/*!
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* forwarded
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* Copyright(c) 2014-2017 Douglas Christopher Wilson
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* MIT Licensed
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*/
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'use strict'
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/**
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* Module exports.
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* @public
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*/
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module.exports = forwarded
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/**
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* Get all addresses in the request, using the `X-Forwarded-For` header.
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*
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* @param {object} req
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* @return {array}
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* @public
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*/
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function forwarded (req) {
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if (!req) {
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throw new TypeError('argument req is required')
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}
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// simple header parsing
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var proxyAddrs = parse(req.headers['x-forwarded-for'] || '')
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var socketAddr = getSocketAddr(req)
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var addrs = [socketAddr].concat(proxyAddrs)
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// return all addresses
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return addrs
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}
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/**
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* Get the socket address for a request.
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*
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* @param {object} req
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* @return {string}
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* @private
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*/
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function getSocketAddr (req) {
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return req.socket
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? req.socket.remoteAddress
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: req.connection.remoteAddress
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}
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/**
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* Parse the X-Forwarded-For header.
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*
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* @param {string} header
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* @private
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*/
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function parse (header) {
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var end = header.length
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var list = []
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var start = header.length
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// gather addresses, backwards
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for (var i = header.length - 1; i >= 0; i--) {
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switch (header.charCodeAt(i)) {
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case 0x20: /* */
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if (start === end) {
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start = end = i
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}
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break
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case 0x2c: /* , */
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if (start !== end) {
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list.push(header.substring(start, end))
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}
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start = end = i
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break
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default:
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start = i
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break
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}
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}
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// final address
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if (start !== end) {
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list.push(header.substring(start, end))
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}
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return list
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}
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