How do I use list.GetChangesBatchAsync() to Get ALL Changes for a Given Change Query?

[adamfisher]

I am trying to create an extension method that will allow me to get ALL of the changes that occurred for a given change query and I thought I would use GetChangesBatchAsync() to do it but I am confused how that is supposed to work to get everything? Won't subsequent calls need the change token? Just wondering how to build up the batch call to get the changes?

public static async Task<IList<IChangeItem>> GetAllChangesAsync(this IList list, ChangeQueryOptions queryOptions)
{
	Batch batch = list.PnPContext.NewBatch()!;
	IEnumerableBatchResult<IChange>? changes = await list.GetChangesBatchAsync(batch, queryOptions);

	// Do something to get ALL changes...

	var results = await list.PnPContext.ExecuteAsync(batch);

	// How do I get all changes in one list to return?
}
}

[jansenbe]

@adamfisher : why do you need multiple calls to get all changes. If you use below you'll get all changes returned. Are you looking into paging the changes? The idea is you initially read the list information you need using regular APIs, then get the last change token (you can use the LatestFirst property of the ChangeQueryOptions) and store the change token. When you later on want to understand what happened you retrieve your stored change token and use that as a point in time to get the changes from.

var changes = await list.GetChangesAsync(new ChangeQueryOptions(true, true));

[adamfisher]

I had over 1,000 changes I needed to process and while I could increase the FetchLimit on the query options, I wasn't sure how I could set that. I just want to get all of the changes at once.

[adamfisher]

I ended up doing this since I couldn't figure out how to use the batch version:

public static async Task<List<IChange>> GetAllChangesAsync(this IList list, ChangeQueryOptions queryOptions)
{
	IList<IChange> changes = await list.GetChangesAsync(queryOptions);
	List<IChange> results = new(changes);

	while (changes.Count > 0)
	{
		var lastChangeToken = changes.Last().ChangeToken;
		queryOptions.ChangeTokenStart = lastChangeToken;
		changes = await list.GetChangesAsync(queryOptions);
		results.AddRange(changes);
	}

	return results;
}

[jansenbe]

That's a good approach @adamfisher .