What is the canonical method for an HTTP client to

Question

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?

Answer 1

Do you wish encoding to be disabled altogether?
Then skip the Accept-Encoding header itself within http request headers.

Do you wish only gzip compression to be absent in the http response?
Then skip gzip from the values list in the http request header.

Do you wish to prioritize different compression techniques that servers support? then use different values between 0 and 1 along-with q argument for each value in the Accept-Encoding http request header. (Currently you are using conflicting value and indicating by weight=0 that you don't know how you'll manage, but you want response to be encoded anyhow)

Answer 2

I think this mod for apache

http://httpd.apache.org/docs/2.2/mod/mod_deflate.html (2)

And this for Nginx

http://wiki.nginx.org/HttpGzipModule (1)

Sounds like what you need depending on which server you plan to use. The rest is up to you!

Please note the nginx module both allows shutting down decompression:

[edit] gzip 
Syntax: gzip on | off  
Default: off 
Context: http
server
location
if in location 
Reference: gzip 



Enables or disables gzip compression. 

And dealing with proxies:

[edit] gzip_proxied 
Syntax: gzip_proxied off | expired | no-cache | no-store | private | no_last_modified | no_etag | auth | any ... 
Default: off 
Context: http 
server
location 
Reference: gzip_proxied 



It allows or disallows the compression of the response for the proxy request in the dependence on the request and the response. The fact that, request proxy, is determined on the basis of line "Via" in the headers of request. In the directive it is possible to indicate simultaneously several parameters: 

off - disables compression for all proxied requests 
expired - enables compression, if the "Expires" header prevents caching 
no-cache - enables compression if "Cache-Control" header is set to "no-cache" 
no-store - enables compression if "Cache-Control" header is set to "no-store" 
private - enables compression if "Cache-Control" header is set to "private" 
no_last_modified - enables compression if "Last-Modified" isn't set 
no_etag - enables compression if there is no "ETag" header 
auth - enables compression if there is an "Authorization" header 
any - enables compression for all requests 
[edit] gzip_types 

Best wishes!

Sources:

1) http://forum.nginx.org/read.php?11,96472,214303

2) http://httpd.apache.org/docs/2.2/mod/mod_deflate.html#inflate (Section Output Decompression)

Answer 3

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.