I thought this was a simple google search, but apparently I'm wrong on that.
I've seen that you should supply:
Accept-Encoding: gzip;q=0,deflate;q=0
in the request headers. However, the article that suggested it also noted that proxies routinely ignore that header. Also, when I supplied it to nginx, it still compressed the response message body.
http://forgetmenotes.blogspot.ca/2009/05/how-to-disable-gzip-compression-in.html
So, how do I tell a web server to disable compression on the response message body?
Many web servers ignore the 'q' parameter. The compressed version of a static resource is often cached and is returned whenever the request accepts it. To avoid getting compressed resources, use
Accept-Encoding: identity
The server should not serve you a compressed representation of the resource in this instance. Nor should any proxy. This is the default accepted encoding if none is given, but your client might add a default that accepts gzip, so explicitly providing 'identity' should do the trick.