XSS escapers

[jknack]

A simple, flexible XSS escape mechanism will be added to Request object and related methods: param, header, etc.... XSS API will be part of the core and a html escaper will be provided from Guava HtmlEscapers. They need to be provided via module.

{
   use(new XSS());

   get("/", req -> {
     // escape `text` param by applying html and/or javascript escapers
     String text = req.param("text", "html", "js");
     return text;
   });
}

• The html and js XSS escapers are provided by a XSS module.
• An XSS module must provide one or more escapers
• Missing escapers are silently ignored.