nginx does not add my custom header to response - nginx

Question

I have a rather simple nginx config, which serves a static file as "endpoint". However, the custom header under /version I want to add, is not added.
Can anyone tell me why?
worker_processes 1;
events {
worker_connections 1024;
}
http {
map $http_accept $img_suffix {
"~*webp" ".webp";
"~*jxr" ".jxr";
}
server {
server_tokens off;
listen 80;
server_name localhost;
root /usr/share/nginx/html;
index index.html index.htm;
include /etc/nginx/mime.types;
gzip on;
gzip_vary on;
gzip_min_length 1000;
gzip_proxied expired no-cache no-store private auth;
gzip_types text/plain text/css application/json application/javascript application/x-javascript text/xml application/xml application/xml+rss text/javascript;
location = /version {
default_type application/json;
# add test header
add_header "TEST" "TEST";
# CORS
add_header "Access-Control-Allow-Headers" "Authorization, Origin, X-Requested-With, Content-Type, Accept, Cache-Control, Last-Modified";
if ($request_method = GET) {
add_header "Access-Control-Allow-Origin" *;
}
if ($request_method = OPTIONS ) {
add_header "Access-Control-Allow-Origin" *;
add_header "Access-Control-Allow-Methods" "GET, OPTIONS, HEAD";
return 200;
}
index version;
}
location / {
# CORS
if ($request_method ~* "(GET|POST)") {
add_header "Access-Control-Allow-Origin" *;
}
if ($request_method = OPTIONS ) {
add_header "Access-Control-Allow-Origin" *;
add_header "Access-Control-Allow-Methods" "GET, POST, OPTIONS, HEAD";
add_header "Access-Control-Allow-Headers" "Authorization, Origin, X-Requested-With, Content-Type, Accept";
return 200;
}
add_header Cache-Control 'max-age=31449600'; # one year
include /etc/nginx/security-headers.conf;
try_files $uri index.html =404;
}
}
}

Answer 1

You cannot have add_header as part of if block. if is part of the rewrite module.
It's an classic example of if is evil
You could probably use map module to set variables and then use them with your add_header directive. There are other options suggested here as well.
How can I add header conditionally in nginx configuration?