node.js - How to receive a zip file in koa server -

i'm implementing webserver using koa. 1 of request handlers needs receive , store large zip file. file not uploaded web page, sent nodejs application. therefore it's not multipart encoded, applcation/octet-stream. how can read such file request? i've noticed there request.socket object not find documentation on how use it.

in other words need opposite this.body = fs.createreadstream(path);