ASPNET MVC中断请求
ASPNET MVC如何正确的中断请求？
感觉是这样？
在aspnet开发过程中如果想要中断当前的http处理，以前在aspnet中一直是Response.End();
在这Response.End()之后的当前请求应有的代码都不会执行了,
但是在aspnetmvc中，就算调用Response.End();还是会执行！！
//aspnet webform
if(ok)
Response.End();
//save不会继续执行
Save();
//aspnet mvc
if (ok)
Response.End();
//save会继续执行
Save();
aspnetmvc action 如何简单处理？
如果你在action中的逻辑需要中断，你可以变通的通过逻辑判断来中断，
比如：
if(ok) { //应有的逻辑
} else { //中断
} //或者
if(!ok) return Content("NO");
但是如果是在过滤器中！
protected virtual void OnActionExecuted(ActionExecutedContext filterContext);
protected virtual void OnActionExecuting(ActionExecutingContext filterContext);
protected virtual void OnAuthorization(AuthorizationContext filterContext);
protected virtual void OnException(ExceptionContext filterContext);
protected virtual void OnResultExecuted(ResultExecutedContext filterContext);
protected virtual void OnResultExecuting(ResultExecutingContext filterContext);
你的 逻辑判断 和 Response.End(); 都是无效的！
我看到很多人都是用的跳转！如果是aspnet mvc web api，你往哪里跳转？你准备返回什么数据？
正确的aspnet mvc filter Cancel Execution姿势！
那就是赋值 filterContext.Result！
例如OnActionExecuting
protected override void OnActionExecuting(ActionExecutingContext filterContext) { var headerAuth = filterContext.HttpContext.Request.Headers["_applogin_"]; if (string.IsNullOrEmpty(headerAuth)) { filterContext.Result = new ContentResult() { Content = "{code:9999,message:'no login'}", ContentEncoding = Encoding.UTF8 }; } base.OnActionExecuting(filterContext); } }
为什么赋值了Context.Result就不会继续执行后面的过滤器和action的代码？
先看下aspnetmvc源码！
aspnet mvc 源码：ControllerActionInvoker.cs
using Microsoft.Web.Infrastructure.DynamicValidationHelper;
using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Threading;
using System.Web.Mvc.Properties;
namespace System.Web.Mvc
{
/// <summary>Represents a class that is responsible for invoking the action methods of a controller.</summary>
public class ControllerActionInvoker : IActionInvoker
{
private static readonly ControllerDescriptorCache _staticDescriptorCache = new ControllerDescriptorCache();
private ModelBinderDictionary _binders;
private Func<ControllerContext, ActionDescriptor, IEnumerable<Filter>> _getFiltersThunk = new Func<ControllerContext, ActionDescriptor, IEnumerable<Filter>>(FilterProviders.Providers.GetFilters);
private ControllerDescriptorCache _instanceDescriptorCache;
/// <summary>Gets or sets the model binders that are associated with the action.</summary>
/// <returns>The model binders that are associated with the action.</returns>
protected internal ModelBinderDictionary Binders
{
get
{
if (this._binders == null)
{
this._binders = ModelBinders.Binders;
}
return this._binders;
}
set
{
this._binders = value;
}
}
internal ControllerDescriptorCache DescriptorCache
{
get
{
if (this._instanceDescriptorCache == null)
{
this._instanceDescriptorCache = ControllerActionInvoker._staticDescriptorCache;
}
return this._instanceDescriptorCache;
}
set
{
this._instanceDescriptorCache = value;
}
}
/// <summary>Initializes a new instance of the <see cref="T:System.Web.Mvc.ControllerActionInvoker" /> class.</summary>
public ControllerActionInvoker()
{
}
internal ControllerActionInvoker(params object[] filters) : this()
{
if (filters != null)
{
this._getFiltersThunk = ((ControllerContext cc, ActionDescriptor ad) =>
from f in filters
select new Filter(f, FilterScope.Action, null));
}
}
/// <summary>Creates the action result.</summary>
/// <returns>The action result object.</returns>
/// <param name="controllerContext">The controller context.</param>
/// <param name="actionDescriptor">The action descriptor.</param>
/// <param name="actionReturnValue">The action return value.</param>
protected virtual ActionResult CreateActionResult(ControllerContext controllerContext, ActionDescriptor actionDescriptor, object actionReturnValue)
