support stt speechmatics (#353)

* support stt speechmatics

* support speechmatics region authentication

* update testcase for speechmatics_stt_uri

lib/utils/speech-utils.js

@@ -7,6 +7,7 @@ const bent = require('bent');
 const fs = require('fs');
 const { AssemblyAI } = require('assemblyai');
 const {decrypt, obscureKey} = require('./encrypt-decrypt');
+const { RealtimeSession } = require('speechmatics');
 
 const TtsGoogleLanguagesVoices = require('./speech-data/tts-google');
 const TtsAwsLanguagesVoices = require('./speech-data/tts-aws');
@@ -54,6 +55,61 @@ const testSonioxStt = async(logger, credentials) => {
   });
 };
 
+const testSpeechmaticsStt = async(logger, credentials) => {
+  const {api_key, speechmatics_stt_uri} = credentials;
+  return new Promise(async(resolve, reject) => {
+    try {
+      const session = new RealtimeSession({ apiKey: api_key, realtimeUrl: speechmatics_stt_uri });
+      let transcription = '';
+      session.addListener('Error', (error) => {
+        reject(error);
+      });
+
+      session.addListener('AddTranscript', (message) => {
+        transcription += message.metadata.transcript;
+      });
+
+      session.addListener('EndOfTranscript', () => {
+        resolve(transcription);
+      });
+
+      session
+        .start({
+          transcription_config: {
+            language: 'en',
+            operating_point: 'enhanced',
+            enable_partials: true,
+            max_delay: 2,
+          },
+          audio_format: { type: 'file' },
+        })
+        .then(() => {
+          //prepare file stream
+          const fileStream = fs.createReadStream(`${__dirname}/../../data/test_audio.wav`);
+
+          //send it
+          fileStream.on('data', (sample) => {
+            session.sendAudio(sample);
+          });
+
+          //end the session
+          fileStream.on('end', () => {
+            session.stop();
+          });
+
+          return;
+
+        })
+        .catch((error) => {
+          reject(error);
+        });
+    } catch (error) {
+      logger.info({error}, 'failed to get speechmatics transcript');
+      reject(error);
+    }
+  });
+};
+
 const testNuanceTts = async(logger, getTtsVoices, credentials) => {
   const voices = await getTtsVoices({vendor: 'nuance', credentials});
   return voices;
@@ -532,6 +588,10 @@ function decryptCredential(obj, credential, logger, isObscureKey = true) {
   } else if ('soniox' === obj.vendor) {
     const o = JSON.parse(decrypt(credential));
     obj.api_key = isObscureKey ? obscureKey(o.api_key) : o.api_key;
+  } else if ('speechmatics' === obj.vendor) {
+    const o = JSON.parse(decrypt(credential));
+    obj.api_key = isObscureKey ? obscureKey(o.api_key) : o.api_key;
+    obj.speechmatics_stt_uri = o.speechmatics_stt_uri;
   } else if ('elevenlabs' === obj.vendor) {
     const o = JSON.parse(decrypt(credential));
     obj.api_key = isObscureKey ? obscureKey(o.api_key) : o.api_key;
@@ -1066,5 +1126,6 @@ module.exports = {
   testWhisper,
   testVerbioTts,
   testVerbioStt,
-  getLanguagesAndVoicesForVendor
+  getLanguagesAndVoicesForVendor,
+  testSpeechmaticsStt
 };