According to microsoft, VB can't be used to create NT services because it doesn't support free threading. Maybe the next version (VB.net or VB7) can do it.
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According to microsoft, VB can't be used to create NT services because it doesn't support free threading. Maybe the next version (VB.net or VB7) can do it.
Sorry to contradict you Frans, but I have a book called "Pure Visual Basic" published by Sams, that tells you how to build NT services.
VB7 will never take me alive I tell you!
Well, never believe microsoft anyway.
Hey guys....thanks for your reply...got it to work...Frans believe it or not but you were able to help me find out the answer....
anyway, just in case you guys are interested in this here's how i got it to work:
Steps:
-> Copy SRVANY.EXE to your system and install it as a Windows NT™ service, for example:
INSTSRV MyService c:\tools\srvany.exe
-> configure via the Services applet ("Startup..." dialog) of the Control Panel as manual or automatic, as appropriate.
-> set via the Services applet ("Startup..." dialog) of the Control Panel the account for the service. If you need access to the screen & keyboard, you must choose the LocalSystem account and click the "Allow Service to Interact with Desktop", otherwise choose any account and specify the correct logon password. Note that the LocalSystem account doesn't have network access.
Specifying the application to start & its parameters:
Run the Registry Editor (REGEDT32.EXE):
-> under HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MyService: create a 'Parameters' key
-> under the above key, create an 'Application' value of type REG_SZ and specify there the full path of your app executable (including the extension). For example:
Application: REG_SZ: D:\TOOLS\VI.EXE
-> OPTIONAL: under the above key, create an 'AppParameters' value of type REG_SZ and specify the parameters for your app. For Example:
AppParameters: REG_SZ: C:\TMP\FOO
-> OPTIONAL: under the above key, create an 'AppDirectory' value of type REG_SZ and specify the current directory to use for the app, eg:
AppDirectory: REG_SZ: C:\TMP
Thanks a lot Frans and you too wossname!
I still can't figure out how I helped you, but I'm glad you figured it out.
well i looked-up the key word "free-threading" and it led me to the topic nt service where i finally found the solution....
thanks again.
Ozned, frans is right because of the fact that VB doesn't support Free Threading. The way you explained works, but is not adviceable (can cause unexpected behavior) and isn't supported by Microsoft.
And yes, in VB.NET it will be possible to create Services.
Hello gijsj! Thanks for your reply.
Yes, I've accepted the fact that Free-Threading is not possible but I was just wondering why the solution i came out with is not supported by microsoft. This solution came from them. In fact, the SRVANY.EXE and INSTSRV.EXE came with Windows NT workstation resource kit and a document that tells you how to get around this.
It's a work around because of the incapabilities of VB, read the following article:
http://support.microsoft.com/support...n_SRCH&SPR=VBB
(NOTE: The Microsoft Windows NT 4.0 Resource Kit documents Srvany.exe as an unsupported tool. Use this tool at your own risk. )
ozned, Yes you can create a NT Service with VB. But you need the NTSVC.OCX and below is some sample code from MSDN :)
Code:Creating an Agent NT Service with VB
Diderick Oerlemans
Wouldn't it be nice to be able to create an agent that's running on your NT Server as an NT service? Well, it's not so hard to do, because it's possible to use VB!
Chris Duke, who runs an excellent site for advanced VB developers at vb.duke.net, got me started on this agent project when he posted some articles about creating an NT service using VB. One thing you need is NTSVC.OCX, an unsupported OCX that Microsoft has been distributing (as source code) on MSDN for some time now.
What I needed to build was an agent that could read e-mail, parse it, and perform some actions on a SQL Server. Once I'd done just that, I published my experiences on vb.duke.net, but because I received so many requests for source code, I thought it would be a good idea to send this document to Visual Basic Developer so more people can benefit from my findings.
Preparations
You'll need to prepare some things before doing the coding. Start by getting the newest active messaging library -- you'll need version 1.1 at a minimum. Next, make sure you install Outlook 8.01 (this is also the minimum version that will work) on the target server (nope, Exchange 5.0 client with the service pack doesn't work!). Also, you'll need to run regsvr32 to register the NTSVC.OCX on both your development PC and the target server.
Then, set up a domain user with a mailbox on Exchange server. The domain user should have enough rights on the target server so it can use the Outlook client. Next, log onto the target server and create the default Exchange profile. After creating your agent and installing it as a service, you should set the service to log onto NT using the domain user you just created.