{
if (actionReturnValue == null)
{
return new EmptyResult();
}
ActionResult arg_2B_0;
if ((arg_2B_0 = (actionReturnValue as ActionResult)) == null)
{
arg_2B_0 = new ContentResult
{
Content = Convert.ToString(actionReturnValue, CultureInfo.InvariantCulture)
};
}
return arg_2B_0;
}
/// <summary>Retrieves information about the controller by using the specified controller context.</summary>
/// <returns>Information about the controller.</returns>
/// <param name="controllerContext">The controller context.</param>
protected virtual ControllerDescriptor GetControllerDescriptor(ControllerContext controllerContext)
{
Type controllerType = controllerContext.Controller.GetType();
return this.DescriptorCache.GetDescriptor(controllerType, () => new ReflectedControllerDescriptor(controllerType));
}
/// <summary>Finds the information about the action method.</summary>
/// <returns>Information about the action method.</returns>
/// <param name="controllerContext">The controller context.</param>
/// <param name="controllerDescriptor">The controller descriptor.</param>
/// <param name="actionName">The name of the action.</param>
protected virtual ActionDescriptor FindAction(ControllerContext controllerContext, ControllerDescriptor controllerDescriptor, string actionName)
{
return controllerDescriptor.FindAction(controllerContext, actionName);
}
/// <summary>Retrieves information about the action filters.</summary>
/// <returns>Information about the action filters.</returns>
/// <param name="controllerContext">The controller context.</param>
/// <param name="actionDescriptor">The action descriptor.</param>
protected virtual FilterInfo GetFilters(ControllerContext controllerContext, ActionDescriptor actionDescriptor)
{
return new FilterInfo(this._getFiltersThunk(controllerContext, actionDescriptor));
}
private IModelBinder GetModelBinder(ParameterDescriptor parameterDescriptor)
{
return parameterDescriptor.BindingInfo.Binder ?? this.Binders.GetBinder(parameterDescriptor.ParameterType);
}
/// <summary>Gets the value of the specified action-method parameter.</summary>
/// <returns>The value of the action-method parameter.</returns>
/// <param name="controllerContext">The controller context.</param>
/// <param name="parameterDescriptor">The parameter descriptor.</param>
protected virtual object GetParameterValue(ControllerContext controllerContext, ParameterDescriptor parameterDescriptor)
{
Type parameterType = parameterDescriptor.ParameterType;
IModelBinder modelBinder = this.GetModelBinder(parameterDescriptor);
IValueProvider valueProvider = controllerContext.Controller.ValueProvider;
string modelName = parameterDescriptor.BindingInfo.Prefix ?? parameterDescriptor.ParameterName;
Predicate<string> propertyFilter = ControllerActionInvoker.GetPropertyFilter(parameterDescriptor);
ModelBindingContext bindingContext = new ModelBindingContext
{
FallbackToEmptyPrefix = parameterDescriptor.BindingInfo.Prefix == null,
ModelMetadata = ModelMetadataProviders.Current.GetMetadataForType(null, parameterType),
ModelName = modelName,
ModelState = controllerContext.Controller.ViewData.ModelState,
PropertyFilter = propertyFilter,
ValueProvider = valueProvider
};
object obj = modelBinder.BindModel(controllerContext, bindingContext);
return obj ?? parameterDescriptor.DefaultValue;
}
/// <summary>Gets the values of the action-method parameters.</summary>
/// <returns>The values of the action-method parameters.</returns>
/// <param name="controllerContext">The controller context.</param>
/// <param name="actionDescriptor">The action descriptor.</param>
protected virtual IDictionary<string, object> GetParameterValues(ControllerContext controllerContext, ActionDescriptor actionDescriptor)
{
