A module to parse Forwarded headers according to RFC 7239.
const sttn = require('7239');
sttn.parseForwardedHeader('for=203.0.113.72;proto=https')
// [{ for: '203.0.113.72', proto: 'https', by: null, host: null }]
sttn.parseForwardedHeader('for=[2001:db8::39]')
// null
app.use(sttn.middleware);The middleware is compatible with Connect (and therefore Express).
It adds a forwarded property to the request, with the value of the last
forwarded element or { for: null, proto: null, by: null, host: null }
if no such object exists or if the header is invalid.