@phnq/message
Version:
Asynchronous, incremental messaging client and server
420 lines (419 loc) • 19.4 kB
JavaScript
"use strict";
var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
return new (P || (P = Promise))(function (resolve, reject) {
function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
step((generator = generator.apply(thisArg, _arguments || [])).next());
});
};
var __asyncValues = (this && this.__asyncValues) || function (o) {
if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
var m = o[Symbol.asyncIterator], i;
return m ? m.call(o) : (o = typeof __values === "function" ? __values(o) : o[Symbol.iterator](), i = {}, verb("next"), verb("throw"), verb("return"), i[Symbol.asyncIterator] = function () { return this; }, i);
function verb(n) { i[n] = o[n] && function (v) { return new Promise(function (resolve, reject) { v = o[n](v), settle(resolve, reject, v.done, v.value); }); }; }
function settle(resolve, reject, d, v) { Promise.resolve(v).then(function(v) { resolve({ value: v, done: d }); }, reject); }
};
var __await = (this && this.__await) || function (v) { return this instanceof __await ? (this.v = v, this) : new __await(v); }
var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
var g = generator.apply(thisArg, _arguments || []), i, q = [];
return i = {}, verb("next"), verb("throw"), verb("return"), i[Symbol.asyncIterator] = function () { return this; }, i;
function verb(n) { if (g[n]) i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; }
function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
function step(r) { r.value instanceof __await ? Promise.resolve(r.value.v).then(fulfill, reject) : settle(q[0][2], r); }
function fulfill(value) { resume("next", value); }
function reject(value) { resume("throw", value); }
function settle(f, v) { if (f(v), q.shift(), q.length) resume(q[0][0], q[0][1]); }
};
var __importDefault = (this && this.__importDefault) || function (mod) {
return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.MessageConnection = exports.ConversationPerspective = void 0;
const log_1 = require("@phnq/log");
const streams_1 = require("@phnq/streams");
const browser_process_hrtime_1 = __importDefault(require("browser-process-hrtime"));
const uuid_1 = require("uuid");
const errors_1 = require("./errors");
const MessageTransport_1 = require("./MessageTransport");
const sign_1 = require("./sign");
/**
* MessageConnection
* =================
* A conversation between agents consists of a single request by one agent, followed by zero or more responses from another agent.
* Accordingly, there are two possible perspectives in any conversation:
*
* 1) Client -- one who sends a message and gets responses,
* 2) Server -- one who waits for messages and sends responses.
*
* The complication in this familiar client/server relationship is that a single MessageConnection instance
* may be both client and server.
*
* As Client
* ---------
* This simply involves calling methods `send()` or `request*()`. Send is one-way so since there will be no response,
* there is no return value. The `request*()` methods return either an async value (i.e. promise) or iterator (multiple
* values).
*
* As Server
* ---------
* The `onReceive` field must be set to act as a server. Implementing `onReceive` involves dealing with an incoming
* message and returning either an async value or an async iterator.
*/
const log = (0, log_1.createLogger)('MessageConnection');
const idIterator = (function* () {
let i = 0;
while (true) {
yield ++i;
}
})();
const possiblyThrow = (message) => {
switch (message.t) {
case MessageTransport_1.MessageType.Anomaly: {
const anomalyMessage = message;
throw new errors_1.Anomaly(anomalyMessage.p.message, anomalyMessage.p.info);
}
case MessageTransport_1.MessageType.Error:
throw new Error(message.p.message);
}
};
var ConversationPerspective;
(function (ConversationPerspective) {
ConversationPerspective["Requester"] = "requester";
ConversationPerspective["Responder"] = "responder";
})(ConversationPerspective = exports.ConversationPerspective || (exports.ConversationPerspective = {}));
const DEFAULT_RESPONSE_TIMEOUT = 30000;
class MessageConnection {
constructor(transport, { signSalt, marshalPayload, unmarshalPayload } = {}) {
this.responseTimeout = DEFAULT_RESPONSE_TIMEOUT;
this.connId = (0, uuid_1.v4)();
this.responseQueues = new Map();
this.attributes = new Map();
this.transport = transport;
this.signSalt = signSalt;
this.marshalPayload = marshalPayload || (p => p);
this.unmarshalPayload = unmarshalPayload || (p => p);
transport.onReceive(message => {
var _a;
let errorMessage;
if (this.signSalt) {
try {
(0, sign_1.verifyMessage)(message, this.signSalt);
}
catch (err) {
errorMessage = {
c: message.c,
s: message.s,
t: MessageTransport_1.MessageType.Error,
p: { message: (_a = err.message) !== null && _a !== void 0 ? _a : 'Failed to verify message', requestPayload: message.p },
};
}
}
const unmarshaledMessage = this.unmarshalMessage(errorMessage || message);
if (unmarshaledMessage.t === MessageTransport_1.MessageType.Request) {
this.handleRequest(unmarshaledMessage);
return;
}
/**
* It is, in fact, possible to receive messages that are not intended for
* this MessageConnection instance. This is because multiple connections
* may share a single MessageTransport; in this case, they will all receive
* every incoming message. Since request ids are assigned by the global
* idIterator, there is a zero collision guarantee.
