FormData part.body.read does not fill buffer about crystal HOT 3 CLOSED

IO.copy continues reading until there is no more data available (i.e. IO#read returns 0).

It seems the documentation needs some clarification.

from crystal.

Per documentation, IO#read does not guarantee to fill the entire slice.
It reads as much data as is immediately available on the socket buffer. This can of course differ depending on utilization of the connection which explains why the code may fill the entire slice sometimes but sometimes not.

If you want to ensure filling the slice, you'll need to do repeated reads until there is no data left. IO#read_fully can be useful for that, but it expects there to be enough data available for a fill. You might also consider IO.copy which has no size requirements.

from crystal.

Thanks for clarifying. IO.copy seems to have the same caveat ("at most"). It would be nice to have a method that reads as much as possible up to a limit. It seems #11896 might address this.

from crystal.