I have a web app that I'm writing right now that is supposed to have "periodical events". For instance, at midnight, the web app should calculate "scores" for all users. I want this done only once during the day.
Is there a way that I can automate this, so it runs automatically at midnight (or whatever hour I choose)?
I don't like the idea of creating a separate script (VBS) to do this, as the calculation would depend on a lot of business logic of the app. I was thinking to put it into a separate Class Library, so it can use the web app logic (which is also in a class library), but is this the best way to go about it?
I also don't like the idea of using the Session_Start() event in the Global.asax to trigger the event by checking the hour manually. There must be some easier way - especially because down the road I expect there will be a lot more of periodical events - some may have to be triggered every fifteen minutes, for example ...
Thanks a lot for any help you can give me.
You should not do this in the web app itself. You are correct to put the business logic in a separate library. Once you have done this, you can use the business logic from anywhere, and therefore, a good solution would be to create a console application that does the nightly jobs, and invoke the console application from Windows Task Scheduler. IIS is not suitable as a host for periodical events.
I guess you are missing the point of separation of concern. Whatever you are asking is a job of a service. You need to develop a separate application as Windows Service that will do all your calculation and to be triggered by any scheduler even Windows Task Scheduler would do. This is what basically done on large scale applications.
Yeah... again awesome "change your architecture and hosting environment so that my answer can be relevant" responses.
Doing what you ask is actually quite easy, take a look at this article: http://www.codeproject.com/Articles/12117/Simulate-a-Windows-Service-using-ASP-NET-to-run-sc
This is a job for a windows service or scheduled task. A web application responds to HTTP requests. Essentially the service's job would be to wake up, run the appropriate calculations and write back to the database. Once in the database, your web application can use the newly calculated values.
Here is some information on windows services: http://msdn.microsoft.com/en-us/library/d56de412.aspx
Related
I'm a bit of a beginner as far as programming is concerned. And looking at stack overflow I haven't found anything that quite answers my question.
I have created a C# console application that is used to push an XML file to a web service that I don't control. It does this by creating an http webrequest. The service will probably be running on windows server 2008, or a win 7 varient. Development is done in VS 2010.
My end goal is to run this program twice a day with little user involement. And I was told that services were the best way to do this. I know that services do not take user input and that outputs are usually to a log file. My console app dosn't take user input but must have the ability to C.R.U.D. files. Beacuse it creates and then reads an XMl file into the web request. If needed I should have no problems having it write any errors to a log file, but at current though it creates/sends an error report via email.
I have 2 questions:
Question 1:
I would like this service to call the application every 12 hours, Is it more reliable/better practice to use a service to determine when to run the application? Or use windows' built in scheduler, or a .net solution like quark? I'm looking for reliability and also, little user involvement. Kind of a set and forget deal.
Question 2:
What would the suggested best practice be for converting my program?
INFO: I have previously created a empty windows service that I would like to fold my application into. (This was done via tutorial, the service contains all that is needed to for a service but it dosn't do anything... yet! OnStart, OnStop, installer etc.) What would be the best way to do it? Should I call my application inside the service's OnStart() method? Our should I add the application as a dll to the service. It's not that I don't think I could do it. It's just my searches on the matter seem to point out that it would be better to just start from a service and add some code to that. My goal would be to minimise the code needed to convert this application.
Thanks for all your help,
Chris
I like standalone programs run by the scheduler because they are easier to write and test.
Services would be more appropriate when they have to be running all the time...say to monitor something.
Question 1: Personally running twice a day seems like a scheduled task type of operation
Question 2: I'd describe it as: more or less put the body of static void Main(string[] args) into the OnStart method. Then also create a timer in OnStart which will call the trigger function in your class. But then I've only stumbled my way through writing windows services so I'm not 100% certain on this advice...
One consideration might be whats the risk of anything failing in the process? If there is a chance of an unhandled exception, the service will die and either would need special settings to restart it or complete error handling to be coded. Where a scheduled task will always automatically retry at the next trigger interval.
I am building a Web application using MVC3 .NET
The app should somehow keep a weekly todo list for each user. On Fridays, all todo lists must be reset.
Can someone help with that.
thanks
You may take a look at Quartz.NET. This being said, the culprit of handling scheduled jobs by a web application is that the web server could unload this ASP.NET application under some circumstances (memory or CPU threshold is hit, the application is not used for a long time, ...). For this reason it is recommended to develop a separate process that will perform those tasks. This process could be hosted for example in a Windows Service which is guaranteed to run all the time.
Another possibility is to simply use the Windows Scheduler in order to launch some custom made executable on a weekly basis which will take care of performing the necessary tasks.
If this is some database-level task, then perhaps a scheduled-task (or crontab on nix). There is no need for MVC to do that. If you really want, the scheduled-task could just hit a route on the web-site.