Dictionary<string, object> dictionary = new Dictionary<string, object>(StringComparer.OrdinalIgnoreCase);
ParameterDescriptor[] parameters = actionDescriptor.GetParameters();
ParameterDescriptor[] array = parameters;
for (int i = 0; i < array.Length; i++)
{
ParameterDescriptor parameterDescriptor = array[i];
dictionary[parameterDescriptor.ParameterName] = this.GetParameterValue(controllerContext, parameterDescriptor);
}
return dictionary;
}
private static Predicate<string> GetPropertyFilter(ParameterDescriptor parameterDescriptor)
{
ParameterBindingInfo bindingInfo = parameterDescriptor.BindingInfo;
return (string propertyName) => BindAttribute.IsPropertyAllowed(propertyName, bindingInfo.Include.ToArray<string>(), bindingInfo.Exclude.ToArray<string>());
}
/// <summary>Invokes the specified action by using the specified controller context.</summary>
/// <returns>The result of executing the action.</returns>
/// <param name="controllerContext">The controller context.</param>
/// <param name="actionName">The name of the action to invoke.</param>
/// <exception cref="T:System.ArgumentNullException">The <paramref name="controllerContext" /> parameter is null.</exception>
/// <exception cref="T:System.ArgumentException">The <paramref name="actionName" /> parameter is null or empty.</exception>
/// <exception cref="T:System.Threading.ThreadAbortException">The thread was aborted during invocation of the action.</exception>
/// <exception cref="T:System.Exception">An unspecified error occurred during invocation of the action.</exception>
public virtual bool InvokeAction(ControllerContext controllerContext, string actionName)
{
if (controllerContext == null)
{
throw new ArgumentNullException("controllerContext");
}
if (string.IsNullOrEmpty(actionName))
{
throw new ArgumentException(MvcResources.Common_NullOrEmpty, "actionName");
}
ControllerDescriptor controllerDescriptor = this.GetControllerDescriptor(controllerContext);
ActionDescriptor actionDescriptor = this.FindAction(controllerContext, controllerDescriptor, actionName);
if (actionDescriptor != null)
{
FilterInfo filters = this.GetFilters(controllerContext, actionDescriptor);
try
{
AuthorizationContext authorizationContext = this.InvokeAuthorizationFilters(controllerContext, filters.AuthorizationFilters, actionDescriptor);
if (authorizationContext.Result != null)
{
this.InvokeActionResult(controllerContext, authorizationContext.Result);
}
else
{
if (controllerContext.Controller.ValidateRequest)
{
ControllerActionInvoker.ValidateRequest(controllerContext);
}
IDictionary<string, object> parameterValues = this.GetParameterValues(controllerContext, actionDescriptor);
ActionExecutedContext actionExecutedContext = this.InvokeActionMethodWithFilters(controllerContext, filters.ActionFilters, actionDescriptor, parameterValues);
this.InvokeActionResultWithFilters(controllerContext, filters.ResultFilters, actionExecutedContext.Result);
}
}
catch (ThreadAbortException)
{
throw;
}
catch (Exception exception)
{
ExceptionContext exceptionContext = this.InvokeExceptionFilters(controllerContext, filters.ExceptionFilters, exception);
if (!exceptionContext.ExceptionHandled)
{
throw;
}
this.InvokeActionResult(controllerContext, exceptionContext.Result);
}
return true;
}
return false;
}
/// <summary>Invokes the specified action method by using the specified parameters and the controller context.</summary>
/// <returns>The result of executing the action method.</returns>
/// <param name="controllerContext">The controller context.</param>
/// <param name="actionDescriptor">The action descriptor.</param>
/// <param name="parameters">The parameters.</param>
protected virtual ActionResult InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary<string, object> parameters)
{
