What if I have website with a button. User clicks on the button and starts a long running process. After a few hours (or minutes) user update webpage and see results. What is the best (and any other) way to implement long running operation on website?
From the user experience point of view I suggest you implement the job like you would implement order handling in an online shop.
When the user starts the job he should be able to track the state of the job. Is the job complete? Did the job fail? What is the progress of the job? He should probably also be able to cancel the job and perhaps modify properties of the job. You could implement an notification mechanism using e-mail or an SMS and the user should be able to control that.
By using JavaScript/AJAX you can provide a more interactive user experience where the job status web page is automatically refreshed at regular intervals in the background without forcing the user to refresh his browser.
The user should be able to leave his computer and later connect to the website from another computer and still be able to get information about pending and completed jobs. This requires some form of user login.
I suggest that you separate the job handling code from the website code. You could expose the job handling user a web service or another similar technology. The website should query the service and display the results providing a user interface on top of the job service.
How long? If it's really going to take hours, you don't want that code running in the web server. Have the server spawn an external process or start a service or something along that line, and put the long running code in there.
You could have that code put status updates somewhere (like in the database) as it runs, and the website can check that when the user comes back to see how it's doing.
I suggest you read up on Threading in asp.Net. For website performance, time consuming processes can be put on a different thread.
A different approach is executing the task with AJAX. This way, you can present the user interface to the user, and start an asynchronous process which handles the request.
Related
My requirement is to create a website in which any number of user can login and click on a button. The task inside that button click will be a long running process (May take hours or days to finish the task). User can logout from the website and can login occasionally to check the status of the task.Is it good to use the idea in this article. Please give some suggestion on this.
Thanks.
MSMQ or SQL Service Broker used to communicate with a Windows Service.
asp.net page sends start request
------------MSMQ------------>
Windows service picks up message
and starts the long running job.
As progress is made, it can be
recorded in a "Jobs" table
client checks status from the Jobs table
IIS app pool recycles
.... days pass
Service completes work, and records
the job as Completed
Service might send email notification
with a link to the webpage
client can later retrieve the rendered job
If you really must stay within IIS, I would still use MSMQ or SQL Server, but you would just have to put your service code in Application_Start.
I am trying to write a website and now I need to do a specific method one per month(at the end of the every month).
Imagine that the method is Method A().
I want to run it at the end of the every month.
So now how to run it ?
UPDATE:
The mission of the website is something else.Just in a part of it I need to do this.
I dont know but I guess maybe running the method in application start at the end of the every month can solve it but I am not sure that its the way or not.
ASP.NET MVC is for writing web applications, not scheduled tasks.
Web applications are architected as request/response systems. They are not suited for background tasks which need to happen at regular intervals. They receive a request, respond to that request, and are done. While idle a web application is subject to the web server's resource management, which could include shutting it down entirely while waiting for the next request.
Instead, what you'll want to use is either a Windows Service or a Console Application (invoked by a task scheduler, such as the one that comes with Windows). This would run continuously in the background or at regular intervals, respectively. This application can be very small, just calling that one method and nothing else.
In short... If you want to run the code in response to a user request then a web application will do the job. If you want to run the code at regular intervals regardless of user requests then a scheduled task is what you want.
Well, that seems like something that doesn't belong on the web site. i.e. it shouldn't be run within ASP.NET anywhere. Maybe it should be run in a back office, or a service that's running on the back end or a database job or a scheduled task. But if all you have is the one job, it would probably be easier to have a button that when pushed calls the method A(), and have it in a logged in portion of the website with some sort rights check to ensure no one but the correct people press it. And you could also put checks, within the method to ensure it's only run once a month. If you can be sure that the rest of the website is being used, you could put in other methods a CheckToSeeIfIShouldCallMethodA method, but all of these seem like worse options than something that runs on the back end.
I have written a web application in asp.net. It has some user roles. There are 3 roles which are Manager, Accountant and Employee. The employees write their expenses in a form and send it to Manager. When manager approves it, it'll be sent to Accountant to pay it. I need to have an idea that when manager doesn't approve the employee's expense in 48 hours, it should send an automatic e-mail to Manager's mail.
I thought that I can write another small console application to handle that by checking every hour. But it would waste resources and decrease performance.
I need a good idea to handle that. How should I do?
There are several options, but if I were you I would go with first or second options.
Console App & scheduler
I would create that console application that every time is run perform the check for you.
Then I will have it run using Windows Scheduler in a daily basis (at 00:05) or a hourly basis if you prefer so. This way Windows Scheduler daemon will launch it every hour and the rest of the time your app is not running.
Check this Microsoft link to see how a scheduled task is created in windows.
Restful Web Service & scheduler
As suggested in #marapet answer, having a restful web service that allow you to perform this action instead of a console application would give you the advantage of having all code in your web application.
Similar as previous one, you should only invoke the restful uri to have your action done. As possible disadvantage, you have to get sure that that uri is not accessible to end users. In usual architecture (Web Server --> Application Server --> DB) this restful service should be in the Application Servers, far away from end user access.
Windows Service
Another option is creating a Windows Service that runs all the time and check the time itself so every hour perform the job (maybe using Quartz or similar). But this does not meet your performance requirements.
The performance hit will be small anyway as your service should check every minute to see if an hour has pass and is time to do its job.. a task pretty easy.
