I'd like to develop a simple solution using .NET for the following problem:
We have several computers in a local network:
10 client computers that may need to execute a program that is only installed on two workstations
The two workstations that are only used to execute the defined program
A server that can be used to install a service available from all previously described computers
When a client computer needs to execute the program, he would send a request to the server, and the server would distribute the job to a workstation when available for execution, and inform the client computer when the execution has been performed.
I'm not very used to web and services development so I'm not sure if it's the best way to go, but below is a possible solution I thought about:
A web service on the server stores in queues or in a database the list of tasks with their status
The client computer calls the web service to execute a program and gets a task id. Then calls it every second with the task id to know if the execution has been performed.
The workstations that are available call the web service every second to know if there is something to execute. If yes, the server assigns the task, and the workstation calls the web service when the execution is completed.
I summarized this in the below figure:
Do you think to a simpler solution?
Have a look at signalr! You could use it as messaging framework and you would not need to poll the service from 2 different diretions. With signalR you would be able to push execution orders to the service and the service will notify the client once the execution has been processed. The workstation would be connected with signalR, too. They would not need to ask for execution orders as the webservice would be able to push execution orders to either all or a specific workstation.
Related
I would like to build a customer billing tool using signalR.
I am unsure if SignalR is the correct technology really, I currently use a scheduled service that runs twice a day.
I would like to send a request to connected clients to perform a billing routine anytime I want. The client will run a number of activities (generate reports, call some stored procedures etc... which can take up to 5 minutes to complete.
I have built a simple system but I am concerned about the long running task on the client. Whilst the long process is running the client is unable to retrieve other requests from the server, once the long task is complete all the requests appear.
Is there any way to just ignore requests on the client until the long task is complete? Or a better way to handle the requests? Maybe SignalR isn’t the best approach.
Here is an example how to listen to Unix signals and stop ServiceStack host.
If I have IRegisteredObjects running in this applications how can I ensure that all IRegisteredObjects receive proper Stop(false) and then Stop(true) calls, and how I can wait until all Stop(true) calls return?
Should I call HostingEnvironment.InitiateShutdown (MSDN)?
In IIS I just rely on the environment, but I am not sure if that functionality is possible at all with self-hosted ServiceStack.
(The question assumes that AWS platform sends SIGTERM before terminating spot instances at least in majority of cases. If AWS just kills instances, IRegisteredObjects are meaningless).
I need to find the most efficient way to communicate from an asp.net web server and a windows C++ application. The windows application does not have any permission to access the database of the asp.net web server.
When the user presses a button, that action with some bytes should be received by the C++ application.
In return, after processing the data on the C++ application, it will send back the result to the web server.
The only way I can think of at the moment is as following:
The asp.net web server will have two web service methods:
the C++ application will call that web service for a method for an interval. if there is a change, then the C++ application will process.
after the C++ application finished its process, it will call a method on that web service to inform about the result.
Any other ways to solve this kind of communication?
Thanks in advance.
If the C++ Application is also on Windows, named pipes would be a good solution. They can be configured to be durable so they can queue messages if either side is not ready to receive the message and they are quite easy to use. They basically look like files that you can read or write from and the data appears on the other side of the "pipe".
Take a look at the documentation (C++) here: http://msdn.microsoft.com/en-us/library/aa365781(v=VS.85).aspx
On the ASP.NET side you would use .NET API's. Here's a nice example to get you started: http://msdn.microsoft.com/en-us/library/bb546085.aspx (This example includes both client and server code.)
Named pipes would be a great solution if the C++ application is located in the same physical server as the ASP.NET application. In that case the OS would be just moving memory between processes for you so it could be very quick.
Additionally, I would configure the C++ Application as a Windows Service so it's always available and can be restarted when the server it's running on is restarted. If keeping it running is very important you could integrate Performance Counters and then have your ops team monitor the counters to make sure it is operating within expected thresholds.
The C++ application can also make a simple GET or POST request with enough information that the webserver can handle in case you don't want to expose a webservice.
