The connector SDK

What every connector shares (connectors/src/sdk.ts, ADR 0008): the interface a connector implements, the context it is given, the vocabulary of refusals, the limits, the helpers, and how the connectors are tested without a network. For contributors who change a connector or add one; operators read Connectors overview.

since 4.1.9

RealityConnector

Form

interface RealityConnector {
  readonly id: string;
  start(ctx: ConnectorContext): Promise<void>;
  stop(): Promise<void>;
  health(): Promise<{ ok: boolean; detail: string; since: string }>;
}

Values and default

• start: open its port or begin polling, with the context below.
• stop: stop taking input, let what is in flight finish (at most DRAIN_MS, 5 000 ms), close every socket.
• health: what GET /health answers (200 when ok, 503 otherwise; a health that throws is unhealthy).

Constraints

A connector receives, validates and normalises its input, treats it as hostile, binds it to a player, gives it a dedupeKey, and proposes; it never runs what it reads, and never sends the Bridge what it saw.

Minimal example

The Telnet connector, connectors/src/telnet/connector.ts, is the shortest of the four.

Behaviour on an unknown field

Not applicable: an interface of the code.

Since

4.1.9.

since 4.1.9

ConnectorContext

Form

Made by createContext({ bridge, gameId, tenantId?, limits?, manifest, connector, write?, now?, retries?, fetch? }).

Values and default

Constraints

propose refuses before the Bridge a kind or a player that is not an identifier, a dedupeKey over 256 characters (shape), a signal the manifest does not declare (not-declared), a payload that is not flat or is too large, and a proposal over the local quota (quota). A call that times out, loses its connection, answers 5xx or answers an acceptance without its sequence is sent again with the same key, retries times (2 by default); a refusal is never retried. After close(), every call is refused stopped.

Minimal example

const r = await ctx.propose({
  source: 'telnet', kind: 'terminal.lamp', playerId, dedupeKey: dedupeKey('telnet', `${session}:${line}`),
  payload: { command: 0, line }, receivedAt: new Date().toISOString(),
});

Behaviour on an unknown field

An answer from the Bridge that is not a JSON object reads as {}.

Since

4.1.9.

since 4.1.9

ProposedSignal

Form

{ source, kind, playerId, sessionId?, dedupeKey, payload, receivedAt }.

Values and default

• source: the connector family, informative; the Bridge checks the manifest's.
• kind: the signal, as the game declares it.
• dedupeKey: the same fact twice has the same key, dedupeKey(source, external id).
• payload: flat JSON (strings, numbers, booleans, null), no markup (< or >), at most limits.maxBytes. It stays in the connector; the Bridge receives its SHA-256 over canonical JSON as evidenceHash.
• receivedAt: ISO time on the connector's clock, sent as occurredAt (the Bridge stamps its own).

Constraints

A nested, marked-up or oversized payload is refused (shape, too-large).

Minimal example

See ConnectorContext.

Behaviour on an unknown field

Not sent: the SDK builds the Bridge's body from the fields above only.

Since

4.1.9.

since 4.1.9

RefusalCode

Form

A fixed vocabulary, never the Bridge's free text.

Values and default

Constraints

Counted in metrics().refused and logged as signal.refused with the code.

Minimal example

if (!r.ok && r.refusal === 'pending') … (the player has too many signals waiting).

Behaviour on an unknown field

A status the table does not name is bridge.

Since

4.1.9.

since 4.1.9

ConnectorLimits

Form

{ maxBytes, maxPerMinute, timeoutMs }, the configuration's limits.

Values and default

maxBytes 4 096 (a payload as canonical JSON, and the largest input read at once), maxPerMinute 60 (proposals per sliding minute, all players together; the Bridge has its own quota per token), timeoutMs 5 000 (one call to the Bridge).

Constraints

A limit left out keeps its default.

Minimal example

"limits": { "maxBytes": 4096, "maxPerMinute": 60, "timeoutMs": 5000 }

Behaviour on an unknown field

Ignored.

Since

4.1.9.

since 4.1.9

Helpers

Form

dedupeKey(source, external), canonicalJson(value), payloadProblem(payload, maxBytes), safeLog(write, connector), within(work, ms), DRAIN_MS, DEFAULT_LIMITS.

Values and default

• dedupeKey: SHA-256 of <source>:<its id outside>, in hexadecimal.
• canonicalJson: JSON with sorted keys, so a payload's hash does not depend on the order it was built in.
• payloadProblem: 'shape', 'too-large' or null.
• safeLog: numbers and booleans as they are; a string only when it is an identifier (letters, digits, ., _, :, -, at most 64), never with an @, a space or a slash; anything else is [redacted]. Field names that are not identifiers are dropped.
• within: resolves done or timeout, whichever comes first (a drain never holds a stop longer).

Constraints

None.

Minimal example

dedupeKey('email', messageId) is the email connector's key.

Behaviour on an unknown field

Not applicable.

Since

4.1.9.

Testing without a network

All in the engine repository, one suite at a time:

# in the engine repository
npx vitest run tests/connectors-*.test.ts
npm run fuzz:connectors -- --cases=200 --seconds=30 --seed=1

• tests/connectors-*.test.ts run the same contract on the four connectors against a real Bridge on a free port (tests/connectors-sdk.test.ts), their hostile fixtures (connectors/test-vectors/), Telnet and SSH under floods, slow clients and a thousand connections, and the four driven under --disallow-code-generation-from-strings.
• npm run fuzz:connectors feeds the connectors' parsers seeded mutations of their corpus (--connector=email|telnet|ssh|open-badge|all, --cases 10 000 by default, --seconds 60, --seed, --json).
• A game's recorded replays (games/<id>/replays/*.json: connector inputs and the signals they made) are replayed through the real connector code by tests/connectors-replays.test.ts, and proved finishable by npm run solve:reality.
• npm run connector-archive-e2e plays the four from their release archive against a Bridge from its own (Linux).

Related identifiers

• quest-n-click-connector, npm run connector: Connectors overview.
• The Bridge's side of a proposal: Guarantees.
• How tests are chosen and run: Which tests run when; mutation testing of the connectors: Mutation testing.