Add Streaming to Deepgram example

streaming-to-deepgram/.env.example

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+DEEPGRAM_TOKEN=XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
+NGROK_TOKEN=25FKaLUXXXXXXXXXXXXX_XXXXXXXXXXXXXXXXXX
+PORT=3000

streaming-to-deepgram/Dockerfile

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+FROM node:18
+
+# Create app directory
+WORKDIR /usr/src/app
+
+# Install app dependencies
+COPY package*.json ./
+RUN npm install
+
+# Bundle app source
+COPY . .
+
+EXPOSE 3000
+CMD [ "node", "app.js" ]

streaming-to-deepgram/app.js

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+require("dotenv").config()
+const ngrok = require('ngrok')
+let wss_url
+
+(async function () {
+    let ngrok_url = await ngrok.connect({
+        authtoken: process.env.NGROK_TOKEN,
+        addr: process.env.PORT
+    })
+    console.log("Please connect a Phone Number with the following Webhook URL:", ngrok_url + '/startStreaming')
+    wss_url = ngrok_url.replace("https://", "wss://")
+})();
+
+const WebSocket = require('ws')
+const wss = new WebSocket.Server({ noServer: true })
+var express = require('express')
+var app = express()
+
+app.use(express.json())
+app.use(express.urlencoded({ extended: true }))
+
+const { RestClient } = require('@signalwire/compatibility-api')
+const { Deepgram } = require("@deepgram/sdk")
+const deepgram = new Deepgram(process.env.DEEPGRAM_TOKEN)
+
+app.post("/startStreaming", async (req, res) => {
+    const response = new RestClient.LaML.VoiceResponse()
+
+    const start = response.start();
+    start.stream({
+        url: wss_url,
+        track: 'both_tracks'
+    })
+    response.pause({ length: 1 })
+    response.say("Please wait one moment.")
+    response.pause({ length: 3 })
+    response.say("Yes, we are open Monday through Friday.")
+    response.pause({ length: 60 })
+
+    res.send(response.toString())
+});
+
+const server = app.listen(process.env.PORT, () => {
+    console.log(`Listening on port ${process.env.PORT}\n`)
+});
+
+function createDeepgramConnection() {
+    return deepgram.transcription.live({
+        punctuate: true,
+        model: "phonecall",
+        encoding: "mulaw",
+        channels: 1,
+        sample_rate: 8000
+    })
+}
+
+function listenForTranscriptionResults(deepgramConnection, callSid, callLeg) {
+    deepgramConnection.addListener("transcriptReceived", (result) => {
+        let data = JSON.parse(result)
+
+        if (data.type == 'Results' && data.channel.alternatives[0].transcript != '') {
+            console.log(callSid, callLeg, data.channel.alternatives[0].transcript)
+        }
+
+    });
+}
+
+server.on('upgrade', (request, socket, head) => {
+    wss.handleUpgrade(request, socket, head, async (ws) => {
+        console.log("New Connection Initiated.")
+
+        const deepgramLiveInbound = createDeepgramConnection()
+        const deepgramLiveOutbound = createDeepgramConnection()
+
+        ws.on('message', (message) => {
+            const msg = JSON.parse(message)
+
+            switch (msg.event) {
+                case "connected":
+                    console.log("A new call was connected.")
+                    break
+
+                case "start":
+                    listenForTranscriptionResults(deepgramLiveInbound, msg.start.callSid, 'inbound')
+                    listenForTranscriptionResults(deepgramLiveOutbound, msg.start.callSid, 'outbound')
+                    break
+
+                case "media":
+                    const payload = Buffer.from(msg.media.payload, "base64")
+
+                    try {
+                        if (msg.media.track === 'inbound' && deepgramLiveInbound.getReadyState() === 1) {
+                            deepgramLiveInbound.send(payload)
+                        } else if (msg.media.track === 'outbound' && deepgramLiveOutbound.getReadyState() === 1) {
+                            deepgramLiveOutbound.send(payload)
+                        }
+                    } catch (error) {
+                        console.log("Error:", error)
+                    }
+
+                    break
+
+                case "stop":
+                    console.log("Call has ended.")
+                    break
+            }
+        });
+    });
+});

streaming-to-deepgram/package.json

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+{
+  "dependencies": {
+    "@deepgram/sdk": "^2.2.0",
+    "@signalwire/compatibility-api": "^3.1.2",
+    "dotenv": "^16.3.1",
+    "express": "^4.18.2",
+    "ngrok": "^5.0.0-beta.2"
+  }
+}