Retrieve page ID on the first OnSave

Question

I have a javascript file which is calling a service call method on the click of Save command. I need to validate this functionality only for pages. However, on the first save in tridion, pages will not have a valid TCM ID ending with "-64". How do I validate if the object is a page and then trigger my method from JavaScript?

Or should this be done only via Event handler? If yes, how?

Thanks,

Keirthana

Update:

A detailed picture of my situation to explain why I need JavaScript:

I am adding a customized tab at the component presentation level (next to the preview tab on the page when you select a component presentation). This tab contains 2 fields with data that I have to store in the APP_DATA table. The input data from the fields is available on the client side JavaScript since we are getting it by accessing the corresponding tab controls using the page object. Hence to save this data to the APP_DATA table, I use a service call which stores and retrieves my data. In this scenario, I get the invalid URI problem on first save since there won't be a valid page ID generated until the server side calls are over.

Answer 1

Here is an untested code sample to get you started.

You can add the code to check if the current page already has a version to know if the event was triggered on first save or not.

Add this to a new class library C# project in Visual Studio, compile it, then add the DLL somewehre on the Content Manager server, then register it in the Tridion/config/Tridion.ContentManager.config file as follows:

...
<extensions>
<add assemblyFileName="C:\pathToTheExtensionDll\Tridion.Extensions.Events.dll"/>
...
</extensions>

Sample Code:

using System;
using Tridion.ContentManager.ContentManagement;
using Tridion.ContentManager.ContentManagement.Fields;
using Tridion.ContentManager.Extensibility;
using Tridion.ContentManager.Extensibility.Events;
using Tridion.Logging;

namespace Tridion.Extensions.Events
{
[TcmExtension("Page Events")]
public partial class PageEventsHandler : global::Tridion.ContentManager.Extensibility.TcmExtension
{
    #region Constructor
    /// <summary>
    /// Constructor to register events with Tridion Content Manager
    /// </summary>
    public PageEventsHandler()
    {
        try
        {
            RegisterEventHandlers();
        }
        catch (Exception e)
        {
            PageEventsHandler.LogMessage("An error occurred while registering event handlers: \n" + e.Message);
        }
    }
    #endregion

    /// <summary>
    /// Registers component (item) related event handlers with Tridion Content Manager
    /// </summary>
    private void RegisterEventHandlers()
    {
        EventSystem.Subscribe<Page, SaveEventArgs>(
            SetPageAppData, 
            EventPhases.Initiated, 
            EventSubscriptionOrder.Early
        );
    }

    /// <summary>
    /// Sets a Page App Data with CP metadata information
    /// </summary>
    /// <param name="subject">Page about to be saved</param>
    /// <param name="args">Event data for the save action</param>
    /// <param name="phase">Current event phase</param>
    private void setPageAppData(Page subject, SaveEventArgs args, EventPhases phase)
    {
        TcmUri pageUri = subject.Id;
        //Add AppData
    }

    #region Class Methods
    /// <summary>
    /// Writes a message to the Tridion log
    /// </summary>
    /// <param name="message">Message to log</param>
    private static void LogMessage(string message)
    {
        Tridion.Logging.Logger.Write(message, "Page Events", LoggingCategory.General);
    }
    #endregion
}
}

Answer 2

Thank you all for your answers, but since this question and answers are getting beyond the original scope of the query, I have posted my exact query at Invalid Page ID when pushing data to APP_DATA filtering down the exact issue.