gather: support for min/max digits and interdigit timeout

lib/tasks/gather.js

@@ -9,6 +9,7 @@ const {
 
 const makeTask = require('./make_task');
 const assert = require('assert');
+const GATHER_STABILITY_THRESHOLD =  Number(process.env.JAMBONZ_GATHER_STABILITY_THRESHOLD || 0.7);
 
 class TaskGather extends Task {
   constructor(logger, opts, parentTask) {
@@ -16,11 +17,14 @@ class TaskGather extends Task {
     this.preconditions = TaskPreconditions.Endpoint;
 
     [
-      'finishOnKey', 'hints', 'input', 'numDigits',
-      'partialResultHook', 'bargein',
+      'finishOnKey', 'hints', 'input', 'numDigits', 'minDigits', 'maxDigits',
+      'interDigitTimeout', 'partialResultHook', 'bargein', 'dtmfBargein',
       'speechTimeout', 'timeout', 'say', 'play'
     ].forEach((k) => this[k] = this.data[k]);
 
+    /* when collecting dtmf, bargein on dtmf is true unless explicitly set to false */
+    if (this.dtmfBargein !== false && this.input.includes('digits')) this.dtmfBargein = true;
+
     this.timeout = (this.timeout || 15) * 1000;
     this.interim = this.partialResultCallback;
     if (this.data.recognizer) {
@@ -123,7 +127,7 @@ class TaskGather extends Task {
           .catch(() => {/*already logged error */});
       }
 
-      if (this.input.includes('digits')) {
+      if (this.input.includes('digits') || this.dtmfBargein) {
         ep.on('dtmf', this._onDtmf.bind(this, cs, ep));
       }
 
@@ -142,17 +146,33 @@ class TaskGather extends Task {
     super.kill(cs);
     this._killAudio(cs);
     this.ep.removeAllListeners('dtmf');
+    clearTimeout(this.interDigitTimer);
     this._resolve('killed');
   }
 
   _onDtmf(cs, ep, evt) {
     this.logger.debug(evt, 'TaskGather:_onDtmf');
-    if (evt.dtmf === this.finishOnKey) this._resolve('dtmf-terminator-key');
+    clearTimeout(this.interDigitTimer);
+    let resolved = false;
+    if (this.dtmfBargein) this._killAudio(cs);
+    if (evt.dtmf === this.finishOnKey && this.input.includes('digits')) {
+      resolved = true;
+      this._resolve('dtmf-terminator-key');
+    }
     else {
       this.digitBuffer += evt.dtmf;
-      if (this.digitBuffer.length === this.numDigits) this._resolve('dtmf-num-digits');
+      const len = this.digitBuffer.length;
+      if (len === this.numDigits || len === this.maxDigits) {
+        resolved = true;
+        this._resolve('dtmf-num-digits');
+      }
+    }
+    if (!resolved && this.interDigitTimeout > 0 && this.digitBuffer.length >= this.minDigits) {
+      /* start interDigitTimer */
+      const ms = this.interDigitTimeout * 1000;
+      this.logger.debug(`starting interdigit timer of ${ms}`);
+      this.interDigitTimer = setTimeout(() => this._resolve('dtmf-interdigit-timeout'), ms);
     }
-    this._killAudio(cs);
   }
 
   async _initSpeech(cs, ep) {
@@ -292,19 +312,20 @@ class TaskGather extends Task {
     }
     if (evt.is_final) this._resolve('speech', evt);
     else {
-      if (this.bargein && evt.alternatives[0].transcript.split(' ').length >= this.minBargeinWordCount) {
-        this.logger.debug('Gather:_onTranscription - killing audio due to bargein');
+      /* google has a measure of stability:
+        https://cloud.google.com/speech-to-text/docs/basics#streaming_responses
+        others do not.
+      */
+      const isStableEnough = typeof evt.stability === 'undefined' || evt.stability > GATHER_STABILITY_THRESHOLD;
+
+      if (this.bargein && isStableEnough &&
+        evt.alternatives[0].transcript.split(' ').length >= this.minBargeinWordCount) {
+        this.logger.debug('Gather:_onTranscription - killing audio due to speech bargein');
         this._killAudio(cs);
       }
-      else {
-        if (this.bargein && evt.alternatives[0].transcript.split(' ').length >= this.minBargeinWordCount) {
-          this.logger.debug('Gather:_onTranscription - killing audio due to bargein');
-          this._killAudio(cs);
-        }
-        if (this.partialResultHook) {
-          this.cs.requestor.request(this.partialResultHook,  Object.assign({speech: evt}, this.cs.callInfo))
-            .catch((err) => this.logger.info(err, 'GatherTask:_onTranscription error'));
-        }
+      if (this.partialResultHook) {
+        this.cs.requestor.request(this.partialResultHook,  Object.assign({speech: evt}, this.cs.callInfo))
+          .catch((err) => this.logger.info(err, 'GatherTask:_onTranscription error'));
       }
     }
   }
@@ -323,6 +344,7 @@ class TaskGather extends Task {
     if (this.resolved) return;
     this.resolved = true;
     this.logger.debug(`TaskGather:resolve with reason ${reason}`);
+    clearTimeout(this.interDigitTimer);
 
     if (this.ep && this.ep.connected) {
       this.ep.stopTranscription({vendor: this.vendor})

lib/tasks/say.js

@@ -21,15 +21,20 @@ class TaskSay extends Task {
     const {updateSpeechCredentialLastUsed} = require('../utils/db-utils')(this.logger, srf);
     const {writeAlerts, AlertType, stats} = srf.locals;
     const {synthAudio} = srf.locals.dbHelpers;
-    const hasVerbLevelTts = this.synthesizer.vendor && this.synthesizer.vendor !== 'default';
-    const vendor = hasVerbLevelTts ? this.synthesizer.vendor : cs.speechSynthesisVendor ;
-    const language = hasVerbLevelTts ? this.synthesizer.language : cs.speechSynthesisLanguage ;
-    const voice = hasVerbLevelTts ? this.synthesizer.voice : cs.speechSynthesisVoice ;
+    const vendor = this.synthesizer.vendor && this.synthesizer.vendor !== 'default' ?
+      this.synthesizer.vendor :
+      cs.speechSynthesisVendor;
+    const language = this.synthesizer.language && this.synthesizer.language !== 'default' ?
+      this.synthesizer.language :
+      cs.speechSynthesisLanguage ;
+    const voice =  this.synthesizer.voice && this.synthesizer.voice !== 'default' ?
+      this.synthesizer.voice :
+      cs.speechSynthesisVoice;
     const engine = this.synthesizer.engine || 'standard';
     const salt = cs.callSid;
     const credentials = cs.getSpeechCredentials(vendor, 'tts');
 
-    this.logger.info({language, voice}, `Task:say - using vendor: ${vendor}`);
+    this.logger.info({vendor, language, voice}, 'TaskSay:exec');
     this.ep = ep;
     try {
       if (!credentials) {

lib/tasks/specs.json

@@ -98,9 +98,13 @@
       "finishOnKey": "string",
       "input": "array",
       "numDigits": "number",
+      "minDigits": "number",
+      "maxDigits": "number",
+      "interDigitTimeout": "number",
       "partialResultHook": "object|string",
       "speechTimeout": "number",
       "listenDuringPrompt": "boolean",
+      "dtmfBargein": "boolean",
       "bargein": "boolean",
       "minBargeinWordCount": "number",
       "timeout": "number",