NGINX HTTP Early Hints (HTTP 103)

Allow nginx to generate its own 103 Early Hints response, when the official release only supports forwarding them from upstreams.

Requires clients to send "Sec-Fetch-Dest: document" header, to avoid the risk of misconfigurations accidentally sending 103 on subresources.

Requirements

• nginx >= 1.29.0 (with 103 Early Hints plumbing)

License

• BSD-2 to match upstream nginx (for easy conversion to a PR)

Building (dynamic module)

As a dynamic module:

./configure --with-compat --add-dynamic-module=/path/to/ngx_http_early_hints
make modules
# copy objs/ngx_http_early_hints_module.so into your modules directory

Then load it:

load_module modules/ngx_http_early_hints_module.so;

Building (static module)

./configure --add-module=/path/to/ngx_http_early_hints

Usage

http {
    server {
        early_hints on;

        location / {
            # Add the resources you want to early hint
            early_hints_link "</css/app.css>; rel=preload; as=style";
            early_hints_link "</js/app.js>; rel=preload; as=script";

            fastcgi_pass unix:/run/php.sock;
        }
    }
}