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TREK/wiki/Real-Time-Collaboration.md
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Maurice 7da0080557 docs(wiki): bring the wiki in line with 4.0.0 (#2034)
* docs(wiki): correct the install and operations pages for 4.0.0

Quick Start passed docker an empty ENCRYPTION_KEY: an assignment prefix is not
expanded on the same command line, so the server silently generated its own key
instead of taking the one the page told you to set. The tag examples pinned to
the 3.x line, the documented tmpfs size did not match the shipped compose file,
and several .env values were described as reaching the container when compose
never interpolates them.

* docs(wiki): match the MCP reference to the registered surface

The scope table was missing the whole Collections group and the totals said 27
scopes across 13 groups where the code registers 29 across 14. The Cloudflare
link on the setup page pointed at an anchor on its own page instead of the
heading on Troubleshooting.

* docs(wiki): correct the plugin and admin pages

Three links to Plugin-Development carried a .md suffix, which does not resolve on
the wiki. The admin pages described tabs, permissions and storage behaviour that
had moved on.

* docs(wiki): bring the feature pages back in line with the app

Costs still documented the old panel, where categories could be added, renamed,
reordered and deleted; they are fixed now and the panel is a day-grouped ledger
with settlements. Trip sharing, journeys, maps, packing, reservations and the
account pages had all drifted in the same way.

* docs(wiki): cover the pages the first pass did not reach

The MCP catalog listed 168 of the 201 registered tools; the settlement tools and
rate_place were missing here and the Collections family from the addon page.
Several resource rows claimed a trips:* scope where the handler asks for
trips:read.

* docs(wiki): tighten the corrections a review picked apart

The audit-log resource is the row id, not the credential id; an admin password
reset does not bump password_version the way the page implied; and a few of the
new paragraphs described behaviour more confidently than the code supports.

* docs(wiki): fix what a last read-through caught

Costs shows every figure in your display currency, not the trip's, and an
expense with no payer still counts against the members it is split between.
Studio's cutoff is a 1024px viewport rather than phones alone, and the
Integrations tab is gated on the providers an admin has configured.

* docs(wiki): the last few the review caught

A passkey satisfies the MFA policy everywhere except the WebSocket handshake,
which still asks for TOTP, so a passkey-only account under that policy gets no
live updates. Mobile optimizes a day from two places, not three. The ctx.db row
carried an unescaped pipe that split the table, and the Backups table linked
with a wiki link whose pipe did the same.
2026-08-25 12:36:52 +02:00

4.4 KiB

Real-Time Collaboration

TREK keeps every trip in sync across all connected members without requiring a page refresh. A dedicated Collab addon adds a second layer on top of that sync: group chat, shared notes, polls, and a "What's Next" widget showing upcoming assigned places.

The Collab tab: chat, shared notes, polls and the What's Next widget side by side

Real-time sync

All changes to a trip — places, day plans, reservations, budget entries, and packing lists — are broadcast instantly to every connected member via WebSocket. You see other people's edits as they happen.

WebSocket transport

Parameter Value
Path /ws
Scope One room per trip
Rate limit 30 messages per 10-second window, plus a looser ceiling of 200 frames per 10 seconds that every frame counts against before it is parsed. Live cursor frames (book:cursor) are exempt from the tighter limit, not from the looser one
Max payload 64 KB per message
Heartbeat Ping every 30 seconds; sockets that miss a pong are terminated
Origin check Only enforced when ALLOWED_ORIGINS is set: an upgrade whose Origin header is not an exact match for a list entry is refused with HTTP 403 during the handshake. An upgrade that sends no Origin header at all is always admitted

Authentication uses a short-lived ephemeral token passed as a query parameter on connect. If authentication fails, the server closes the connection with one of these codes:

  • 4001 — missing, invalid, or expired token; user not found
  • 4403 — site-wide MFA is required but the account does not have MFA enabled

An origin rejection happens before the socket exists, so it produces no close code at all — the browser just reports a failed connection. And because clients that send no Origin header are exempt, curl and other CLI clients keep connecting while every browser fails, which makes it look like a client bug. If real-time sync stops working behind a reverse proxy, check that ALLOWED_ORIGINS lists the exact scheme, host, and port the browser uses: the comparison is a plain string match, so https://trek.example.com matches neither http://trek.example.com nor https://trek.example.com:443. See Environment-Variables and Reverse-Proxy.

The Collab addon

The Collab addon (collab) must be enabled by an admin before the panel is visible inside a trip. Once enabled, it provides four sub-features that can each be toggled independently:

Sub-feature What it provides
Chat Group chat with reactions, replies, and URL previews
Notes Categorized, pinnable, markdown-formatted shared notes
Polls Single- or multiple-choice votes with optional deadlines
What's Next Upcoming assigned places across all trip days

Admin: enable the Collab addon and individual sub-features in Admin-Addons.

On desktop the panel shows Chat as a fixed 380 px column on the left when other sub-features are also enabled; if only Chat is on, it expands to fill the full width. Notes, Polls, and What's Next share the remaining space on the right. On mobile a tab bar at the top lets you switch between the enabled sub-features one at a time. Disabled sub-features are hidden from the tab bar.

Conflict handling

TREK uses a last-write-wins model. Each mutation is applied on the server and the resulting canonical state is broadcast to all connected clients. If two members edit the same field at the same time, the change that reaches the server last is the one that sticks; all clients converge to that server-authoritative state.

On reconnect, any locally queued mutations are flushed to the server before the client re-fetches trip data, so offline changes are applied before the latest state is read back.

There is no operational-transform or CRDT merge — simultaneous edits to the same field are not merged; one silently wins.

Access control

All Collab reads require trip membership. Writing — sending messages, creating notes, creating polls, voting — requires the collab_edit permission. Members without collab_edit can read but cannot post or interact.

Collab-Chat · Collab-Notes · Collab-Polls · Whats-Next-Widget · Trip-Planner-Overview · Admin-Addons