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.
Related
I want to send data from intranet web application that is running on server to a window application running on local machine??
which would be the best way to perform this task?
i am comfortable with wcf services.
can anyone please post any link to get some hint regarding this ..thanks.
Have a look at ZeroMQ (if you're on .NET, look at NetMQ).
I need to implement simple file watcher utility. I have decided to implement this in a simple windows service which will internally use FileSystemWatcher. The purpose is to monitor given directory path (or ftp) and copy the file to some other server wherever new file comes in after checking some predefined logic
As I am using .net 3.5; client suggested me to use WCF. I have very less experience in WCF.
I am not sure how I can create WCF service which will function like WindowsService and can be deployed in services on windows server.
To be a futuristic is it a good idea to create WCF service instead of windows service, or I should insist on window service.
Windows Service != WCF
You can't create a WCF service that acts functions like a windows service. A WCF service waits for messages from third parties and acts on them, a windows service is a process that is always running in the background. WCF tries to solve the problem of separating out the communication mechanism (transport protocols such as Tcp, Http, Named Pipe, etc) from the service interfaces.
File Watcher Utility
While in theory it's possible to create a new Flat-File binding in WCF that "could" have it's address set to a file system location, one does not exist directly in the .NET framework. Looking at the Custom Bindings article on MSDN it's not immediately obvious to me how one would construct a File System binding. These are the defined transport options available:
TCP
HTTP
HTTPS
Named Pipes (IPC)
Peer-to-Peer (P2P)
Message Queueing (MSMQ)
Custom
If communication must be done through file drops, then WCF does not solve your problem.
Where WCF Might Work
What the client might have meant is to create a WCF endpoint that does the copy the file to some other server wherever new file comes in after checking some predefined logic, but you would still want to have a windows service with a FileWatcher monitoring the input directory.
If you have multiple clients that need to be able to perform that same logic and then send the output to that other server then it might make sense to make the WCF service, otherwise it's over-engineered at this point.
You should choose the simplest option until you find a need to change, with the simplest option being a Windows Service.
There is a coding principle call YAGNI (you ain't gonna need it) that applies in this case as simply wrapping something up in a WCF service would do nothing but add unneeded complexity for the majority of cases. Simply put do the minimum viable solution and extend only when you need to.
PS. If you are using the FileSystemWatcher over network shares note that there are documented problems with it and you should use a combination of a poll + FileSystemWatcher. There are lots of explanations on Stack Overflow about it.
In your use case, the Windows Service makes a lot more sense and I think that to be the more appropriate solution. You need something that is always running and monitoring a directory and thats exactly the use case which Windows services are very good at.
I would consider talking to the client and explaining the Windows Services are the more appropriate solution to this kind of use case. Also, windows services are not old hat, they are there to solve exactly these kinds of use cases and WCF / windows services complement each other.
Both features have Service in their names by they have virtually nothing in common.
A Windows service runs constantly on a single machine.
A WCF service is code than can be called remotely by other machines.
It simply depends on what you need to do. A Windows Service and a "WCF service" have little in common.
The question here is whether you need a HTTP endpoint or not. If you do, you could even host a WCF service in your windows service to provide that. Keep in mind that a WCF is only used as a way to communicate between applications.
Reading your description, though, it doesn't seem like you need it.
WCF Service in a Managed Windows Service
First of all thanks for taking the time to read my question. Here is what I am trying to accomplish followed by what I have so far on this.
What I want to do is create a Windows application (or server of sorts) that would listen for requests from an ASP.NET application. The windows application would be installed and would listen for messages from ASP.NET application and then do some processing. The flow is like this:
A user downloads the desktop application and registers their IP address on my web site. After downloading the desktop app, the ASP.NET application can then send requests to that particular desktop client for further processing. I think further processing is independent of the resolution in this case that's why i have skipped over details on what processing would be done. But if you think it is important, please let me know and I will add those details as well.
I have looked into creating a TCP server that would listen for requests. Because the user has already registered their IP address on my web site, my web site assigns them a unique identifier and stores the ID alongwith IP address in database. Now, the ASP.NET site can send requests to that desktop application.
I have looked into creating a TCP server for this purpose. While researching I also came across PNRP and it seems something like what I am trying to do.
Can you guys recommend some solutions or where I should be looking at for this scenario? Should I create a simple TCPLISTENER or may be go with PNRP approach? Or something else?
The basic requirement is for a web application to be able to communicate with a desktop application. The web application would be servicing numerous users and each user would have a desktop application installed. Which user for which desktop client question would be addressed by the web application that would maintain a database of unique user id's and their corresponding IP Address.
Thanks in advance for your help.
You could use .NET remoting or a web-service in the desktop app. Use WCF or WSE for the latter. You can use COM to add windows firwall rules.
Whatever you do, take firewalling/NAT into account. It might be easier for the client application to poll the server (initiate the connection) otherwise you open a can of worms by trying to have a remotely-accessible server in your user's computer without having to do some very manual configurations on the user's networking equipment.
Once you have that part sorted out, what I used in your situation was .NET Remoting. At the time WCF had not come out and when it did it was to crippled for my needs. TCP IP sockets were too raw (I had to write too much code) and so Remoting solved my problem ideally (a hand full lines of code to set up the connection, and everything was automatic from there on).
EDIT: I use an excellent third party library that makes Remoting even more flexible (flexible enough that I am still waiting for WCF to catch up with the featureset so that I stop using Remoting, and no luck yet!). Check out http://www.genuinechannels.com/ to see all the features they have. It includes making calls from server to client, and that sounds exactly like what you need to do. Check it out.
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.
I am building an ASP.NET website which will collect data from a user and submit it to a 3rd party webservice. The webservice is somewhat unreliable and for this reason there is a backup service.
If a call to the primary service fails (timeout or some other error) then I need to flip a bit in a static class which will trip the system to use the secondary service.
At this point, I need to start polling the primary service (with dummy data) to see if it is back up (at which point I will receive an OK code in return). At this point I need to flip the bit back so that the website starts using the primary service again.
I've had a read of this Should I use a Windows Service or an ASP.NET Background Thread? and I think that separating out the code into a Windows Service would be the cleanest method of performing the polling, but then how would I communicate with the web appication.
One thought I've had is to expose a webservice that the Windows Service could use to communicate into the webapp but this seems both messy and over-kill.
I'd appreciate your thoughts and experiences performing similar tasks.
Thanks
I think the Windows service is the way to go, definitely.
As for the communication between the service and your web site, the best answer depends on the size and scale of your solution. If you are building something that needs to be reliable, I'd suggest you implement some sort of queue between your ASP.NET site and your Windows service. You have a lot of options here too, depending on budget and ability: BizTalk, MSMQ, and SQL Server queues (SSIS). Alternatively if you are looking for something smaller scale, I'd recommend you just stick it into a database table somewhere.
I would avoid using files on the file system because you will encounter issues with file locks and multithreading. I would also avoid directly communicating with the service because you risk losing the in-memory queue if the service fails for any reason.
Edited to add:
If reliability isn't a concern here, you could use a WPF named-pipes hosted service for communication between your website and your Windows service. This avoids much of the overheads normally involved in classic Web Services and is surprisingly quick. The only down-side is that self-hosting a WPF service is tricky and can be difficult to keep the service up.