I have a simple service with the following code:
on Program.Main method I have the code which is generated by vs itself(2010):
static void Main()
{
ServiceBase[] ServicesToRun;
ServicesToRun = new ServiceBase[]
{
new Service1()
};
ServiceBase.Run(ServicesToRun);
}
And in Service1.cs I have:
protected override void OnStart(string[] args)
{
System.Media.SoundPlayer myPlayer = new System.Media.SoundPlayer(#"C:\doorbell-1.wav");
myPlayer.Play();
}
protected override void OnStop()
{
}
I have omit writing the usual automatically generated c# codes to reduce the complexity.
Logically a sound should be played when I start the service but nothing happens when I start the service. Please note that:
1-I install the service using installUtill.exe.
2-The service runs under the localSystem account privilege.
3-Duration of the mentioned .wav file is 3Seconds.
How can I play that sound?
Thanks in advance.
The simple answer is that you can't. Windows Services do not interact with the desktop, and thus they are not capable of using desktop functions like audio services.
Remember, Windows is a multi-user operating system. Can you imagine what would happen if 5 simultaneously logged in users started playing audio?
All users have what's known as a "Windows Station", and there is a special Windows Station for the user logged into the physical computer. Windows Services have a null or unique (non-interactive) Windows Station, and thus cannot interact with the console WS.
This Windows Station is what is used to redirect audio, and the audio in the console WS goes to the speakers. All other audio either is redirected to the network station they're using, or does nothing.
A more complex answer is that it might be possible, since the Windows Audio service is itself another service, and you might be able to interact with it directly, but this would be very low level and something you are probably not skilled enough to do.
Finally, it's possible to make services interact with the desktop. However, this is considered a deprecated function and is not always easy to use. It's also a huge security vulnerability, and makes your service susceptible to being used by malware to compromise a machine.
I've been searching all over the internet whole the last night.
This question has been answered so many times but a simple answer is never given. If you have the same question there is a very simple but a tricky way to do something when the service asks for it.
Let's say you want to play a song when service starts.
first of all create an EventLog class:
public class EventLogEngine
{
private string _sourceName, _logName;
public EventLogEngine(string sourceName, string logName)
{
if (!EventLog.SourceExists(sourceName))
EventLog.CreateEventSource(sourceName, logName);
_sourceName = sourceName; _logName = logName;
}
public void WriteLog(string message, EventLogEntryType eventType, int Id)
{
EventLog.WriteEntry(_sourceName, message, eventType, Id);
}
}
protected override void OnStart(string[] args)
{
EventLogEngine eventWriter = new EventLogEngine("mySource","myLog");
eventWriter.WriteLog("sourceName","Service started",EventLogEntryType.Information,"anyId");
}
There is nothig about playing a sound till here and there is nothing complicated yet. But how to play a sound or do something else? Here is the answer :)
1-Go to control panel and open Event Viewer
2-Find your event log and click on it
3-On the right panel you will see your entries which you have write through your code.
4-Right click on the entry and select Attach Task To This Event!
So far you should have understood what I am going to do. right?
5-Select that option and declare what do you want to do when this entry is set. You can simply attach as many as tasks you wish.
Now write a program that plays a sound (Ex:in vb6) and tell Event Viewer to carry out this program each time this entry gets written(each time your service starts)
It is possible to play sounds from a windows service.
Play wave file from a Windows Service (C#)
Playing a sound from a service doesn't violate the rules of interactivity because it's not an interactive function: it's a notification.
Related
I am not able to detect this Logon event in Windows.
Here is my code:
namespace ConsoleApplication2
{
public class MyService: ServiceBase
{
public MyService()
{
CanPauseAndContinue = true;
CanHandleSessionChangeEvent = true;
}
protected override void OnSessionChange(SessionChangeDescription changeDescription)
{
base.OnSessionChange(changeDescription);
}
}
class Program
{
static void Main(string[] args)
{
MyService tpl = new MyService();
Thread t = new Thread(delegate()
{
while (true) { }
});
t.Start();
}
}
}
How do I test run this app and then remote desktop into my laptop? I can see the event generated in Windows EventViewer, but my OnSessionChange is never called (I added a breakpoint inside).
