Express_Crud_Example/node_modules/mongodb/lib/sdam/srv_polling.js
2022-01-28 22:33:42 +01:00

121 lines
4.0 KiB
JavaScript

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.SrvPoller = exports.SrvPollingEvent = void 0;
const dns = require("dns");
const error_1 = require("../error");
const logger_1 = require("../logger");
const mongo_types_1 = require("../mongo_types");
const utils_1 = require("../utils");
/**
* Determines whether a provided address matches the provided parent domain in order
* to avoid certain attack vectors.
*
* @param srvAddress - The address to check against a domain
* @param parentDomain - The domain to check the provided address against
* @returns Whether the provided address matches the parent domain
*/
function matchesParentDomain(srvAddress, parentDomain) {
const regex = /^.*?\./;
const srv = `.${srvAddress.replace(regex, '')}`;
const parent = `.${parentDomain.replace(regex, '')}`;
return srv.endsWith(parent);
}
/**
* @internal
* @category Event
*/
class SrvPollingEvent {
constructor(srvRecords) {
this.srvRecords = srvRecords;
}
hostnames() {
return new Set(this.srvRecords.map(r => utils_1.HostAddress.fromSrvRecord(r).toString()));
}
}
exports.SrvPollingEvent = SrvPollingEvent;
/** @internal */
class SrvPoller extends mongo_types_1.TypedEventEmitter {
constructor(options) {
var _a, _b, _c;
super();
if (!options || !options.srvHost) {
throw new error_1.MongoRuntimeError('Options for SrvPoller must exist and include srvHost');
}
this.srvHost = options.srvHost;
this.srvMaxHosts = (_a = options.srvMaxHosts) !== null && _a !== void 0 ? _a : 0;
this.srvServiceName = (_b = options.srvServiceName) !== null && _b !== void 0 ? _b : 'mongodb';
this.rescanSrvIntervalMS = 60000;
this.heartbeatFrequencyMS = (_c = options.heartbeatFrequencyMS) !== null && _c !== void 0 ? _c : 10000;
this.logger = new logger_1.Logger('srvPoller', options);
this.haMode = false;
this.generation = 0;
this._timeout = undefined;
}
get srvAddress() {
return `_${this.srvServiceName}._tcp.${this.srvHost}`;
}
get intervalMS() {
return this.haMode ? this.heartbeatFrequencyMS : this.rescanSrvIntervalMS;
}
start() {
if (!this._timeout) {
this.schedule();
}
}
stop() {
if (this._timeout) {
clearTimeout(this._timeout);
this.generation += 1;
this._timeout = undefined;
}
}
schedule() {
if (this._timeout) {
clearTimeout(this._timeout);
}
this._timeout = setTimeout(() => this._poll(), this.intervalMS);
}
success(srvRecords) {
this.haMode = false;
this.schedule();
this.emit(SrvPoller.SRV_RECORD_DISCOVERY, new SrvPollingEvent(srvRecords));
}
failure(message, obj) {
this.logger.warn(message, obj);
this.haMode = true;
this.schedule();
}
parentDomainMismatch(srvRecord) {
this.logger.warn(`parent domain mismatch on SRV record (${srvRecord.name}:${srvRecord.port})`, srvRecord);
}
_poll() {
const generation = this.generation;
dns.resolveSrv(this.srvAddress, (err, srvRecords) => {
if (generation !== this.generation) {
return;
}
if (err) {
this.failure('DNS error', err);
return;
}
const finalAddresses = [];
for (const record of srvRecords) {
if (matchesParentDomain(record.name, this.srvHost)) {
finalAddresses.push(record);
}
else {
this.parentDomainMismatch(record);
}
}
if (!finalAddresses.length) {
this.failure('No valid addresses found at host');
return;
}
this.success(finalAddresses);
});
}
}
exports.SrvPoller = SrvPoller;
/** @event */
SrvPoller.SRV_RECORD_DISCOVERY = 'srvRecordDiscovery';
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