However, personally I'd simply partition the data with a week-number (or a start date), so that when I get the data, I'm getting the data for the week starting (your date). Then:
there is nothing to do
you have access to history as needed
i.e. add StartDate (or similar) as a column on your existing storage, and use that to select the most timely data. You will get calls about "I need the data from last week" - you might as well built it in from the outset. Besides... if something isn't done on Friday, that doesn't mean it ceases to exist...
do you expect the application to always be up and running? what if nobody is using it on midnight between Thursday and Friday? How can you then execute those jobs?
in general since a web application is not surely running at any given time, you cannot rely on timers inside the web application.
I think best solutions in this case would be to either create a windows service which will be installed on the server and will be always running by definition... a bit like reinventing same things again and again...
or you could also set a scheduled task in windows to call your web application, creating a request to a specific page every Friday, then the web application gets invoked with some parameters and you can do what you need.
How do I send email on daily, weekly and monthly bases using c#.net?
I was thinking of creating a windows service application but I don't know how to do it and if it's the right way to take.
Your thoughts are greatly appreciated.
A windows service is probably the best option.
In your service have a timer that fires with whatever resolution you need (every minute/hour/day etc) and on the timer tick even send your emails.
There are many tutorials for creating windows services with .NET.
A Windows service will do the trick. A good benefit of a Windows service is that it starts up when Windows starts up (or can be set to, anyway). So the machine can be left fairly unattended (as a good server should) and doesn't need anybody logged into it for the service to run. So if that's an important consideration for your scenario then perhaps a Windows service would be the way to go.
If you just want to create a console application instead (which can generally be easier to create/test/debug) then you can schedule it with the native Windows task scheduler. However, unless I'm mistaken, I think a user needs to be logged in to the machine in order for it to run. At least under certain circumstances. So a Windows service is probably your best bet for an unattended task.
As for creating the service, Visual Studio should have a project template for that. The scheduling would be handled with a Timer.
You could also use the Windows Task Scheduler. Quartz.Net seems to be the right tool, too (never used it though).
Windows Service is a good choice.
Remember to save state to disk (file or database) because service restart (for example, due to a reboot) is possible. For example, your next email delivery is a week in the future, you have to save that date to disk. So when your server is down due to a power failure 3 days later and recover after another day, your Windows Service can still set the right timer according to the date saved to disk.
Create a console application, which would be launched from the Windows task scheduler. Creating a windows service is unnecessarily complex, IMO, since you are simply having the program execute in response to time intervals; not other unpredictable external events where you would need a 'listener' type application. KISS!
I'm trying to build a basic application which will have 2 separate components which are:
1. Continually poll an external process and store the results within a DB
2. Grab the results from the DB and display it in a webpage
I'm looking to do this in .Net so I would normally say to do the first component in a Windows Service and the second in ASP.net with a relational dbms like sql server.
The problem with this is that i want to use webhosting to deploy this and they don't tend to allow Windows Services (unless you pay a fortune). So is it feasible to do the polling component in a seperate asp.net page, or maybe create a spawning worker thread within a single asp.net page that will do the polling for me?
Any opinions/input appreciated.
Thanks :)
Consider this blogpost dealing with Easy Background Tasks in ASP.NET. Some suggestions, lessons learned, etc in the comments. I think I remember a podcast where the scale of the site has forced a move of this code to a Windows Service. You may/not have the same scaling needs.
You could have a static method set up a polling thread under ASP.NET, so yes.
SO is a treasure trove of information, and the ASP.Net background task comes from a question that was asked during the beta. SO actually uses something similar to this to award badges.
I have personally used this to do exactly what you are saying.
Where/What is the external process?
If you have any control over that, could you not place your service there?
ASP is fundamentally designed for requests, not for long running processes, you may get something working, but it will never be as robust as something designed for the job.
I'm making a small application that is supposed to download info from the web every day at 2am. It will download the information and write the strings to an XML file of my choosing.
Using .NET and C#.
My initial approach was to install a service on the users computer and have that run, but I'm not so sure. I've not even used it so much in the past, only once.
Which is the best (read: time tested :P ) approach to this very common problem.
You can either build your application as a Windows Service, as you mentioned.
Or else it would probably be a better idea to create a normal console application, and launch it automatically at 2.00am with the Windows Task Scheduler.
You can consider both methods as popular and "time-tested".
I would suggest having a console app, which calls data fetching algo in a separate public class (not the main method).
Like Daniel mentioned, run it via Windows Task Scheduler which itself will take care of most scheduling requirements.
This allows the solution to be scaled in the future if need be. E.g. convert into Windows Service, full GUI Winform or even SQL server scheduled tasks etc.