Keeping Headers During NGINX Rewrite

Question

I am attempting to set up an NGINX proxy to redirect all requests to one of two servers based on the contents of a query string argument. Essentially:

https://my.site.com/api/...&server=a

should redirect to

https://a.site.com/api/...&server=a

and

https://my.site.com/api/...&server=b

should redirect to

https://b.site.com/api/...&server=b

I appear to have a config that does the basic work of rewriting the hostname and keeping the query string intact:

error_log /dev/stdout info;
worker_processes 1;

events {
    worker_connections 1024;
    accept_mutex off;
}

http {
    access_log /dev/stdout combined;
    sendfile on;

    server {
        listen 443 ssl;
        server_name         $hostname;
        ssl_certificate     /etc/ssl/nginx.crt;
        ssl_certificate_key /etc/ssl/nginx.key;
        ssl_protocols       TLSv1 TLSv1.1 TLSv1.2;
        ssl_ciphers         HIGH:!aNULL:!MD5;

        location ~ /api/ {
            if ($arg_server !~ "^(a|b)$") { return 404; }
            rewrite ^ $scheme://my.site.$arg_server.com$uri;
        }
    }
}

However, I cannot seem to get all the headers in the original request to survive the journey -- the Authorization header, for example, does not seem to arrive at https://[server].site.com/api/...

My understanding was that all headers were kept by default? Is that not true?

score 2 · Accepted Answer · answered Jul 17 '17 at 16:21

I was able to do what I wanted to achieve by getting rid of rewrite and replacing it with proxy_pass and resolver entries:

    location /api/ {
        if ($arg_server !~ "^(a|b)$") { return 404; }

        resolver dns.site.com;
        proxy_pass $schemes://my.site.$arg_server.com$request_uri;
    }

Keeping Headers During NGINX Rewrite

1 Answers1