121 lines
3.0 KiB
JavaScript
121 lines
3.0 KiB
JavaScript
'use strict';
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const net = require('net');
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const address = require('address');
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const debug = require('debug')('detect-port');
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module.exports = (port, callback) => {
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let hostname = '';
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if (typeof port === 'object' && port) {
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hostname = port.hostname;
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callback = port.callback;
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port = port.port;
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} else {
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if (typeof port === 'function') {
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callback = port;
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port = null;
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}
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}
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port = parseInt(port) || 0;
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let maxPort = port + 10;
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if (maxPort > 65535) {
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maxPort = 65535;
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}
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debug('detect free port between [%s, %s)', port, maxPort);
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if (typeof callback === 'function') {
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return tryListen(port, maxPort, hostname, callback);
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}
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// promise
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return new Promise(resolve => {
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tryListen(port, maxPort, hostname, (_, realPort) => {
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resolve(realPort);
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});
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});
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};
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function tryListen(port, maxPort, hostname, callback) {
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function handleError() {
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port++;
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if (port >= maxPort) {
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debug('port: %s >= maxPort: %s, give up and use random port', port, maxPort);
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port = 0;
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maxPort = 0;
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}
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tryListen(port, maxPort, hostname, callback);
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}
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// use user hostname
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if (hostname) {
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listen(port, hostname, (err, realPort) => {
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if (err) {
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if (err.code === 'EADDRNOTAVAIL') {
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return callback(new Error('the ip that is not unknown on the machine'));
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}
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return handleError();
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}
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callback(null, realPort);
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});
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} else {
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// 1. check null
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listen(port, null, (err, realPort) => {
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// ignore random listening
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if (port === 0) {
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return callback(err, realPort);
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}
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if (err) {
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return handleError(err);
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}
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// 2. check 0.0.0.0
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listen(port, '0.0.0.0', err => {
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if (err) {
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return handleError(err);
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}
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// 3. check localhost
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listen(port, 'localhost', err => {
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// if localhost refer to the ip that is not unkonwn on the machine, you will see the error EADDRNOTAVAIL
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// https://stackoverflow.com/questions/10809740/listen-eaddrnotavail-error-in-node-js
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if (err && err.code !== 'EADDRNOTAVAIL') {
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return handleError(err);
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}
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// 4. check current ip
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listen(port, address.ip(), (err, realPort) => {
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if (err) {
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return handleError(err);
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}
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callback(null, realPort);
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});
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});
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});
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});
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}
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}
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function listen(port, hostname, callback) {
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const server = new net.Server();
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server.on('error', err => {
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debug('listen %s:%s error: %s', hostname, port, err);
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server.close();
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if (err.code === 'ENOTFOUND') {
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debug('ignore dns ENOTFOUND error, get free %s:%s', hostname, port);
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return callback(null, port);
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}
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return callback(err);
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});
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server.listen(port, hostname, () => {
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port = server.address().port;
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server.close();
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debug('get free %s:%s', hostname, port);
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return callback(null, port);
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});
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}
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