id,summary,reporter,owner,description,type,status,priority,milestone,component,version,resolution,keywords,cc,uname,nginx_version 2055,"Using addition_filter and changing the added file: still returning ""304 Not Modified""",sijanec@…,,"Hello! I have just stumbled upon a nginx bug. When using add_before_body and/or add_after_body commands from ngx_http_addition_filter_module, the server will respond with ""304 Not Modified"" even if the added file has changed. After investigation I figured out that this error could be applied to everything that uses ngx_http_subrequest to gather data. The request structure will remain with the same last_modified_time even if the subrequest contains data that was modified after this time. The solution to this problem would be to overwrite the request structure headers_out.last_modified_time with the last_modified_time in the structure, generated by ngx_http_subrequest, if it's in the future, but that would not be enough. The problem is that ngx_http_subrequest does not populate the request struct, specified as it's fourth argument, with headers_out.last_modified_time, it stays at -1, but that wouldn't help very much in this particular case. Even setting the headers_out.last_modified_time to -1 in addition_filter_module would not work and would not fix the issue, because the filter modules do not execute before not_modified module (nginx/auto/modules:142). Well, at last resort, the not_modified module could load configuration of addition_filter module and, if addition is to be done, return to the next module. But that would not work either; the not_modified module source is included before the addition_filter so it's module struct and relying configurations are not available at the time of compilation. Proof of bug: Run nginx with attached nginx.conf and create files /tmp/add.html and /tmp/index.html with some content. Load http://localhost:8080/ in a modern Firefox browser. Then change the file /tmp/add.html and nginx will proceed to report ""304 Not Modified"" and your browser's copy will after page refresh remain with the old /tmp/add.html file added at the beginning of the response. Regards!",defect,closed,minor,,nginx-module,1.19.x,wontfix,,,Linux kondenzator 5.3.0-59-generic #53~18.04.1-Ubuntu SMP Thu Jun 4 14:58:26 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux,"a@kondenzator:~[1]$ /tmp/nginx/objs/nginx -V nginx version: nginx/1.19.3 built by gcc 7.5.0 (Ubuntu 7.5.0-3ubuntu1~18.04) configure arguments: --with-http_addition_module a@kondenzator:~[0]$ "