What does the term "Backchannel Request" means and how to make backchannel requests

Question

To be more specific:

I'm actually trying to integrate to Baseacamp using their new Basecamp api which supports OAuth 2.0. and thx to their poor resources & documentation i'm stuck at #4 of this documentation which says i have to make a backchannel request to get the access token (i have successfully completed 1-3 steps which means i have the verification code and state).

So if anyone have any idea about this beast then pls help me fight this ;)

I have used jso OAuth 2.0 lib which helped me complete 1-3 steps but this lib uses implicit authentication grant and basecamp uses authorization code grant. So i guess i have to do some manual client-server dance which is why i need to know what this Back Channel request means and how to make one?

Answer 1

What Is a Back Channel?

Simply, a back channel is an outbound connection to a server on the Internet, automatically established by client software running a PC behind your firewall. It can also be as innocuous as some small bit of information ("cookies") left on a client desktop in an easily accessible location. The purposes of back channel connections and information gathering cookies are numerous, and can be classified as Useful, Questionable, and Evil.