Add call transfer example, make all functions async

.gitignore

@@ -142,6 +142,6 @@ dist
 .svelte-kit
 
 # Ignore Fly.io configuration file
-.toml
+fly.toml
 
 # End of https://www.toptal.com/developers/gitignore/api/node

README.md

@@ -233,7 +233,7 @@ For our `placeOrder` function, the arguments passed will look like this:
 }
 ```
 ### Returning Arguments to GPT
-Your function should always return a value: GPT tends to get confused when the function returns nothing, and may continue trying to call the function expecting an answer. If your function doesn't have any data to return to the GPT, you should still consider returning a response that says something like "The function to do (X) ran successfully."
+Your function should always return a value: GPT will get confused when the function returns nothing, and may continue trying to call the function expecting an answer. If your function doesn't have any data to return to the GPT, you should still return a response with an instruction like "Tell the user that their request was processed successfully." This prevents the GPT from calling the function repeatedly and wasting tokens. 
 
 Any data that you return to the GPT should match the expected format listed in the `returns` key of `function-manifest.js`.
 

app.js

@@ -30,6 +30,7 @@ app.ws('/connection', (ws) => {
   ws.on('error', console.error);
   // Filled in from start message
   let streamSid;
+  let callSid;
 
   const gptService = new GptService();
   const streamService = new StreamService(ws);
@@ -44,7 +45,9 @@ app.ws('/connection', (ws) => {
     const msg = JSON.parse(data);
     if (msg.event === 'start') {
       streamSid = msg.start.streamSid;
+      callSid = msg.start.callSid;
       streamService.setStreamSid(streamSid);
+      gptService.setCallSid(callSid);
       console.log(`Twilio -> Starting Media Stream for ${streamSid}`.underline.red);
       ttsService.generate({partialResponseIndex: null, partialResponse: 'Hello! I understand you\'re looking for a pair of AirPods, is that correct?'}, 1);
     } else if (msg.event === 'media') {

functions/checkInventory.js

@@ -1,4 +1,4 @@
-function checkInventory(functionArgs) {
+async function checkInventory(functionArgs) {
   const model = functionArgs.model;
   console.log('GPT -> called checkInventory function');
 

functions/checkPrice.js

@@ -1,4 +1,4 @@
-function checkPrice(functionArgs) {
+async function checkPrice(functionArgs) {
   let model = functionArgs.model;
   console.log('GPT -> called checkPrice function');
   if (model?.toLowerCase().includes('pro')) {

functions/function-manifest.js

@@ -89,6 +89,32 @@ const tools = [
       }
     },
   },
+  {
+    type: 'function',
+    function: {
+      name: 'transferCall',
+      description: 'Transfers the customer to a live agent in case they request help from a real person.',
+      parameters: {
+        type: 'object',
+        properties: {
+          callSid: {
+            type: 'string',
+            description: 'The unique identifier for the active phone call.',
+          },
+        },
+        required: ['callSid'],
+      },
+      returns: {
+        type: 'object',
+        properties: {
+          status: {
+            type: 'string',
+            description: 'Whether or not the customer call was successfully transfered'
+          },
+        }
+      }
+    },
+  },
 ];
 
 module.exports = tools;

functions/placeOrder.js

@@ -1,4 +1,4 @@
-function placeOrder(functionArgs) {
+async function placeOrder(functionArgs) {
   const {model, quantity} = functionArgs;
   console.log('GPT -> called placeOrder function');
 

functions/transferCall.js

@@ -0,0 +1,20 @@
+require('dotenv').config();
+
+const transferCall = async function (call) {
+
+  console.log('Transferring call', call.callSid);
+  const accountSid = process.env.TWILIO_ACCOUNT_SID;
+  const authToken = process.env.TWILIO_AUTH_TOKEN;
+  const client = require('twilio')(accountSid, authToken);
+
+  return await client.calls(call.callSid)
+    .update({twiml: `<Response><Dial>${process.env.TRANSFER_NUMBER}</Dial></Response>`})
+    .then(() => {
+      return 'The call was transferred successfully, say goodbye to the customer.';
+    })
+    .catch(() => {
+      return 'The call was not transferred successfully, advise customer to call back later.';
+    });
+};
+
+module.exports = transferCall;

scripts/outbound-call.js

@@ -1,3 +1,8 @@
+/*
+  You can use this script to place an outbound call
+  to your own mobile phone.
+*/
+
 require('dotenv').config();
 
 async function makeOutBoundCall() {

services/gpt-service.js

@@ -22,6 +22,12 @@ class GptService extends EventEmitter {
     this.partialResponseIndex = 0;
   }
 
+  // Add the callSid to the chat context in case
+  // ChatGPT decides to transfer the call.
+  setCallSid (callSid) {
+    this.userContext.push({ 'role': 'system', 'content': `callSid: ${callSid}` });
+  }
+
   async completion(text, interactionCount, role = 'user', name = 'user') {
     if (name != 'user') {
       this.userContext.push({ 'role': role, 'name': name, 'content': text });
@@ -77,7 +83,7 @@ class GptService extends EventEmitter {
         }
 
         const functionToCall = availableFunctions[functionName];
-        let functionResponse = functionToCall(functionArgs);
+        let functionResponse = await functionToCall(functionArgs);
 
         // Step 4: send the info on the function call and function response to GPT
         this.userContext.push({
@@ -86,7 +92,7 @@ class GptService extends EventEmitter {
           content: functionResponse,
         });
         // extend conversation with function response
-
+        console.log(this.userContext);
         // call the completion function again but pass in the function response to have OpenAI generate a new assistant response
         await this.completion(functionResponse, interactionCount, 'function', functionName);
       } else {

services/stream-service.js

@@ -8,6 +8,7 @@ class StreamService extends EventEmitter {
     this.expectedAudioIndex = 0;
     this.audioBuffer = {};
     this.streamSid = '';
+    this.callSid = '';
   }
 
   setStreamSid (streamSid) {

test/transferCall.test.js

@@ -0,0 +1,31 @@
+require('dotenv').config();
+const setTimeout = require('timers/promises').setTimeout;
+const transferCall = require('../functions/transferCall');
+
+test('Expect transferCall to successfully redirect call', async () => {
+
+  async function makeOutBoundCall() {
+    const accountSid = process.env.TWILIO_ACCOUNT_SID;
+    const authToken = process.env.TWILIO_AUTH_TOKEN;
+
+    const client = require('twilio')(accountSid, authToken);
+
+    const sid = await client.calls
+      .create({
+        url: `https://${process.env.SERVER}/incoming`,
+        to: process.env.YOUR_NUMBER,
+        from: process.env.FROM_NUMBER
+      })
+      .then(call => call.sid);
+
+    return sid;
+  }
+
+  const callSid = await makeOutBoundCall();
+  console.log(callSid);
+  await setTimeout(10000);
+
+  const transferResult = await transferCall(callSid);
+
+  expect(transferResult).toBe('The call was transferred successfully');
+}, 20000);