highascg

AMCP transport: `casparcg-connection` migration

HighAsCG uses the casparcg-connection npm package (v6.x, CommonJS) as the default AMCP transport. The public API (appCtx.amcp.*, REST, WebSocket) is unchanged.

Environment variables

Variable	Default	Purpose
`HIGHASCG_AMCP_LEGACY_TRANSPORT`	unset (`0`)	Set to `1` to use legacy `TcpClient` + `AmcpProtocol` instead of the library
`HIGHASCG_AMCP_SEND_TIMEOUT_MS`	`15000`	Short AMCP reply timeout
`HIGHASCG_AMCP_LONG_RESPONSE_MS`	`120000`	Long replies (CLS, INFO CONFIG, thumbnails, …)
`HIGHASCG_AMCP_CONNECT_SETTLE_MS`	`600`	Delay before first VERSION after TCP connect
`HIGHASCG_AMCP_HEALTH_MS`	`0`	Periodic VERSION health interval (`0` = off)

Architecture

Default: ConnectionManager → CasparCG (library TCP only) → AmcpConnectionAdapter → AmcpClient + AmcpProtocol
Plain AMCP: The adapter writes normal command lines (MIXER 1-10 …) on the library socket. It does not use sendCustom() / REQ <id> (Caspar logs those as 400 ERROR on standard builds). Incoming lines are parsed by AmcpProtocol, not the library’s REQ/RES deserializer (_processIncomingData is disabled after connect).
Batch: BEGIN…COMMIT payloads use one raw socket.write via adapter.send(); replies are drained from the same socket tap (so 202 COMMIT PARTIAL is recognized)
Rollback: HIGHASCG_AMCP_LEGACY_TRANSPORT=1 restores the pre-migration stack

What stayed in HighAsCG

Module	Reason
`amcp-batch.js`	CG-aware pre-commit, chunking, DEFER/COMMIT orchestration
`amcp-command-plan.js`	`[HTML]`, NDI, STING, route clips
`amcp-simulated.js`	Offline mode
Engine `raw()` / `batchSendChunked`	Unchanged call sites

Typed vs raw commands

See amcp-mapping.md (Transport column). All production commands go through _send() (plain AMCP). Library typed methods are opt-in only (useLibraryTyped on the adapter, not enabled by default).

Batch transport (T5.1)

The library exposes begin() / commit() / discard(), but HighAsCG keeps amcp-batch.js and sends one raw BEGIN\r\n…\r\nCOMMIT\r\n payload via adapter.send(). Replies are read from the underlying TCP socket so 202 COMMIT PARTIAL is not dropped by the library’s RESPONSE_REGEX.

Tests

npm run test:highascg:migration      # Parity + batch + send-after + offline REST (no Caspar)
npm run test:highascg:live           # Live Caspar (library transport)
npm run test:highascg:legacy         # Live Caspar (HIGHASCG_AMCP_LEGACY_TRANSPORT=1)
npm run test:highascg:migration:all  # Full automated gate (one node --test run)
npm run test:highascg:air-paths      # T7.4 proxies: chunked batch, DEFER batch, reconnect

Manual playout QA: amcp-migration-qa-checklist.md.

Work order

Full task list: work/WO_CASPARCG_CONNECTION_MIGRATION.md.

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