77 lines
2.3 KiB
JavaScript
77 lines
2.3 KiB
JavaScript
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// Licensed to the Software Freedom Conservancy (SFC) under one
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// or more contributor license agreements. See the NOTICE file
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// distributed with this work for additional information
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// regarding copyright ownership. The SFC licenses this file
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// to you under the Apache License, Version 2.0 (the
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// "License"); you may not use this file except in compliance
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// with the License. You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing,
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// software distributed under the License is distributed on an
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// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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// KIND, either express or implied. See the License for the
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// specific language governing permissions and limitations
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// under the License.
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'use strict'
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const net = require('net')
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/**
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* Tests if a port is free.
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* @param {number} port The port to test.
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* @param {string=} opt_host The bound host to test the {@code port} against.
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* Defaults to {@code INADDR_ANY}.
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* @return {!Promise<boolean>} A promise that will resolve with whether the port
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* is free.
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*/
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function isFree(port, opt_host) {
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return new Promise((resolve, reject) => {
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const server = net.createServer().on('error', function (e) {
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if (e.code === 'EADDRINUSE' || e.code === 'EACCES') {
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resolve(false)
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} else {
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reject(e)
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}
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})
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server.listen(port, opt_host, function () {
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server.close(() => resolve(true))
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})
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})
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}
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/**
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* @param {string=} opt_host The bound host to test the {@code port} against.
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* Defaults to {@code INADDR_ANY}.
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* @return {!Promise<number>} A promise that will resolve to a free port. If a
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* port cannot be found, the promise will be rejected.
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*/
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function findFreePort(opt_host) {
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return new Promise((resolve, reject) => {
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const server = net.createServer()
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server.on('listening', function () {
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resolve(server.address().port)
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server.close()
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})
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server.on('error', (e) => {
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if (e.code === 'EADDRINUSE' || e.code === 'EACCES') {
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resolve('Unable to find a free port')
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} else {
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reject(e)
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}
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})
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// By providing 0 we let the operative system find an arbitrary port
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server.listen(0, opt_host)
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})
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}
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// PUBLIC API
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module.exports = {
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findFreePort,
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isFree,
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}
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