You could use network sockets. It's been a long time since I have done anything with them so I can't be much help. Research Winsock (aka Windows Sockets API).
You could use WCF services and connect to them using your C++ client. You will have to research consuming WCF services from C++ client.
As #parapura suggested you could use simple HTTPRequest get & post methods. You could create your own http handler for these request to customize the response.
As you suggested you could use simple web services.
I need to build a Windows Service in VB.net under Visual Studio 2003. This Windows service should read the flat file (Huge file of about a million records) from the local folder and upload it to the corresponding database table. This should be done in Rollback mode (Database transaction). While transferring data to table, the service should also be listening to additional client requests. So, if in between client requests for a cancel operation, then the service should rollback the transactions and give feedback to the client. This windows service also keeps writing continuously to two log files about the status and error records.
My client is ASPX page (A website).
Can somebody help me explain how to organize and achieve this functionality in a windows service(Processing and listening for additional client requests simultaneously. Ex. Cancellation request).
Also could you suggest me the ideal way of achieving this (like if it is best to implement it as web service or windows service or just a remote object or some other way).
Thank you all for your help in advance!
You can architect your service to spawn "worker threads" that do the heavy lifting, while it simply listens for additional requests. Because future calls are likely to have to deal with the current worker, this may work better than, say, architecting it as a web service using IIS.
The way I would set it up is: service main thread is listening on a port or pipe for a communication. When it gets a call to process data, it spawns a worker thread, giving it some "status token" (could be as simple as a reference to a boolean variable) which it will check at regular intervals to make sure it should still be running. Thread kicks off, service goes back to listening (network classes maintain a buffer of received data so calls will only fail if they "time out").
If the service receives a call to abort, it will set the token to a "cancel" value. The worker thread will read this value on its next poll and get the message, rollback the transaction and die.
This can be set up to have multiple workers processing multiple files at once, belonging to callers keyed by their IP or some unique "session" identifier you pass back and forth.
You can design your work like what FTP do. FTP use two ports, one for commands and another for data transfer.
You can consider two classes, one for command parsing and another for data transfer, each one on separate threads.
Use a communication channel (like a privileged queue) between threads. You can use Syste.Collections.Concurrent if you move to .NET 4.0 and more threading features like CancellationTokens...
WCF has advantages over web service, but comparing it to windows service needs more details of your project. In general WCF is easier to implement in compare to windows service.
I want to develop a web application using ASP.NET running on IIS.
If a user submits a MAXIMA input command, the code behind will ask a custom windows service to create a new distinct temporary process executing an external assembly.
More precisely, there is only one windows service serving for all users, but each user will be associated with a distinct, temporary process running an external assembly.
The windows service contains a single socket listening on a certain port and a list of asynchronous sockets for communication. Each socket of the list will communicate with a distinct, temporary process running an external assembly which works as a client socket.
Note that: I use a process rather than an application domain because the external assembly is a batch file (not managed assembly).
My questions are:
How to call windows service from code behind?
How to associate each user with a distinct, temporary process?
How to improve scalability if there are more and more users working simultaneously?
If the Maxima input command entered by a user cause long-running process, what is the wise way to notify the user about the progress?
The following link provide you with more detail about my project: https://sourceforge.net/projects/aspmaxima/forums/forum/1190702/topic/3786806
Thank you in advance.
You should not be using codebehind in an MVC app.
Scalability while interoprating with unmanaged code is hard. The only sane way to do this is to decompose the problem.
When you launch an unmanaged app, it already has its own process.
Multiple task flows in a service called from a web app, with monitoring? You're describing Windows Server AppFabric. Host your service with AppFabric, and you won't have to write all of this yourself.
Regarding scalability, when you're dealing with unmanaged processes, you're going to have to limit the number which can start concurrently. Trial and error will be necessary to determine the optimum on specific hardware.
You can only monitor an unmanaged task's progress if that app specifically provides for it.
Launching arbitrary unmanaged code from a service is dangerous, because the launched app, by default, inherits the service's (typically raised) permissions. Consider using specific, limited credentials for the launched app instead of the default.