Protocol is very simple: bencoded dictionary is sent over TCP.

* "v" key contains the data you want to paste
* optional "e" key, holding the desired filename extension, without the
  leading dot, up to 9 characters long

"hello world" => d1:v11:hello worlde
"http://example.com/" and "url" extension => d1:e3:url1:v18:http://example.come