我有一个MVC5应用程序.有一个特定的操作可以处理上传的大型CSV文件,有时在此任务期间需要用户提供其他信息.例如,在第5行,软件需要向用户显示他确实想要用它做什么,等等.在
Winforms环境中,这很容易,但我不知道如何在网上实现相同的功能. .
我更喜欢同步方式,以便在确认之前阻止服务器线程.否则我觉得我必须完全重写逻辑.
让事情变得更加困难的是,我不仅需要简单的确认,而且还会不时地为用户提供更复杂的选择,这些选择无法在客户端同步实现(只有原生的简单确认)是同步AFAIK).
任何建议或提示将不胜感激,更完整的简短指南.
例
在这个例子中,客户端调用一个返回数字0,1,2,…,99,100的方法.假设我们的用户可能讨厌5个可分割的数字.我们需要实现一个允许用户使用的功能如果他们这样做,就排除这些数字.用户不喜欢为未来做好计划,因此他们希望在处理过程中实时选择他们喜欢的数字.
[Controller]
public enum ConfirmResult {
Yes = 0,
No = 1,
YesToAll = 2,
NoToAll = 3
}
...
public JsonResult SomeProcessingAction() {
var result = new List<int>();
for (int i = 0; i <= 100; i++) {
if (i%5==0) {
// sketch implementation for example purposes
if (Confirm(string.Format("The number {0} is dividable by 5. Are you sure you want to include it?", i) == ConfirmResult.No)
continue;
}
result.Add(i);
}
return Json(result);
}
public ConfirmResult Confirm(string message) {
// ... show confirm message on client-side and block until the response comes back... or anything else
}
[Javascript]
// sketch...
$.post('mycontroller/someprocessing', function(result) {
$('#results').text("Your final numbers: " + result.join(', '));
});
最佳答案 我把一个例子放在一起,然后把它放在github上让你看一看.
MVC5 long running input-required example.
请注意,这不一定是设计此方法的最佳方式.这是我最初的方法,没有经过深思熟虑.可能存在更灵活或更复杂或更推荐的模式.
基本上它只是在更改时将Job的状态存储在数据库中(在示例中使用Entity Framework).
与某些类型的长期运行的“同步”方法相比,持久化到磁盘或数据库具有明显的优势.
>它在等待输入时不会锁定资源
>在发生崩溃或服务器超时的情况下,它可以防止数据丢失
>如果您希望在扩展环境中运行或恢复,或者在完全不同的服务器(例如,非前置VM)上,它可以提供灵活性.
>它可以更好地管理当前正在运行的作业.
对于这个例子,我选择不使用Signalr,因为它不会增加重要的价值.在长时间运行的作业(例如,5分钟)的情况下,亚秒响应不会增加用户体验.我建议你每1-2秒从javascript轮询一次.更简单.
请注意,一些代码是非常hackish;例如,在ResumableJobState表上复制输入字段.
流程可能看起来像这样,
>上传文件>在我的例子中返回文件名//不是impl
>调用StartJob(文件名)>返回(Json)Job
>民意调查GetJobState(jobId)>返回(Json)Job
>如果填充了(Json)Job.RequiredInputType,则向用户显示适当的表单以将输入发回
>使用适当形式的正确输入类型调用PostInput
>工作将恢复
这是主JobController的转储.
public class JobController : Controller
{
private Context _context;
private JobinatorService _jobinatorService;
public JobController()
{
_context = new Context();
_jobinatorService = new JobinatorService(_context);
}
public ActionResult Index()
{
ViewBag.ActiveJobs = _context.LongRunningJobs.Where(t => t.State != "Completed").ToList();//TODO, filter by logged in User
return View();
}
[HttpPost]
public JsonResult StartJob(string filename)//or maybe you've already uploaded and have a fileId instead
{
var jobState = new ResumableJobState
{
CurrentIteration = 0,
InputFile = filename,
OutputFile = filename + "_output.csv"
};
var job = new LongRunningJob
{
State = "Running",
ResumableJobState = jobState
};
_context.ResumableJobStates.Add(jobState);
_context.LongRunningJobs.Add(job);
var result = _context.SaveChanges();
if (result == 0) throw new Exception("Error saving to database");
_jobinatorService.StartOrResume(job);
return Json(job);
}
[HttpGet]
public JsonResult GetJobState(int jobId)
{
var job = _context.LongRunningJobs.Include("ResumableJobState.RequiredInputType").FirstOrDefault(t => t.Id == jobId);
if (job == null)
throw new HttpException(404, "No job found with that Id");
return Json(job, JsonRequestBehavior.AllowGet);
}
[HttpPost]
public JsonResult PostInput(int jobId, RequiredInputType userInput)
{
if (!ModelState.IsValid)
throw new HttpException(500, "Bad input");
var job = _context.LongRunningJobs.Include("ResumableJobState.RequiredInputType").FirstOrDefault(t => t.Id == jobId);
job.ResumableJobState.BoolInput = userInput.BoolValue;
job.ResumableJobState.IntInput = userInput.IntValue;
job.ResumableJobState.FloatInput = userInput.FloatValue;
job.ResumableJobState.StringInput = userInput.StringValue;
_context.SaveChanges();
if (job == null)
throw new HttpException(404, "No job found with that Id");
if (userInput.InputName == job.ResumableJobState.RequiredInputType.InputName)//Do some checks to see if they provided input matching the requirements
_jobinatorService.StartOrResume(job);
//TODO have the jobinator return the State after it's resumed, otherwise we need another Get to check the state.
return Json(job);
}
/// <summary>
/// Stuff this in it's own service. This way, you could use it in other places; for example starting scheduled jobs from a cron job
/// </summary>
public class JobinatorService//Ideally use Dependency Injection, or something good practicey to get an instance of this
{
private Context _context = new Context();
private string _filePath = "";
public JobinatorService(Context context)
{
_context = context;
_filePath = AppDomain.CurrentDomain.GetData("DataDirectory").ToString() + "/";
}
public void StartOrResume(LongRunningJob job)
{
Task.Run(() =>
{
using (var inputFile = System.IO.File.OpenRead(_filePath + job.ResumableJobState.InputFile))
using (var outputFile = System.IO.File.OpenWrite(_filePath + job.ResumableJobState.OutputFile))
{
inputFile.Position = job.ResumableJobState.CurrentIteration;
for (int i = (int)inputFile.Position; i < inputFile.Length; i++)//casting long to int, what could possibly go wrong?
{
if (job.State == "Input Required" && job.ResumableJobState.RequiredInputType != null)
{//We needed input and received it
//You might want to do a switch..case on the various inputs, and branch into different functions
if (job.ResumableJobState.RequiredInputType.InputName == "6*7")
if (job.ResumableJobState.RequiredInputType.IntValue.Value == 42)
break;//Pass Go, collect 42 dollars;
}
outputFile.WriteByte((byte)inputFile.ReadByte());//Don't try this at home!
job.ResumableJobState.CurrentIteration = i;//or row, or line, or however you delimit processing
job.ResumableJobState.InputFileBufferReadPosition = inputFile.Position;//or something
if (i % 7 == 0)
job.ResumableJobState.RequiredInputType = _context.RequiredInputTypes.First(t => t.InputName == "Row 7 Input");
if (i % 42 == 0)
job.ResumableJobState.RequiredInputType = _context.RequiredInputTypes.First(t => t.InputName == "6*7");
if (job.ResumableJobState.RequiredInputType != null)
job.State = "Input Required";
_context.SaveChanges();
if (job.State != "Running")
return;
}
job.State = "Completed";
_context.SaveChanges();
}
});
return;
}
}
}
