knowledge/content/docs/software/nginx.adoc

:source-highlighter: pygments
:source-language: nginx

== Nginx

=== Redirecting image requests to webp versions

[source]
----
http {
    map $http_accept $webp_suffix {
        "~*webp"  ".webp";
    }

    server {
        location ~ \.(png|jpe?g)$ {
            try_files $uri$webp_suffix $uri =404;
            expires 1y;
        }
    }
}
----

=== Redirecting to a canonical domain

Instead of complex rules to redirect certain requests, just add a separate `server` block:

[source]
----
server {
    server_name www.example.com;
    return 301 $scheme://example.com$request_uri;
}
----

=== Logging only partial IP addresses

This assumes nginx is behind a proxy that sends a trusted `X-Forwarded-For` header, but the
same can easily be done with the remote IP directly.

[source]
----
server {
    map $http_x_forwarded_for $forwarded_anon {
        ~(?P<ip>\d+\.\d+\.\d+)\.    $ip.0;
        ~(?P<ip>[^:]+:[^:]+):       $ip::;
        default                     0.0.0.0;
    }

    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$forwarded_anon"';
}
----