drachtio-rtpengine-playback-server.js

const Srf = require('drachtio-srf');
const srf = new Srf();
const rtpengineClient = require('rtpengine-client').Client;
const { v4: uuid } = require('uuid');
const sdpTransform = require('sdp-transform');

const config = {
  'drachtio': {
    "host": "drachtio",
    "port": 9022,
    "secret": "cymru"
  },
  'rtpengine': {
    'host': 'rtpengine',
    'port': 22222
  }
}

const rtpengine = new rtpengineClient()

srf.connect(config['drachtio'], (err, srf) => {
  if (err) return console.log(`error connecting to drachtio: ${err}`);
});

function createDummyUA(legASdp) {
  return new Promise((resolve, reject) => {
    let ua = {}
    ua.toTag = uuid()
    let tempSdp = sdpTransform.parse(legASdp)
    tempSdp.origin.sessionVersion += 1
    tempSdp.media = tempSdp.media.map((item) => {
      //item['direction'] = 'inactive'
      item.connection.ip = '127.0.0.1'
      item.port = 31337
      return item
    });
    ua.sdp = sdpTransform.write(tempSdp)
    console.log(ua)
    resolve(ua)
  });
}

srf.invite(async(req, res) => {
  console.log(`[${req.get('call-id')}] Sending rtpengine offer, invite SDP`)//, req.body)
  // Take our Leg A offer and rewrite it to suit the media proxy
  let rewrittenOffer = await rtpengine.offer(config['rtpengine'], {
    'sdp': req.body,
    'call-id': req.get('call-id'),
    'from-tag': req.getParsedHeader('From')['params']['tag'],
    //'media-echo': 'backwards',
    'replace': ['origin', 'session connection'] // IP hiding
  })
  console.log(`[${req.get('call-id')}] Got response from rtpengine, creating dummy UA for answer`)//, rewrittenOffer.sdp)
  // Create a dummy UA (leg B) with our media proxy offer
  let dummyUA = await createDummyUA(rewrittenOffer.sdp)
  // Prepare an answer response for leg A
  console.log(`[${req.get('call-id')}] Sending answer to rtpengine for parsing`)//, rewrittenOffer.sdp)
  let answer = await rtpengine.answer(config['rtpengine'], {
    'sdp': dummyUA.sdp,
    'call-id': req.get('call-id'),
    'to-tag': dummyUA.toTag,
    'from-tag': req.getParsedHeader('From')['params']['tag'],
    'replace': ['origin', 'session connection'] // IP hiding
  })
  // Send our prepared answer to leg A, allowing it to connect to the media session
  let uas = await srf.createUAS(req, res, {
    localSdp: answer.sdp
  })
  uas.on('destroy', async () => {
    console.log("Leg A destroyed")
    let rtpResult = await rtpengine.query(config['rtpengine'], {
      'call-id': req.get('call-id')
    })
    console.log(`[${req.get('call-id')}] Call query result:`)
    console.dir(rtpResult, { depth: null });
    await rtpengine.delete(config['rtpengine'], {
      'call-id': req.get('call-id'),
      'from-tag': req.getParsedHeader('From')['params']['tag']
    })

  });

  console.log(`[${req.get('call-id')}] Dialog created, playing test media`)
  let playMediaTest = await rtpengine.playMedia(config['rtpengine'], {
    'call-id': req.get('call-id'),
    'from-tag': req.getParsedHeader('From')['params']['tag'],
    //'flags': ['all'],
    'file': '/test.mp3'
  })
  if (playMediaTest['duration']) {
    await new Promise(resolve => setTimeout(resolve, playMediaTest['duration']));
  }
  uas.destroy()

});