bug: The gzip plugin does not work in special scenarios

[zuiyangqingzhou]

Current Behavior

0. Openresty as the upstream, the configuration file is as follows

pid logs/nginx.pid;
events {
    worker_connections 1024;
}

http {
    server {
        listen 8866;
        location / {
	    content_by_lua '
	    	 ngx.say("hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world.")
	    ';
        }
    }
}

1. enable the proxy-rewrite plugin，config as follow

 "gzip": {
      "buffers": {
        "number": 64,
        "size": 4096
      },
      "comp_level": 5,
      "disable": false,
      "min_length": 200,
      "types": "*",
      "vary": true
    }

2. send a request without a via header

curl http://127.0.0.1:9080/test_gzip -H 'accept-encoding: gzip' -i

• output

HTTP/1.1 200 OK
Content-Type: text/plain; charset=utf-8
Transfer-Encoding: chunked
Connection: keep-alive
Date: Thu, 02 Mar 2023 12:33:53 GMT
Server: Openresty
Vary: Accept-Encoding
Content-Encoding: gzip

Warning: Binary output can mess up your terminal. Use "--output -" to tell
Warning: curl to output it to your terminal anyway, or consider "--output
Warning: <FILE>" to save to a file.

3. send a request with a via header

curl http://127.0.0.1:9080/test_gzip -H 'accept-encoding: gzip' -i -H 'via: aaa'

• output

HTTP/1.1 200 OK
Content-Type: text/plain; charset=utf-8
Transfer-Encoding: chunked
Connection: keep-alive
Date: Thu, 02 Mar 2023 12:36:11 GMT
Server: Openresty
Vary: Accept-Encoding

hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world. hello, world.

Expected Behavior

The compression behavior of apisix should not be affected by the via header

Error Logs

none

Steps to Reproduce

Same as above

Environment

• APISIX version (run apisix version): 2.10.5
• Operating system (run uname -a): amzn2.x86_64
• OpenResty / Nginx version (run openresty -V or nginx -V): openresty/1.19.9.1
• etcd version, if relevant (run curl http://127.0.0.1:9090/v1/server_info): 3.5
• APISIX Dashboard version, if relevant:
• Plugin runner version, for issues related to plugin runners:
• LuaRocks version, for installation issues (run luarocks --version):

[tokers]

2.10.5 is too old. Try the latest version to see if the gzip plugin works.

[spacewander]

It is Nginx itself that disables the gzip, see code
https://github.com/nginx/nginx/blob/4ace957c4e08bcbf9ef5e9f83b8e43458bead77f/src/http/ngx_http_core_module.c#L2071-L2159
and configuration:
http://nginx.org/en/docs/http/ngx_http_gzip_module.html#gzip_proxied
APISIX so far doesn't have option to override this behavior.

[spacewander]

Or we can override it via custom Nginx conf: https://github.com/apache/apisix/blob/master/docs/en/latest/customize-nginx-configuration.md

[zuiyangqingzhou]

Or we can override it via custom Nginx conf: https://github.com/apache/apisix/blob/master/docs/en/latest/customize-nginx-configuration.md

Got it. Thank you for your reply. Maybe we can provide an option to reset via header in gzip plugin ? @spacewander

[spacewander]

PR is welcome!

[zuiyangqingzhou]

PR is welcome!

OK

[github-actions]

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[github-actions]

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