object actionReturnValue = actionDescriptor.Execute(controllerContext, parameters);
return this.CreateActionResult(controllerContext, actionDescriptor, actionReturnValue);
}
internal static ActionExecutedContext InvokeActionMethodFilter(IActionFilter filter, ActionExecutingContext preContext, Func<ActionExecutedContext> continuation)
{
filter.OnActionExecuting(preContext);
if (preContext.Result != null)
{
return new ActionExecutedContext(preContext, preContext.ActionDescriptor, true, null)
{
Result = preContext.Result
};
}
bool flag = false;
ActionExecutedContext actionExecutedContext = null;
try
{
actionExecutedContext = continuation();
}
catch (ThreadAbortException)
{
actionExecutedContext = new ActionExecutedContext(preContext, preContext.ActionDescriptor, false, null);
filter.OnActionExecuted(actionExecutedContext);
throw;
}
catch (Exception exception)
{
flag = true;
actionExecutedContext = new ActionExecutedContext(preContext, preContext.ActionDescriptor, false, exception);
filter.OnActionExecuted(actionExecutedContext);
if (!actionExecutedContext.ExceptionHandled)
{
throw;
}
}
if (!flag)
{
filter.OnActionExecuted(actionExecutedContext);
}
return actionExecutedContext;
}
/// <summary>Invokes the specified action method by using the specified parameters, controller context, and action filters.</summary>
/// <returns>The context for the ActionExecuted method of the <see cref="T:System.Web.Mvc.ActionFilterAttribute" /> class.</returns>
/// <param name="controllerContext">The controller context.</param>
/// <param name="filters">The action filters.</param>
/// <param name="actionDescriptor">The action descriptor.</param>
/// <param name="parameters">The parameters.</param>
protected virtual ActionExecutedContext InvokeActionMethodWithFilters(ControllerContext controllerContext, IList<IActionFilter> filters, ActionDescriptor actionDescriptor, IDictionary<string, object> parameters)
{
ActionExecutingContext preContext = new ActionExecutingContext(controllerContext, actionDescriptor, parameters);
Func<ActionExecutedContext> seed = () => new ActionExecutedContext(controllerContext, actionDescriptor, false, null)
{
Result = this.InvokeActionMethod(controllerContext, actionDescriptor, parameters)
};
Func<ActionExecutedContext> func = filters.Reverse<IActionFilter>().Aggregate(seed, (Func<ActionExecutedContext> next, IActionFilter filter) => () => ControllerActionInvoker.InvokeActionMethodFilter(filter, preContext, next));
return func();
}
/// <summary>Invokes the specified action result by using the specified controller context.</summary>
/// <param name="controllerContext">The controller context.</param>
/// <param name="actionResult">The action result.</param>
protected virtual void InvokeActionResult(ControllerContext controllerContext, ActionResult actionResult)
{
actionResult.ExecuteResult(controllerContext);
}
internal static ResultExecutedContext InvokeActionResultFilter(IResultFilter filter, ResultExecutingContext preContext, Func<ResultExecutedContext> continuation)
{
filter.OnResultExecuting(preContext);
if (preContext.Cancel)
{
return new ResultExecutedContext(preContext, preContext.Result, true, null);
}
bool flag = false;
ResultExecutedContext resultExecutedContext = null;
try
{
resultExecutedContext = continuation();
}
catch (ThreadAbortException)
{
resultExecutedContext = new ResultExecutedContext(preContext, preContext.Result, false, null);
filter.OnResultExecuted(resultExecutedContext);
throw;
}
catch (Exception exception)
{
flag = true;
resultExecutedContext = new ResultExecutedContext(preContext, preContext.Result, false, exception);
filter.OnResultExecuted(resultExecutedContext);
if (!resultExecutedContext.ExceptionHandled)
{
throw;
}
}
if (!flag)
{
filter.OnResultExecuted(resultExecutedContext);
}
