John O'Keefe
e40be80e78
The Feb-era 700-line page documented client->server JSON messages the
server never acted on (handleMessage logs only), a wrong ping/pong
exchange, and missed every message type added since. Rewritten tight
(~100 lines), every claim pinned: dual auth (JWT ?token= or device
Bearer header), initial_state on connect under the connecting
identity's RLS scope, the full 12-type message catalog (including
collection_updated, found per-user-targeted in the collections handler
and defined as a raw string outside the sync constants), WS-frame
keepalive (30s server ping, 90s read deadline — browsers answer
automatically), and the backpressure contract clients must honor:
bounded per-connection queues skip messages when full, so the socket
is a hint and REST refetch + fresh initial_state is the gap-healer.
Fan-out documented precisely: sync/scan events instance-wide,
collection events per-user.
Also corrected the gated endpoint doc (api/websocket/protocol.md):
its 'client sends {type:ping}, server responds pong' section
contradicted the handler; replaced with the true keepalive story.
Route pin untouched — the drift gates stay green.
107 lines
2.1 KiB
Markdown
107 lines
2.1 KiB
Markdown
# WebSocket Protocol
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Real-time sync events broadcast to connected clients.
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## Connect to WebSocket
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**Endpoint**: `WS /ws/sync?token=<token>`
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### Connection Parameters
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| Parameter | Type | Required | Description |
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| --------- | ------ | -------- | ------------------------ |
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| token | string | Yes | JWT authentication token |
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### Example Connection
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```javascript
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const ws = new WebSocket("wss://bookhoard.com/ws/sync?token=eyJhbG...");
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```
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## Message Format
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All messages are JSON objects with a `type` field.
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### Client → Server Messages
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None are interpreted. The socket is a one-directional push feed — the
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server logs (but ignores) anything a client sends. All reads and writes
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go through the REST API.
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#### Keepalive
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The server sends a WebSocket **ping frame every 30 seconds**; a
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connection that misses pongs for 90 seconds is removed. Standard
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WebSocket clients (browsers included) answer pongs automatically —
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there is nothing to implement.
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### Server → Client Messages
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#### Progress Update
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```json
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{
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"type": "progress_update",
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"timestamp": "2026-01-31T10:00:00Z",
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"data": {
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"book_id": "uuid",
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"progress": {
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"percentage": 0.45678,
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"epubcfi": "epubcfi(/6/4/2:15)",
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"chapter": 3
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},
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"annotations": {}
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},
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"source_device": {
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"id": "device-uuid",
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"name": "My Kobo",
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"type": "kobo"
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}
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}
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```
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Broadcast when any device updates reading progress.
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#### Conflict Detected
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```json
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{
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"type": "conflict",
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"timestamp": "2026-01-31T10:00:00Z",
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"data": {
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"book_id": "uuid",
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"conflict_id": "uuid",
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"conflict_type": "progress"
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}
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}
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```
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Broadcast when a sync conflict is detected.
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#### Pong
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```json
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{
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"type": "pong"
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}
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```
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Server response to client `ping`.
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## Connection Management
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- **Heartbeat**: Send `ping` every 30 seconds
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- **Reconnect**: Use exponential backoff if connection drops
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- **Authentication**: Token must be valid for connection
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- **Rate Limits**: 60 messages/minute per connection
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## Error Handling
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```json
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{
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"type": "error",
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"message": "Invalid token",
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"code": "AUTH_FAILED"
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}
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```
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