connect ASP.NET web application to Windows Service application - c#

I have one windows service application and one ASP.NET web application, both created by C#. Both applications get data from the database(SQL server).
Once I update database from web application, how could I inform service application to reload data from database?
Right now our solution is to use service controller to restart windows service application. Is there any low cost solution, like communication between service application and web application?
By the way, my boss hate polling method...
If wcf is a choice, can anyone post some materials?
Thanks a lot!

you can implement workflow services that runs as a windows service. That service must have an activy that can be called over net.tcp request and processes your request. I'm using this solution and works fine.
Other way is the service use the database to check if it's necessary to perform the reload.

You can take advantage of Service Broker
In a nutshell: using the SqlDependency class you can wire up an event in C# that will fire whenever a table gets updated. At that point in time, you can re-load the new data.

Related

Pass Event From .NET Web Application to .NET C# Standalone Application

Looking to create a web application that will modify a value in a database. When this occurs, I need a C# standalone application to recoginize this occurred and pull the value that was modified.
When the web app updates the DB, can I fire an event to the standalone app so that it can call a stored proc and pull in the new value? What is the most efficient approach to accomplish this task?
You could convert your standalone app to a WCF service then call the service (server-side) when the form that does your database update is posted.
If you don't want to convert your standalone app (or can't), a quick hack that would still use WCF would be a simple one-line WCF app that uses System.Diagnostics.Process.Start() to invoke your standalone app. Again, just invoke the service from your server-side logic after you've processed your database update.
I mention WCF as a solution because you're obviously already hosting your solution on IIS, that's exactly where you'd host your WCF app, and it's so darned simple to make WCF service calls from server-side code in .Net web apps.

Transfer data between websites

I need some architectural advice on how to build a background service application.
Background:
I have 2 websites, and I need to transfer some data from website A to website B. Service
would have to run in a background (as windows service) and should connect (every 5 minutes)
to websites's A database directly (MSSQL) grab some data and insert this data through
websites's B API (API is build on MVC Web Api). Both websites are hosted on a same virtual
machine (Windows Server 2008 R2 Datacenter), but this might change (website B can be switched to another virtual server or cloud hosting as Windows Azure or Amazon AWS).
Question:
What do you suggest (best practices) and what guidelines you can give me? I want this to
be scalable and fast as possible and that service will receive multiple requests.
Thank you,
Jani
If it is important to know what data was transferred, then:
Add logs - log4net for instance
Issue tickets if the process stops, and close the ticket when it restarts, this way you will know if a process fails. Depending on the amount of data use you could use Redis/Riak.
Put monitoring on each service A and B, and you might also consider restarting the service via IIS on fail down.

How to run a program in WCF?

I am new to WCF and i am designing a project in which i want to run a crawler program (coded in c#) which crawlers some websites and it stores the crawled data in the tables of database (sql server db). I want that crawler runs repeatedly after 30 minutes and updated the database.
I want to then use the service on my hosted platform so that i can use the data from tables in web form (i.e. .aspx page)
Is it okay to use WCF for this purpose ?
Please suggest me how to move on ?
Thanks
Windows Communication Foundation (WCF) is responsible for communication between 2 points with different channel technology. you will use WCF if you want to send/receive some data between two point regardless channel technology (TCP/UDP/NetPipe/MSMQ , ...)
But you first need to design you crawler application which is configured to fetch data from your target web sites, then you need to design a schedular application using
http://quartznet.sourceforge.net/
to run your crawlers.
after running and storing your web pages you can use WCF if you need to do replication or synchronization with center server but it is optional
You could use a WCF service to do this but I would go for another setup:
I'd build a Windows application that is scheduled to run every 30 minutes by the Windows Task Scheduler. A simple console application might be fine.
I'd use a Web application (possibly ASP MVC) to query the database.
As you can see there is no need to use WCF at all.
An exception can/must be made when the server is not yours but you are using a hosting provider who doesn't allow you to schedule a Windows task. In that case you might want to run the crawling process by hand through the web application and have it repeat itself after 30 minutes.
Some hosting providers do allow the scheduling of tasks but in a different way so it might be worth to investigate.

