This question is a Follow up to This
In the project I am currently working on, I have a windows service which is actually a TCP/IP server which is connected to some set of hardware.. The windows service collects data from the hardware and stores into a database and may also send some configuration commands to the hardware.. There is an asp.net website through which the user may ask the windows service for some data or even send some configuration commands for hardware through windows service..
As of now I am considering to host WCF inside the windows service and make asp.net to consume this service.. So, I want the WCF to invoke some of the procedures in my windows service when the user requests through the website.. is it possible? if it is please explain..I have searched a lot for this type of communication but all in vain.. if it is not possible suggest me some alternative approach to WCF... Please help, will be grateful.
If you make your WCF service a singleton you can create an instance to it and pass that to the ServiceHost. You can pass constructor an interface implemented in the windows service which the WCF service can use to talk to the Windows service - this interface implementation can act as a broker for the communication between the WCF service and the windows service
Related
Currently I'm working on a design for a Windows Service application to fetch reports from an Oracle database, aggregate them to a message and send it to an external WCF SOAP service.
I would be grateful for some design suggestions concerning Windows services.
Should Windows Services use e.g. dedicated WAS/self-hosted WCF service (net.pipe/net.tcp) that provides data to achieve better separation / reusability?
So I would add a WCF service (net.pipe) that provides data (e.g. a GetReport method).
The Windows Service application would call GetReport and call the remote SOAP service to forward the aggregated message. The remote service and its client code are likely to change. It might be adapted for different customer projects.
If I understand correctly, your windows service will periodically fetch some data from the database and upload that data to a remote web service.
This means that your windows service is a client in terms of WCF communication and you won't need to implement any WCF server code inside it.
All you'll have to do is to connect to the remove web service and upload the data, e.g. using a client proxy generated for this remove service.
I don't think that it is required to add another WCF service that provides the data instead of querying the database directly as long as you don't have the requirement that another application will use the same WCF service. Until then I wouldn't add the service for the following reasons:
Another WCF service increases the complexity of the deployment and makes it harder to install and configure.
The connection to the new WCF service is another point that can break.
If you handle lots of data, getting them from the database directly is much more efficient instead of transferring them over a service protocol. As I understand your question, you aggregate the data in the windows service not in the database. Therefore you'd have to move the aggregation code to the new service also.
As said before, this recommendation will change once you have another potential client to the new service. In order to prepare for that, you should of course choose a design in your windows service that separates concerns well and is a good starting point to move some components later.
I am creating a client application that downloads and displays market data from Yahoo! for a university project, but that also sends out notifications to mobiles (so far using Google cloud messaging). So far it's a WPF client and the "server" is a class library - so far working. What I was wondering, is can you mix this server with a WCF service - the WCF service I was planning on using for registering devices, as well as accepting and parsing commands.
So I would call .Start() on my server object, and it will be constantly running in the background, while a WCF REST service runs alongside it - or would I be better simply having a thread running on the server that can accept input... sorry if this is confusing, but just wondering if it can, or has been done before or any advice. :)
Just to explain a bit better
The client front end and the "server" are running on the same machine - I was calling it a server because it is not only updating the front end, but sending out GCM notifications at the same time. I was wondering if maybe a WCF service could be added to make it simpler to handle adding devices to a database ("server" reads a list of device reg ids from a database, sends notifications to these) by allowing an android app to details via REST or something similiar
I would explore wrapping the class library in a Windows Service (which is essentially a process that runs continuously, and can be stopped/started/paused) and keep your WCF service as a web service for client communication.
How the WCF client service communicates with the Windows service is up to you - whether you store the data in a shared database, keep it in memory and have another WCF layer communicating between the two, etc. A shared database would be the most straightforward, especially if you want to persist the data for use by other apps/services as well.
WCF Service would be useful if you had one notification service on your server with multiple WPF client application connecting to it. If you have just one application running on the same server then not sure if it will be worth the overhead.
The usual pattern is to host WCF service in IIS, that way it always starts whenever first request is received. WCF is very flexible though, therefore you can host in in Windows Service, Console Application, etc.
I have a C# form application that connects to a electronic device using the serial port.
The class "'SerialCommunicationManager'" hooks up to the serial port on application startup and handles the dirty business of talkning to the device.
What I would like is to expose the following methods.
Write()
SerialDataReceived event
SerialDataTransmitted event
Primarily a local website running on the same machine is the one I want to expose the methods for, but in the future I imagine the need for external applications as well.
What is the easiest way to expose the functionality?
TCPIP client server?
Web service? (Can I create a web service inside a WinForm?)
other?
Big thanks
//David
I would recommend self-hosting a WCF Service. This provides you a huge amount of flexibility in terms of how you serve and expose this information, including being able to change the method by which its served via configuration.
It seems to me, that if you would like to do it properly, you should break apart your forms app, and create:
a service that handles serial comm and has an API exposed through remoting
a Forms app that uses the API and makes a way with the service
Then, depending on the locality of your web site, if it will remain local (or near local - LAN):
web site should use remoting to call the service
else, if you plan to have multiple web sites:
web service hosted inside the IIS that will wrap remoting API
web site that will use web service
However, if it is too much work to do - just use remoting and expose needed methods to the web site.
In a recent project we did the following:
Write a Console application (or Windows Service, depending on your needs) that communicates with the electronic device.
Make the Console application host a .NET 4 WCF service.
Write a .NET 2 Windows Forms application to communicate through Web Services with the console application.
In this context, I could imagine the website you are mentioning to also use Web Services (WSDL) to communicate with the Console application.
Can I use WCF for communicating between 2 windows service? If yes, How?
It depends on the type of message you want to transfer. There is a lot of possible solutions:
MSMQ messages
Duplex contracts
Named pipes
Basically you need to setup a WCF service on each windows service. You can use the WCF 4.0 discovery features to dynamically find the each service.
Sure; you'd usually define a service contract (interface) which the two services will use to exchange messages; then one of the windows services would host a WCF service (in this case, where the two services are in the same machine, you'd usually use a local-only binding, such as named pipes). Then the second win service can act as a client for the WCF service on the other windows services. Is there any specific issue you're facing?
Yes, It is possible. You can use ServiceHost class to host a WCF service in a windows service without dependency to IIS.
I using two WCF services. WCF service A is hosted in my .NET Winform application and WCF Service B is hosted on a Windows Service.
I am able to instantiate a client for WCF Service B and use the methods - i.e. call the WCF service hosted on Windows service from the .NET Winform app.
I am not able to accomplish the reverse with WCF Service A - i.e. call the WCF Service hosted on the .NET Winform application from the Windows Service. The call to the method times out.
I have used the WCF Test client from the Visual Studio command prompt and it can successfully make calls to WCF Service A.
Is this due to a security issue or something from the Windows Service?
Please advise.
Thanks in advance!
Subbu
I think the only viable approach (without the extreme of having some messaging infrastructure), is to have the service invoke operations back on your client via a WCF callback. A good example of this can be found here:
What steps do I need to take to use WCF Callbacks?
This is good for dealing with events that happen server side and allowing the client to respond to them. If events isn't what you're looking for, then your client could just register with the server (specifying the callback contract), and then the server can invoke your client at will.