Background: This is largely a learning exercise. I am working on a task scheduling program. I have been asked to make it so that the application I am working on will send emails to users telling them they have messages waiting to be looked at. I already have the part that sends emails working right, but that only works when the user is actively on a page. I essentially want to make it so that the server decides to send emails at a certain time for instance midnight to tell users how many messages and meetings they have unread updates on during that day. I am not familiar with how to make the app do work when not receiving input from the user.
What I am looking for: How do I make ASP run a function on at a scheduled time.
Here we had difficulties with the functionality of a browser when scheduling the browser (starting with a specific page) on the server.
A Temporary solution was to make one page in your project that reloads after waiting 5 minutes <META http-equiv='refresh' content='6000'>, and start this page on a client or on the server. Note: The copy running on the server stops when rebooting the server.
The final solution was to make a .Net package using the right server-side objects, and schedule this package in task scheduler.
Use Windows Schedule Task to get IE to run the page at a scheduled interval.
e.g.
You will have to make sure that it runs unattended and with an account that is allowed to run it. Also you will want the page to close the window after having finished.
(How to configure and what Schedule Task looks like varies depending on your Windows Version)
Related
I need to run a long running task like report export, report import feature which will take few minutes to hour to complete the task. I want to start the task as soon as user gives command from the asp.net mvc view.
I found various web portals, but I couldn't find the exact solution I was looking for or might be I didn't got their idea (or, limited by my experience). I don't need something that runs at certain time interval or at certain time-stamp of the day/week. I only need the background job to be executed on user request and update the task as completed in DB after it's done. So, the background job need to be always triggered by user only.
I assume the ideal solution will be something like, Background service/job is always in ready state to accept trigger from my web application in some kind of port and as soon as it receives command from web application, it (a) either send everything to job when requested for action (b) or, just poke job to start its task (based on the updated db table entry made just before the call action) . So, the user can browse through other pages in the application and can view the progress of all such tasks in one of the view (where he can even cancel or see the completed task). Note, that there can be simultaneous request for the job from different web users which should be treated as separate job (As data export differs based on user access-rights).
I want to go with the simple method, with 100% assurance of task to be done/not done as recorded in db (no crashing of service). What are the best approaches (except azure jobs) as i want to implement the service within same server and I have access to the server/virtual machine to install windows services/packages if needed.
Take look at this great article that Hanselman wrote:
How to run Background Tasks in ASP.NET
Also Hangfire is a mature library that can make development of application long running process more easy.
Hangfire is an open-source framework that helps you to create, process and manage your background jobs, i.e. operations you don't want to put in your request processing pipeline
We use SOLR for autocomplete search in our web application. We have a nightly process that adds a bunch of data to our database, and once that process finishes, we need to import that data from the database into our SOLR server.
Currently that import process is done manually in the following sequence:
Check if ondeck SOLR server is idle
Tell ondeck server to do a full import of the data, server status is "busy"
Poll ondeck server every so often and when it finishes, the status reverts to idle.
Swap the ondeck server (with the new information) with the live SOLR server.
Run a stored procedure on our database.
We have an administrative tools page on our web app. What I want to do is put a button on that page that kicks off that process (via AJAX call to our web application) and tells the user that the process has been kicked off. The entire process takes about an hour to do so I can't have the AJAX call run for an hour and then get back to the page telling the user that the process is finished.
I need it done asynchronously. The process has to be kicked off, once it gets kicked off, it informs the user that it's begun, and then the application has continue waiting on each step of the process and then call the next step until it finishes. What does the code in MVC 4 look like to make this happen? I've been looking at the tutorials on MSDN on async and await but I'm a little confused.
I may suggest you to take a look on Websokets (or long poling if you have to support old browsers). There is a really nice library called SignalR which will handle all complex staff for you. It use websockets if it is supported by client browser or automatically switch to long poling if it's not. It has good documentation and a lot of expamles on the Internet.
Scenario
I have an web application which needs some calculations and processing on data. This job is a long running job(few hours). Job is initiated by user.
Requirement.
User Clicks on Process Data.
Some functions are called to start data processing.
Data Processing runs for hours.
User is given feedback of percentage completed etc.
Even if user logs off and then again log on he should get this feedback.
The requirement is somewhat similar to Spiceworks. Where it runs in background to detect the devices/computers in network and the user is notified in his page about the progress. But spicework uses windows service. We don't want to us windows service.
Now the question is.
What if user closes the page, will the task still run in background.
This task has to be completed fully.If terminated in between output will not have any meaning.
How to actually to design this long running process. In ASP.Net environment.
Also is there a way to show all/same user who logs in the status of processing.
There are multiple ways to schedule a job in the background. You can use SQL Job, Windows Service or Scheduled Tasks.
I would design it like this:
From my ASP.NET page - I will store an indication in the database for the job to start which will then be picked by the scheduled task. This task is nothing but a console application which pulls data from the database to see which tasks user initiated and then take the next action in there.. For the percetage complete you can store those values from your job into DB and your page will access the dB to show it to user anytime they come to the page.