Using the service OCX
Create a main form and drop the NTSVC.OCX on it. Fill in the name and display name properties. Initialization of the service should take place in the load event of the main form:
Private Sub Form_Load()
Dim strDisplayName As String
On Error GoTo Err_Load
strDisplayName = NTService.DisplayName
If Command = "-install" Then
NTService.Interactive = True
If NTService.Install Then
MsgBox strDisplayName &" installed successfully"
Else
MsgBox strDisplayName & " failed to install"
End If
End
ElseIf Command = "-uninstall" Then
If NTService.Uninstall Then
MsgBox strDisplayName & " uninstalled _
successfully" Else
MsgBox strDisplayName &" failed to uninstall"
End If
End
ElseIf Command = "-debug" Then
NTService.Debug = True
ElseIf Command <> "" Then
MsgBox "Invalid command option"
End
End If
' Enable Pause/Continue. Must be set before
' StartService is called or in design mode
NTService.ControlsAccepted = svcCtrlPauseContinue
' connect service to Windows NT services controller
NTService.StartService
Exit Sub
Err_Load:
ServiceLog ("[" & Err.Number & "] " & _
Err.Description)
End Sub
As you can see, we start by parsing the command line option, to determine whether the service should be (un)installed. In other cases -- for example, when the service is started by the NT service control manager -- it will start the service with the NTService.StartService method.
The OCX also exposes a very handy function to log events to the NT application log. I wrote a little wrapper sub to use this function: Public Sub ServiceLog(strMessage As String)
Call NTService.LogEvent(svcMessageError, _
svcEventError, strMessage)
End Sub
Due to the sample too long, so I continue it here.
Code:Because you usually don't have a console for your service (except when (un)installing), you should log all errors and other useful stuff. For example, you could have the form load error handler log any errors using the ServiceLog subroutine. The service OCX will raise the following event when starting: Private Sub NTService_Start(Success As Boolean)
On Error GoTo Err_start
'Start SQL Server connection
Success = StartSQL()
If Success Then
ServiceLog ("SQL connection established")
Else
ServiceLog ("SQL connection failed")
End If 'Start Mail connection
Success = (StartMail() = 0) If Success Then
ServiceLog ("Mail session established")
Else
ServiceLog ("Mail session failed")
End If
'Enable timer
Timer.Interval = 1000
Timer.Enabled = True
Exit Sub
Err_start:
ServiceLog ("[" & Err.Number & "] " & )
Err.Description)End Sub
What I've done here is initialize the SQL Server connection and start a mail session (more about this later). The SQL Server connection should pose no difficulties. In my case, I used DB-Library and integrated security, but ADO or RDO should also work. I also initialized a timer control (for polling the mailbox) on the main form. If you set the Success Boolean to false, the OCX will notify the NT service control manager that the service couldn't be started -- Success to true does the opposite. Note that all relevant information is again logged to the application log using the ServiceLog wrapper sub.
When the service is stopped (using the NT service control manager, for example), the following event procedure is fired: Private Sub NTService_Stop()
On Error GoTo Err_stop
Call StopSQL
Call StopMail
Unload Me
Exit Sub
Err_stop:
ServiceLog ("[" & Err.Number & "] " & _
Err.Description)
End Sub
It does the obvious -- disconnects from SQL Server, closes the mail session, unloads the form, and thus ends the service.
Using active messaging
This is where most people who mailed me got stuck. I again stress the fact that you need the newest versions of active messaging (or CDO, for Collaboration Data Objects, as it's called these days) and Outlook installed. Active messaging version 1.0 will not work, and Outlook 8.0 will not work.
I created a generic class to hold my active messaging session (this isn't required, of course). In the main form, the following function initializes the class (clsMail is a private var in the main form) and calls the logon method: Private Function StartMail() As Long
StartMail = 0
Set clsMAIL = New clsMailService
If Not clsMAIL.Logon(True, XCHANGE_PROFILE, _
XCHANGE_PASSWORD) Then
StartMail = clsMAIL.LastError
End If
End Function
There are two constants used for the profile name and the password. This is the profile you created for the domain user, which your service uses to log on to NT. Here's the logon method: Public Function Logon(Optional strProfile As String, _
Optional strPassword As String) As Boolean Logon = True
If IsMissing(strProfile) Then strProfile = ""
If IsMissing(strPassword) Then strPassword = ""
If Not CheckSession() Then
Logon = False
Exit Function End If
On Error GoTo Err_logon
objSession.Logon strProfile, strPassword, False, _
True, 0, True
Exit Function
Err_logon:
Logon = False
'Set the class error props for later inspection
lngError = Err.Number
strError = Err.Description Exit Function
End Function
The catch is in the parameters for the logon method of the session object. Here's the description:
Profilename: The profilename you created on the target server
Password: The domain password of the user you created
Showdialog: False
NewSession: True (doesn't matter)>
Parentwindow: 0 (doesn't matter)
NoMail: True (very important setting)
The NoMail setting is where it can all go wrong. It tells MAPI whether it should start the mailspooler. The default is to start it (NoMail = False). There's one big problem with the mailspooler -- it's not accessible within the security context of a service. (Actually, the mailspooler is started outside any security context. This is a somewhat complex story, but there's a document available through MSDN for the diehards.) Solution: Set NoMail to True. I use a little check function to check whether the session is already initialized. If not, a new session object is created: Private Function CheckSession() As Boolean
CheckSession = True
On Error GoTo Err_Fail
