YouTube Middleman is a light-weighted software written in Java used to download youtube videos in any number (batch) with the download manager you desire.
It runs a small HTTPServer on your computer which forwards video-file to the software which sends a youtube-link to it. Works excellent for bulk downloads or long lists.
xLightweb is an easy to use http network library to build high performance, scalable network applications. The library includes a HTTPClient and a HTTPServer. xLightweb’s programming API supports an asynchronous and synchronous programming style.