Alex2Node/dist/esm/messages/build.js
David feff828ec1 dispatch: typed handlers, respond/defer/error, automatic ErrorResponse, watchdog
src/dispatcher.ts routes a directive to capability.on(name | "*"), device.onDirective() or
device.onReportState(), with the payload checked by the descriptor of the interface. The
DirectiveContext answers with respond/report/defer/error; respond() and report() start from
device.state(). A handler or 1.x listener that throws or rejects is answered with INTERNAL_ERROR
(an AlexaError with itself) and reported through "error", never as an unhandled rejection.
Undeclared interface, unknown directive, AdjustMode on an unordered mode and a missing handler
get INVALID_DIRECTIVE, a bad payload INVALID_VALUE; a device with an "Event" or "ReportState"
listener keeps the answer to itself. Every answer passes the dispatcher: the first one per
correlationToken is published, a second is refused. No answer within answerWithinMs (6500,
0 = off, unref'd timer) sends INTERNAL_ERROR and emits "unanswered". A messageId that arrived
in the last 60 s is dropped. New: "unknownEndpoint", options answerUnknownEndpoints, publisher,
timers, and bridge.receive() to run a bridge without a broker. 168 tests pass (18 new).

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
2026-09-28 19:49:41 +00:00

125 lines
5.5 KiB
JavaScript

// Every message the bridge publishes, built from plain values. Nothing here reads the clock or makes an id unless
// the caller leaves messageId or a time out, so a test that passes both compares whole objects.
import { randomUUID } from "crypto";
import { errorNamespace } from "./errors.js";
import { isoTime } from "./property.js";
/** A message that would be dropped on its way to Alexa, refused where it is built. */
export class MessageError extends Error {
constructor(endpointId, problem) {
super(`${endpointId}: ${problem}`);
this.endpointId = endpointId;
this.problem = problem;
this.name = "MessageError";
}
}
// The fields in the order of the examples
function header(namespace, name, fields) {
return {
namespace,
name,
...(fields.instance ? { instance: fields.instance } : {}),
messageId: fields.messageId ?? randomUUID(),
...(fields.correlationToken !== undefined ? { correlationToken: fields.correlationToken } : {}),
payloadVersion: fields.payloadVersion ?? "3",
};
}
/**
* The answer to a directive (alexa-response.html, "Synchronous response"). An endpoint with nothing to report
* answers with an empty list of properties, not without a context (state-reporting-for-smart-home-addons.html,
* "Directive response example for a property that isn't retrievable").
*/
export function response(fields) {
return {
event: {
header: header(fields.namespace ?? "Alexa", fields.name ?? "Response", fields),
endpoint: { endpointId: fields.endpointId },
payload: fields.payload ?? {},
},
context: { properties: [...(fields.context ?? [])] },
};
}
/** The answer to ReportState: every retrievable property of the endpoint. */
export function stateReport(fields) {
return response({ ...fields, name: "StateReport", namespace: "Alexa", payload: {} });
}
/**
* "The directive arrived, the answer follows": no context, the state is in the Response that follows
* (alexa-response.html, "Deferred response example").
*/
export function deferredResponse(fields) {
const { estimatedDeferralInSeconds } = fields;
return {
event: {
header: header("Alexa", "DeferredResponse", fields),
endpoint: { endpointId: fields.endpointId },
payload: estimatedDeferralInSeconds === undefined ? {} : { estimatedDeferralInSeconds },
},
};
}
/** The answer to a directive the endpoint could not follow (alexa-errorresponse.html). */
export function errorResponse(fields) {
return {
event: {
header: header(fields.namespace ?? errorNamespace(fields.type), "ErrorResponse", fields),
endpoint: { endpointId: fields.endpointId },
payload: { type: fields.type, message: fields.message, ...fields.extra },
},
};
}
/** The same property of the same instance, whatever its value. */
export const sameProperty = (a, b) => a.namespace === b.namespace && a.name === b.name && (a.instance ?? "") === (b.instance ?? "");
/**
* A change of state nobody asked for. The header has no correlationToken (message-guide.html, "Header object").
* A property that changed is left out of the context: it is reported in one of the two (same page, "Context
* object"). Throws MessageError when nothing changed: Alex2MQTT drops such a report without a word.
*/
export function changeReport(fields) {
const { endpointId, changed, context = [] } = fields;
if (changed.length === 0) {
throw new MessageError(endpointId, "a ChangeReport needs at least one property that changed, this one has none. "
+ "Add the changed property before unchanged(), or send no report when nothing changed");
}
return {
event: {
header: header("Alexa", "ChangeReport", { messageId: fields.messageId }),
endpoint: { endpointId },
payload: { change: { cause: { type: fields.cause ?? "PHYSICAL_INTERACTION" }, properties: [...changed] } },
},
context: { properties: context.filter((property) => !changed.some((other) => sameProperty(property, other))) },
};
}
/** The answer to Activate and Deactivate of a scene (alexa-scenecontroller.html). */
export function sceneEvent(fields) {
return {
event: {
header: header("Alexa.SceneController", fields.activated ? "ActivationStarted" : "DeactivationStarted", fields),
endpoint: { endpointId: fields.endpointId },
payload: { cause: { type: fields.cause ?? "VOICE_INTERACTION" }, timestamp: isoTime(fields.timestamp) },
},
context: {},
};
}
/** Somebody rang (alexa-doorbelleventsource.html). */
export function doorbellPress(fields) {
return {
event: {
header: header("Alexa.DoorbellEventSource", "DoorbellPress", { messageId: fields.messageId }),
endpoint: { endpointId: fields.endpointId },
payload: { cause: { type: fields.cause ?? "PHYSICAL_INTERACTION" }, timestamp: isoTime(fields.timestamp) },
},
};
}
/** An event of a button or a sensor that routines start on (alexa-simpleeventsource.html). */
export function simpleEvent(fields) {
return {
event: {
header: header("Alexa.SimpleEventSource", "Event", {
instance: fields.instance,
messageId: fields.messageId,
payloadVersion: "1.0",
}),
endpoint: { endpointId: fields.endpointId },
payload: { id: fields.id, timestamp: isoTime(fields.timestamp) },
},
};
}