MVC4的WebAPI进程启动 [英] MVC4 WebApi process launcher
问题描述
我有一个的 MVC4 REST API 的试图启动一个进程在一个新的线程。我正与框架4.5，并尝试使用同步，等待clausules。
I have a MVC4 API REST trying to launch a process in a new thread. I am working with framework 4.5 and trying to use sync and await clausules.
我的code是这样的：
My code looks like:
[AcceptVerbs("POST")]
public HttpResponseMessage Launch(string id)
{
runProcessAsync(id); // 1
return Request.CreateResponse(HttpStatusCode.Accepted); // 2
}
protected async void runProcessAsync(string id)
{
int exitcode = await runProcess(id); // 3
string exitcodesz = string.Format("exitcode: {0}", exitcode); // 4
// do more stuff with exitcode
}
protected Task<int> runProcess(string id)
{
var tcs = new TaskCompletionSource<int>();
var process = new Process
{
StartInfo = { FileName = @"C:\a_very_slow_task.bat" },
EnableRaisingEvents = true
};
process.Exited += (sender, args) => tcs.SetResult(((Process)sender).ExitCode);
process.Start();
return tcs.Task;
}
}
在理想情况下，有人会执行API REST调用（/任务/ slowtask /发射）与POST谓词和期望202（接受）非常快的。
Ideally, someone will perform a api rest call ( /task/slowtask/launch ) with POST verb and expect a 202 (accepted) very fast.
使用招网络调试我提出的要求，code进入启动（// 1），然后去计谋（// 3），缓慢的任务是创建并启动和接受返回（ // 2）。但在这一点上，提琴手不显示202的结果。见所附图片：
Using Fiddler Web Debugger I make the request, the code enters into Launch (// 1), then goes to the await (// 3), the slow task is created and started and a Accepted is returned (// 2). But at this point, Fiddler doesn't show the 202 result. See attached image:
<一个href="http://imageshack.us/photo/my-images/703/fiddler1.png/">http://imageshack.us/photo/my-images/703/fiddler1.png/
在缓慢的任务结束后，code继续捕捉退出code（// 4），然后在202被捕获到提琴手。
When the slow task ends, the code continues capturing the exitcode (// 4) and then the 202 is captured into Fiddler.
这是非常奇怪的，因为我做了回很久以前。我缺少的是什么？我如何改变才能返回202非常快，忘了任务code。
That is very weird, because I did the return long time ago. What I am missing? how can I change that code in order to return a 202 very fast and forget about the task.
注意：我知道如何与非框架4.5的功能做到这一点，我想学习如何使用异步/计谋。
Note: I know how to do this with non framework 4.5 features, I am trying to learn how to use async / await.
推荐答案
我想这是因为 runProcessAsync（）运行在请求的同步环境。如果你不希望出现这种情况，你可以使用 Task.Run（（）=＆GT; runProcessAsync（ID））; 。但要小心，因为IIS可以在这段时间内回收您的AppDomain，所以有机会的话 runProcessAsync（）将无法完成。
I think this is because runProcessAsync() runs on the request's synchronization context. If you don't want that, you can use Task.Run(() => runProcessAsync(id));. But be careful with this, because IIS can recycle your AppDomain during that time, so there is a chance runProcessAsync() won't complete.
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