David
feff828ec1
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>
282 lines
14 KiB
JavaScript
282 lines
14 KiB
JavaScript
import { deferredResponse, errorResponse, response, sameProperty, stateReport } from "./messages/build.js";
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import { AlexaError } from "./messages/errors.js";
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import { StateBuilder } from "./messages/StateBuilder.js";
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import { SchemaError } from "./registry/schema.js";
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import * as topics from "./topics.js";
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import { asError } from "./transport.js";
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// unref: a directive that waits for its answer does not keep a process alive that is otherwise done
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const processTimers = {
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setTimeout(run, ms) {
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const timer = setTimeout(run, ms);
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timer.unref();
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return timer;
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},
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clearTimeout(timer) {
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clearTimeout(timer);
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},
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};
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/** Alex2MQTT gives up on a directive after DIRECTIVE_BUDGET_MS: the answer of the watchdog has to be there before. */
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export const ANSWER_WITHIN_MS = topics.DIRECTIVE_BUDGET_MS - 500;
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// How long a directive is remembered: its messageId, to drop the copy of a mirroring broker, and that it was
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// answered, to drop a second answer. A deferred answer may take this long and still find its directive.
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const REMEMBERED_MS = 60000;
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// A directive no handler can be called for. A device with a 1.x listener answers it by itself.
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class RoutingError extends AlexaError {
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}
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const key = (endpointId, id) => `${endpointId}\n${id}`;
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class Context {
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constructor(dispatcher, device, exchange, raw) {
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this.dispatcher = dispatcher;
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this.device = device;
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this.exchange = exchange;
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this.raw = raw;
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this.payload = raw.payload ?? {};
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}
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get endpointId() { return this.exchange.endpointId; }
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get namespace() { return this.exchange.namespace; }
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get name() { return this.exchange.name; }
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get instance() { return this.raw.header.instance ?? ""; }
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get correlationToken() { return this.exchange.correlationToken; }
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get receivedAt() { return this.exchange.receivedAt; }
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get answered() { return this.exchange.answered; }
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get deferred() { return this.exchange.deferred; }
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get reportState() { return this.namespace === "Alexa" && this.name === "ReportState"; }
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async respond(fill, options = {}) {
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const { endpointId, correlationToken } = this;
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const own = this.capability?.descriptor.responseFor?.(this.name);
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const payload = own?.payload ? own.payload.parse(options.payload ?? {}, "payload") : options.payload;
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const context = this.state(fill);
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return this.answer(response({ endpointId, correlationToken, namespace: own?.namespace, name: own?.name, payload, context }));
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}
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async report(fill) {
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if (!this.reportState) {
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throw new Error(`report() answers ReportState with a StateReport: answer ${this.namespace}.${this.name} with respond()`);
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}
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const { endpointId, correlationToken } = this;
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return this.answer(stateReport({ endpointId, correlationToken, context: this.state(fill) }));
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}
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defer(estimatedDeferralInSeconds) {
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const { endpointId, correlationToken } = this;
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if (this.capability && !this.capability.descriptor.deferrable)
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this.dispatcher.noteDeferral(this.namespace);
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// Always where the first answer goes: a second DeferredResponse is refused there
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const topic = topics.response(this.dispatcher.rootTopic, endpointId);
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return this.dispatcher.send(topic, deferredResponse({ endpointId, correlationToken, estimatedDeferralInSeconds }));
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}
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error(typeOrError, message = "", extra = {}) {
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const { endpointId, correlationToken } = this;
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let error;
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if (typeOrError instanceof AlexaError)
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error = typeOrError;
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else if (typeOrError instanceof Error)
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error = new AlexaError("INTERNAL_ERROR", typeOrError.message);
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else
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error = new AlexaError(typeOrError, message, extra);
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const { type, alexaMessage, namespace } = error;
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return this.answer(errorResponse({ endpointId, correlationToken, type, message: alexaMessage, extra: error.extra, namespace }));
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}
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// The state of the device, and over it what the handler says about this directive
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state(fill) {
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const whole = new StateBuilder();
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this.device.stateProvider?.(whole);
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const own = new StateBuilder();
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fill?.(own);
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return [...whole.context.filter((property) => !own.context.some((other) => sameProperty(property, other))), ...own.context];
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}
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answer(message) {
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const topic = this.deferred ? topics.deferred : topics.response;
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return this.dispatcher.send(topic(this.dispatcher.rootTopic, this.endpointId), message);
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}
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}
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export class Dispatcher {
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constructor(options) {
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this.options = options;
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/**
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* What the devices of the bridge publish through. An answer to a directive that waits is let through once, and a
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* DeferredResponse once before it; everything else passes.
