From 740c2b89b4f5c3a96a1507ea0df942e329ad8590 Mon Sep 17 00:00:00 2001
From: Dave Horton <daveh@beachdognet.com>
Date: Tue, 12 Oct 2021 12:22:52 -0400
Subject: [PATCH] Dial: dtmf detection now based on SIP INFO events from sbcs
 and rtpengine

---
 lib/tasks/dial.js | 71 ++++++++++++++++++++++++-----------------------
 1 file changed, 37 insertions(+), 34 deletions(-)

diff --git a/lib/tasks/dial.js b/lib/tasks/dial.js
index 8ab8b49c..b040a7e0 100644
--- a/lib/tasks/dial.js
+++ b/lib/tasks/dial.js
@@ -131,7 +131,7 @@ class TaskDial extends Task {
   get name() { return TaskName.Dial; }
 
   get canReleaseMedia() {
-    return !process.env.ANCHOR_MEDIA_ALWAYS && !this.dtmfHook && !this.listenTask && !this.transcribeTask;
+    return !process.env.ANCHOR_MEDIA_ALWAYS && !this.listenTask && !this.transcribeTask;
   }
 
   async exec(cs) {
@@ -146,13 +146,12 @@ class TaskDial extends Task {
           this.epOther.play(this.dialMusic).catch((err) => {});
         }
       }
-      if (this.epOther) this._installDtmfDetection(cs, this.epOther, this.parentDtmfCollector);
       await this._attemptCalls(cs);
       await this.awaitTaskDone();
       this.logger.debug({callSid: this.cs.callSid}, 'Dial:exec task is done, sending actionHook if any');
       await this.performAction(this.results, this.killReason !== KillReason.Replaced);
-      this._removeDtmfDetection(cs, this.epOther);
-      this._removeDtmfDetection(cs, this.ep);
+      this._removeDtmfDetection(cs.dlg);
+      this._removeDtmfDetection(this.dlg);
     } catch (err) {
       this.logger.error({err}, 'TaskDial:exec terminating with error');
       this.kill(cs);
@@ -162,8 +161,8 @@ class TaskDial extends Task {
   async kill(cs, reason) {
     super.kill(cs);
     this.killReason = reason || KillReason.Hangup;
-    this._removeDtmfDetection(this.cs, this.epOther);
-    this._removeDtmfDetection(this.cs, this.ep);
+    this._removeDtmfDetection(cs.dlg);
+    this._removeDtmfDetection(this.dlg);
     this._killOutdials();
     if (this.sd) {
       this.sd.kill();
@@ -236,35 +235,39 @@ class TaskDial extends Task {
     this.dials.clear();
   }
 
-  _installDtmfDetection(cs, ep, dtmfDetector) {
-    if (ep && this.dtmfHook && !ep.dtmfDetector) {
-      ep.dtmfDetector = dtmfDetector;
-      ep.on('dtmf', this._onDtmf.bind(this, cs, ep));
-    }
+  _installDtmfDetection(cs, dlg) {
+    dlg.on('info', this._onInfo.bind(this, cs, dlg));
   }
-  _removeDtmfDetection(cs, ep) {
-    if (ep) {
-      delete ep.dtmfDetector;
-      ep.removeAllListeners('dtmf');
-    }
+  _removeDtmfDetection(dlg) {
+    dlg && dlg.removeAllListeners('info');
   }
 
-  _onDtmf(cs, ep, evt) {
-    if (ep.dtmfDetector) {
-      const match = ep.dtmfDetector.keyPress(evt.dtmf);
-      if (match) {
-        this.logger.debug({callSid: this.cs.callSid}, `Dial:_onDtmf triggered dtmf match: ${match}`);
-        const requestor = ep.dtmfDetector === this.parentDtmfCollector ?
-          cs.requestor :
-          (this.sd ? this.sd.requestor : null);
-        if (!requestor) {
-          this.logger.info(`Dial:_onDtmf got digits on B leg after adulting: ${evt.dtmf}`);
-        }
-        else {
-          requestor.request(this.dtmfHook, {dtmf: match, ...cs.callInfo.toJSON()})
-            .catch((err) => this.logger.info(err, 'Dial:_onDtmf - error'));
-        }
-      }
+  _onInfo(cs, dlg, req, res) {
+    res.send(200);
+    if (req.get('Content-Type') !== 'application/dtmf-relay') return;
+
+    const dtmfDetector = dlg === cs.dlg ? this.parentDtmfCollector : this.childDtmfCollector;
+    if (!dtmfDetector) return;
+    let requestor, callSid, callInfo;
+    if (dtmfDetector === this.parentDtmfCollector) {
+      requestor = cs.requestor;
+      callSid = cs.callSid;
+      callInfo = cs.callInfo;
+    }
+    else {
+      requestor = this.sd?.requestor;
+      callSid = this.sd?.callSid;
+      callInfo = this.sd?.callInfo;
+    }
+    if (!requestor) return;
+    const arr = /Signal=([0-9#*])/.exec(req.body);
+    if (!arr) return;
+    const key = arr[1];
+    const match = dtmfDetector.keyPress(key);
+    if (match) {
+      this.logger.info({callSid}, `Dial:_onInfo triggered dtmf match: ${match}`);
+      requestor.request(this.dtmfHook, {dtmf: match, ...callInfo.toJSON()})
+        .catch((err) => this.logger.info(err, 'Dial:_onDtmf - error'));
     }
   }
 
@@ -274,7 +277,6 @@ class TaskDial extends Task {
     debug(`Dial:__initializeInbound allocated ep for incoming call: ${ep.uuid}`);
 
     /* send outbound legs back to the same SBC (to support static IP feature) */
-    //if (!this.proxy) this.proxy = `${cs.req.source_address}:${cs.req.source_port};transport=tcp`;
     if (!this.proxy) this.proxy = `${cs.req.source_address}:${cs.req.source_port}`;
 
     if (this.dialMusic) {
@@ -478,7 +480,8 @@ class TaskDial extends Task {
       dialCallSid: sd.callSid,
     });
 
-    if (this.childDtmfCollector) this._installDtmfDetection(cs, this.ep, this.childDtmfCollector);
+    if (this.parentDtmfCollector) this._installDtmfDetection(cs, cs.dlg);
+    if (this.childDtmfCollector) this._installDtmfDetection(cs, this.dlg);
 
     if (this.transcribeTask) this.transcribeTask.exec(cs, this.ep);
     if (this.listenTask) this.listenTask.exec(cs, this.ep);