const url = require('url')
module.exports = setWarning
function setWarning (reqOrRes, code, message, replace) {
// Warning = "Warning" ":" 1#warning-value
// warning-value = warn-code SP warn-agent SP warn-text [SP warn-date]
// warn-code = 3DIGIT
// warn-agent = ( host [ ":" port ] ) | pseudonym
// ; the name or pseudonym of the server adding
// ; the Warning header, for use in debugging
// warn-text = quoted-string
// warn-date = <"> HTTP-date <">
// (https://tools.ietf.org/html/rfc2616#section-14.46)
const host = url.parse(reqOrRes.url).host
const jsonMessage = JSON.stringify(message)
const jsonDate = JSON.stringify(new Date().toUTCString())
const header = replace ? 'set' : 'append'
reqOrRes.headers[header](
'Warning',
`${code} ${host} ${jsonMessage} ${jsonDate}`
)
}
