I want know is there any way to get key pressing from client in cs2d.

I know that default Lua library does not provide such functionality.

But I do remember BrunoRZ ( currently never online for recent 2 years ) made script that firing projectiles by pressing key F6 or F7 and other effects by pressing numbers in keyboard ( e.g : 0 ~ 9 )

Actually I thought it's possible to make functions by pressing numbers in cs2d with cs2d hook - parse and cs2d command - slot0 ~ slot9.
However parse can not handle client's parsing but only server.

So I want know if anyone knows the Lua library related in such things exist or other ways to work.

It is not possible to achieve that key processing thing you're asking for. The only free keys dedicated to server scripts are the serveraction ones (by default F1, F2 and F3)

You can use menu to map the number keys though (through its invisible mode)