Method waitForPortOpenOSUtl

src/tcpportscanner.ts:256–298

* This is the most unobtrusive way of figuring out if a port is open. It does not try * to create servers or clients but use system commands to figure out if a port is open * On Mac, the runtime is not bad 1.5 to 2X of the time take to do it the other ways. * On windows, surprise!, it

(port: number, retryTimeMs = 100, timeOutMs = 5000, fallback = true, doLog = true)

     * @param fallback Fallback to using the intrusive method if proper OS command is not available
     */
    public static waitForPortOpenOSUtl(port: number, retryTimeMs = 100, timeOutMs = 5000, fallback = true, doLog = true): Promise<void> {
        const cmd = TcpPortScanner.getOsNetProbeCmd().replace('XYZZY', port.toString());
        logEnable = logEnable || doLog;
        ConsoleLog(cmd);
        if (fallback && (cmd === '?')) {
            return TcpPortScanner.waitForPortOpen(port, TcpPortScanner.DefaultHost, true, retryTimeMs, timeOutMs);
        }

        const rexStr = TcpPortScanner.OSNetProbeCmdRegexpStr.replace('XYZZY', port.toString());
        ConsoleLog(rexStr);
        const rex = new RegExp(rexStr);
        const startTimeMs = Date.now();
        let first = true;
        retryTimeMs = Math.max(retryTimeMs, 1);
        return new Promise(function tryAgain(resolve, reject) {
            if (cmd === '?') {
                return reject(new Error('failed'));
            }
            child_process.exec(cmd, (error, stdout) => {
                if (error && !cmd.startsWith('lsof')) {
                    // lsof returns an error code if nothing matches. May match later
                    return reject(error);
                } else if (rex.test(stdout)) {
                    ConsoleLog(stdout.match(rex).join('\n'));
                    return resolve();
                } else {
                    if (first) {
                        // ConsoleLog(stdout);
                        first = false;
                    }
                    const t = Date.now() - startTimeMs;
                    if (t < timeOutMs) {
                        ConsoleLog(`waitForPortOpenOSUtl: Setting timeout for ${retryTimeMs}ms, curTime = ${t}ms`);
                        setTimeout(() => {
                            tryAgain(resolve, reject);
                        }, retryTimeMs);
                    } else {
                        return reject(new Error('timeout'));
                    }
                }
            });
        });
    }

    /**
     * This is the workhorse function for all kinds of status queries on port:localhost