TIL how to redirect uppercase paths to lowercase in Nginx
2025-06-15 • 1 min

For a generic redirect for all paths:

location ~ [A-Z] {
    rewrite_by_lua_block {
        ngx.redirect(string.lower(ngx.var.uri), 301);
    }
}

For a specific path:

location ~* ^/FOO(.*) {
    return 301 /foo$1;
}

For a specific path with query parameters:

location ~* ^/FOO(.*) {
    return 301 /foo$1$is_args$args;
}

For a specific path with query parameters and any request method:

location ~* ^/FOO(.*) {
    return 308 /foo$1$is_args$args;
}

# Ingress-Nginx

There is no native annotation for uppercase redirection in ingress-nginx so we must also use the server-snippet annotation:

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  annotations:
    nginx.ingress.kubernetes.io/server-snippet: |
      location ~* ^/FOO(.*) {
        return 308 /foo$1$is_args$args;
      }

Note that the server-snippet annotation can only be used once per host. Using the annotation more than once per host, even when the ingresses are in different namespaces, will cause server-snippet to be ignored by ingress-nginx.

# References

Edited: 2025-06-15
#nginx #kubernetes