Is my code wrong or is the way I am testing wrong?
Normally multiple concurrent remote desktop sessions are not allowed on any of Windows desktop systems. So to use RDP to login as a different user then I assume that you have hacked this, or are using windows server (which rules out XP!).
Regardless, each user logged into the system will therefore have their own applications running and each set of applications are unique to that user. So App1 could be run independently by each user.
That means that your console application cannot detect the other user that is logged on.
To do this you must use a Windows Service. This runs in the background and can detect and work for multiple users and also detect login and logout. See this SO link
This is the purpose of inheriting MyService from ServiceBase. If you are not running the application as a service, then you are not running it correctly!
You need to first install your application as a service and then run it like a service.
You say that you don't think your application can run as a service. I'm not sure why, but if this is the case then you would have to instead look at creating some kind of script to run your application upon start-up/login.
This way, every time somebody logs in then your application would run. This might anyway be simpler for you.
Here is my scenario, I have a windows service that runs a task every 20 minutes, the task is: requesting updates from an API hosted by a remote website.
The response is a list of JSON objects, When the Service receives the list, it carries out a set of operations then appends more JSON objects, finally the service must push the list to a running console application.
My very specific question is: how to transfer this data from the windows service to the console App both directly and professionally
By directly I mean without intermediate solution like writing in a temp file or saving in SQL table ... etc.
By professionally I mean the best optimal solution especially without p/Invoke from the service to the console App.
You would definitely need a medium to communicate between these two processes. The communication can be done in a lot of ways on the same system.
With your explanation in Question it looks like one way communication. May be you can go for Inter-process communication via sockets(raw level) or Use a messaging framework for communication(WCF/SignalR) or you can even use a Message Queue system(MSMQ/RabbitMQ) etc.
You can get a specific answer if you can narrow down your question.
A nice, clean, 'modern' way of doing this, would be to host a Web API directly in the console application, and accept JSON input.
This is relatively easy to set up, and very easy to test and use.
Other methods include .NET remoting (which is not very modern any more), some other kind of service, like WCF, or any of the multitude of windows IPC methods.
I wrote an answer here that has some applicable code. Basically, the OP there wanted to send strings from a Windows Forms application to a console application and have the console application print the strings.
My recommendation is to use a Message Queue.
A few quick notes: first, you may have to enable the feature in Windows if you've never done so. Also, I guess under certain configurations of Windows you can't create the Message Queue directly from C#; if that's the case for you, you can create it manually (or there's probably a way to do it as part of an install script or something).
Here's the Windows Forms code:
private void button1_Click(object sender, EventArgs e)
{
// Or whatever name you end up calling it if you created the queue manually
const string myQueue = ".\\myQueue";
// It's possible that this won't work on certain computers
// If not, you'll have to create the queue manually
// You'll also need to turn the Message Queueing feature on in Windows
// See the following for instructions (for Windows 7 and 8): https://technet.microsoft.com/en-us/library/cc730960(v=ws.11).aspx
if (!MessageQueue.Exists(myQueue))
{
MessageQueue.Create(myQueue);
}
using (MessageQueue queue = new MessageQueue(myQueue))
{
queue.Formatter = new XmlMessageFormatter(new[] { typeof(string) });
queue.Send("Test");
}
}
Console application:
static void Main(string[] args)
{
// Or whatever name you use
const string myQueue = ".\\myQueue";
// See my comment on the corresponding line in the Windows Forms application
if (!MessageQueue.Exists(myQueue))
{
MessageQueue.Create(myQueue);
}
MessageQueue queue = new MessageQueue(myQueue);
queue.Formatter = new XmlMessageFormatter(new[] { typeof(string) });
while (true)
{
Message message = queue.Receive();
string messageText = message.Body.ToString();
// Close if we received a message to do so
if (messageText.Trim().ToLower() == "exit")
{
break;
}
else
{
Console.WriteLine(messageText);
}
}
}
I'm working on an intranet website.
All users should get desktop popups from the webserver whenever something new is posted on the website.
