How to upload a large amount of data to .xlsx/.xls

Question

PHP

The option from PEAR is not suitable. There is a limit on the number of characters.
PHPExcel is not suitable because it eats a lot of memory.
Issuing a binary with Content-Type: application/xls to the browser is not suitable. the file must have a column with the date/number type.
Putting ∞ RAM is not an option.
I think to unpack xlsx and php to generate the same files, but this is a bit inadequate ...
Tell me, please, what should I do?

Answer 1

I think to unpack xlsx and php to generate the same files, but this is a bit inadequate...

Quite normal, and should work quickly.
Did the same myself. Collected style files, data, etc. => Packed => Renamed to xls.

Answer 2

Collect csv - convert to xlsx using Unoconv - then open in the same PHPExcel and set the column type.