mcs/class/System.Web.Mvc3/Mvc/Async/AsyncControllerActionInvoker.cs

   1 namespace System.Web.Mvc.Async {
   2     using System;
   3     using System.Collections.Generic;
   4     using System.Linq;
   5     using System.Threading;
   6
   7     public class AsyncControllerActionInvoker : ControllerActionInvoker, IAsyncActionInvoker {
   8
   9         private static readonly object _invokeActionTag = new object();
  10         private static readonly object _invokeActionMethodTag = new object();
  11         private static readonly object _invokeActionMethodWithFiltersTag = new object();
  12
  13         public virtual IAsyncResult BeginInvokeAction(ControllerContext controllerContext, string actionName, AsyncCallback callback, object state) {
  14             if (controllerContext == null) {
  15                 throw new ArgumentNullException("controllerContext");
  16             }
  17             if (String.IsNullOrEmpty(actionName)) {
  18                 throw Error.ParameterCannotBeNullOrEmpty("actionName");
  19             }
  20
  21             ControllerDescriptor controllerDescriptor = GetControllerDescriptor(controllerContext);
  22             ActionDescriptor actionDescriptor = controllerDescriptor.FindAction(controllerContext, actionName);
  23             if (actionDescriptor != null) {
  24                 FilterInfo filterInfo = GetFilters(controllerContext, actionDescriptor);
  25                 Action continuation = null;
  26
  27                 BeginInvokeDelegate beginDelegate = delegate(AsyncCallback asyncCallback, object asyncState) {
  28                     try {
  29                         AuthorizationContext authContext = InvokeAuthorizationFilters(controllerContext, filterInfo.AuthorizationFilters, actionDescriptor);
  30                         if (authContext.Result != null) {
  31                             // the auth filter signaled that we should let it short-circuit the request
  32                             continuation = () => InvokeActionResult(controllerContext, authContext.Result);
  33                         }
  34                         else {
  35                             if (controllerContext.Controller.ValidateRequest) {
  36                                 ValidateRequest(controllerContext);
  37                             }
  38
  39                             IDictionary<string, object> parameters = GetParameterValues(controllerContext, actionDescriptor);
  40                             IAsyncResult asyncResult = BeginInvokeActionMethodWithFilters(controllerContext, filterInfo.ActionFilters, actionDescriptor, parameters, asyncCallback, asyncState);
  41                             continuation = () => {
  42                                 ActionExecutedContext postActionContext = EndInvokeActionMethodWithFilters(asyncResult);
  43                                 InvokeActionResultWithFilters(controllerContext, filterInfo.ResultFilters, postActionContext.Result);
  44                             };
  45                             return asyncResult;
  46                         }
  47                     }
  48                     catch (ThreadAbortException) {
  49                         // This type of exception occurs as a result of Response.Redirect(), but we special-case so that
  50                         // the filters don't see this as an error.
  51                         throw;
  52                     }
  53                     catch (Exception ex) {
  54                         // something blew up, so execute the exception filters
  55                         ExceptionContext exceptionContext = InvokeExceptionFilters(controllerContext, filterInfo.ExceptionFilters, ex);
  56                         if (!exceptionContext.ExceptionHandled) {
  57                             throw;
  58                         }
  59
  60                         continuation = () => InvokeActionResult(controllerContext, exceptionContext.Result);
  61                     }
  62
  63                     return BeginInvokeAction_MakeSynchronousAsyncResult(asyncCallback, asyncState);
  64                 };
  65
  66                 EndInvokeDelegate<bool> endDelegate = delegate(IAsyncResult asyncResult) {
  67                     try {
  68                         continuation();
  69                     }
  70                     catch (ThreadAbortException) {
  71                         // This type of exception occurs as a result of Response.Redirect(), but we special-case so that
  72                         // the filters don't see this as an error.
  73                         throw;
  74                     }
  75                     catch (Exception ex) {
  76                         // something blew up, so execute the exception filters
  77                         ExceptionContext exceptionContext = InvokeExceptionFilters(controllerContext, filterInfo.ExceptionFilters, ex);
  78                         if (!exceptionContext.ExceptionHandled) {
  79                             throw;
  80                         }
  81                         InvokeActionResult(controllerContext, exceptionContext.Result);
  82                     }
  83
  84                     return true;
  85                 };
  86
  87                 return AsyncResultWrapper.Begin(callback, state, beginDelegate, endDelegate, _invokeActionTag);
  88             }
  89             else {
  90                 // Notify the controller that no action was found.