I was looking to make my own windows service that would subscribe to the server ( Making use of something like SignalR ) and then this service would show a simple popup notifying the user whenever the server sends out a message.
But instead of building this myself i was wondering if something like this isn't already out there. I've been looking around a bit but couldn't find anything.
I'm mainly a web developer and have never built a windows service or C# desktop application so i would prefer using some existing code.
Does anyone know of such a thing ?
For building a Windows Service try Top Shelf: http://docs.topshelf-project.com/en/latest/
In general it is easy as one, two, three...
public class TownCrier
{
readonly Timer _timer;
public TownCrier()
{
_timer = new Timer(1000) {AutoReset = true};
_timer.Elapsed += (sender, eventArgs) => Console.WriteLine("It is {0} and all is well", DateTime.Now);
}
public void Start() { _timer.Start(); }
public void Stop() { _timer.Stop(); }
}
public class Program
{
public static void Main()
{
HostFactory.Run(x =>
{
x.Service<TownCrier>(s =>
{
s.ConstructUsing(name=> new TownCrier());
s.WhenStarted(tc => tc.Start());
s.WhenStopped(tc => tc.Stop());
});
x.RunAsLocalSystem();
x.SetDescription("Sample Topshelf Host");
x.SetDisplayName("Stuff");
x.SetServiceName("Stuff");
});
}
}
I'm working on an intranet website. All users should get desktop
popups from the webserver whenever something new is posted on the
website.
using timer is not a good technique over here as updates are not guaranteed in particular interval or session .but you can take that as an option based on the need.
I was looking to make my own windows service that would subscribe to
the server ( Making use of something like SignalR ) and then this
service would show a simple popup notifying the user whenever the
server sends out a message.
Yes exactly like a chat application that would frequently have messages and users get a pop up.ASP.NET SignalR is a library for ASP.NET developers that simplifies the process of adding real-time web functionality to applications. Real-time web functionality is the ability to have server code push content to connected clients instantly as it becomes available, rather than having the server wait for a client to request new data.
But instead of building this myself i was wondering if something like
this isn't already out there. I've been looking around a bit but
couldn't find anything.
References for SignalR Link1,Link2,Link3
I'm mainly a web developer and have never built a windows service or
C# desktop application so i would prefer using some existing code.
Making C# desktop or windows service is not a big deal as you already are a programmer.Some existing codes for updations pop up is here.
for the signalr Server side, I would suggest you use a C# winform.
for the client side, you can use JavaScript inside any html file to 'receive' the message from the signalr Server, then you can popup an alert message or whatever you want, however, in this case you have to make sure the users are browsing that html file in a browser, otherwise the message won't be received.
there's no ready code since signalr support different types of servers as well as different types of clients, I believe you need to write your own code. Actually Signalr is quite easy to use, write your own code may be faster than using the others.
This question: SignalR Chat App in WinForm With Remote Clients looks like it might point you inthe right direction. Specifically this article:
https://damienbod.wordpress.com/2013/11/01/signalr-messaging-with-console-server-and-client-web-client-wpf-client/
you could probably use DesktopToast: https://github.com/emoacht/DesktopToast
or Growl: http://www.growlforwindows.com/
I'm quite new to development of Windows Services (my background is in Web Development) and I'm a bit confused by the development process for Windows Services.
As I understand it, the service has to be installed every time you compile the code, and then run from the Services MMC snapin.
This seems like an awfully painful process to go through every time you make a change to your code.
Can someone shed some light on the 'recommended' approach for building services?
Thanks
To debug services, I generally use the following boilerplate for Main:
static void Main()
{
ServiceBase[] servicesToRun = new ServiceBase[] { new MyService(); };
#if !DEBUG
//run the service normally using ServiceBase.Run
ServiceBase.Run(servicesToRun);
#else
//debug the process as a non-service by invoking OnStart and then sleeping
foreach (ServiceBase s in servicesToRun)
{
var serviceType = s.GetType();
var onStartMethod = serviceType.GetMethod("OnStart", System.Reflection.BindingFlags.Instance |
System.Reflection.BindingFlags.NonPublic);
onStartMethod.Invoke(s, new object[] { new string[0] });
}
Debug.WriteLine("done starting services");
while (true)
Thread.Sleep(200);
#endif
}
What this does is use reflection to get the OnStart protected method for each service, invoke it, then sit in a sleep loop to keep the process running.
