Method isPortInUse

src/tcpportscanner.ts:57–89

* Checks to see if the port is in use by creating a server on that port. You should use the function * `isPortInUseEx()` if you want to do a more exhaustive check or a general purpose use for any host * * @param port port to use. Must be > 0 and <= 65535 * @param host host ip ad

(port: number, host: string, seq: number = 9999)

     * in which case the Node.js default rules apply.
     */
    public static isPortInUse(port: number, host: string, seq: number = 9999): Promise<boolean> {
        ConsoleLog(`isPortInUse: testing port ${host}:${port}`);
        return new Promise((resolve, reject) => {
            const server = net.createServer((c) => {
            });
            server.once('error', (e) => {
                const code: string = (e as any).code;
                if (code && (code === 'EADDRINUSE') || (code === 'EACCES')) {
                    // console.log(`port ${host}:${port} is used`, code);
                    if (code === 'EACCES') {
                        // Technically, EACCES means permission denied, so we consider it as used
                        ConsoleLog(`isPortInUse: port ${host}:${port} returned code EACCES?, ${seq}`);
                    }
                    ConsoleLog(`isPortInUse: port ${host}:${port} is busy, ${seq}`);
                    resolve(true);				// Port in use
                } else {
                    // This should never happen so, log it always
                    ConsoleLog(`isPortInUse: port ${host}:${port} unexpected error , ${seq}`, e);
                    reject(e);					// some other failure
                }
                server.close();
            });

            server.once('close', () => {
                ConsoleLog(`isPortInUse: port ${host}:${port} is free, ${seq}`);
                resolve(false);
            });

            server.listen(port, host, () => {
                server.close();
            });
        });
    }

    /**
     * Checks to see if the port is in use by creating a server on that port if a localhost or alias