sending DTMF inband from updateCall/command (#536)

* sending DTMF inband from updateCall/command

* wip

* wip

lib/session/call-session.js

@@ -1187,6 +1187,38 @@ class CallSession extends Emitter {
     }
   }
 
+  /**
+   * perform live call control - send RFC 2833 DTMF
+   * @param {obj} opts
+   * @param {string} opts.dtmf.digit - DTMF digit
+   * @param {string} opts.dtmf.duration - Optional, Duration
+   */
+  async _lccDtmf(opts, callSid) {
+    const {dtmf} = opts;
+    const {digit, duration = 250} = dtmf;
+    if (!this.hasStableDialog) {
+      this.logger.info('CallSession:_lccDtmf - invalid command as we do not have a stable call');
+      return;
+    }
+    try {
+      const dlg = callSid === this.callSid ? this.dlg : this.currentTask.dlg;
+      const res = await dlg.request({
+        method: 'INFO',
+        headers: {
+          'Content-Type': 'application/dtmf',
+          'X-Reason': 'Dtmf'
+        },
+        body: `Signal=${digit}
+Duration=${duration} `
+      });
+      this.logger.debug({res}, `CallSession:_lccDtmf
+ got response to INFO DTMF digit=${digit} and duration=${duration}`);
+      return res;
+    } catch (err) {
+      this.logger.error({err}, 'CallSession:_lccDtmf - error sending INFO RFC 2833 DTMF');
+    }
+  }
+
   /**
    * perform live call control -- whisper to one party or the other on a call
    * @param {array} opts - array of play or say tasks
@@ -1270,6 +1302,8 @@ class CallSession extends Emitter {
     else if (opts.sip_request) {
       const res = await this._lccSipRequest(opts, callSid);
       return {status: res.status, reason: res.reason};
+    } else if (opts.dtmf) {
+      await this._lccDtmf(opts, callSid);
     }
     else if (opts.record) {
       await this.notifyRecordOptions(opts.record);
@@ -1452,6 +1486,13 @@ class CallSession extends Emitter {
           });
         break;
 
+      case 'dtmf':
+        this._lccDtmf(data, call_sid)
+          .catch((err) => {
+            this.logger.info({err, data}, `CallSession:_onCommand - error sending RFC 2833 DTMF ${data}`);
+          });
+        break;
+
       default:
         this.logger.info(`CallSession:_onCommand - invalid command ${command}`);
     }