  91                 return BeginInvokeAction_ActionNotFound(callback, state);
  92             }
  93         }
  94
  95         private static IAsyncResult BeginInvokeAction_ActionNotFound(AsyncCallback callback, object state) {
  96             BeginInvokeDelegate beginDelegate = BeginInvokeAction_MakeSynchronousAsyncResult;
  97
  98             EndInvokeDelegate<bool> endDelegate = delegate(IAsyncResult asyncResult) {
  99                 return false;
 100             };
 101
 102             return AsyncResultWrapper.Begin(callback, state, beginDelegate, endDelegate, _invokeActionTag);
 103         }
 104
 105         private static IAsyncResult BeginInvokeAction_MakeSynchronousAsyncResult(AsyncCallback callback, object state) {
 106             SimpleAsyncResult asyncResult = new SimpleAsyncResult(state);
 107             asyncResult.MarkCompleted(true /* completedSynchronously */, callback);
 108             return asyncResult;
 109         }
 110
 111         protected internal virtual IAsyncResult BeginInvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary<string, object> parameters, AsyncCallback callback, object state) {
 112             AsyncActionDescriptor asyncActionDescriptor = actionDescriptor as AsyncActionDescriptor;
 113             if (asyncActionDescriptor != null) {
 114                 return BeginInvokeAsynchronousActionMethod(controllerContext, asyncActionDescriptor, parameters, callback, state);
 115             }
 116             else {
 117                 return BeginInvokeSynchronousActionMethod(controllerContext, actionDescriptor, parameters, callback, state);
 118             }
 119         }
 120
 121         protected internal virtual IAsyncResult BeginInvokeActionMethodWithFilters(ControllerContext controllerContext, IList<IActionFilter> filters, ActionDescriptor actionDescriptor, IDictionary<string, object> parameters, AsyncCallback callback, object state) {
 122             Func<ActionExecutedContext> endContinuation = null;
 123
 124             BeginInvokeDelegate beginDelegate = delegate(AsyncCallback asyncCallback, object asyncState) {
 125                 ActionExecutingContext preContext = new ActionExecutingContext(controllerContext, actionDescriptor, parameters);
 126                 IAsyncResult innerAsyncResult = null;
 127
 128                 Func<Func<ActionExecutedContext>> beginContinuation = () => {
 129                     innerAsyncResult = BeginInvokeActionMethod(controllerContext, actionDescriptor, parameters, asyncCallback, asyncState);
 130                     return () =>
 131                         new ActionExecutedContext(controllerContext, actionDescriptor, false /* canceled */, null /* exception */) {
 132                             Result = EndInvokeActionMethod(innerAsyncResult)
 133                         };
 134                 };
 135
 136                 // need to reverse the filter list because the continuations are built up backward
 137                 Func<Func<ActionExecutedContext>> thunk = filters.Reverse().Aggregate(beginContinuation,
 138                     (next, filter) => () => InvokeActionMethodFilterAsynchronously(filter, preContext, next));
 139                 endContinuation = thunk();
 140
 141                 if (innerAsyncResult != null) {
 142                     // we're just waiting for the inner result to complete
 143                     return innerAsyncResult;
 144                 }
 145                 else {
 146                     // something was short-circuited and the action was not called, so this was a synchronous operation
 147                     SimpleAsyncResult newAsyncResult = new SimpleAsyncResult(asyncState);
 148                     newAsyncResult.MarkCompleted(true /* completedSynchronously */, asyncCallback);
 149                     return newAsyncResult;
 150                 }
 151             };
 152
 153             EndInvokeDelegate<ActionExecutedContext> endDelegate = delegate(IAsyncResult asyncResult) {
 154                 return endContinuation();
 155             };
 156
 157             return AsyncResultWrapper.Begin(callback, state, beginDelegate, endDelegate, _invokeActionMethodWithFiltersTag);
 158         }
 159
 160         private IAsyncResult BeginInvokeAsynchronousActionMethod(ControllerContext controllerContext, AsyncActionDescriptor actionDescriptor, IDictionary<string, object> parameters, AsyncCallback callback, object state) {
 161             BeginInvokeDelegate beginDelegate = delegate(AsyncCallback asyncCallback, object asyncState) {
 162                 return actionDescriptor.BeginExecute(controllerContext, parameters, asyncCallback, asyncState);
 163             };
 164
 165             EndInvokeDelegate<ActionResult> endDelegate = delegate(IAsyncResult asyncResult) {
 166                 object returnValue = actionDescriptor.EndExecute(asyncResult);
 167                 ActionResult result = CreateActionResult(controllerContext, actionDescriptor, returnValue);
 168                 return result;
 169             };
 170
 171             return AsyncResultWrapper.Begin(callback, state, beginDelegate, endDelegate, _invokeActionMethodTag);
 172         }
 173
 174         private IAsyncResult BeginInvokeSynchronousActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary<string, object> parameters, AsyncCallback callback, object state) {
