composer/packagist — pull request #119 by GromNaN (2012-03-22 23:14:58+00:00)
Title: Validate freshness of the packages.json to return 304 response if possible

Try to improve performance of packages.json by returning a 304 response based on last package update.

When composer will become able to cache this file, that will allow it to revalidate the file without actually downloading its content.

(Sorry if it's broken, I haven't tested)