Serving the file

On the fly

With the route imported, GET /llms.txt builds the file on each request, with a public Cache-Control of max_age seconds. The file is rendered whole before the response starts, into a php://temp buffer that spills to a temporary file past 256 KiB, so the memory stays flat and:

• a listener failing half way gives an error page, never a truncated 200 left in the caches
• the response carries a Content-Length and an ETag, and answers 304 Not Modified to a matching If-None-Match

Dumped

php bin/console llms-txt:dump
php bin/console llms-txt:dump --base-url=https://example.com   # without "framework.router.default_uri"
php bin/console llms-txt:dump var/llms_txt                     # another directory

The file is streamed to a temporary file next to it, renamed once complete: the web server never serves a half written file, and a failing listener leaves the previous one in place.

• Into public/ (the default): the web server serves it without booting Symfony. The route is a fallback until the first dump: remember to dump again, from a cron or after a deployment, or the file goes stale.
• Elsewhere (dump_directory: '%kernel.project_dir%/var/llms_txt'): the controller serves the dumped file when there is one, with ETag and Last-Modified, and builds it on the fly otherwise.