How to consume Windows Communication Foundation (WCF) by a Windows Service - c#

When i create a Windows Service for getting information from a Web Application(ASP.NET c#) for scheduling some task in the client machine.
To consume WCF from the web application. I added WCF reference
to Window Service project as a service reference, everything seems fine. It
updated app.config file, added service reference etc.
it was not working. Any idea will be very helpful.
My Code is shown below
string result = string.Empty;
BasicHttpBinding myBinding = new BasicHttpBinding();
EndpointAddress myEndpoint = new EndpointAddress("http://test.com/Service.svc/DevicesService");
using (ChannelFactory<IDevicesService> myChannelFactory = new ChannelFactory<IDevicesService>(myBinding, myEndpoint))
{
IDevicesService wcfClient1 = myChannelFactory.CreateChannel();
result = wcfClient1.CheckNetworkConnection(IPLocalHost);
if (!string.IsNullOrEmpty(result) && result.Equals(IPLocalHost))
{
EventLog.WriteEntry("Test connection succeeded");
}
else
{
EventLog.WriteEntry("No live connection currently available");
}
((IClientChannel)wcfClient1).Close();
}

I find it easier, when building a windows service, to build a console application that performs the same work as the service will. I abstract out the actual working code (e.g. your code snippet above) into a separate assembly and then just invoke it from either my service's start method or the console's main method.
If you move your code above into a console application, does it work? If it doesn't, can you step through it and let us know where it fails. And when it fails, what exception information are you seeing?
Let us know and we'll help!

Related

Consume WCF Service over named pipe hosted in WPF app from Windows Service

I host a WCF Service in a WPF appilication which updates the GUI using a named pipe. In a Windows Service I consume this WCF-Service to update the GUI.
I host it in my WPF app with the following code:
private ServiceHost serviceHost;
public MainWindow()
{
InitializeComponent();
try
{
string address = "net.pipe://localhost/Path/ServiceName";
serviceHost = new ServiceHost(typeof(ComGUIService));
NetNamedPipeBinding binding = new NetNamedPipeBinding(NetNamedPipeSecurityMode.None);
serviceHost.AddServiceEndpoint(typeof(IComService), binding, address);
serviceHost.Open();
}
catch (Exception ex)
{
// TODO: Logging & Handling
}
}
And consume it in my Windows service:
string address = "net.pipe://localhost/Path/ServiceName";
NetNamedPipeBinding binding = new NetNamedPipeBinding(NetNamedPipeSecurityMode.None);
EndpointAddress ep = new EndpointAddress(address);
IComService channel =
ChannelFactory<IComService>.CreateChannel(
binding, ep
);
try
{
channel.SendUpdatedStatus("test");
}
catch (Exception e)
{
// Throws: The pipe endpoint net.pipe://localhost/... could not be found on your local machine
}
System.IO.PipeException: There was no endpoint listening at net.pipe://localhost/... that could accept the message
The strange thing is, the exact same code works when it is excecuted in a Console app and the communication to the WPF app is successfull. Is there something special about the communication between a Windows Service and a desktop app through named pipes? Is this even possible?
I had the same issue going on. The problem is your service runs in session 0 when running as a service and your app in session 2. You see it working when running the service as a console, because both apps are running under the same session 2 (no additional perms needed). The named pipe has to be created in a shared memory space for the service to actually see the named pipe, and when they are running different sessions you will see this problem crop up. The solution is to simply allow "create Local Object" permission to the necessary users/groups. Go into group policy editor. Windows Settings -> Security Settings -> local Policies -> User Rights Assignments -> Create global objects (add user group to this permission and you should be good to go!). Good luck!
I managed to get it working. The only thing I had to do was to run the WPF application with administrative privileges. Why the communication between those application only works when the WPF application is running as Administrator is still a mystery.

