Running a WMI Subscriber from a script can be a useful tool for managing and monitoring your system. WMI (Windows Management Instrumentation) is a powerful technology that allows you to access and control various aspects of your Windows operating system. In this article, we will explore how to run a WMI Subscriber from a script, providing step-by-step instructions for entry-level users.
What is a WMI Subscriber?
Before we dive into the details of running a WMI Subscriber from a script, let's first understand what a WMI Subscriber is. In WMI, a Subscriber is a component that receives and processes event notifications. These notifications are triggered by various events happening on your system, such as a file being created or a process starting or stopping. By running a WMI Subscriber, you can automate actions based on these events, such as sending an email or executing a script.
Step 1: Create a WMI Event Query
The first step in running a WMI Subscriber from a script is to create a WMI event query. This query defines the events you want to monitor and the conditions that trigger them. To create a WMI event query, follow these steps:
- Open a text editor, such as Notepad, to create your script.
- Start by creating an instance of the WMI event query language (WQL) class. This class allows you to define your event query. Use the following code:
Set objWMIService = GetObject("winmgmts:\\.\root\cimv2")
Set objEventQuery = objWMIService.ExecNotificationQuery("SELECT * FROM __InstanceCreationEvent WHERE TargetInstance ISA 'CIM_DirectoryContainsFile' AND TargetInstance.GroupComponent='Win32_Directory.Name=""C:\\\\Temp""'")
In this example, we are monitoring the creation of files in the "C:\Temp" directory. You can modify the query to suit your specific requirements.
Step 2: Create a WMI Event Handler
Once you have defined your event query, the next step is to create a WMI event handler. This handler specifies the actions to be taken when the event is triggered. To create a WMI event handler, follow these steps:
- Continue editing your script in the text editor.
- Create an instance of the WMI event sink class. This class represents the event handler. Use the following code:
Set objEventSink = WScript.CreateObject("WbemScripting.SWbemSink", "EventHandler_")
In this example, we are creating an event handler named "EventHandler_". You can choose any name you prefer.
- Create a subroutine to handle the events. Use the following code:
Sub EventHandler_OnObjectReady(objObject, objAsyncContext)
' Add your code here to handle the event
End Sub
In this subroutine, you can write your code to perform the desired actions when the event is triggered. For example, you can send an email, log the event to a file, or execute a script.
Step 3: Connect the WMI Event Query and Event Handler
Now that you have created both the WMI event query and the event handler, the final step is to connect them. This connection allows the event handler to receive and process the event notifications. To connect the WMI event query and event handler, follow these steps:
- Continue editing your script in the text editor.
- Connect the event query and event handler using the following code:
Set objEventSource = objWMIService.ExecNotificationQueryAsync(objEventQuery, objEventSink)
In this example, we are connecting the event query and event handler using the "ExecNotificationQueryAsync" method. This method establishes the connection and starts monitoring the events defined in the event query.
Step 4: Run the WMI Subscriber
With the event query and event handler connected, you are now ready to run the WMI Subscriber. To run the WMI Subscriber, follow these steps:
- Save your script with a ".vbs" file extension, such as "subscriber.vbs".
- Open a command prompt by pressing the Windows key + R, typing "cmd", and pressing Enter.
- Navigate to the directory where you saved your script using the "cd" command. For example, if you saved your script in the "C:\Scripts" directory, use the following command:
cd C:\Scripts
- Run the script by typing the script's filename and pressing Enter. For example, if you named your script "subscriber.vbs", use the following command:
subscriber.vbs
Once the script is running, it will monitor the events defined in the event query and execute the actions specified in the event handler when those events occur.
Congratulations! You have successfully learned how to run a WMI Subscriber from a script. By following the steps outlined in this article, you can automate actions based on events happening on your system, enhancing your system management and monitoring capabilities.
References
| Number | Source |
|---|---|
| 1 | https://docs.microsoft.com/en-us/windows/win32/wmisdk/event-queries |
| 2 | https://docs.microsoft.com/en-us/windows/win32/wmisdk/wmi-tasks-for-scripts-and-applications |