return resultExecutedContext;
}
/// <summary>Invokes the specified action result by using the specified action filters and the controller context.</summary>
/// <returns>The context for the ResultExecuted method of the <see cref="T:System.Web.Mvc.ActionFilterAttribute" /> class.</returns>
/// <param name="controllerContext">The controller context.</param>
/// <param name="filters">The action filters.</param>
/// <param name="actionResult">The action result.</param>
protected virtual ResultExecutedContext InvokeActionResultWithFilters(ControllerContext controllerContext, IList<IResultFilter> filters, ActionResult actionResult)
{
ResultExecutingContext preContext = new ResultExecutingContext(controllerContext, actionResult);
Func<ResultExecutedContext> seed = delegate
{
this.InvokeActionResult(controllerContext, actionResult);
return new ResultExecutedContext(controllerContext, actionResult, false, null);
};
Func<ResultExecutedContext> func = filters.Reverse<IResultFilter>().Aggregate(seed, (Func<ResultExecutedContext> next, IResultFilter filter) => () => ControllerActionInvoker.InvokeActionResultFilter(filter, preContext, next));
return func();
}
/// <summary>Invokes the specified authorization filters by using the specified action descriptor and controller context.</summary>
/// <returns>The context for the <see cref="T:System.Web.Mvc.AuthorizeAttribute" /> object.</returns>
/// <param name="controllerContext">The controller context.</param>
/// <param name="filters">The authorization filters.</param>
/// <param name="actionDescriptor">The action descriptor.</param>
protected virtual AuthorizationContext InvokeAuthorizationFilters(ControllerContext controllerContext, IList<IAuthorizationFilter> filters, ActionDescriptor actionDescriptor)
{
AuthorizationContext authorizationContext = new AuthorizationContext(controllerContext, actionDescriptor);
foreach (IAuthorizationFilter current in filters)
{
current.OnAuthorization(authorizationContext);
if (authorizationContext.Result != null)
{
break;
}
}
return authorizationContext;
}
/// <summary>Invokes the specified exception filters by using the specified exception and controller context.</summary>
/// <returns>The context for the <see cref="T:System.Web.Mvc.HandleErrorAttribute" /> object.</returns>
/// <param name="controllerContext">The controller context.</param>
/// <param name="filters">The exception filters.</param>
/// <param name="exception">The exception.</param>
protected virtual ExceptionContext InvokeExceptionFilters(ControllerContext controllerContext, IList<IExceptionFilter> filters, Exception exception)
{
ExceptionContext exceptionContext = new ExceptionContext(controllerContext, exception);
foreach (IExceptionFilter current in filters.Reverse<IExceptionFilter>())
{
current.OnException(exceptionContext);
}
return exceptionContext;
}
internal static void ValidateRequest(ControllerContext controllerContext)
{
if (controllerContext.IsChildAction)
{
return;
}
HttpContext current = HttpContext.Current;
if (current != null)
{
ValidationUtility.EnableDynamicValidation(current);
}
controllerContext.HttpContext.Request.ValidateInput();
}
}
}
附上简单注释：
/// <summary>
/// 执行一个 控制器方法
/// </summary>
/// <param name="controllerContext"></param>
/// <param name="actionName"></param>
/// <returns></returns>
public virtual bool InvokeAction(ControllerContext controllerContext, string actionName)
{
if (controllerContext == null)
{
throw new ArgumentNullException("controllerContext");
}
if (string.IsNullOrEmpty(actionName))
{
throw new ArgumentException(MvcResources.Common_NullOrEmpty, "actionName");
}
//根据请求获取控制信息
ControllerDescriptor controllerDescriptor = this.GetControllerDescriptor(controllerContext);
//根据请求和控制器获取action信息
