Content Security Policy for Rack

A long time ago I have implemented Content Security Policy as Rack middleware for my Ruby on Rails project. In short, CSP is a XSS mitigation mechanism. Server responds with HTTP header which defines trustworthy sources for different types of content (js, css, images) and browser restricts content from other sources. It's very powerful and you definitely should implement it along with other header-based security features (like X-Frame-Options, Origin, Strict-Transport-Security) especially as long as it won't take much time.

A couple of days ago I decided that it worths to publish middleware as a separate gem. I googled a bit and found csp_easy. However, it lacked few features (hash-based directives configuration, support to WebKit, Report-Only mode) and specs, so I decided not to fork and push my changes (I know it looks bad), but just to publish my own version.

Project is on Github. Read instructions and improve security of your Rack-based web application!