# Jibo Hub-Shim Server: Architecture & Protocol

## Overview
The hub-shim server emulates the Jibo cloud hub's `/v1/listen` WebSocket protocol, allowing the robot to run skills and menu flows entirely offline. It acts as a bridge between the robot's jetstream service (binary) and local ASR/NLU logic, providing the expected protocol and responses for seamless skill operation.

## Key Features
- Listens on a configurable port (default: 9000) and path (`/v1/listen`)
- Accepts WebSocket connections from the robot's jetstream service
- Handles CONTEXT, LISTEN, CLIENT_ASR, and CLIENT_NLU messages
- Runs local ASR (via HTTP) and NLU (via rule-based inference)
- Sends TURN_RESULT responses that resolve the robot's local turn promise
- Fully mimics the cloud hub protocol, including transID/requestID echo

## Protocol Flow
1. **Connection**: Jetstream binary opens a WebSocket to `/v1/listen`.
2. **CONTEXT**: Robot sends context (skill, runtime info).
3. **LISTEN**: Robot requests a listen turn, providing rules and mode.
4. **ASR**: hub-shim runs local ASR (or accepts client-supplied text).
5. **NLU**: hub-shim infers intent/entities from text and rules.
6. **TURN_RESULT**: hub-shim sends a TURN_RESULT with status `SUCCEEDED`, echoing the transID as requestID, and including asr/nlu/match objects.
7. **Skill Advances**: The robot's local turn promise resolves, and the skill/menu flow continues.

## Message Types
- **CONTEXT**: Sets skill/runtime context for the turn.
- **LISTEN**: Initiates a listen turn; includes rules and mode.
- **CLIENT_ASR/CLIENT_NLU**: (Optional) Supplies ASR text or NLU result directly.
- **TURN_RESULT**: Final result; must have `status: 'SUCCEEDED'`, `global: false`, and correct asr/nlu/match.

## Key Implementation Details
- **requestID**: Always set to the incoming transID for local turns.
- **asr/nlu/match**: Structured to match the robot's expected ListenResult format.
- **No global-only results**: All results are sent as local TURN_RESULTs to resolve the skill's local turn.
- **Skill-specific NLU**: Rule-based inference for menu/intro/yes-no flows.

## Configuration
- `config.json` controls port, ASR service URL, and logging.
- ASR service must be running and reachable by hub-shim.

## Debugging
- Logs all connections, requests, and results.
- Use robot-logger on the robot to trace skill flow and intent resolution.

## Example TURN_RESULT
```
{
  "type": "TURN_RESULT",
  "msgID": "...",
  "transID": "...",
  "ts": 1234567890,
  "requestID": "...", // matches transID
  "data": {
    "status": "SUCCEEDED",
    "global": false,
    "result": {
      "asr": { "text": "face", "confidence": 1 },
      "nlu": { "intent": "face", ... },
      "match": { "onRobot": true }
    }
  },
  "final": true
}
```

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# See also: hub-shim source code for full protocol details.