Question: Is it possible to do an attended transfer?

medexdev commented 3 years ago

Instead of a blind transfer, is it possible to do an attended transfer? I think jsSIP supports it.

cloudwebrtc commented 3 years ago

https://github.com/flutter-webrtc/dart-sip-ua/blob/master/lib/src/sip_ua_helper.dart#L395 It should be supported, but these APIs still need to be exported and tested.

medexdev commented 3 years ago

Please forgive me if I'm mistaken. sip_ua_helper calls rtc_session.refer() which calls ReferSubscriber.sendRefer(). But ReferSubscriber only takes URI target instead of RTCSession target. According to this documentation on sipjs, do we need to pass a RTCSession target if we want to do an attender transer? https://sipjs.com/guides/transfer/

medexdev commented 3 years ago

Looking at the code again, I see that the replace is in the option. So it looks like it's supported. Let me give it a try.

medexdev commented 3 years ago

After exposing a few private variables through getters, I was able to get attended transfer working.

stale[bot] commented 3 years ago

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eScoops commented 1 year ago

After exposing a few private variables through getters, I was able to get attended transfer working.

What exactly did you need to do to get this to work?

medexdev commented 1 year ago

After exposing a few private variables through getters, I was able to get attended transfer working.

What exactly did you need to do to get this to work?

I did not end up using this option. But it was adding this in sip_ua_helper.dart.refer() method.

  void refer(dynamic target, [Map<String, dynamic> options]) {
    assert(_session != null, 'ERROR(refer): rtc session is invalid!');
    ReferSubscriber refer = _session.refer(target, options);

Then passing the options to rtc_session (which already takes it as an optional arg). Then you call refer with the 'replaces' option. If you look the source code for refer_subscriber.dart, you can see that it checks for options['replaces'].

    if (options['replaces'] != null) {
      replaces = options['replaces'].call_id;
      replaces += ';to-tag=${options['replaces'].to_tag}';
      replaces += ';from-tag=${options['replaces'].from_tag}';
      replaces = Utils.encodeURIComponent(replaces);
    }

melio-matt commented 1 year ago

Hello, I've followed the changes mentioned on altering sip_ua_helper.dart which is straight forward. Where do you get the to_tag and from_tag from, I've got access to both sessions of the two calls and am trying to refer one to the other?

I can see how I can implement this by create another function in my code that replicates the sip_ua_helper.dart's function so I can call the session's refer method directly and not have to alter the code. It would be good if the code base contained a method to do this though.

DeviArunaMurugan commented 1 year ago

If you share the code for attended call transfer would be appreciated.

Thanks in advance.

DeviArunaMurugan commented 1 year ago

If you share the code for attended call transfer would be appreciated.

melio-matt commented 1 year ago

What I did was to add a getFromTag and getToTag that return _from_tag and _to_tag in the RTCSession object (rtc_session.dart).

Then from one of the calls (Call class) call the refer function as below:

// the call id has the from tag appended to it so we need to remove 
String callId = transferingToCall.session.id!;
callId = callId.substring(0, callId.length - fromTag.length);

transferingCall.refer(transferingToCall.remote_identity!, {
                            "replaces": AttendedTransferData(callId, fromTag, toTag),
                          });

I previously had one of the calls on hold and was speaking to the other call at the time.