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Ekklesia f6c3bac732 Parent Call coordinator
Sits between the classrooms, Companion and ProPresenter, and owns the
truth about a parent call: validation, ids, the queue, expiry,
duplicates, mode, approval, delivery, and every status a classroom is
told. Companion is an operator surface and holds no state.

Built after querying the church's own ProPresenter rather than working
from the assumed contract, which turned out to be wrong in two ways: the
message is called Parent Caller, not Parent Call, and its tokens are
Name and Room rather than child and room.

The finding that shaped the design is recorded in
docs/propresenter-api.md. A trigger carrying a token name the message
does not have still returns 204, and still puts the message on screen
showing the previous call's values. So a 204 is not evidence on its own:
the adapter reads the live message and refuses to trigger unless the
configured tokens exist in it. Without that, a typo in .env would call
the wrong child's parents and report success.

Nothing claims more than it knows. A successful API call is reported as
sent to sanctuary, never as displayed.

The state machine is pure and synchronous, with time passed in and
effects returned, so the awkward cases are testable properly: two rooms
calling at once, an approval for the wrong id, an approval arriving
after the request went stale, and a clear timer firing after the next
call has gone up. The queue is in memory and dies with the process,
because a parent call surfacing ten minutes late would be worse than one
that was lost.

81 tests, then the whole thing end to end on Control: a request through
the real broker and the real coordinator to the real ProPresenter, with
the correct child and room on the sanctuary screen, the coordinator's
own clear timer taking it down again, mode off sending nothing, and a
duplicate id not sending twice.
2026-09-06 15:15:11 -05:00

3.2 KiB

ProPresenter API, as actually observed

Recorded against the church's own machine on 2026-09-06, not from documentation. Re-run parent-call-probe to refresh this.

Host              10.30.0.2:1025   (the MacBook, "MacBook-Pro")
ProPresenter      21.3
Platform          mac, macOS 26.6.2
api_version       v1

Endpoints that exist

Request Result
GET /version 200 + JSON. Note: not /v1/version, which 404s
GET /v1/messages 200 + array of messages
GET /v1/message/{id} 200 + one message
POST /v1/message/{id}/trigger 204, ~34ms
GET /v1/message/{id}/clear 204, ~7ms
POST /v1/message/{unknown-uuid}/trigger 404

{id} accepts either the uuid or the URL-encoded name — both returned 204. The coordinator uses the uuid, resolved from the name, so that renaming the message in ProPresenter is noticed rather than silently changing which message is triggered.

The message that already exists

The spec assumed a message called Parent Call with tokens child and room. The real one is different, which is why this was checked:

name    Parent Caller
uuid    7D044452-B5A1-49F5-AC9C-1FD53A9A7353
index   2
text    {Name}'s parent please go to the {Room}
tokens  Name, Room          <- capitalised
        visible_on_network: true

Nothing was created or renamed. The coordinator is configured to match what is there.

Because the template reads "...please go to the {Room}", the room token wants a human room name — "Nursery", not the nursery slug the topic uses. The coordinator maps slug to display name, configurably.

The finding that shaped the design

An unknown token name is silently accepted.

POST /v1/message/{uuid}/trigger
[{"name":"child","text":{"text":"SHOULD NOT APPEAR"}}]

-> HTTP 204
-> message goes on screen showing the PREVIOUS token values

Verified deliberately, with a known baseline set and cleared first, and a 2 second settle before reading state.

Two things follow, and both are in the adapter:

  1. A 204 does not mean the right thing was displayed. If the token names were misconfigured, every parent call would return 204 — so the teacher would be told "Sent to sanctuary" — while the sanctuary screen showed the previous child's name and room. In a church that is the worst failure this system could have: the wrong family walks out. So the coordinator reads the live message definition and refuses to trigger unless the configured token names actually exist in it. A mismatch is reported as an error and never as success.

  2. Token values persist between triggers. Every trigger therefore sends both tokens, always, so a call can never inherit half of the one before it.

Timing

The API returns before its own state settles: reading /v1/messages immediately after a 204 can still show the previous values, and the new ones appear within about a second. Nothing in the coordinator reads back state to confirm a trigger, so this only matters to anyone debugging by hand — do not believe a read taken in the same second.

is_active goes true on trigger and false on clear, and token values survive a clear.