How to invoke WCF method programmatically from windows service

I have successfully compiled and run Windows Service with WCF. With installutil, the Windows Service is successfully getting installed and started. I think I am at the end of my development and just need to invoke/call the method DoJobs() inside WCF. I don't need any user interaction and so I don't have any Windows forms or anything. I just want to invoke/call my WCF function programmatically just after serviceHost.Open();
The base address in app.config file is
http://localhost:8733/Design_Time_Addresses/WcfServiceLibrary1/Service1/
I am deploying my WCF from Windows service with the following code.
// Create a ServiceHost for the CalculatorService type and provide the base address.
serviceHost = new ServiceHost(typeof(WcfServiceLibrary1.Service1));
// Open the ServiceHostBase to create listeners and start listening for messages.
serviceHost.Open();
I have also added the service reference and created the below proxy, but not sure of its use.
WcfServiceLibrary1.WCFServiceRef.Service1Client
I have searched tutorials, the examples show how to invoke the WCF function on button_click event of any form after running Windows service. I just want to do that programmatically on start-up of Windows Service.
EDIT: The code inside my DoJobs() fetches the active tab url of firefox with DDE Client, which throws exception when done only in a Windows Service project but runs successfully when done in WCF project. Please see this for reference.
So I made a C#.Net solution with WCF called from a Windows Service and then I called DoJobs() inside Windows Service as shown below.
WcfServiceLibrary1.WCFServiceRef.Service1Client wcfObj = null;
...
protected override void OnStart(string[] args)
{
if (serviceHost != null)
{
serviceHost.Close();
}
serviceHost = new ServiceHost(typeof(WcfServiceLibrary1.Service1));
serviceHost.Open();
if (wcfObj == null)
{
wcfObj = new WcfServiceLibrary1.WCFServiceRef.Service1Client();
wcfObj.DoJobs();
}
}
But, it makes the call happen at the windows service layer, and is throwing the same DdeClient exceptions.
Can the base address url help any way to programmatically invoke DoJobs() in Web-Service? OR there are some other solutions.
Any help is highly appreciated.
Thanks.
This is my aggregated answer from my various comments I made to your post and to Noctis's answer (specifically that we did not know you were using DDE in the OP):
You can't use Dynamic Data Exchange (DDE) in a Windows Service because the latter does not have a message pump. Also DDE requires a Window handle to be passed as a parameter to DDE functions. You can use DDE in programs which do have a message pump does as a WinForms app. See this article for more information
Once your GUI app is running you can either minimize it to a Sys Tray icon or hide the app completely so the user is unaware. Regardless of its visible nature you should have no problem utilising DDE since it will have a message pump.
Now it may be the case you could add a message pump to a Windows Service but I wouldn't recommend it because it falls into the category of because you can do a thing, does not mean you should do a thing. A topic for another time. It's very similar to a recent SO question about how to display a WinForm in a console app - by default you can't and if you managed to you end up with an odd hybrid with much re-inventing of wheels. Not to mention its an ugly hack.
In summary, my best advice is to proceed with a GUI app.
Assuming you have :
// I'm assuming this is your proxy?
var proxy = WcfServiceLibrary1.WCFServiceRef.Service1Client;
// All you need to do is :
proxy.DoJobs() ;
Having seen your update and Micky`s answers, I'm just wondering why you're using DDE. Not sure what your requirements look like, but you can always use your MSMQ to send messages and queue things.

WCF Service application without gui that will stay alive

[WCF newbie]
I have a basic client-server WCF project.
My Service is "gui"less application, meaning that I created winform application, removed the Form1.cs and the lines that starts the gui.
The service is running ok, I am using servicehost.open..
My problem is that it is "serial" (sync), so after a second the application exists.
How can i keep the application alive and listening to the host ?
I need to halt the process and then to host.close when I want to end it.
Thanks
This is code of service:
class Program
{
public static Uri BaseAddress;
[STAThread]
static void Main(string[] args)
{
string baseAddressStr = "http://localhost:7000/someservice";
BaseAddress = new Uri(baseAddressStr);
using (ServiceHost host = new ServiceHost(typeof(MyClass)BaseAddress))
{
ServiceMetadataBehavior smb = new ServiceMetadataBehavior();
smb.HttpGetEnabled = true;
smb.MetadataExporter.PolicyVersion = PolicyVersion.Policy15;
host.Description.Behaviors.Add(smb);
host.Open();
host.Close();
}
}
}
I don't think you want to host your WCF service in a windowless WinForms app.
If you want it to stay open indefinitely, the way to go is to host the WCF service in a Windows Service. Here you have a basic sample.
The benefits should be obvious:
Can run even if no user is logged in.
Does not require a workaround for keeping the application open.
Additionally, you should consider externalizing your WCF configuration (like the base address, service behavior) to the application configuration file. You don't want to rebuild and redeploy your service each time something (anything) changes in the configuration, which may vary from development, test, acceptance and production environments.

