GitHub - jshttp/on-headers: Execute a listener when a response is about to write headers. (original) (raw)
Execute a listener when a response is about to write headers.
Installation
This is a Node.js module available through thenpm registry. Installation is done using thenpm install command:
API
var onHeaders = require('on-headers')
onHeaders(res, listener)
This will add the listener listener to fire when headers are emitted for res. The listener is passed the response object as it's context (this). Headers are considered to be emitted only once, right before they are sent to the client.
When this is called multiple times on the same res, the listeners are fired in the reverse order they were added.
Examples
var http = require('http') var onHeaders = require('on-headers')
http .createServer(onRequest) .listen(3000)
function addPoweredBy () { // set if not set by end of request if (!this.getHeader('X-Powered-By')) { this.setHeader('X-Powered-By', 'Node.js') } }
function onRequest (req, res) { onHeaders(res, addPoweredBy)
res.setHeader('Content-Type', 'text/plain') res.end('hello!') }