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proxy-agent.js
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proxy-agent.js
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'use strict'
const { kProxy, kClose, kDestroy } = require('../core/symbols')
const { URL } = require('node:url')
const Agent = require('./agent')
const Pool = require('./pool')
const DispatcherBase = require('./dispatcher-base')
const { InvalidArgumentError, RequestAbortedError, SecureProxyConnectionError } = require('../core/errors')
const buildConnector = require('../core/connect')
const kAgent = Symbol('proxy agent')
const kClient = Symbol('proxy client')
const kProxyHeaders = Symbol('proxy headers')
const kRequestTls = Symbol('request tls settings')
const kProxyTls = Symbol('proxy tls settings')
const kConnectEndpoint = Symbol('connect endpoint function')
function defaultProtocolPort (protocol) {
return protocol === 'https:' ? 443 : 80
}
function defaultFactory (origin, opts) {
return new Pool(origin, opts)
}
const noop = () => {}
class ProxyAgent extends DispatcherBase {
constructor (opts) {
if (!opts || (typeof opts === 'object' && !(opts instanceof URL) && !opts.uri)) {
throw new InvalidArgumentError('Proxy uri is mandatory')
}
const { clientFactory = defaultFactory } = opts
if (typeof clientFactory !== 'function') {
throw new InvalidArgumentError('Proxy opts.clientFactory must be a function.')
}
super()
const url = this.#getUrl(opts)
const { href, origin, port, protocol, username, password, hostname: proxyHostname } = url
this[kProxy] = { uri: href, protocol }
this[kRequestTls] = opts.requestTls
this[kProxyTls] = opts.proxyTls
this[kProxyHeaders] = opts.headers || {}
if (opts.auth && opts.token) {
throw new InvalidArgumentError('opts.auth cannot be used in combination with opts.token')
} else if (opts.auth) {
/* @deprecated in favour of opts.token */
this[kProxyHeaders]['proxy-authorization'] = `Basic ${opts.auth}`
} else if (opts.token) {
this[kProxyHeaders]['proxy-authorization'] = opts.token
} else if (username && password) {
this[kProxyHeaders]['proxy-authorization'] = `Basic ${Buffer.from(`${decodeURIComponent(username)}:${decodeURIComponent(password)}`).toString('base64')}`
}
const connect = buildConnector({ ...opts.proxyTls })
this[kConnectEndpoint] = buildConnector({ ...opts.requestTls })
this[kClient] = clientFactory(url, { connect })
this[kAgent] = new Agent({
...opts,
connect: async (opts, callback) => {
let requestedPath = opts.host
if (!opts.port) {
requestedPath += `:${defaultProtocolPort(opts.protocol)}`
}
try {
const { socket, statusCode } = await this[kClient].connect({
origin,
port,
path: requestedPath,
signal: opts.signal,
headers: {
...this[kProxyHeaders],
host: opts.host
},
servername: this[kProxyTls]?.servername || proxyHostname
})
if (statusCode !== 200) {
socket.on('error', noop).destroy()
callback(new RequestAbortedError(`Proxy response (${statusCode}) !== 200 when HTTP Tunneling`))
}
if (opts.protocol !== 'https:') {
callback(null, socket)
return
}
let servername
if (this[kRequestTls]) {
servername = this[kRequestTls].servername
} else {
servername = opts.servername
}
this[kConnectEndpoint]({ ...opts, servername, httpSocket: socket }, callback)
} catch (err) {
if (err.code === 'ERR_TLS_CERT_ALTNAME_INVALID') {
// Throw a custom error to avoid loop in client.js#connect
callback(new SecureProxyConnectionError(err))
} else {
callback(err)
}
}
}
})
}
dispatch (opts, handler) {
const headers = buildHeaders(opts.headers)
throwIfProxyAuthIsSent(headers)
if (headers && !('host' in headers) && !('Host' in headers)) {
const { host } = new URL(opts.origin)
headers.host = host
}
return this[kAgent].dispatch(
{
...opts,
headers
},
handler
)
}
/**
* @param {import('../types/proxy-agent').ProxyAgent.Options | string | URL} opts
* @returns {URL}
*/
#getUrl (opts) {
if (typeof opts === 'string') {
return new URL(opts)
} else if (opts instanceof URL) {
return opts
} else {
return new URL(opts.uri)
}
}
async [kClose] () {
await this[kAgent].close()
await this[kClient].close()
}
async [kDestroy] () {
await this[kAgent].destroy()
await this[kClient].destroy()
}
}
/**
* @param {string[] | Record<string, string>} headers
* @returns {Record<string, string>}
*/
function buildHeaders (headers) {
// When using undici.fetch, the headers list is stored
// as an array.
if (Array.isArray(headers)) {
/** @type {Record<string, string>} */
const headersPair = {}
for (let i = 0; i < headers.length; i += 2) {
headersPair[headers[i]] = headers[i + 1]
}
return headersPair
}
return headers
}
/**
* @param {Record<string, string>} headers
*
* Previous versions of ProxyAgent suggests the Proxy-Authorization in request headers
* Nevertheless, it was changed and to avoid a security vulnerability by end users
* this check was created.
* It should be removed in the next major version for performance reasons
*/
function throwIfProxyAuthIsSent (headers) {
const existProxyAuth = headers && Object.keys(headers)
.find((key) => key.toLowerCase() === 'proxy-authorization')
if (existProxyAuth) {
throw new InvalidArgumentError('Proxy-Authorization should be sent in ProxyAgent constructor')
}
}
module.exports = ProxyAgent