Place conference members on hold as they join, then un-hold ALL? - twilio

Question

I'm building a Conference Call console app, where my client wants a Start Call button (instead of starting automatically when the moderator enters.) Since there's no API method for starting a conference, I'm thinking the conference will "start" when the first member enters, but then they'll immediately be put on hold. Later, the moderator will press the "Start Conference" button which will un-hold all the participants. I have 2 questions:
Can I add a .then to the dial.conference() that puts that call on hold, or some other way of doing it from that same runtime function? Or do I have to make an api call from my app when I get the callbackstatus that the member has joined?
When I have 175 participants waiting on hold, do I have to send the list of all their CallSids, or is there some way to un-hold all of them?
Thanks...

Answer 1

Can I add a .then to the dial.conference() that puts that call on hold, or some other way of doing it from that same runtime function? Or do I have to make an api call from my app when I get the callbackstatus that the member has joined?
You dial them into the conference via a <Dial> and <Conference> TwiML, see here. You would set the startConferenceOnEnter attribute to false for all of the participants, see here, that puts them "on hold".
When I have 175 participants waiting on hold, do I have to send the list of all their CallSids, or is there some way to un-hold all of them?
You have two options: A) You can have the moderator dial in and set the startConferenceOnEnter attribute to true for them, this would start the conference. B) If you want a button somewhere in your UI you would need to use the Twilio Rest API, specifically the Conference Resource. The status should be in init and you should set it to in-progress. But I'm not sure about that, an alternative would be to get the moderator via the Conference Participant Resource and then set the startConferenceOnEnter attribute to true. You need to experiment a bit.

Answer 2

Here's what I ended up doing. Let's say the Conference is called Capistrano. I put all the participants into Capistrano with startConferenceOnEnter = false. They're happy.
Then, when a moderator calls in, I recognize them by their phone numbers and I put them into a different conference, Capistrano-backstage. They can chat with each other, etc.
Then, when they press the Start Call button, I make an API call that <Dial> them from Capisrano-backstage to Capistrano, with startConferenceOnEnter = true.
Effectively, the conference started when they pushed the button, but really, it started because they entered. Thanks to #philnash for the assist on the code:
// start-conference receives the Confname, Language and the CallSids of all facilitators 'backstage'
// then moves them all to the conference, which starts it.
// This is your new function. To start, set the name and path on the left.
exports.handler = function(context, event, callback) {
switch (event.Language) {
case 'es-MX':
connectnow = 'Ahora lo estare conectando con '+ event.Confname ;
break;
default :
connectnow = 'Now starting ' + event.Confname;
break;
}
const client = context.getTwilioClient();
const twiml = new Twilio.twiml.VoiceResponse();
twiml.say(connectnow, {voice: 'Polly.Kendra', language: event.Language});
const dial = twiml.dial();
// conf-backstage settings for facilitators
dial.conference({
statusCallback: context.STATUSCALLBACKURL,
statusCallbackEvent: 'start join speaking mute leave',
startConferenceOnEnter: true,
endConferenceOnExit: false,
muted: false,
},
event.Confname);
function transfer(CallSid) {
return client.calls(CallSid).update({ twiml: twiml });
}
Promise.all(event.callSid.map(transfer))
.then(() => {
return callback(null, "success");
})
.catch((error) => {
return callback(error);
});
};