websocket - Netty channel().read() on channel without any data currently present

Question

im trying to figure out how to implement back-pressure in netty and i found that autoread=true and using explicit ctx.channel().read() might work but im not sure how it works and was not able to find more details.

Specifically, i was wondering what happens if read() is called. Are the semantics that netty will try to read from underlying channel (lets say websocket connection)? What if there are no data ready to be read? Will the read succeed without reading any data? Or will i be guaranteed that if i call read once, it will keep trying to read until there are some data available?

Thanks

question from:https://stackoverflow.com/questions/65902638/netty-channel-read-on-channel-without-any-data-currently-present

Answer 1

read() basically just tell the Channel to read the next chunk of data when there is something ready, which either means directly or at some point later. So yeah you are guaranteed that if you call read() it will read at some point.