Cursor Pagination

[StephenStrickland]

Love the project.

I'm looking to implement cursor based pagination, any easy way to do that currently with Gridify?
[edit: spelling]

[alirezanet]

Interesting question, maybe soon I would provide some built-in feature for it but right now gridify doesn't support it directly

[StephenStrickland]

Would you be interested a PR or a RFC to talk through potential implementation?

[alirezanet]

ofc would be nice and helpful !

[cmenzi]

@StephenStrickland Did you already started with it? I've tried it, but it's not that easy.,

One issue is that a lot of extension methods relies on IGridifyQuery, which already derives from IGridifyPagination. So, we would need to re-design this heavily, I guess.

I've introduced a IGridifyCursorPagination and also some extension methods on it

IQueryable<T> ApplyCursorPaging<T>(this IQueryable<T> query, IGridifyCursorPagination? gridifyCursorPagination)

public interface IGridifyCursorPagination : IGridifyOrdering
{
    int Limit { get; set; }

    string Cursor { get; set; }
}

But then methods like Gridify, GridifyQueryable, GridifyAsync, GridifyQueryableAsync not working anymore, as they need a IGridifyQuery, which as I mentioned already implements IGridifyPagination.

I think we need to include IGridifyOrdering as we need remember the ordering of the columns. Not sure we also need to remember the filter. We also need include ordering of the id always id asc as last order statement.

Open Questions:

• How to handle Guids as Ids?
• What if the user specify ordering id desc by himself?
• How to handle different namings of the id columns. We need to order by some determinist id or compound key?

The idea would then be to base64 encode the cursor with the orderings and the nextToken and return as Cursor property.

I've found this good article here: https://medium.com/@george_16060/cursor-based-pagination-with-arbitrary-ordering-b4af6d5e22db

Other inputs:

• https://docs.gitlab.com/ee/api/rest/#keyset-based-pagination
• https://github.com/mrahhal/MR.AspNetCore.Pagination

Maybe we could go the way as GitLab by adding pagination=keyset to the model. But I don't really like that.

[cmenzi]

@StephenStrickland @alirezanet You can find my first implementation ideas here. It's not really ready yet, but maybe to start some dicusssions

master...cmenzi:Gridify:feature/cursor-based

[cmenzi]

@alirezanet Yes, I also don't like those breaking changes. Yeah, that could be an option.

Option 1) You mean keep IGridifyQuery as it is and try to add side-by-side implementation with IGridifyCursorQuery and necessary extentions methods.

Option 2) Yes, for a version 3 we could do that. Question is if how would the model GridifyQuery look like? Having all properties for both paging method in it? Or having different models? ...

I would try to do another suggestion - less intrusive :-) - for option 1.

[alirezanet]

Option 1- Yes this way we don't break anything.
Option 2- anyway we need to improve the library in v3 ... not sure yet ... needs some investigations

[cmenzi]

Here 2nd attempt with option 1: https://github.com/alirezanet/Gridify/compare/master...cmenzi:Gridify:feature/cursor-option-1?expand=1

Still need to do some refactorings. But if the direction now is ok, I will raise a the PR after I've done all the clean ups, docs, ...

[alirezanet]

Nice! 🚀 Looks much better.
would be nice if you can also add some documentation explaining how it works and what are the limitations in the docs

[alirezanet]

@StephenStrickland can you test this branch and let me know if it works for you?