Invoke a method in a Console application that is currently running.

I have a console application I wrote in C# that polls multiple devices, collects some data, and stores the information on a database. The application runs on our web server, and I was wondering how to invoke a method call from the command console (so I can exec a command from php that will be read by the console application, a shell command would work as well).
Anyone got any ideas? I've been floating around 'the google' and have found nothing that will supply my current needs.
Also, i'm not adverse to making changes to the console application if an overhaul is needed there. Please, if your answer is COM Interop, provide a GOOD example of how I would build and call this from PHP / Apache2.
You could create a Service like this:
[ServiceContract]
public interface IService
{
[OperationContract]
[WebInvoke(
Method = "GET",
UriTemplate = "/magic")]
void MagicMethod();
}
And a service implementation like this:
public class Service : IService
{
public void MagicMethod()
{
//magic here
}
}
to start a HTTP Service it should look like this:
WebServiceHost host = new WebServiceHost(typeof(Service), new Uri("http://127.0.0.1:8080"))
ServiceEndpoint ep = host.AddServiceEndpoint(typeof(IService), new WebHttpBinding(), "");
ServiceDebugBehavior stp = host.Description.Behaviors.Find<ServiceDebugBehavior>();
stp.HttpHelpPageEnabled = false;
host.Open();
This will start a HTTP server on port 8080.
Then you can make a HTTP Get request to 'http://localhost:8080/magic' to invoke the method call.
Perhaps your console app can poll a directory for a certain file, and react to that.
Then your php app will only need to create that file and the console app should notice it and do whatever you want. I'm not really sure what you want to do.
I would look at using WCF. Your C# application would host a WCF service and then your PHP application could call into it, I believe PHP5 comes with a SOAP library which should make this relatively simple. Any other application you write will be able to easily call in to, especially if they're written in .NET.
I imagine COM would work fine, but I like the scalability of WCF, as if you have to end up moving these applications onto separate servers then you wouldn't need to change anything besides a URL.
There's a good example on this blog. If you're using PHP5 it should be a doddle, if you're having to use 4 then it will still be possible but will require just a bit more legwork.

Mono WCF issue on OSX

I've written a mono compatible application that works fine on a Windows machine and mostly works on my mac. The area that currently doesn't work is the layer that uses the WCF (ChannelFactory) to communicate between server and client.
The issue appears to be when I try and open the ChannelFactory on the Server, here is a code snippet:
string address = "21"; // added this for simplicity in conveying the problem...
string server_address = "net.tcp://192.168.1.122:4505/DeviceServer/";
string serviceAddress = string.Format(server_address, address);
ThreadedServiceHost<DeviceService, IDeviceContract> DeviceHost =
new ThreadedServiceHost<DeviceService, IDeviceContract>(serviceAddress, address, new NetTcpBinding());
EndpointAddress endPoint = new EndpointAddress(
new Uri(string.Format(serviceaddress, address) + address));
System.ServiceModel.Channels.Binding binding = new NetTcpBinding();
teeGlobal.ServerDeviceFactory = new ChannelFactory<IDeviceChannel>(binding, endPoint);
teeGlobal.ServerDeviceFactory.Open();
The issue is with the .Open() call - it just appears to hang on my mac. Creating the endpoint takes a lot longer to create than on my PC (about 3-4 seconds) but I can live with this if I can get the WCF layer to function.
Does anyone have any suggestions on how to progress with this issue?
The most recent stable release of Mono is 2.8.2 (http://www.go-mono.com/mono-downloads/download.html)
You really need to try with this version before doing anything else. The WCF stack in 2.6.x was more of a 'preview' than anything else, and only some common scenarios actually worked. 2.8 is much more complete.

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