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*/
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this.publisher = { publish: (topic, message) => this.publish(topic, message) };
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// Both oldest first. The directives by endpoint and correlationToken, when they arrived by endpoint and messageId.
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this.exchanges = new Map();
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this.arrived = new Map();
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this.deferralNoted = new Set();
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const { answerWithinMs = ANSWER_WITHIN_MS } = options;
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if (typeof answerWithinMs !== "number" || !(answerWithinMs >= 0)) {
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throw new Error(`answerWithinMs is ${String(answerWithinMs)}: pass the milliseconds a handler has to answer in, or 0 for no limit`);
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}
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this.rootTopic = options.rootTopic;
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this.answerWithinMs = answerWithinMs;
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this.timers = options.timers ?? processTimers;
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}
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/** Publish an answer; one that is not published is reported to the bridge. */
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async send(topic, message) {
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const result = await this.publish(topic, message);
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if (!result.ok)
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this.options.fail(result.error);
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return result;
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}
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/** defer() for an interface Amazon documents no DeferredResponse for: said once, the DeferredResponse is sent. */
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noteDeferral(namespace) {
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if (this.deferralNoted.has(namespace))
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return;
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this.deferralNoted.add(namespace);
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this.options.log(`warning: Amazon documents no DeferredResponse for ${namespace}, Alexa may not wait for the answer`);
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}
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/** The text of a message on the directive topic of endpointId. Resolves when the handlers are done. */
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async dispatch(endpointId, text) {
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const { log, emit } = this.options;
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let raw;
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try {
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raw = JSON.parse(text);
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}
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catch (err) {
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// Without a correlationToken there is nothing to answer
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log(`the directive for ${endpointId} is dropped: it is not JSON`, err);
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return;
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}
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if (typeof raw !== "object" || raw === null || typeof raw.header !== "object" || raw.header === null) {
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log(`the directive for ${endpointId} is dropped: it has no header`);
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return;
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}
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const { namespace, name, messageId } = raw.header;
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const correlationToken = typeof raw.header.correlationToken === "string" ? raw.header.correlationToken : "";
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const receivedAt = Date.now();
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this.forget(receivedAt);
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if (typeof messageId === "string") {
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if (this.arrived.has(key(endpointId, messageId))) {
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log(`the directive ${messageId} for ${endpointId} is dropped: it arrived before`);
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return;
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}
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this.arrived.set(key(endpointId, messageId), receivedAt);
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}
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const device = this.options.getDevice(endpointId);
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if (!device) {
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log(`No device found for endpointId: ${endpointId}`);
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emit("unknownEndpoint", { endpointId, namespace, name });
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// Off by default: the endpoint may belong to another bridge on the same root topic
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if (this.options.answerUnknownEndpoints) {
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const message = `${endpointId} is not an endpoint of this bridge`;
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await this.send(topics.response(this.rootTopic, endpointId), errorResponse({ endpointId, correlationToken, type: "NO_SUCH_ENDPOINT", message }));
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}
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return;
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}
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const exchange = { endpointId, namespace, name, correlationToken, receivedAt, answered: false, deferred: false };
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if (correlationToken) {
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this.exchanges.set(key(endpointId, correlationToken), exchange);
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this.watch(exchange);
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}
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const ctx = new Context(this, device, exchange, raw);
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emit("directive", { endpointId, namespace, name });
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// The 1.x listeners first, called one by one: emit() would let what one of them throws out, and lose what an
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// async one rejects with
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const event = ctx.reportState ? "ReportState" : "Event";
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const listeners = device.rawListeners(event);
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const running = listeners.map((listener) => this.isolated(ctx, () => listener.call(device, raw, ...(ctx.reportState ? [] : [namespace]))));
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running.push(this.isolated(ctx, () => this.route(device, ctx)(ctx), listeners.length > 0));
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await Promise.all(running);
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}
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// The handler for the directive, the payload of ctx checked for it
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route(device, ctx) {
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const { endpointId, namespace, name, instance } = ctx;
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const refused = (type, problem) => new RoutingError(type, problem);
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if (ctx.reportState) {
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if (device.reportStateHandler)
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return device.reportStateHandler;
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if (device.stateProvider)
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return (context) => context.report();
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throw refused("INVALID_DIRECTIVE", `${endpointId} has no handler for ReportState: register one with onReportState() or state() of the device`);