The advantage is that a windows service is easier to control and monitor than a Scheduled tasks
DB job
Yet another option... If your app uses SQL Server you can have a t-sql job that runs daily or hourly. I wouldn't recommend this option unless you really have performance problems.
The problem with this is that you would be splitting the logic and responsibilities of your code. A future developer or admin would find hard to maintain your app.
If you'd like to keep the logic within the web application for simplicity (depending on the total size of your solution, this may or may not be desired):
For a given URL, have the web app check for due approvals and sends emails out if needed. Be sure to keep track of emails sent in order to prevent sending the same email multiple times.
Call this URL in a regular interval. You may use a scheduled task or a third party url monitoring service to do this.
You may call the URL with a simple VBScript (or wget, or curl, or powershell, or whatever is fastest for you), which in turn you can automate by using the task scheduler (see also).
An example script in vbscript for calling an URL:
Function LoadUrl(url)
Dim objRequest
Set objRequest = CreateObject("MSXML2.ServerXMLHTTP.6.0")
objRequest.open "POST", url , false
objRequest.Send
LoadUrl = objRequest.responseText
Set objRequest = Nothing
End Function
Checking every hour won't affect performance. Even checking every minute is probably fine, depending on your database. The simplest option is a console program fired as a Scheduled Task. You can also try a Windows Service but they're a bit trickier.
Also give some thought how you'll count the 48 hours. If an employee puts in expenses just before the weekend then 48 hours will probably elapse every time and you'll end up with a manager having lots of emails in their Inbox on Monday morning. That could cause some friction :)
I want to Scheduling in Asp.net
I have following options to implement this
To write SQLServer JOB(I dont want to do this.Dont want to go outside of .Net environment)
Second option is I will write windows service and this window service will call asp.net
webservice then this webservice calls asp.net method
(I also dont need to do this because my hosting provider might not be allow me to install
window service)
Third option is I call my scheduling method in Application_Start event in global class
(Drawback is, webserver will kill thread any time )
To call Scheduling Code in Page_Load event of Home Page(Might be nobody visits my website for hours
,Also page execution might be slow due to scheduling code)
I also found some online services that calls your page at given interval,some are given below
http://www.cronservice.co.uk/new/
http://scheduler.codeeffects.com
Anybody give me bettor solution of this and also explain why it is bettor?
Thanks in Advance
The ASP.NET application isn't the right place to implement scheduling. I would suggest creating a service or a scheduled task that runs in short intervals.
You don't have many options in a shared hosting environment. My host (WinHost) allows remote access to their database, so I was able to create an executable that ran on a local server with Task Scheduler.
The performance isn't great since the database is accessed over the internet, but it's still better than attempting to run pseudo scheduled tasks with ASP.NET.
Some hosts also offer a service that will request a url within your site on a scheduled basis. However, this didn't work for me because the task I had to run took longer than the request timeout.
There is no one solution that fits all. SQL jobs and windows jobs (scheduled thru windows task scheduler) are very widely used. In one of my previous work places they had jobs that ran on multiple platforms (mainframe,windows,sql server). Failure in some of these jobs, would cost in thousands by the day. So they employed something called ESP. This software monitored jobs on all platforms and sent a message to the control room in case of a failure.
If you throw some more light on the requirement, we might be able to help you better.
ASP.NET is not the right place to house your Scheduled Tasks. I'm using Quartz.net when I have to create Scheduled Tasks.
Create a page that launches your task and place it at the URL http://www.mydomain.com/runtask.
Create a scheduled task on your home PC that sends a request to http://www.mydomain.com/runtask.
You'll need to keep your home PC on all the time.
Ideally I would go with number 1 as you get full control/history/error reporting etc. You can write an SSIS job in .NET and have SQL server schedule it.
However, I have had a similar problem with shared hosting that is very restrictive. What I did was create a page which runs the process on page load (using validation in the querystring for security). I then used a machine I have which is always on to schedule a Windows Task Scheduler (this is part of Windows as standard) to call a bit of VB script that opens the browser and then shuts it.
A client came to me with a request to have a web app that does a lot of processing in the backend (reads from a file, writes to a web service). My question is that since this "process" (when the user clicks 'Go') may take hours, how do I make it so the processing continues after the user closes the web page? Please let me know if this does not make any sense and I can give more information. Any help would be greatly appreciated, thanks!
You have to create MS Windows Service for it.
You have provide for that Service some database table which client is going to use by your Website functionality.
This is, basically, a "batch job" requirement, and that's how I suggest that you approach it.
The client would use the web-page, not to perform the work, but rather to manage the list of batch jobs that are performing the work .. scheduling them, starting or stopping them, viewing their status and current output, and so on. (Yup, just like they did it in the 1970's, but without "//FOOBAR JOB (123,456)" ... thank god.
The user goes to the web-page and enters a request. A back-end service process on the host (the batch job manager...) now starts the job, perhaps on one computer; perhaps on several at a time. The user can, meanwhile, log off the web-site and do whatever he pleases. Then, he can come back at any time, go back to whatever the job-monitoring web page may be, and see how things are going. Stop the job, suspend/resume, what have you.
There are lots of batch-job monitoring tools out there already, for all sorts of environments, both free and commercial. So, it's not like you have to build all this stuff; you merely have to identify what off-the-shelf package works best for you and for your client.
The best possible solution will be to do the work in a windows service, and use your web app just to trigger the processing.