This example is assuming MyService is the service class that inherits from ServiceBase, which overrides OnStart to spawn off thread(s) and do its thing.
Here I'm using the DEBUG compile-time constant as the controlling factor of whether to start normally or debug as a non-service. If DEBUG is defined it will run in-process as a non-service. Otherwise it does its normal thing calling ServiceBase.Run. Feel free to use a command-line argument or whatever works best for you.
You may need some tweaks or re-factoring most of the logic to console app for easier testing, debugging, as what comes out of the box is really painful.
Here are some resources :
http://candordeveloper.com/2012/12/27/debugging-a-windows-service-application-without-install/
Running Windows Service Application without installing it
the easiest of them might be putting
#if DEBUG
//your logic
#endif
in your logic, putting a breakpoint and hitting F5, this is what i do most of the time.
Would be interesting to know if there is even better ways :)
Answers from Bravo 11 and Ic. give some good tips and tricks. I will add some:
Be aware that running as as service has also some implications regarding login / security context:
running under SYSTEM, you cannot access network file shares normally (there is a way adding the machine account to the ACL however)
running under a (domain) user account needs "logon as service" privileges, which is IMHO the most common cause of service starting problems in enterprise environments (the GPO settings may be adjusted). In addition, you do not have access to the desktop, so if a popup will be displayed waiting for the user, the service hangs.
in the development phase, you can swap DLLs or even the EXE if the service is not currently running without uninstall / install
use Windows event log extensively.
These differences between services and "normal application" are important enough for me to let this run directly on a server as often as possible.
In my services, I use:
protected override void OnStart(string[] args)
{
// this is not just a simple message, this has to be called very early before any worker thread
// to prevent a race condition in the .NET code of registering the event source
EventLog.WriteEntry("XXXXService is starting", EventLogEntryType.Information, 1000);
....
And do not forget that OnStart() and OnStop()should not contain long running code. You normally start a worker thread in OnStart() which runs until some notification (set in OnStop) was triggered.
Basically I need my application to run from system start until system shutdown. I figured out the following approach:
create MyApp.exe and MyService.exe
MyApp should install MyService as a service
MyService is supposed to run at startup and periodically check if MyApp is running. If it's not than start it.
That's the code I wrote for my service:
protected override void OnStart(string[] args)
{
while(true)
{
int processesCount =
Process.GetProcessesByName(Settings.Default.MyAppName).Count() +
Process.GetProcessesByName(Settings.Default.MyAppName + ".vshost").Count() +
Process.GetProcessesByName(Settings.Default.MyAppUpdaterName).Count();
if(processesCount==0)
{
//restore
var p = new Process { StartInfo = { FileName = Settings.Default.MyAppName, Arguments = "" } };
p.Start();
}
else
{
}
System.Threading.Thread.Sleep(3000);
}
}
How can I install this process so that it starts on windows start?
I'm not sure if this infinite loop in OnStart method is a good idea. Is it?
Is the general idea ok?
What I've done is have a windows service that runs the logic and main application code. Then if you need a GUI for it, have the windows service expose a web service via WCF and create a windows app that calls to the web service. On install, put you windows app in the windows startup.
This model will have the main application code running all the time, but the GUI is only up when a user is logged in.
Is the general idea ok?
As Hans points out in comments this is hostile to the user and fortunately won't work on Vista or later because services run in their own windows station. Put whatever logic you need to run all the time in the service and use an IPC mechanism such as WCF to communicate with an (optionally) running UI. If the user disables the service or exits the GUI respect their wishes...
How can I install this process so that it starts on windows start?
Add an entry to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run or HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Runthat points to your GUI application.
I'm not sure if this infinite loop in OnStart method is a good idea.
Is it?
No. You need to return from OnStart if you need to do work after OnStart returns create a Thread to do that work.