If objSession Is Nothing Then
Set objSession = CreateObject("MAPI.Session")
End If
Exit Function Err_Fail:
CheckSession = False
'Set the class error props for later inspection
lngError = Err.Number
strError = Err.Description
Exit Function
End Function
Building the rest
As mentioned previously, there's a timer control on the main form. I use it to call a method of the mail class (ProcessMessages): Private Sub TIMER_Timer()
Dim lngNumber As Long
On Error GoTo Err_Timer
'disable the timer while processing
Timer.Interval = 0
Timer.Enabled = False
lngNumber = clsMAIL.ProcessMessages()
If lngNumber < 0 Then
ServiceLog "MAIL ERROR: [" & clsMAIL.LastError _
& "] " & clsMAIL.LastErrorMessage
End If
'enable the timer
Timer.Interval = 1000
Timer.Enabled = True
Exit Sub
Err_Timer:
Timer.Enabled = True
ServiceLog ("[" & Err.Number & "] " & _
Err.Description)
End Sub
This method parses new messages in an Exchange folder. For each new message, it performs types of actions on a SQL Server database -- for example, retrieving information -- and sends results back to the sender: Public Function ProcessMessages(Optional strType as _
String) As Long
'Dims omitted in this listing
ProcessMessages = 0On Error GoTo Err_mapi
'Get messages collection for selected inbox
Set objInMessages = objSession.Inbox.Messages
'Initialize Filter for fast processing
Set objMessageFilter = objInMessages.Filter
objMessageFilter.Unread = True
If not IsMissing(strType) Then
objMessageFilter.Subject = strType
End If
'Traverse the message collection
For Each objInMsg In objInMessages
'Go process the message, adding any results to the
'strReturn variable
lngCounter = lngCounter + 1
strReturn = ParseOrder(objInMsg.Text)
'Prepare and send the return message
Set objOutMsg = objSession.Outbox.Messages.Add
objOutMsg.Subject = strType & " CONFIRMATION"
objOutMsg.Text = strReturn
Set objRecip = objOutMsg.Recipients.Add
Set objRecip.AddressEntry = objInMsg.Sender
objRecip.Resolve
objOutMsg.Update
objOutMsg.Send False, False, 0
'Mark message as read
objInMsg.Unread = False
objInMsg.Update
Next
'Return number processed
ProcessMessages = lngCounter
Set objInMessages = Nothing
Exit Function
Err_mapi:
ProcessMessages = -1
'Set the class error properties for later inspection
lngError = Err.Number
strError = Err.Description
Exit Function
End Function
Well, as you can probably see already, the possibilities are endless. At my company, we just built one for guarding both our Web and Exchange servers. This agent polls our clients' servers and checks whether everything is still working. It will notify the correct people if there's trouble. In the new Exchange Server 5.5, it's possible to create agents using server-side scripting. This will probably end the use for mail-reading agents running on Exchange servers. But if you want your agents on a separate server, I can't think of a simpler way to create them. [Readers might also want to explore the Windows NT Resource Kit's SRVANY.exe, which lets you run any NT application as a service. -- Ed.]
Diderick Oerlemans is an IT consultant and partner in I-Cube BV, a small IT service company located in Delft, The Netherlands. He has more than six years' experience in developing information systems using Microsoft products. He and his team develop all kinds of client/server systems for midsize and large companies in The Netherlands. www.i-cube.nl, [email protected].
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I have the NTservice OCX
works great and is very simple
Just put in on a from add 10 lines of code and thats it
email for it
[email protected]
Chris & Kurtsimons, I know it can be done but it isn't recommended.
If you'd understand the inner working of a Service it's pretty easy to figure out that it is a hack.
Maybe nice to play around with but definitly not for a commercial/production environment.
gijsj, why you said it is not for a commercial/production environment?
First,
Because it can causes instable behavior. As I already told, it's a hack/work around.
Second,
It's not supported by Microsoft. So when your Web - Exchange Server (your previous post) is having trouble Microsoft will not give guaranty or support for it. This seems a pretty good reason to me.
Hi guys! First of all, I would like to thank all of you for all the insights you've posted on my question. It surely helped me a lot.
I dont think there's anything wrong finding a solution that will require you to "hack"/edit the system registry. Microsoft warns those who do especially for those who doesnt understand system services and system registry, coz if you make just one mistake...it can cause serious damage to your operating system or other applications running inside windows.
Vendors comes out with possible solutions like providing OCX to developers so that they dont have to undergo the process of trying to hack their registry and cause potential system damage. But my guess is, the OCX will do that for you, i mean, edit the registry the correct and accurate way. In other words, these solutions shields us from having to do these stuff and screw our system. But if you know the ins/outs of services and the system registry then i guess its ok.
I'm not going to pretend i'm an expert (coz i really am not)....these are just my comments.
Once again, thank you very much for your insights!
Hey Chris, kurtsimons, do you know where i can get the ocx? Thanks a bunch!
Cheers!!!
Am I wrong but...
All a service is is a program that runs in the background with its own user settings, almost like having two people logged in at a time.
The basic settings give the service admin rights on the local machine only.
How is this different than having an app that runs when a user logs in with that users rights?
why would it be less stable
Hi Kursimmons! Where can I get the OCX you have?
thanks.
ozned, you can get it from Here
If you wish to have more info, juz take sometimes on this search results
Good Luck!
email me and i'll send it to you
[email protected]