Customizing event logging

By handling events, you can customize how the system logs records into its Event log.

The system raises the following types of related events:

EventLogEvents.LogEvent.Before - allows you to customize the data logged for events or cancel logging for certain types of events.
EventLogEvents.LogEvent.After - allows you to perform custom actions after events are successfully logged, for example duplicate certain types of events into a custom log.

Note: Performing demanding operations during event logging can have a negative impact on the performance of the website (particularly on sites under heavy load where a large number of events is logged).

Example

The following example demonstrates how to disable logging for events of a specific type and modify the Description text for certain events.

Open your Kentico project in Visual Studio (using the WebSite.sln or WebApp.sln file).
Create a custom module class.
- Either add the class into a custom project within the Kentico solution (recommended) or directly into the Kentico web project (into a custom folder under the CMSApp project for web application installations, into the App_Code folder for web site installations).
Override the module’s OnInit method and assign a handler method to the EventLogEvents.LogEvent.Before event.
Perform the required actions within the handler method.
- Access the data of the logged event through the Event property of the handler’s LogEventArgs parameter.
- To cancel the logging of an event, call the Cancel method of the handler’s LogEventArgs parameter.




using CMS;

using CMS.DataEngine;
using CMS.EventLog;
using CMS.Base;

// Registers the custom module into the system
[assembly: RegisterModule(typeof(CustomInitializationModule))]

public class CustomInitializationModule : Module
{
    // Module class constructor, the system registers the module under the name "CustomInit"
    public CustomInitializationModule()
        : base("CustomInit")
    {
    }

    // Contains initialization code that is executed when the application starts
    protected override void OnInit()
    {
        base.OnInit();

        // Assigns a handler to the LogEvent.Before event
        EventLogEvents.LogEvent.Before += LogEvent_Before;
    }

    private void LogEvent_Before(object sender, LogEventArgs e)
    {
        // Gets an object representing the event that is being logged
        EventLogInfo eventLogRecord = e.Event;

        // Cancels logging for events with the "CREATEOBJ" or "UPDATEOBJ" event codes.
        // Disables event log records notifying about the creation or update of objects in the system,
        // but still allows events related to object deletion.
        string eventCode = eventLogRecord.EventCode;
        if (eventCode.EqualsCSafe("CREATEOBJ") || eventCode.EqualsCSafe("UPDATEOBJ"))
        {
            e.Cancel();
        }

        // Adds a custom message to the Description field for events of the Information type
        if (eventLogRecord.EventType.EqualsCSafe("I"))
        {
            eventLogRecord.EventDescription += " Custom message";
        }
    }
}