*/
const responseQueue = this.responseQueues.get(unmarshaledMessage.c);
if (responseQueue) {
switch (unmarshaledMessage.t) {
case MessageTransport_1.MessageType.Response:
case MessageTransport_1.MessageType.Anomaly:
case MessageTransport_1.MessageType.Error:
case MessageTransport_1.MessageType.End:
responseQueue.enqueue(unmarshaledMessage);
responseQueue.flush();
break;
case MessageTransport_1.MessageType.Multi:
responseQueue.enqueue(unmarshaledMessage);
break;
}
}
});
}
get onReceive() {
return this.receiveHandler;
}
set onReceive(receiveHandler) {
this.receiveHandler = receiveHandler;
}
get id() {
return this.connId;
}
getAttribute(key) {
return this.attributes.get(key);
}
/**
* Set a keyed value on the connection. This key/value pair are cached on the
* connection instance.
* @param key the key
* @param value the value
*/
setAttribute(key, value) {
this.attributes.set(key, value);
}
deleteAttribute(key) {
this.attributes.delete(key);
}
send(data) {
return __awaiter(this, void 0, void 0, function* () {
yield this.requestOne(data, false);
});
}
requestOne(data, expectResponse = true) {
var _a, e_1, _b, _c;
return __awaiter(this, void 0, void 0, function* () {
const resp = yield this.request(data, expectResponse);
if (typeof resp === 'object' && resp[Symbol.asyncIterator]) {
const resps = [];
try {
for (var _d = true, _e = __asyncValues(resp), _f; _f = yield _e.next(), _a = _f.done, !_a;) {
_c = _f.value;
_d = false;
try {
const r = _c;
resps.push(r);
}
finally {
_d = true;
}
}
}
catch (e_1_1) { e_1 = { error: e_1_1 }; }
finally {
try {
if (!_d && !_a && (_b = _e.return)) yield _b.call(_e);
}
finally { if (e_1) throw e_1.error; }
}
if (resps.length > 1) {
log.warn('requestOne: multiple responses were returned -- all but the first were discarded');
}
return resps[0];
}
else {
return resp;
}
});
}
requestMulti(data) {
return __awaiter(this, void 0, void 0, function* () {
const resp = yield this.request(data);
if (typeof resp === 'object' && resp[Symbol.asyncIterator]) {
return resp;
}
else {
return (function () {
return __asyncGenerator(this, arguments, function* () {
yield yield __await(resp);
});
})();
}
});
}
request(data, expectResponse = true) {
return __awaiter(this, void 0, void 0, function* () {
return this.doRequest(data, expectResponse);
});
}
marshalMessage(message) {
switch (message.t) {
case MessageTransport_1.MessageType.Request:
return Object.assign(Object.assign({}, message), { p: this.marshalPayload(message.p) });
case MessageTransport_1.MessageType.Response:
case MessageTransport_1.MessageType.Multi:
return Object.assign(Object.assign({}, message), { p: this.marshalPayload(message.p) });
}
return message;
}
unmarshalMessage(message) {
switch (message.t) {
case MessageTransport_1.MessageType.Request:
return Object.assign(Object.assign({}, message), { p: this.unmarshalPayload(message.p) });
case MessageTransport_1.MessageType.Response:
case MessageTransport_1.MessageType.Multi:
return Object.assign(Object.assign({}, message), { p: this.unmarshalPayload(message.p) });
}
return message;
}
signMessage(message) {
if (this.signSalt) {
return (0, sign_1.signMessage)(message, this.signSalt);
}
return message;
}
doRequest(payload, expectResponse) {
return __awaiter(this, void 0, void 0, function* () {
const reqId = idIterator.next().value;
const responseQueues = this.responseQueues;
const source = this.id;
const requestMessage = this.signMessage({
t: MessageTransport_1.MessageType.Request,
c: reqId,
p: payload,
s: source,
});
const conversation = {
perspective: ConversationPerspective.Requester,
request: requestMessage,
responses: [],
};
const start = (0, browser_process_hrtime_1.default)();
const responseQueue = new streams_1.AsyncQueue();
