nginx reverse-proxy rewriting custom header (NOT URL) - nginx

Question

I am trying to rewrite custom header information like "Author" (not part of the URL) using nginx reverse proxy.
The header information "Author:" should be rewritten from "test123" to e.g. "BASIC"
command:
admin1#nginx1:~$ curl -x 192.168.175.134:80 http://home1.MyWeb.eu:8081/home1/index.html?t=1 -H "Author: test123" -vk
TCPdump on apache:
--
GET /home1/index.html?t=1 HTTP/1.0
Host: home1.MyWeb.eu
Connection: close
User-Agent: curl/7.58.0
Accept: */*
Proxy-Connection: Keep-Alive
Author: test123
wanted result:
--
GET /home1/index.html?t=1 HTTP/1.0
Host: home1.MyWeb.eu
Connection: close
User-Agent: curl/7.58.0
Accept: */*
Proxy-Connection: Keep-Alive
Author: BASIC

Answer 1

You can use the proxy_set_header in your configuration. I.e.:
proxy_set_header Author "BASIC";

Answer 2

I made with setting variables. A little ugly but seems to work.
location / {
<...>
set $rewritten_header $http_myheader;
if ($http_myheader = "something") {
set $rewritten_header somethingelse;
}
proxy_set_header Myheader $rewritten_header;
}
The above will rewrite your header only if the condition match. Otherwise keep original value.
I think more elegant to use map in case you have a large mapping.

Answer 3

Hi I have solved the issue like this:
curl -x localhost:80 https://www.dummy.com -H "Authorization: test12" -vk
NGINX configuration:
server {
listen 127.0.0.2:443 ssl;
# the included file below contains ssl certificates
include snippets/www.dummy.com.conf;
root /var/www/html;
set $MyAuthorization 'Basic bGaa9zX25ljYhhWxlcl9=';
location / {
proxy_pass https://www;
proxy_set_header Host www.dummy.com;
proxy_set_header Authorization $MyAuthorization;
}
}