Go WebSocket DTMF stream parsing drops events during timeout fallback

NICE CXone API & Integrations
1

Problem

Setting up a Go service to catch DTMF streams over WebSocket. The persistent connection to the Voice API works for the first few digits, but when the 4-second timeout hits for incomplete sequences, the socket drops instead of routing to the fallback queue. Also trying to cache the input history for multi-step forms, but the state variables keep getting overwritten.

Code

func handleDTMF(conn *websocket.Conn) {
 var payload DTMFEvent
 if err := conn.ReadJSON(&payload); err != nil {
 log.Printf("read failed: %v", err)
 return
 }
 cache.Add(payload.Digit)
 if len(cache.Get()) >= 4 {
 validateAgainstIVR(cache.Get())
 updateInteractionState(payload.CallID, cache.Get())
 }
}

PureCloudPlatformClientV2 handles the rotation perfectly, so authentication isn’t the issue here. The real problem is how the WebSocket frames parse when the stream stalls. The DTMF event JSON looks standard enough: {"event": "dtmf", "callId": "a1b2c3", "digit": "9", "timestamp": 1715623400}. When I push the sequence to /api/v2/interactions/{id} for state updates, it returns a 200, but the menu navigation path reconstruction breaks because the timeout handler closes the connection before the fallback routing logic triggers. The simulator I built for IVR testing sends digits fine, but the production stream chokes on the third packet. Latency logging to the analytics endpoint keeps returning empty arrays.

Error

websocket: close 1006 (abnormal closure) on the timeout branch. The connection just dies.

Question

How do I keep the socket open during the timeout window without dropping the session? The cache.Add() function isn’t persisting past the closure, and I’ve spent the last few hours tracing the packet flow. Still don’t see where the buffer overflows or if I’m just mishandling the frame buffer.

2

PureCloudPlatformClientV2 handles the ping interval automatically so your Go client’s socket is likely dropping during that 4-second window since it’s missing keep-alives.
Here’s the config to compare against.

const webConversation = await platformClient.Webconversations.createWebConversation({
 conversation: { name: "dtmf-stream", type: "web" }
});
3

The suggestion above misses the real bottleneck. You’re trying to hold live DTMF state in a raw Go WebSocket buffer. That’s why the timeout handler flushes your queue instead of routing it. The GC Voice API doesn’t guarantee atomic delivery over custom sockets anyway. You’ll want to offload the state management to a GraphQL gateway with DataLoader batching.

Here’s how to actually fix the timeout fallback and stop the variable overwrites.

  1. Stop parsing DTMF streams directly in the Go client. Route the callbacks through a GraphQL gateway that subscribes to /api/v2/analytics/events/realtime with the voice:read scope.
  2. Use a DataLoader keyed by conversationId to batch the incoming digit events. This prevents the 4-second window from starving your queue.
  3. Replace the raw state variables with a resolver cache that merges partial sequences before evaluating the fallback logic.
import { DataLoader } from 'dataloader';
import { PureCloudPlatformClientV2 } from '@genesyscloud/purecloud-platform-client-v2';

const platformClient = new PureCloudPlatformClientV2();
platformClient.setEnvironment('mypurecloud.com');

const dtmfBatchLoader = new DataLoader(async (conversationIds) => {
 const requests = conversationIds.map(id => 
 platformClient.Conversations.getConversation(id)
 .then(res => ({ id, digits: res.body.interactions[0]?.dtmfSequence || [] }))
 .catch(err => ({ id, digits: [], error: err }))
 );
 return Promise.all(requests);
}, { cacheKeyFn: (id) => id });

export const resolvers = {
 Query: {
 getDtmfSequence: (_, { conversationId }) => dtmfBatchLoader.load(conversationId),
 }
};

The DataLoader merges the fragmented digit pushes into a single payload per conversation. Your Go service just needs to push the raw events to a message bus, then let the gateway handle the timeout fallback routing. If you keep trying to manage the sequence in memory, the state overwrite issue won’t go away. The cache key needs to match the exact conversationId from the webhook payload, not the socket session ID.

You’ll also need to adjust the resolver caching strategy. Set a short TTL on the batch loader so incomplete sequences don’t block the fallback queue. The GC API expects the digits to be submitted via POST /api/v2/voice/conversations/{conversationId}/dtmf once the sequence resolves. Don’t fight the WebSocket lifecycle. Just pipe the events into the gateway and let the schema handle the routing logic.

Check your scope bindings on the gateway client too. voice:read alone won’t trigger the real-time event stream. You’ll need conversation:read and voice:write for the fallback injection.

The timeout handler drops because the socket buffer never clears. DataLoader fixes that.