if (expectResponse) {
responseQueue.maxWaitTime = this.responseTimeout;
responseQueues.set(reqId, responseQueue);
}
yield this.transport.send(requestMessage);
if (expectResponse) {
const iter = responseQueue.iterator();
const firstMsg = (yield iter.next()).value;
conversation.responses.push({ message: firstMsg, time: (0, browser_process_hrtime_1.default)(start) });
const onConversation = this.onConversation;
if (firstMsg.t === MessageTransport_1.MessageType.Multi) {
return (function () {
return __asyncGenerator(this, arguments, function* () {
var _a, e_2, _b, _c;
yield yield __await(firstMsg.p);
try {
try {
for (var _d = true, _e = __asyncValues(responseQueue.iterator()), _f; _f = yield __await(_e.next()), _a = _f.done, !_a;) {
_c = _f.value;
_d = false;
try {
const message = _c;
if (message.s === firstMsg.s) {
conversation.responses.push({ message, time: (0, browser_process_hrtime_1.default)(start) });
possiblyThrow(message);
if (message.t === MessageTransport_1.MessageType.Multi) {
yield yield __await(message.p);
}
}
else {
log.warn('Received responses from multiple sources for request -- keeping the first, ignoring the rest: %s', JSON.stringify(payload));
}
}
finally {
_d = true;
}
}
}
catch (e_2_1) { e_2 = { error: e_2_1 }; }
finally {
try {
if (!_d && !_a && (_b = _e.return)) yield __await(_b.call(_e));
}
finally { if (e_2) throw e_2.error; }
}
if (onConversation) {
onConversation(conversation);
}
}
finally {
responseQueues.delete(reqId);
}
});
})();
}
else {
responseQueues.delete(reqId);
if (onConversation) {
onConversation(conversation);
}
possiblyThrow(firstMsg);
return firstMsg.p;
}
}
});
}
handleRequest(message) {
var _a, e_3, _b, _c;
return __awaiter(this, void 0, void 0, function* () {
const source = this.id;
const conversation = {
perspective: ConversationPerspective.Responder,
request: message,
responses: [],
};
const start = (0, browser_process_hrtime_1.default)();
const requestPayload = message.p;
const respond = (m) => {
const signedMessage = this.signMessage(this.marshalMessage(m));
this.transport.send(signedMessage);
conversation.responses.push({ message: signedMessage, time: (0, browser_process_hrtime_1.default)(start) });
};
if (!this.receiveHandler) {
throw new Error('No receive handler set.');
}
try {
const result = yield this.receiveHandler(requestPayload);
if (typeof result === 'object' && result[Symbol.asyncIterator]) {
try {
for (var _d = true, _e = __asyncValues(result), _f; _f = yield _e.next(), _a = _f.done, !_a;) {
_c = _f.value;
_d = false;
try {
const responsePayload = _c;
respond({ p: responsePayload, c: message.c, s: source, t: MessageTransport_1.MessageType.Multi });
}
finally {
_d = true;
}
}
}
catch (e_3_1) { e_3 = { error: e_3_1 }; }
finally {
try {
if (!_d && !_a && (_b = _e.return)) yield _b.call(_e);
}
finally { if (e_3) throw e_3.error; }
}
respond({ c: message.c, s: source, t: MessageTransport_1.MessageType.End, p: 'END' });
}
else if (result) {
const responsePayload = result;
respond({ p: responsePayload, c: message.c, s: source, t: MessageTransport_1.MessageType.Response });
}
else {
// kill the async queue
}
}
catch (err) {
if (err instanceof errors_1.Anomaly) {
const anomalyMessage = {
p: { message: err.message, info: err.info, requestPayload },
c: message.c,
s: source,
t: MessageTransport_1.MessageType.Anomaly,
};
respond(anomalyMessage);
}
else {
const errMessage = err.message || String(err);
const errorMessage = {
p: { message: errMessage, requestPayload },
c: message.c,
s: source,
t: MessageTransport_1.MessageType.Error,
};
respond(errorMessage);
}
}
finally {
if (this.onConversation) {
this.onConversation(conversation);
}
}
});
}
}
exports.MessageConnection = MessageConnection;