WebChat

WebChat is OpenPollen's built-in web chat channel, providing a real-time conversation interface with streaming responses.

Configuration

Enable WebChat in openpollen.json:

{
  "channels": {
    "webchat": {
      "enabled": true,
      "port": 3001,
      "assistantName": "OpenPollen"
    }
  }
}

Field	Type	Default	Description
enabled	boolean	true	Enable WebChat
port	number	3001	HTTP + WebSocket service port
assistantName	string	OpenPollen	Assistant name shown in UI

Architecture

WebChat uses WebSocket for bidirectional communication:

Browser UI  ←→  WebSocket  ←→  WebchatAdapter  ←→  MessageRouter  ←→  Agent

Connection Flow

1. Client accesses the WebChat page via HTTP
2. Page establishes a WebSocket connection
3. Server performs protocol handshake (Protocol v3)
4. On success, returns connId and supported methods
5. Client sends RPC requests, server returns responses or events

WebSocket Protocol

OpenPollen WebChat uses a custom RPC protocol (v3) with three frame types:

Request Frame

{
  "type": "req",
  "id": "unique-id",
  "method": "chat.send",
  "params": { "text": "Hello" }
}

Response Frame

{
  "type": "res",
  "id": "unique-id",
  "ok": true,
  "payload": {}
}

Event Frame

{
  "type": "event",
  "event": "chat.delta",
  "payload": {
    "runId": "...",
    "state": "delta",
    "message": {
      "role": "assistant",
      "content": [{ "type": "text", "text": "Hello!" }]
    }
  }
}

Chat Event States

State	Description
delta	Streaming output chunk
final	Complete response
error	Error occurred
aborted	User interrupted

Error Codes

Code	Description
INVALID_FRAME	Invalid frame format
METHOD_NOT_FOUND	Method does not exist
UNAVAILABLE	Service unavailable
INTERNAL	Internal error
BAD_PARAMS	Invalid parameters
ABORT_FAILED	Abort failed
SESSION_NOT_FOUND	Session not found

Features

• Streaming responses: Agent replies pushed to browser in real-time
• Session management: Supports /new, /resume commands
• Heartbeat: Tick events sent every 30 seconds
• Abort support: Users can cancel Agent execution mid-stream
• History: Chat history persisted via Memory system