OpenTokとNexmoによるWebRTCとPSTNの接続

const session = OT.initSession(apiKey, sessionId);
const publisher = OT.initPublisher('publisher');
session.on({
 streamCreated: (event) => {
   const subscriberClassName = `subscriber-${event.stream.streamId}`;
   const subscriber = document.createElement('div');
   subscriber.setAttribute('id', subscriberClassName);
   document.getElementById('subscribers').appendChild(subscriber);
   session.subscribe(event.stream, subscriberClassName);
 },
 streamDestroyed: (event) => {
   console.log(`Stream ${event.stream.name} ended because ${event.reason}.`);
 },
 sessionConnected: (event) => {
   session.publish(publisher);
 },
});

session.connect(token, (error) => {
 if (error) {
   console.log('error connecting to session');
 }
});

/**
* When the room/:roomId request is made, either a template is rendered is served with the
* sessionid, token, pinCode, roomId, and apiKey.
*/

app.get('/room/:roomId', (req, res) => {
  const { roomId } = req.params;
  let pinCode;
  if (app.get(roomId)) {
    const sessionId = app.get(roomId);
    const token = generateToken(sessionId);
    pinCode = app.get(sessionId);
    renderRoom(res, sessionId, token, roomId, pinCode);
  } else {
    pinCode = generatePin();
    OT.createSession({
      mediaMode: 'routed',
    }, (error, session) => {
      if (error) {
        return res.send('There was an error').status(500);
      }
      const { sessionId } = session;
      const token = generateToken(sessionId);
      app.set(roomId, sessionId);
      app.set(pinCode, sessionId);
      renderRoom(res, sessionId, token, roomId, pinCode);
    });
  }
});

/**
* When the dial-out get request is made, the dial method of the OpenTok Dial API is invoked
*/

app.get('/dial-out', (req, res) => {
  const { roomId } = req.query;
  const { conferenceNumber } = config;
  const sipTokenData = `{"sip":true, "role":"client", "name":"'${conferenceNumber}'"}`;
  const sessionId = app.get(roomId); // grabbing the sessionId from the mapping we created earlier
  const token = generateToken(sessionId, sipTokenData);
  const options = setSipOptions();
  const sipUri = `sip:${conferenceNumber}@sip.nexmo.com;transport=tls`;
  OT.dial(sessionId, token, sipUri, options, (error, sipCall) => {
    if (error) {
      res.status(500).send('There was an error dialing out');
    } else {
      app.set(conferenceNumber + roomId, sipCall.connectionId);
      res.json(sipCall);
    }
  });
});

app.get('/nexmo-events', (req, res) => {
  console.log('call event', req.query);
  res.status(200).send();
});

app.get('/nexmo-answer', (req, res) => {
  const { serverUrl } = config;
  const ncco = [];
  if (req.query['SipHeader_X-OpenTok-SessionId']) {
    ncco.push({
      action: 'conversation',
      name: req.query['SipHeader_X-OpenTok-SessionId'],
    });
  } else {
    ncco.push(
      {
        action: 'talk',
        text: 'Please enter a a pin code to join the session'
      },
      {
        action: 'input',
        eventUrl: [`${serverUrl}/nexmo-dtmf`]
      }
    )
  }

  res.json(ncco);
});

app.post('/nexmo-dtmf', (req, res) => {
  const { dtmf } = req.body;
  let sessionId;

  if (app.get(dtmf)) {
    sessionId = app.get(dtmf);
  }

  const ncco = [
  {
    action: 'conversation',
    name: sessionId,
  }];

  res.json(ncco);
});

/**
* When the hang-up get request is made, the forceDisconnect method of the OpenTok API is invoked
*/
app.get('/hang-up', (req, res) => {
  const { roomId } = req.query;
  const { conferenceNumber } = config;
  if (app.get(roomId) + app.get(conferenceNumber + roomId)) {
    const sessionId = app.get(roomId);
    const connectionId = app.get(conferenceNumber + roomId); 
    OT.forceDisconnect(sessionId, connectionId, (error) => {
      if (error) {
        res.status(500).send('There was an error hanging up');
      } else {
        res.status(200).send('Ok');
      }
    });
  } else {
    res.status(400).send('There was an error hanging up');
  }
});

const port = process.env.PORT || '3000';
app.listen(port, () => console.log(`listening on port ${port}`));