Refactor and document command line arguments

README.md

@@ -72,6 +72,21 @@ Alternatively install the module globally like in the old days:
  airplanejs
  ```
 
+### Options
+
+The following options are available when running `airplanejs`:
+
+- `--help` - Show help (alias: `-h`)
+- `--version` - Output AirplaneJS version (alias: `-v`)
+- `--device <index>` - Select RTL dongle (alias: `-d`, default: `0`)
+- `--frequency <hz>` - Set custom frequency (alias: `-f`, default: `2000000`)
+- `--gain <gain>` - Set custom tuner gain (alias: `-g`)
+- `--max-gain` - Set tuner gain to highest possible value (default: on)
+- `--auto-gain` - Disable manual tuner gain (default: off)
+- `--enable-agc` - Use Automatic Gain Control (default: off)
+- `--port <port>` - Set custom HTTP server port (alias: `-p`, default: `3000`)
+- `--no-browser` - Disable automatic opening of default browser
+
 ## License
 
 MIT

server.js

@@ -18,13 +18,19 @@ const DEFAULT_RATE = 2000000
 const DEFAULT_FREQ = 1090000000
 const ASYNC_BUF_NUMBER = 12
 const DATA_LEN = 16 * 16384 // 256k
-const AUTO_GAIN = -100 // Use automatic gain
-const MAX_GAIN = 999999 // Use max available gain
 
 process.on('SIGINT', exit)
 
 const argv = require('minimist')(process.argv.slice(2))
-argv.openBrowser = argv.openBrowser !== false // default to true
+
+if (argv.help || argv.h) {
+ help()
+ process.exit()
+}
+if (argv.version || argv.v) {
+ console.log(require('./package').version)
+ process.exit()
+}
 
 const ASSETS_FILES = fs.readdirSync(path.join(__dirname, 'assets'))
 
@@ -49,13 +55,13 @@ function onMsg (msg) {
  store.addMessage(msg)
 }
 
-function setupDevice (opts) {
- opts = {
-  gain: MAX_GAIN,
-  dev_index: 0,
-  enable_agc: true,
-  freq: DEFAULT_FREQ
- }
+function setupDevice () {
+ let gain = argv.gain || argv.g
+ const findMaxGain = !('gain' in argv || 'g' in argv)
+ const autoGain = argv['auto-gain'] || false
+ const enableAgc = argv['enable-agc'] || false
+ const devIndex = argv.device || argv.d || 0
+ const freq = argv.frequency || argv.f || DEFAULT_FREQ
 
  const ppmError = 0
  const vendor = Buffer.alloc(256)
@@ -71,33 +77,34 @@ function setupDevice (opts) {
  debug('Found %d device(s):', deviceCount)
  for (let j = 0; j < deviceCount; j++) {
  rtlsdr.get_device_usb_strings(j, vendor, product, serial)
- debug('%d: %s, %s, SN: %s %s', j, vendor, product, serial, j === opts.dev_index ? '(currently selected)' : '')
+ debug('%d: %s, %s, SN: %s %s', j, vendor, product, serial, j === devIndex ? '(currently selected)' : '')
  }
 
- const dev = rtlsdr.open(opts.dev_index)
+ const dev = rtlsdr.open(devIndex)
  if (typeof dev === 'number') {
  console.error('Error opening the RTLSDR device: %s', dev)
  process.exit(1)
  }
 
  // Set gain, frequency, sample rate, and reset the device
- rtlsdr.set_tuner_gain_mode(dev, opts.gain === AUTO_GAIN ? 0 : 1)
- if (opts.gain !== AUTO_GAIN) {
- if (opts.gain === MAX_GAIN) {
+ rtlsdr.set_tuner_gain_mode(dev, autoGain ? 0 : 1)
+ if (!autoGain) {
+ if (findMaxGain) {
  // Find the maximum gain available
  const gains = new Int32Array(100)
  const numgains = rtlsdr.get_tuner_gains(dev, gains)
- opts.gain = gains[numgains - 1]
- debug('Max available gain is: %d', opts.gain / 10)
+ gain = gains[numgains - 1]
+ debug('Max available gain is: %d', gain / 10)
  }
- rtlsdr.set_tuner_gain(dev, opts.gain)
- debug('Setting gain to: %d', opts.gain / 10)
+ debug('Setting gain to: %d', gain / 10)
+ rtlsdr.set_tuner_gain(dev, gain)
  } else {
- debug('Using automatic gain control.')
+ debug('Using automatic gain control')
  }
+
  rtlsdr.set_freq_correction(dev, ppmError)
- if (opts.enable_agc) rtlsdr.set_agc_mode(dev, 1)
- rtlsdr.set_center_freq(dev, opts.freq)
+ if (enableAgc) rtlsdr.set_agc_mode(dev, 1)
+ rtlsdr.set_center_freq(dev, freq)
  rtlsdr.set_sample_rate(dev, DEFAULT_RATE)
  rtlsdr.reset_buffer(dev)
  debug('Gain reported by device: %d', rtlsdr.get_tuner_gain(dev) / 10)
@@ -169,22 +176,41 @@ function startServer () {
  fn(req, res)
  })
 
- if (argv.port) listen(argv.port)
+ const customPort = argv.port || argv.p
+
+ if (customPort) listen(customPort)
  else getPort({port: 3000}).then(listen)
 
  function listen (port) {
  server.listen(port, function () {
  const url = 'http:https://localhost:' + port
- if (argv.openBrowser) {
+ if (argv.browser === false) {
+ console.log('Server running at: %s', url)
+ } else {
  console.log('Opening %s in your favorite browser...', url)
  opn(url)
- } else {
- console.log('Server running at: %s', url)
  }
  })
  }
 }
 
+function help () {
+ console.log('Usage:')
+ console.log(' airplanejs [options]')
+ console.log()
+ console.log('Options:')
+ console.log(' --help -h Show this help')
+ console.log(' --version -v Output AirplaneJS version')
+ console.log(' --device -d <index> Select RTL dongle (default: 0)')
+ console.log(' --frequency -f <hz> Set custom frequency (default: 2000000)')
+ console.log(' --gain -g <gain> Set custom tuner gain')
+ console.log(' --max-gain Set tuner gain to highest possible value (default: on)')
+ console.log(' --auto-gain Disable manual tuner gain (default: off)')
+ console.log(' --enable-agc Use Automatic Gain Control (default: off)')
+ console.log(' --port -p <port> Set custom HTTP server port (default: 3000)')
+ console.log(' --no-browser Disable automatic opening of default browser')
+}
+
 function exit () {
  console.log('Closing down RTL-SDR device...')
  rtlsdr.cancel_async(dev)