openresty+nginx erased my ETag when gzip enabled. how can I prevent this ?

paynechu · 2013-08-14T11:58:02+00:00

Hello! On Tue, Aug 13, 2013 at 2:08 PM, David | StyleFlare wrote: > Using OSX Lion. > > Trying to build the latest openresty, here is the output. &...

openresty+nginx erased my ETag when gzip enabled. how can I prevent this ?

paynechu

Hi, I'm trying to implement conditional GET base on ETag. But nginx will erased my ETag when the request Accept-Encoding set to gzip. Any ways to prevent this?

---

content_by_lua '

ngx.header.etag = 'hello'

ngx.say('hello')

curl -i -X GET http://localhost/ -> the etag appear properly

curl -i -X GET http://localhost/ -H "Accept-Encoding: gzip" -> the etag gone

agentzh

Hello!

On Tue, Aug 13, 2013 at 8:58 PM, Payne Chu wrote:
> Hi, I'm trying to implement conditional GET base on ETag. But nginx will
> erased my ETag when the request Accept-Encoding set to gzip. Any ways to
> prevent this?
>

There's not much that we can do on the ngx_lua module side.

You need to patch the standard ngx_http_gzip_module (in the nginx
core) and makes it not clear the etag header if certain condition is
met (like if it is a weak etag). See the discussion in the following
thread on the nginx mailing list:

    http://forum.nginx.org/read.php?2,240120,240120

Regards,
-agentzh

paynechu

thanks agentzh,

that's also how I do now :)~

On Thursday, August 15, 2013 3:05:34 AM UTC+8, agentzh wrote:

Hello!

On Tue, Aug 13, 2013 at 8:58 PM, Payne Chu wrote:
> Hi, I'm trying to implement conditional GET base on ETag. But nginx will
> erased my ETag when the request Accept-Encoding set to gzip. Any ways to
> prevent this?
>

There's not much that we can do on the ngx_lua module side.

You need to patch the standard ngx_http_gzip_module (in the nginx
core) and makes it not clear the etag header if certain condition is
met (like if it is a weak etag). See the discussion in the following
thread on the nginx mailing list:

http://forum.nginx.org/read.php?2,240120,240120

Regards,
-agentzh

jijilu

hello

I certainly agree that nginx supports gzip compression for *responses*. And it's great at that :)

But I haven't seen the gzip module do *decompression* for *requests*.

That is, if a request body is compressed (say a POST of a large request containing some client data which is compressed, including *request* header Content-Encoding: gzip), does nginx support decompressing that request before handing the (now decompressed) request to some backend server?

or, to use the http://math2.org/luasearch/zip.html#zip_open maybe need many temp files?

@jijilu

On 2013-8-16, at 下午2:37, Payne Chu <pay...@gmail.com> wrote:

thanks agentzh,

that's also how I do now :)~

On Thursday, August 15, 2013 3:05:34 AM UTC+8, agentzh wrote:
Hello!

On Tue, Aug 13, 2013 at 8:58 PM, Payne Chu wrote:
> Hi, I'm trying to implement conditional GET base on ETag. But nginx will
> erased my ETag when the request Accept-Encoding set to gzip. Any ways to
> prevent this?
>

There's not much that we can do on the ngx_lua module side.

You need to patch the standard ngx_http_gzip_module (in the nginx
core) and makes it not clear the etag header if certain condition is
met (like if it is a weak etag). See the discussion in the following
thread on the nginx mailing list:

http://forum.nginx.org/read.php?2,240120,240120

Regards,
-agentzh

.