how to check if user id or conversation id or user alreadt exists in sunshine via node.js - smooch

Question

I am auto replying a predefined welcome message to user when they are posting a message via fb page or WhatsApp. I want if user already exists in sunshine then not to reply to that user else reply them with welcome message. How can I check if user already exists?
'use strict';
// Imports
`enter code here`const express = require('express');
const bodyParser = require('body-parser');
const SunshineConversationsApi = require('sunshine-conversations-client');
var request = require('request')
// Config
let defaultClient = SunshineConversationsApi.ApiClient.instance;
let basicAuth = defaultClient.authentications['basicAuth'];
basicAuth.username = 'app_XXXXXXX';
basicAuth.password = 'XXXXXXXXXXXXXXXXX-bSwG85aM8qldJzTt4rgZlf_XQukWKE8ADMno85g';
const PORT = 5050;
const apiInstance = new SunshineConversationsApi.MessagesApi()
// Server https://expressjs.com/en/guide/routing.html
const app = express();
app.use(bodyParser.json());
// Expose /messages endpoint to capture webhooks
https://docs.smooch.io/rest/#operation/eventWebhooks
app.post('/messages', function(req, res) {
console.log('webhook PAYLOAD:\n',
JSON.stringify(req.body.events[0].payload.conversation.id, null, 4));
const appId = req.body.app.id;
const trigger = req.body.events[0].type;
// Call REST API to send message https://docs.smooch.io/rest/#operation/postMessage
if (trigger === 'conversation:message') {
const authorType = req.body.events[0].payload.message.author.type;
const displayName=req.body.events[0].payload.message.author.displayName;
if(authorType === 'user'){
const conversationId = req.body.events[0].payload.conversation.id;
console.log(conversationId);
console.log(displayName);
check_conversation_ID_with_sunshine(appId,conversationId);
//sendMessage(appId, conversationId);
res.end();
}
}
});
// Listen on port
app.listen(PORT, () => {
console.log(`App listening on port ${PORT}`);
});
async function sendMessage(appId, conversationId){
let messagePost = new SunshineConversationsApi.MessagePost();
messagePost.setAuthor({type: 'business'});
messagePost.setContent({type: 'text', text: 'Thanks boy'});
let response = await apiInstance.postMessage(appId, conversationId, messagePost);
//console.log('API RESPONSE:\n', response);
}

Answer 1

So [a simple] overall process could be:
User message comes in (including userId and conversationId)
fetch user's conversation
if len(response['messages']) == 1 (messages in the conversation)
send welcome message
(else no-op)
The caveat is that you could get false-negatives, if users send multiple messages, in quick succession, right at the beginning (instead of just one).
Some safe ways to do it would be to either:
look for the welcome message at the start of the convo (second message?)
i.e. iterate over [the first few] response['messages'], inspecting each one's text/metadata
when sending the welcome message, add a metadata flag on the conversation (e.g.: metadata.['welcomeSent']: True), searching for this flag for returning users
Doc references
Get a conversation's messages
doc page: https://docs.smooch.io/rest/#operation/listMessages
endpoint: https://api.smooch.io/v2/apps/{appId}/conversations/{conversationId}/messages
authentication: Basic, etc.
payload: <none>
response payload: {messages:[...], meta:{...}, links:{}}