ActionDescriptor actionDescriptor = this.FindAction(controllerContext, controllerDescriptor, actionName);
//action不为空
if (actionDescriptor != null)
{
//获取或滤器信息
FilterInfo filters = this.GetFilters(controllerContext, actionDescriptor);
try
{
//获取aspnetmvc自带的Authorization信息
AuthorizationContext authorizationContext = this.InvokeAuthorizationFilters(controllerContext, filters.AuthorizationFilters, actionDescriptor);
//这里我们可以看到，在授权的代码里面也可以赋值，当在获取授权时赋值了Result,当前执行会被返回Result，action的代码和过滤器的代码将不会执行
if (authorizationContext.Result != null)
{
this.InvokeActionResult(controllerContext, authorizationContext.Result);
}
else
{
//判断请求数据验证
if (controllerContext.Controller.ValidateRequest)
{
ControllerActionInvoker.ValidateRequest(controllerContext);
}
//获取请求参数
IDictionary<string, object> parameterValues = this.GetParameterValues(controllerContext, actionDescriptor);
//获取执行上下文
ActionExecutedContext actionExecutedContext = this.InvokeActionMethodWithFilters(controllerContext, filters.ActionFilters, actionDescriptor, parameterValues);
//开始执行过滤器和action
this.InvokeActionResultWithFilters(controllerContext, filters.ResultFilters, actionExecutedContext.Result);
}
}
catch (ThreadAbortException)
{
throw;
}
catch (Exception exception)
{
ExceptionContext exceptionContext = this.InvokeExceptionFilters(controllerContext, filters.ExceptionFilters, exception);
if (!exceptionContext.ExceptionHandled)
{
throw;
}
this.InvokeActionResult(controllerContext, exceptionContext.Result);
}
return true;
}
return false;
}
//执行过滤器和action
// System.Web.Mvc.ControllerActionInvoker
protected virtual ActionExecutedContext InvokeActionMethodWithFilters(ControllerContext controllerContext, IList<IActionFilter> filters, ActionDescriptor actionDescriptor, IDictionary<string, object> parameters)
{
ActionExecutingContext preContext = new ActionExecutingContext(controllerContext, actionDescriptor, parameters);
Func<ActionExecutedContext> seed = () => new ActionExecutedContext(controllerContext, actionDescriptor, false, null)
{
//执行action
Result = this.InvokeActionMethod(controllerContext, actionDescriptor, parameters)
};
//反序filters，以active执行的seed为基础，累加计算filters得到一个 ActionExecutedContext
//这里面就是重点了，大概的意思是先执行所有过滤器，最后执行active，如果中途过滤器产生了Context.Result，则不会继续执行后面的过滤器和active，
Func<ActionExecutedContext> func = filters.Reverse<IActionFilter>()
.Aggregate(seed, (Func<ActionExecutedContext> next, IActionFilter filter) =>
() => ControllerActionInvoker.InvokeActionMethodFilter(filter, preContext, next));
return func();
}
// System.Web.Mvc.ControllerActionInvoker
internal static ActionExecutedContext InvokeActionMethodFilter(IActionFilter filter, ActionExecutingContext preContext, Func<ActionExecutedContext> continuation)
{
//调用OnActionExecuting
filter.OnActionExecuting(preContext);
if (preContext.Result != null)
{
return new ActionExecutedContext(preContext, preContext.ActionDescriptor, true, null)
{
Result = preContext.Result
};
}
bool flag = false;
ActionExecutedContext actionExecutedContext = null;
try
{
//真正的执行action
actionExecutedContext = continuation();
}
catch (ThreadAbortException)
{
actionExecutedContext = new ActionExecutedContext(preContext, preContext.ActionDescriptor, false, null);
filter.OnActionExecuted(actionExecutedContext);
throw;
}
catch (Exception exception)
{
flag = true;
actionExecutedContext = new ActionExecutedContext(preContext, preContext.ActionDescriptor, false, exception);
filter.OnActionExecuted(actionExecutedContext);
if (!actionExecutedContext.ExceptionHandled)
{
throw;
}
}
if (!flag)
{
filter.OnActionExecuted(actionExecutedContext);
}
return actionExecutedContext;
}
从以上代码我们可以看出，一个action的执行流程是这样的：
1>根据请求获取Controller和action的信息
2>获取应该有的过滤器
3>Authorization验证，如果不通过则返回
4>ValidateRequest,验证请求数据
5>执行过滤器和active，如果在中途过滤器产生Result，则后面的过滤器和active将不会执行！
所以，最正确的方法就是在过滤器中赋值Result！