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}
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const capability = device.capability(namespace, instance);
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const declared = `${namespace}${instance ? ` "${instance}"` : ""}`;
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if (!capability)
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throw refused("INVALID_DIRECTIVE", `${declared} is not declared on ${endpointId}`);
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ctx.capability = capability;
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const directive = capability.descriptor.directives[name];
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// An interface the library only names describes no directive: its handlers get the payload as it arrived
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if (!directive && capability.descriptor.tier !== 3)
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throw refused("INVALID_DIRECTIVE", `${name} is not a directive of ${namespace}`);
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if (directive?.when && !directive.when(capability)) {
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throw refused("INVALID_DIRECTIVE", `${declared} as ${endpointId} declares it does not take ${name}`);
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}
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const handler = capability.handlerFor(name) ?? device.directiveHandler;
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if (!handler) {
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throw refused("INVALID_DIRECTIVE", `${endpointId} has no handler for ${namespace}.${name}: register one with on("${name}", handler) of the capability`);
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}
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try {
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if (directive)
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ctx.payload = directive.payload.parse(ctx.payload, "payload");
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}
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catch (err) {
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throw err instanceof SchemaError ? refused("INVALID_VALUE", err.message) : err;
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}
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return handler;
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}
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// Runs a listener or a handler. What it throws or rejects with answers the directive and goes no further.
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async isolated(ctx, run, answersItself = false) {
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try {
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await run();
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}
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catch (thrown) {
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if (thrown instanceof RoutingError && answersItself)
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return;
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const err = asError(thrown);
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// An AlexaError is the answer the handler chose. Anything else is a fault in it, and so is an answer too many.
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if (!(err instanceof AlexaError) || ctx.answered)
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this.options.fail(err);
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if (!ctx.answered)
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await ctx.error(err);
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}
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}
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watch(exchange) {
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const within = this.answerWithinMs;
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if (within === 0)
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return;
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exchange.watchdog = this.timers.setTimeout(() => {
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exchange.watchdog = undefined;
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const { endpointId, namespace, name, correlationToken } = exchange;
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const message = `no answer within ${within / 1000} s`;
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this.options.emit("unanswered", { endpointId, namespace, name, correlationToken });
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this.options.fail(new Error(`${endpointId}: ${namespace}.${name} got ${message} and is answered with INTERNAL_ERROR. `
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+ "Answer in the handler, or defer() first when the device takes longer"));
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void this.send(topics.response(this.rootTopic, endpointId), errorResponse({ endpointId, correlationToken, type: "INTERNAL_ERROR", message }));
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}, within);
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}
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publish(topic, message) {
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const { event } = message;
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const token = event?.header?.correlationToken;
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const exchange = typeof token === "string" ? this.exchanges.get(key(event?.endpoint?.endpointId ?? "", token)) : undefined;
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if (exchange) {
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const deferral = event?.header?.name === "DeferredResponse";
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const { endpointId, namespace, name } = exchange;
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if (exchange.answered || (deferral && exchange.deferred)) {
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const was = exchange.answered ? "answered" : "deferred";
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const error = new Error(`nothing was published to ${topic}: ${namespace}.${name} for ${endpointId} was ${was} before, and Alex2MQTT takes one answer`);
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return Promise.resolve({ ok: false, topic, error });
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}
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if (deferral)
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exchange.deferred = true;
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else
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exchange.answered = true;
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if (exchange.watchdog !== undefined) {
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this.timers.clearTimeout(exchange.watchdog);
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exchange.watchdog = undefined;
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}
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}
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return this.options.publisher.publish(topic, message);
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}
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// Drops what is older than REMEMBERED_MS. A directive the watchdog still waits for is kept.
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forget(now) {
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const old = (since) => now - since > REMEMBERED_MS;
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for (const [id, since] of this.arrived) {
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if (!old(since))
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break;
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this.arrived.delete(id);
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}
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for (const [id, exchange] of this.exchanges) {
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if (!old(exchange.receivedAt))
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break;
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if (exchange.watchdog === undefined)
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this.exchanges.delete(id);
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}
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}
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}
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