc/ActionMethodSelector.cs

   1 /* ****************************************************************************\r
   2  *\r
   3  * Copyright (c) Microsoft Corporation. All rights reserved.\r
   4  *\r
   5  * This software is subject to the Microsoft Public License (Ms-PL). \r
   6  * A copy of the license can be found in the license.htm file included \r
   7  * in this distribution.\r
   8  *\r
   9  * You must not remove this notice, or any other, from this software.\r
  10  *\r
  11  * ***************************************************************************/\r
  12 \r
  13 namespace System.Web.Mvc {\r
  14     using System;\r
  15     using System.Collections.Generic;\r
  16     using System.Globalization;\r
  17     using System.Linq;\r
  18     using System.Reflection;\r
  19     using System.Text;\r
  20     using System.Web.Mvc.Resources;\r
  21 \r
  22     internal sealed class ActionMethodSelector {\r
  23 \r
  24         public ActionMethodSelector(Type controllerType) {\r
  25             ControllerType = controllerType;\r
  26             PopulateLookupTables();\r
  27         }\r
  28 \r
  29         public Type ControllerType {\r
  30             get;\r
  31             private set;\r
  32         }\r
  33 \r
  34         public MethodInfo[] AliasedMethods {\r
  35             get;\r
  36             private set;\r
  37         }\r
  38 \r
  39         public ILookup<string, MethodInfo> NonAliasedMethods {\r
  40             get;\r
  41             private set;\r
  42         }\r
  43 \r
  44         private AmbiguousMatchException CreateAmbiguousMatchException(List<MethodInfo> ambiguousMethods, string actionName) {\r
  45             StringBuilder exceptionMessageBuilder = new StringBuilder();\r
  46             foreach (MethodInfo methodInfo in ambiguousMethods) {\r
  47                 string controllerAction = Convert.ToString(methodInfo, CultureInfo.CurrentUICulture);\r
  48                 string controllerType = methodInfo.DeclaringType.FullName;\r
  49                 exceptionMessageBuilder.AppendLine();\r
  50                 exceptionMessageBuilder.AppendFormat(CultureInfo.CurrentUICulture, MvcResources.ActionMethodSelector_AmbiguousMatchType, controllerAction, controllerType);\r
  51             }\r
  52             string message = String.Format(CultureInfo.CurrentUICulture, MvcResources.ActionMethodSelector_AmbiguousMatch,\r
  53                 actionName, ControllerType.Name, exceptionMessageBuilder);\r
  54             return new AmbiguousMatchException(message);\r
  55         }\r
  56 \r
  57         public MethodInfo FindActionMethod(ControllerContext controllerContext, string actionName) {\r
  58             List<MethodInfo> methodsMatchingName = GetMatchingAliasedMethods(controllerContext, actionName);\r
  59             methodsMatchingName.AddRange(NonAliasedMethods[actionName]);\r
  60             List<MethodInfo> finalMethods = RunSelectionFilters(controllerContext, methodsMatchingName);\r
  61 \r
  62             switch (finalMethods.Count) {\r
  63                 case 0:\r
  64                     return null;\r
  65 \r
  66                 case 1:\r
  67                     return finalMethods[0];\r
  68 \r
  69                 default:\r
  70                     throw CreateAmbiguousMatchException(finalMethods, actionName);\r
  71             }\r
  72         }\r
  73 \r
  74         internal List<MethodInfo> GetMatchingAliasedMethods(ControllerContext controllerContext, string actionName) {\r
  75             // find all aliased methods which are opting in to this request\r
  76             // to opt in, all attributes defined on the method must return true\r
  77 \r
  78             var methods = from methodInfo in AliasedMethods\r
  79                           let attrs = (ActionNameSelectorAttribute[])methodInfo.GetCustomAttributes(typeof(ActionNameSelectorAttribute), true /* inherit */)\r
  80                           where attrs.All(attr => attr.IsValidName(controllerContext, actionName, methodInfo))\r
  81                           select methodInfo;\r
  82             return methods.ToList();\r
  83         }\r
  84 \r
  85         private static bool IsMethodDecoratedWithAliasingAttribute(MethodInfo methodInfo) {\r
  86             return methodInfo.IsDefined(typeof(ActionNameSelectorAttribute), true /* inherit */);\r
  87         }\r
  88 \r
  89         private static bool IsValidActionMethod(MethodInfo methodInfo) {\r
  90             return !(methodInfo.IsSpecialName ||\r
  91                      methodInfo.GetBaseDefinition().DeclaringType.IsAssignableFrom(typeof(Controller)));\r
  92         }\r
  93 \r
  94         private void PopulateLookupTables() {\r
  95             MethodInfo[] allMethods = ControllerType.GetMethods(BindingFlags.InvokeMethod | BindingFlags.Instance | BindingFlags.Public);\r
  96             MethodInfo[] actionMethods = Array.FindAll(allMethods, IsValidActionMethod);\r
  97 \r
  98             AliasedMethods = Array.FindAll(actionMethods, IsMethodDecoratedWithAliasingAttribute);\r
  99             NonAliasedMethods = actionMethods.Except(AliasedMethods).ToLookup(method => method.Name, StringComparer.OrdinalIgnoreCase);\r
 100         }\r
 101 \r
 102         private static List<MethodInfo> RunSelectionFilters(ControllerContext controllerContext, List<MethodInfo> methodInfos) {\r
 103             // remove all methods which are opting out of this request\r
 104             // to opt out, at least one attribute defined on the method must return false\r
 105 \r
 106             List<MethodInfo> matchesWithSelectionAttributes = new List<MethodInfo>();\r
 107             List<MethodInfo> matchesWithoutSelectionAttributes = new List<MethodInfo>();\r
 108 \r
 109             foreach (MethodInfo methodInfo in methodInfos) {\r
 110                 ActionMethodSelectorAttribute[] attrs = (ActionMethodSelectorAttribute[])methodInfo.GetCustomAttributes(typeof(ActionMethodSelectorAttribute), true /* inherit */);\r
 111                 if (attrs.Length == 0) {\r
 112                     matchesWithoutSelectionAttributes.Add(methodInfo);\r
 113                 }\r
 114                 else if (attrs.All(attr => attr.IsValidForRequest(controllerContext, methodInfo))) {\r
 115                     matchesWithSelectionAttributes.Add(methodInfo);\r
 116                 }\r
 117             }\r
 118 \r
 119             // if a matching action method had a selection attribute, consider it more specific than a matching action method\r
 120             // without a selection attribute\r
 121             return (matchesWithSelectionAttributes.Count > 0) ? matchesWithSelectionAttributes : matchesWithoutSelectionAttributes;\r
 122         }\r
 123 \r
 124     }\r
 125 }\r