Here is another thread where long running tasks in IIS are discussed:
Can I use threads to carry out long-running jobs on IIS?
What are your most successful ways of running a long process, like 2 hours, in asp.net and return information to the client on the progress.
I've heard creating a windows service, httphandler and remoting can be successful.
Just a suggestion...
If you have logic that you are tyring to utilize already in asp.net... You could make an external app (windows service, console app, etc.) that calls a web service on your asp.net page.
For example, I had a similiar problem where the code I needed was asp.net and I needed to update about 3000 clients using this code. It started timing out, so I exposed the code through a web service. Then, instead of trying to run the whole 3000 clients at through asp.net all at once, I used a console app that is run by a nightly sql server job that ran the web service once for each client. This way all the time consuming processing was handled by the console app that doesn't have the time out issue, but the code we had already wrote in asp.net did not have to be recreated. In the end slighty modifying the design of my existing architecture allowed me easily get around this problem.
It really depends on the environment and constraints you have to deal with...Hope this helps.
There are two ways that I have handled this. First, you can simply run the process and let the client time out. This has two drawbacks: the UI isn't in synch and you are tying up an IIS thread for non-html purposes (I did this for a process that used to return quickly enough but that grew beyond time-out limits).
The better way to handle this is to write a "Service" application that handles the request as passed through a database table (put the details of the request there). Then you can create a window that gives the user a "window" into ongoing progress on the task (e.g. how many records have been processed or emails sent). This status window can either have a link to permit the user to refresh or you can automate the refresh using Ajax callbacks on a timer.
This isn't directly applicable but I wrote code that will let you run processes similar to "scheduled tasks" inside of ASP.NET without needing to use windows services or any type of cron jobs.
Scheduled Tasks in ASP.NET!
I very much prefer WCF service to scheduled tasks. You might (off the top of my head) pass an addr to the WCF service as a sort of 'callback' that the service can call with progress reports as it works.
I'd shy away from scheduled tasks... too course grained.
We require that in a ASP.Net application, a .Net process should be invoked every day at a specified time automatically. This process needs to interact with the database (SQL Server 2005) and generate billing on a daily basis. We are using a shared hosting hence we are not able to create a windows service or create SQL Server jobs. How can this be achieved without user intervention?
You could try the technique described here, used at StackOverflow itself (or at least it was used here at one point). In a nutshell:
At startup, add an item to the HttpRuntime.Cache with a fixed
expiration.
When cache item expires, do your work, such as WebRequest or what have
you.
Re-add the item to the cache with a fixed expiration.
To get it to run at a specific time instead of an interval, you could lower the interval and simply modify your working method to check the time itself.
As the comments in the original article linked above note, this isn't a perfect solution, and no one should prefer it over a proper scheduling technique if one is available. See When Does Asp.Net Remove Expired Cache Items? for some additional qualifications.
Yes, use Windows Scheduler. Depending on how it's configured you might need to be logged in for the scheduler to run.
You could always schedule a task to run a webservice..
http://weblogs.asp.net/jgalloway/archive/2005/10/24/428303.aspx
The scheduler would run a VBS file with the following..
Set oServerXML = CreateObject("Msxml2.ServerXMLHTTP")
oServerXML.Open "GET","http://my.hostedservice.com/myService.asmx/myService?aParam=Value
oServerXML.setRequestHeader "Content-Type","application/x-www-form-urlencoded"
oServerXML.Send
Set oServerXML = nothing
Can't be done, unfortunately.
IIS only responds to requests, and SQL Server only wakes up for jobs.
The closest you'll be able to do is to put your routine in an ASPX page, not linked from the site and not with an obvious name, and trigger it by a request from some other machine out on the Internet.
The other machine could be a Windows, Linux, Mac, whatever you have available, and all of those platforms have ways of scheduling events (service, cron, etc.) that can make the request to trigger the update on the server.
There are ways to run "services" in .Net by using cache expiration to trigger the task.
More at CodeProject
You can use a Scheduled Task, but this might not work in a shared hosting environment either.
You could setup a webservice or page on your website to kickoff the process, then have a scheduled task on a desktop machine hit that page/service once daily to start the process. Hacky, but it might work.
Being .NET ignorant, I would imagine there's some kind of .NET based scheduler framework available for this (much like Quartz for Java).
Or you could simply fire off a long running thread that spends the bulk of its time sleeping, wake up every minute, check the time, check it's list of "things to do", fire off the ones that need to be done. Level of sophistication being as far as you want to take it, but the primary goal of keeping the primary scheduling thread "alive", "at all costs".
What i can think about now are:
Create a dll which contain the
schedule logic you want, and make
sure that this dll schedule function
will not stop and will loop for ever,
then you will need a page on that
server this page will fire this dll
functions. "you will need to call
this page at least once to start the
scheduler".
Create an application "holds schedule logic" on another machine, may be your Home PC, and make your pc application call the functions on the server through webservices or pages