id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	uname	nginx_version
2477	"proxy_redirect is missing feature for HTTP header ""Link"""	jochenwezel@…		"**PLEASE NOTE:** please ignore space chars in urls in following ticket (I had to ""remove"" all external links to be able to post this ticket, here: ""Maximum number of external links per post exceeded"")

**Used configuration**

Given is a reverse proxy configuration like
{{{#!text
location / {
    proxy_pass     https :// upstream/;
    proxy_redirect https :// upstream/ /;
}
}}}

As the documentation at `https :// nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_redirect` explains, `proxy_redirect` will change Location headers redirect. This is required and good and works.

**HTTP Response of upstream server**

My wordpress 6 system now starts to send HTTP responses like:
{{{#!text
HTTP/1.1 200 OK
Server: nginx/1.18.0 (Ubuntu)
Date: Wed, 29 Mar 2023 15:31:02 GMT
Content-Type: text/html; charset=UTF-8
Transfer-Encoding: chunked
Connection: keep-alive
Link: <https :// upstream/index.php/wp-json/>; rel=""https://api.w.org/""
Link: <https :// upstream/index.php/wp-json/wp/v2/pages/69>; rel=""alternate""; type=""application/json""
Link: <https :// upstream/>; rel=shortlink
Vary: Accept-Encoding
Content-Encoding: gzip
}}}

**HTTP protocol standard**

Since I've never seen this type of 'link' header before, this was a real surprise to me. But it seems that it's a feature which exists for many years, now: ` https :// www.w3.org/wiki/LinkHeader `

**Problem description**

The problem is, that the many Link headers remain unchanged and are delivered (as they are) to the client. Of course, the client machine doesn't know anything about my upstream server and can't access it to load these linked urls.

The result is, that my nginx reverse proxy response to the client contains unchanged Link headers
{{{#!text
Link: <https :// upstream/index.php/wp-json/>; rel=""https://api.w.org/""
Link: <https :// upstream/index.php/wp-json/wp/v2/pages/69>; rel=""alternate""; type=""application/json""
Link: <https :// upstream/>; rel=shortlink
}}}

**Feature request**

So, `proxy_redirect` should (by default) substitute in headers
* `Location`
* `Link` [array]

Optionally, the substitution of Link headers could be configured with another switch (e.g. `proxy_redirect_links`) to on|off|default

"	enhancement	new	critical		nginx-core	1.18.x			jochenwezel@…	"Linux revproxy02 5.15.0-69-generic #76-Ubuntu SMP Fri Mar 17 17:19:29 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux
"	"nginx version: nginx/1.18.0 (Ubuntu)
built with OpenSSL 3.0.2 15 Mar 2022
TLS SNI support enabled
configure arguments: --with-cc-opt='-g -O2 -ffile-prefix-map=/build/nginx-d8gVax/nginx-1.18.0=. -flto=auto -ffat-lto-objects -flto=auto -ffat-lto-objects -fstack-protector-strong -Wformat -Werror=format-security -fPIC -Wdate-time -D_FORTIFY_SOURCE=2' --with-ld-opt='-Wl,-Bsymbolic-functions -flto=auto -ffat-lto-objects -flto=auto -Wl,-z,relro -Wl,-z,now -fPIC' --prefix=/usr/share/nginx --conf-path=/etc/nginx/nginx.conf --http-log-path=/var/log/nginx/access.log --error-log-path=/var/log/nginx/error.log --lock-path=/var/lock/nginx.lock --pid-path=/run/nginx.pid --modules-path=/usr/lib/nginx/modules --http-client-body-temp-path=/var/lib/nginx/body --http-fastcgi-temp-path=/var/lib/nginx/fastcgi --http-proxy-temp-path=/var/lib/nginx/proxy --http-scgi-temp-path=/var/lib/nginx/scgi --http-uwsgi-temp-path=/var/lib/nginx/uwsgi --with-compat --with-debug --with-pcre-jit --with-http_ssl_module --with-http_stub_status_module --with-http_realip_module --with-http_auth_request_module --with-http_v2_module --with-http_dav_module --with-http_slice_module --with-threads --add-dynamic-module=/build/nginx-d8gVax/nginx-1.18.0/debian/modules/http-geoip2 --with-http_addition_module --with-http_gunzip_module --with-http_gzip_static_module --with-http_sub_module
"