 175             return AsyncResultWrapper.BeginSynchronous(callback, state,
 176                 () => InvokeSynchronousActionMethod(controllerContext, actionDescriptor, parameters),
 177                 _invokeActionMethodTag);
 178         }
 179
 180         public virtual bool EndInvokeAction(IAsyncResult asyncResult) {
 181             return AsyncResultWrapper.End<bool>(asyncResult, _invokeActionTag);
 182         }
 183
 184         protected internal virtual ActionResult EndInvokeActionMethod(IAsyncResult asyncResult) {
 185             return AsyncResultWrapper.End<ActionResult>(asyncResult, _invokeActionMethodTag);
 186         }
 187
 188         protected internal virtual ActionExecutedContext EndInvokeActionMethodWithFilters(IAsyncResult asyncResult) {
 189             return AsyncResultWrapper.End<ActionExecutedContext>(asyncResult, _invokeActionMethodWithFiltersTag);
 190         }
 191
 192         protected override ControllerDescriptor GetControllerDescriptor(ControllerContext controllerContext) {
 193             Type controllerType = controllerContext.Controller.GetType();
 194             ControllerDescriptor controllerDescriptor = DescriptorCache.GetDescriptor(controllerType, () => new ReflectedAsyncControllerDescriptor(controllerType));
 195             return controllerDescriptor;
 196         }
 197
 198         internal static Func<ActionExecutedContext> InvokeActionMethodFilterAsynchronously(IActionFilter filter, ActionExecutingContext preContext, Func<Func<ActionExecutedContext>> nextInChain) {
 199             filter.OnActionExecuting(preContext);
 200             if (preContext.Result != null) {
 201                 ActionExecutedContext shortCircuitedPostContext = new ActionExecutedContext(preContext, preContext.ActionDescriptor, true /* canceled */, null /* exception */) {
 202                     Result = preContext.Result
 203                 };
 204                 return () => shortCircuitedPostContext;
 205             }
 206
 207             // There is a nested try / catch block here that contains much the same logic as the outer block.
 208             // Since an exception can occur on either side of the asynchronous invocation, we need guards on
 209             // on both sides. In the code below, the second side is represented by the nested delegate. This
 210             // is really just a parallel of the synchronous ControllerActionInvoker.InvokeActionMethodFilter()
 211             // method.
 212
 213             try {
 214                 Func<ActionExecutedContext> continuation = nextInChain();
 215
 216                 // add our own continuation, then return the new function
 217                 return () => {
 218                     ActionExecutedContext postContext;
 219                     bool wasError = true;
 220
 221                     try {
 222                         postContext = continuation();
 223                         wasError = false;
 224                     }
 225                     catch (ThreadAbortException) {
 226                         // This type of exception occurs as a result of Response.Redirect(), but we special-case so that
 227                         // the filters don't see this as an error.
 228                         postContext = new ActionExecutedContext(preContext, preContext.ActionDescriptor, false /* canceled */, null /* exception */);
 229                         filter.OnActionExecuted(postContext);
 230                         throw;
 231                     }
 232                     catch (Exception ex) {
 233                         postContext = new ActionExecutedContext(preContext, preContext.ActionDescriptor, false /* canceled */, ex);
 234                         filter.OnActionExecuted(postContext);
 235                         if (!postContext.ExceptionHandled) {
 236                             throw;
 237                         }
 238                     }
 239                     if (!wasError) {
 240                         filter.OnActionExecuted(postContext);
 241                     }
 242
 243                     return postContext;
 244                 };
 245             }
 246             catch (ThreadAbortException) {
 247                 // This type of exception occurs as a result of Response.Redirect(), but we special-case so that
 248                 // the filters don't see this as an error.
 249                 ActionExecutedContext postContext = new ActionExecutedContext(preContext, preContext.ActionDescriptor, false /* canceled */, null /* exception */);
 250                 filter.OnActionExecuted(postContext);
 251                 throw;
 252             }
 253             catch (Exception ex) {
 254                 ActionExecutedContext postContext = new ActionExecutedContext(preContext, preContext.ActionDescriptor, false /* canceled */, ex);
 255                 filter.OnActionExecuted(postContext);
 256                 if (postContext.ExceptionHandled) {
 257                     return () => postContext;
 258                 }
 259                 else {
 260                     throw;
 261                 }
 262             }
 263         }
 264
 265         private ActionResult InvokeSynchronousActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary<string, object> parameters) {
 266             return base.InvokeActionMethod(controllerContext, actionDescriptor, parameters);
 267         }
 268
 269     }
 270 }