132 lines
2.6 KiB
JavaScript
132 lines
2.6 KiB
JavaScript
/*!
|
|
* on-headers
|
|
* Copyright(c) 2014 Douglas Christopher Wilson
|
|
* MIT Licensed
|
|
*/
|
|
|
|
'use strict'
|
|
|
|
/**
|
|
* Module exports.
|
|
* @public
|
|
*/
|
|
|
|
module.exports = onHeaders
|
|
|
|
/**
|
|
* Create a replacement writeHead method.
|
|
*
|
|
* @param {function} prevWriteHead
|
|
* @param {function} listener
|
|
* @private
|
|
*/
|
|
|
|
function createWriteHead (prevWriteHead, listener) {
|
|
var fired = false
|
|
|
|
// return function with core name and argument list
|
|
return function writeHead (statusCode) {
|
|
// set headers from arguments
|
|
var args = setWriteHeadHeaders.apply(this, arguments)
|
|
|
|
// fire listener
|
|
if (!fired) {
|
|
fired = true
|
|
listener.call(this)
|
|
|
|
// pass-along an updated status code
|
|
if (typeof args[0] === 'number' && this.statusCode !== args[0]) {
|
|
args[0] = this.statusCode
|
|
args.length = 1
|
|
}
|
|
}
|
|
|
|
return prevWriteHead.apply(this, args)
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Execute a listener when a response is about to write headers.
|
|
*
|
|
* @param {object} res
|
|
* @return {function} listener
|
|
* @public
|
|
*/
|
|
|
|
function onHeaders (res, listener) {
|
|
if (!res) {
|
|
throw new TypeError('argument res is required')
|
|
}
|
|
|
|
if (typeof listener !== 'function') {
|
|
throw new TypeError('argument listener must be a function')
|
|
}
|
|
|
|
res.writeHead = createWriteHead(res.writeHead, listener)
|
|
}
|
|
|
|
/**
|
|
* Set headers contained in array on the response object.
|
|
*
|
|
* @param {object} res
|
|
* @param {array} headers
|
|
* @private
|
|
*/
|
|
|
|
function setHeadersFromArray (res, headers) {
|
|
for (var i = 0; i < headers.length; i++) {
|
|
res.setHeader(headers[i][0], headers[i][1])
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Set headers contained in object on the response object.
|
|
*
|
|
* @param {object} res
|
|
* @param {object} headers
|
|
* @private
|
|
*/
|
|
|
|
function setHeadersFromObject (res, headers) {
|
|
var keys = Object.keys(headers)
|
|
for (var i = 0; i < keys.length; i++) {
|
|
var k = keys[i]
|
|
if (k) res.setHeader(k, headers[k])
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Set headers and other properties on the response object.
|
|
*
|
|
* @param {number} statusCode
|
|
* @private
|
|
*/
|
|
|
|
function setWriteHeadHeaders (statusCode) {
|
|
var length = arguments.length
|
|
var headerIndex = length > 1 && typeof arguments[1] === 'string'
|
|
? 2
|
|
: 1
|
|
|
|
var headers = length >= headerIndex + 1
|
|
? arguments[headerIndex]
|
|
: undefined
|
|
|
|
this.statusCode = statusCode
|
|
|
|
if (Array.isArray(headers)) {
|
|
// handle array case
|
|
setHeadersFromArray(this, headers)
|
|
} else if (headers) {
|
|
// handle object case
|
|
setHeadersFromObject(this, headers)
|
|
}
|
|
|
|
// copy leading arguments
|
|
var args = new Array(Math.min(length, headerIndex))
|
|
for (var i = 0; i < args.length; i++) {
|
|
args[i] = arguments[i]
|
|
}
|
|
|
|
return args
|
|
}
|