MonoRail/Castle.MonoRail.ActiveRecordSupport/ARFetchAttribute.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.ActiveRecordSupport
  16 {
  17         using System;
  18         using System.Reflection;
  19         using Castle.Components.Binder;
  20         using Castle.MonoRail.Framework;
  21
  22         /// <summary>
  23         /// Mark a parameter with this attribute to instruct the <see cref="SmartDispatcherController" />
  24         /// to load an <c>ActiveRecord</c> instance of the parameter type, using the request parameter
  25         /// as the identifier.
  26         /// </summary>
  27         /// <remarks>
  28         /// The <see cref="ARFetchAttribute"/> only loads an instance
  29         /// based on the primary key value obtained from <see cref="IRequest.Params"/>
  30         /// <para>For example:</para>
  31         /// <code>
  32         /// public class CustomerController : ARSmartDispatcherController
  33         /// {
  34         ///     public void UpdateCustomerLocation([ARFetch("customer.id")] Customer customer, [ARFetch("location.id")] Location location)
  35         ///     {
  36         ///       customer.Location = location;
  37         ///       customer.Save();
  38         ///
  39         ///       RedirectToAction("index");
  40         ///     }
  41         /// }
  42         /// </code>
  43         /// The code above assumes that you have the fields
  44         /// <c>customer.id</c> and <c>location.id</c> on the form being
  45         /// submitted.
  46         /// </remarks>
  47         [AttributeUsage(AttributeTargets.Parameter), Serializable]
  48         public class ARFetchAttribute : Attribute, IParameterBinder
  49         {
  50                 private String requestParameterName;
  51                 private String eager;
  52                 private bool create, required;
  53                 private IDataBinder binder;
  54
  55                 /// <summary>
  56                 /// Constructs an <see cref="ARFetchAttribute"/>
  57                 /// specifying the parameter name and the create and require behavior
  58                 /// </summary>
  59                 /// <param name="requestParameterName">The parameter name to be read from the request</param>
  60                 /// <param name="create"><c>true</c> if you want an instance even when the record is not found</param>
  61                 /// <param name="required"><c>true</c> if you want an exception if the record is not found</param>
  62                 public ARFetchAttribute(String requestParameterName, bool create, bool required) : base()
  63                 {
  64                         this.requestParameterName = requestParameterName;
  65                         this.create = create;
  66                         this.required = required;
  67                 }
  68
  69                 /// <summary>
  70                 /// Constructs an <see cref="ARFetchAttribute"/> using the
  71                 /// parameter name as the <see cref="ARFetchAttribute.RequestParameterName"/>
  72                 /// </summary>
  73                 public ARFetchAttribute() : this(null, false, false)
  74                 {
  75                 }
  76
  77                 /// <summary>
  78                 /// Constructs an <see cref="ARFetchAttribute"/> specifing the
  79                 /// parameter name
  80                 /// <seealso cref="ARFetchAttribute.RequestParameterName"/>
  81                 /// </summary>
  82                 public ARFetchAttribute(String requestParameterName) : this(requestParameterName, false, false)
  83                 {
  84                 }
  85
  86                 /// <summary>
  87                 /// Constructs an <see cref="ARFetchAttribute"/> using the
  88                 /// parameter name as the <see cref="ARFetchAttribute.RequestParameterName"/>
  89                 /// and the create and require behavior
  90                 /// </summary>
  91                 /// <param name="create"><c>true</c> if you want an instance even when the record is not found</param>
  92                 /// <param name="require"><c>true</c> if you want an exception if the record is not found</param>
  93                 public ARFetchAttribute(bool create, bool require) : this(null, create, require)
  94                 {
  95                 }
  96
  97                 /// <summary>
  98                 /// The parameter name to be read from the request. The parameter value will
  99                 /// be used as the primary key value to load the target object instance.
 100                 /// </summary>
 101                 public String RequestParameterName
 102                 {
 103                         get { return requestParameterName; }
 104                         set { requestParameterName = value; }
 105                 }
 106
 107                 /// <summary>
 108                 /// When set to <c>true</c> an instance of
 109                 /// the target type will be created if the record
 110                 /// is not found. The default is <c>false</c>.
 111                 /// </summary>
 112                 public bool Create
 113                 {
 114                         get { return create; }
 115                         set { create = value; }
 116                 }
 117
 118                 /// <summary>
 119                 /// When set to <c>true</c>, an exception will be thrown
 120                 /// if the record specified is not found. The default is <c>false</c>.
 121                 /// </summary>
 122                 public bool Required
 123                 {
 124                         get { return required; }
 125                         set { required = value; }
 126                 }
 127
 128                 /// <summary>
 129                 /// Comma-separated list of lazy associations to eager-fetch, when loading the ActiveRecord object.
 130                 /// </summary>
 131                 public String Eager
 132                 {
 133                         get { return eager; }
 134                         set { eager = value; }
 135                 }
 136
 137                 public virtual int CalculateParamPoints(IEngineContext context, IController controller, IControllerContext controllerContext, ParameterInfo parameterInfo)
 138                 {
 139                         String paramName = RequestParameterName ?? parameterInfo.Name;
 140
 141                         return context.Request.Params.Get(paramName) != null ? 10 : 0;
 142                 }
 143
 144                 public virtual object Bind(IEngineContext context, IController controller, IControllerContext controllerContext, ParameterInfo parameterInfo)
 145                 {
 146                         EnsureBinderExists();
 147
 148                         ARFetcher fetcher = new ARFetcher(binder.Converter);
 149
 150                         return fetcher.FetchActiveRecord(parameterInfo, this, context.Request);
 151                 }
 152
 153                 private void EnsureBinderExists()
 154                 {
 155                         if (binder == null)
 156                         {
 157                                 binder = CreateBinder();
 158                         }
 159                 }
 160
 161                 /// <summary>
 162                 /// Creates the data binder implementation.
 163                 /// </summary>
 164                 /// <returns></returns>
 165                 protected virtual IDataBinder CreateBinder()
 166                 {
 167                         return new DataBinder();
 168                 }
 169         }
 170 }