发布于 2016-06-29 01:46:30 | 143 次阅读 | 评论: 0 | 来源: 网友投递
ASP.NET
ASP.NET 是.NET FrameWork的一部分,是一项微软公司的技术,是一种使嵌入网页中的脚本可由因特网服务器执行的服务器端脚本技术,它可以在通过HTTP请求文档时再在Web服务器上动态创建它们。 指 Active Server Pages(动态服务器页面) ,运行于 IIS(Internet Information Server 服务,是Windows开发的Web服务器)之中的程序 。
根据controller的名字正确的实例化了一个controller对象。回到MVCHandler的BeginProcessRequest方法,可以看到,当得到controller对象之后,首先判断它是不是IAsyncController,如果是则会创建委托用来异步执行。通常情况下,我们都是继承自Controller类,这不是一个IAsyncController,于是会直接执行Controller的Execute方法。Execute方法是在Controller的基类ControllerBase中定义的,这个方法除去一些安全检查,初始化了ControllerContext(包含了ControllerBase和Request的信息),核心是调用了ExecuteCore方法,这在ControllerBase是个抽象方法,在Controller类中有实现:
protected override void ExecuteCore() {
PossiblyLoadTempData();
try {
string actionName = RouteData.GetRequiredString("action");
if (!ActionInvoker.InvokeAction(ControllerContext, actionName)) {
HandleUnknownAction(actionName);
}
}
finally {
PossiblySaveTempData();
}}
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 = GetControllerDescriptor(controllerContext);
ActionDescriptor actionDescriptor = FindAction(controllerContext, controllerDescriptor, actionName);
if (actionDescriptor != null) {
FilterInfo filterInfo = GetFilters(controllerContext, actionDescriptor);
try {
AuthorizationContext authContext = InvokeAuthorizationFilters(controllerContext, filterInfo.AuthorizationFilters, actionDescriptor);
if (authContext.Result != null) {
// the auth filter signaled that we should let it short-circuit the request
InvokeActionResult(controllerContext, authContext.Result);
}
else {
if (controllerContext.Controller.ValidateRequest) {
ValidateRequest(controllerContext);
}
IDictionary<string, object> parameters = GetParameterValues(controllerContext, actionDescriptor);
ActionExecutedContext postActionContext = InvokeActionMethodWithFilters(controllerContext, filterInfo.ActionFilters, actionDescriptor, parameters);
InvokeActionResultWithFilters(controllerContext, filterInfo.ResultFilters, postActionContext.Result);
}
}
catch (ThreadAbortException) {
// This type of exception occurs as a result of Response.Redirect(), but we special-case so that
// the filters don't see this as an error.
throw;
}
catch (Exception ex) {
// something blew up, so execute the exception filters
ExceptionContext exceptionContext = InvokeExceptionFilters(controllerContext, filterInfo.ExceptionFilters, ex);
if (!exceptionContext.ExceptionHandled) {
throw;
}
InvokeActionResult(controllerContext, exceptionContext.Result);
}
return true;
}
// notify controller that no method matched
return false;}
private void PopulateLookupTables() {
MethodInfo[] allMethods = ControllerType.GetMethods(BindingFlags.InvokeMethod | BindingFlags.Instance | BindingFlags.Public);
MethodInfo[] actionMethods = Array.FindAll(allMethods, IsValidActionMethod);
AliasedMethods = Array.FindAll(actionMethods, IsMethodDecoratedWithAliasingAttribute);
NonAliasedMethods = actionMethods.Except(AliasedMethods).ToLookup(method => method.Name, StringComparer.OrdinalIgnoreCase);
}FindActionMethod方法如下:
public MethodInfo FindActionMethod(ControllerContext controllerContext, string actionName) {
List<MethodInfo> methodsMatchingName = GetMatchingAliasedMethods(controllerContext, actionName);
methodsMatchingName.AddRange(NonAliasedMethods[actionName]);
List<MethodInfo> finalMethods = RunSelectionFilters(controllerContext, methodsMatchingName);
switch (finalMethods.Count) {
case 0:
return null;
case 1:
return finalMethods[0];
default:
throw CreateAmbiguousMatchException(finalMethods, actionName);
} }
static FilterProviders() {
Providers = new FilterProviderCollection();
Providers.Add(GlobalFilters.Filters);
Providers.Add(new FilterAttributeFilterProvider());
Providers.Add(new ControllerInstanceFilterProvider());
}
Filter Type | Interface | Description |
Authorization | IAuthorizationFilter | Runs first |
Action | IActionFilter | Runs before and after the action method |
Result | IResultFilter | Runs before and after the result is executed |
Exception | IExceptionFilter | Runs if another filter or action method throws an exception |
protected virtual AuthorizationContext InvokeAuthorizationFilters(ControllerContext controllerContext, IList<IAuthorizationFilter> filters, ActionDescriptor actionDescriptor) {
AuthorizationContext context = new AuthorizationContext(controllerContext, actionDescriptor);
foreach (IAuthorizationFilter filter in filters) {
filter.OnAuthorization(context);
if (context.Result != null) {
break;
}
}
return context;}
protected virtual ActionExecutedContext InvokeActionMethodWithFilters(ControllerContext controllerContext, IList<IActionFilter> filters, ActionDescriptor actionDescriptor, IDictionary<string, object> parameters) {
ActionExecutingContext preContext = new ActionExecutingContext(controllerContext, actionDescriptor, parameters);
Func<ActionExecutedContext> continuation = () =>
new ActionExecutedContext(controllerContext, actionDescriptor, false /* canceled */, null /* exception */) {
Result = InvokeActionMethod(controllerContext, actionDescriptor, parameters)
};
// need to reverse the filter list because the continuations are built up backward
Func<ActionExecutedContext> thunk = filters.Reverse().Aggregate(continuation,
(next, filter) => () => InvokeActionMethodFilter(filter, preContext, next));
return thunk();
}
static void AggTest()
{
int[] data = { 1, 2, 3, 4 };
var res = data.Aggregate("String", (str, val) => str + val.ToString());
Console.WriteLine(res);
}
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 /* canceled */, null /* exception */) {
Result = preContext.Result
};
}
bool wasError = false;
ActionExecutedContext postContext = null;
try {
postContext = continuation();
}
catch (ThreadAbortException) {
// This type of exception occurs as a result of Response.Redirect(), but we special-case so that
// the filters don't see this as an error.
postContext = new ActionExecutedContext(preContext, preContext.ActionDescriptor, false /* canceled */, null /* exception */);
filter.OnActionExecuted(postContext);
throw;
}
catch (Exception ex) {
wasError = true;
postContext = new ActionExecutedContext(preContext, preContext.ActionDescriptor, false /* canceled */, ex);
filter.OnActionExecuted(postContext);
if (!postContext.ExceptionHandled) {
throw;
}
}
if (!wasError) {
filter.OnActionExecuted(postContext);
}
return postContext;
}
f3.Executing->f2.Executing->f1.Exectuing->InvokeActionMethod->f1.Executed->f2->Executed->f3.Executed.
public object Execute(ControllerBase controller, object[] parameters) {
return _executor(controller, parameters);
}
public object Execute(ControllerBase controller, object[] parameters) {
return MethodInfo.Invoke(controller, parameters);
//return _executor(controller, parameters);
}