[Feature] Export operation

[tabacitu]

Discussed in https://github.com/Laravel-Backpack/CRUD/discussions/2667

^{Originally posted by **tabacitu** April 13, 2020} Instead of using DataTable's magic to export rows, we should create an Export operation. That way: - we could even customize how it's done, add different export formats, etc; - it would fix the problem of having to see all entries that are exported (known limitation of the DataTables export when using AJAX); The way I see it: - the operation adds a single "Export" button to the bottom stack; - click the button and it opens a modal; in that modal, you can - choose which columns to show in the export; - (maybe) reorder the columns in the export; - choose the export format (XLS, CSV, PDF); - choose to export: - All rows (124.141 entries) - Filtered rows (45.133 entries) - Currently visible rows (25 rows) - Currently selected rows (5 rows) - click "Download" and you get the file you want; the file itself is generated using [PHP generators](https://www.php.net/manual/en/language.generators.syntax.php), so that you can export even millions of rows;

[mamarmite]

Hi @tabacitu, I've started this feature as if it were in the backpack namespace : https://github.com/mamarmite/export-operation Is it ok ? Anyhow feel free to ask to change it until it's finished or anything.

For now the basic setup for the operation as a package is setup.

The feature implemented :

• [X] Add the button to the crud list operation if the crud controller have the operation.
• [X] Takes the columns setup in the operation setup function and export them to CSV (only for now).
• [ ] No modal for now.
• [ ] I choose to start the development with the export functionality of the operation. So I've chosen the drop down as the DT implementation and it was quicker.

Notes I've got time to implement the excel export.

I didn't dig and testing into https://github.com/yajra/laravel-datatables-export (it need livewire and I wouldn't have it to be requested in the current project I'm implementing this.

I will push my progress to the repo linked earlier. Feel free to comments /

[tabacitu]

@jorgetwgroup , @pxpm and @maurohmartinez - please have a meeting about this, for Pedro to brief you guys on its status. We have it, but... it's not perfect. Reach a conclusion on how to move forward and let's do this 💪

@jorgetwgroup has the details on the deadline and everything, so let's follow his lead.

Take it away @jorgetwgroup 🙏