Convert Window desktop application into Window service

I have a window desktop application, developed in C#.NET (.NET framework 4.0), but now I want to convert it into window services. There is one Window Form in desktop application. How is it possible? Any code or helping link is welcomed.
Thanks
It entirely depends upon what the application does. The main thing you have to remember is that when an app is running as a service it cannot have any user interaction, as it runs unattended.
Take a look at this for more background:
Introduction to Windows Service Applications
Or look at using SrvStart (a freeware utility) to run an existing app as a service:
Using SrvStart to Run Any Application as a Windows Service
There are also commercial tools that can convert Windows apps to run as services such as:
FireDaemon
AlwaysUp
Once an app is running as a service all comunication between a seprate UI presentation app is cross process - so you need to manage that. Depending on your skill set probably the easiest way to do that today is WCF. Your first step is to define the interface between the GUI client application and the service (what calls does GUI need to make on the serivice, are they oneway or duplex (return data), does the service need to trigger events client side (which requires a callback interface)? etc).
Once that is decided you can go ahead and start building your WCF service. That is a dll that needs to be hosted - in your case by a service host - this is quite straight forward and there is plenty on infomation available about that (basically just a few lines of boiler plate code and then run a utility to register the service). It is useful to test your server using a Command line host in place of the service host (easier to debug etc) - so worth while setting up 2 host projects (one service, one cmd line).
I've personally never tried a form client with a WCF service - if your form is simple you might find it easier to dev your client in WPF. The client uses the interface you defined to make calls on the server and the WCF generated proxy code impliments that interface to manage the tranport accross process (or machine). WCF is very flexible via configuration files about the transport to be used (namedpipes, tcp, http etc). Bon courage!
Ricibob's answer is correct. I started the way he suggested. I needed WCF Data Services because I had to edit some data in the db. And I got stuck when I found out that WCF Data Services doesn't support Enums. My business objects widely used enums and now I don't know what to do.

IIS vs Windows Service?

I have a C# application that needs to always be running. I originally planned on making this a windows service but I now have a requirement to make the application host a web admin console.
I haven't played with IIS in quite a few years so my question is this:
What would you recommend I use?
I've thought about making a windows service and embedding a web server such as Cassini but so far I'm not very happy with the open source web servers I've looked at.
Can IIS handle this? Do people use it for this type of scenario, and if so how?
This sounds like a job for two separate projects.
One is the original Windows Service. Windows Services are well suited for what you're doing.
The second is the Web Project that will be used to administer the Windows Service. This is the part that runs in IIS.
It depends on what you mean by always running. An ASP.NET web application deployed in IIS could very well be unloaded by the web server if there aren't any requests for certain amount of time killing all background threads. So if you want an ever running background thread it would be better suited to use a Windows Service. As far as the web admin is concerned, well, here you don't have much choice: ASP.NET in IIS. In order to do something useful those two applications should be able to find a common language to talk. So you could use a database to store the results into which could be used by both applications.
IIS will run your app on first request, not on server boot. So you will still need to run a service to ensure your app is always running.
You can use IIS as a webserver for your web admin part, and link your ASP.net app with your service by means of a configuration database (easy) or webservices (a little more tricky).
Windows and Web services are two very different creatures. A web service will expose external methods that you can implement against an application, while a windows service is an entity within itself. If you're planning on using this service on a timed interval to perform an operation, a Windows service would be the right way to go. If you use a web service, you will need to invoke the method you wish to run from a secondary application.
If you need to queue commands against your windows service, you could always create a database that was accessible by both your website and your windows service. This way you could send commands and query data between the two. Placing a web service in to serve as an intermidary between the two may be overkill.

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